← B.Pharm Semester 1

BP104T — Human Anatomy, Physiology and Pathophysiology I

4 hrs/week · 4 credits · 60 hours · 100 marks (40 internal + 60 end-semester). Notes follow the PCI B.Pharm (NEP 2020) Semester 1 syllabus, unit by unit.

Units in this subject

1. Unit 1 — Human Body, Cell & Tissue, Cell Injury, Integumentary System
2. Unit 2 — Skeletal System, Joints, Bones and Joint Diseases
3. Unit 3 — Body Fluids, Blood, Lymphatic System, Inflammation, Haematological Diseases
4. Unit 4 — Peripheral Nervous System and Special Senses
5. Unit 5 — Cardiovascular System

B.Pharm Semester I (NEP 2020) · 4 credits · 60 hours · 100 marks

These are unit-wise notes covering the full BP104T theory syllabus. Read them topic by topic, then use the FAQ blocks to test yourself. Where a diagram is suggested, draw it yourself once — this subject is visual, and examiners reward labelled diagrams.

Unit I — Introduction to Human Body, Cell & Tissue Organisation, Cell Injury, Integumentary System

1.1 Definition and scope of anatomy, physiology and pathophysiology

• Anatomy is the study of the structure of the body and the relationship between body parts. Branches you will meet: gross anatomy (visible structures), microscopic anatomy or histology (tissues), developmental anatomy, and surface anatomy.
• Physiology is the study of how those structures function — the chemical and physical processes that keep the body working.
• Pathophysiology is the study of what goes wrong: how normal function changes during disease. As a pharmacy student, this is the bridge between this subject and pharmacology — you learn the disease mechanism here, and the drug action later.
• Pharmacy relevance: you cannot understand why a drug works (or harms) without knowing the normal structure and function it acts on. Every drug chapter in pharmacology assumes this base.

1.2 Levels of structural organisation

Six levels, from smallest to largest:

1. Chemical level — atoms and molecules (water, proteins, DNA).
2. Cellular level — the cell, the smallest living unit.
3. Tissue level — groups of similar cells doing one job (muscle tissue, nervous tissue).
4. Organ level — two or more tissues forming a structure with a specific function (heart, liver).
5. Organ-system level — organs working together (cardiovascular system).
6. Organismal level — all systems together: the human being.

The body has 11 organ systems: integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic/immune, respiratory, digestive, urinary, and reproductive.

1.3 Basic life processes

Organisation, metabolism (catabolism + anabolism), responsiveness, movement, growth, differentiation, and reproduction. Keep this list ready — it is a favourite one-mark question.

1.4 Homeostasis and feedback systems

Homeostasis is the maintenance of a stable internal environment (temperature ~37 °C, blood pH 7.35–7.45, blood glucose ~70–110 mg/dL fasting) despite outside changes. Every feedback loop has three parts: a receptor (detects the change), a control centre (usually the brain or an endocrine gland, decides the response), and an effector (muscle or gland that carries it out).

• Negative feedback — the response reverses the change. Most common. Examples: blood glucose regulation (high glucose → insulin release → glucose falls), body temperature control (sweating and vasodilation when hot).
• Positive feedback — the response strengthens the change. Rare, used when a rapid complete event is needed. Examples: oxytocin release during childbirth (contractions → more oxytocin → stronger contractions), blood clotting (platelet activation recruits more platelets).

Exam angle: "Explain homeostasis with a suitable example" is a standard short answer. Draw the loop: stimulus → receptor → control centre → effector → response.

1.5 Basic anatomical terminologies

• Anatomical position: body upright, feet together, palms facing forward. All directional terms assume this.
• Planes: sagittal (divides left/right), frontal or coronal (divides front/back), transverse or horizontal (divides upper/lower).
• Directional terms: superior (toward head) / inferior (toward feet); anterior or ventral (front) / posterior or dorsal (back); medial (toward midline) / lateral (away from midline); proximal (nearer the trunk or point of attachment) / distal (farther); superficial (near surface) / deep (away from surface).
• Body cavities: dorsal cavity (cranial + vertebral/spinal cavities, housing brain and spinal cord) and ventral cavity (thoracic cavity with pleural and pericardial cavities, and the abdominopelvic cavity).
• Abdominopelvic regions: right/left hypochondriac, epigastric, right/left lumbar, umbilical, right/left iliac (inguinal), hypogastric. Quadrants: RUQ, LUQ, RLQ, LLQ — used clinically to locate pain (e.g., RLQ pain suggests appendicitis).

Diagram tip: draw the anatomical position with the three planes, and the nine abdominopelvic regions as a 3×3 grid. Both are common 2–3 mark questions.

1.6 Structure and functions of the cell

The cell is the structural and functional unit of life. Main parts:

• Plasma (cell) membrane — phospholipid bilayer with embedded proteins, cholesterol, and a carbohydrate coat (glycocalyx). Fluid-mosaic model. Functions: selective barrier, transport, cell recognition, communication.
• Cytoplasm — cytosol plus organelles.
• Nucleus — contains DNA in chromosomes; controls the cell. Has nuclear envelope with pores, nucleolus (makes ribosomes).
• Mitochondria — powerhouse; aerobic respiration produces ATP. Has its own DNA.
• Ribosomes — protein synthesis; free (for use inside the cell) or on rough ER (for export).
• Endoplasmic reticulum — rough ER (protein folding and transport), smooth ER (lipid synthesis, detoxification, calcium storage in muscle as sarcoplasmic reticulum).
• Golgi apparatus — modifies, packages, and ships proteins in vesicles.
• Lysosomes — digestive enzymes; break down worn-out organelles and foreign particles.
• Cytoskeleton — microtubules, microfilaments (actin), intermediate filaments; gives shape and moves things inside the cell.
• Centrosome/centrioles — organise cell division.

1.7 Transport across the cell membrane

Passive transport (no energy, down the concentration gradient):

• Simple diffusion — small lipid-soluble molecules (O₂, CO₂) cross directly.
• Facilitated diffusion — via channel proteins (e.g., aquaporins for water) or carrier proteins (e.g., glucose via GLUT transporters). No energy, but saturable.
• Osmosis — water movement across a semipermeable membrane toward higher solute concentration. Key pharmacy concept: isotonic, hypotonic (cell swells), hypertonic (cell shrinks) solutions.
• Filtration — water and solutes pushed through by hydrostatic pressure (e.g., at the glomerulus).

Active transport (needs ATP, moves against the gradient):

• Primary active transport — the sodium–potassium pump (Na⁺/K⁺ ATPase): pumps 3 Na⁺ out and 2 K⁺ in. Maintains the resting membrane potential and cell volume. Digoxin acts by inhibiting this pump — remember this for pharmacology.
• Secondary active transport — uses the Na⁺ gradient made by the primary pump. Symport (same direction, e.g., Na⁺/glucose in the intestine — this is how oral rehydration works) and antiport (opposite directions, e.g., Na⁺/Ca²⁺ exchanger).

Vesicular transport (for large particles): endocytosis — phagocytosis (cell eating, e.g., neutrophils), pinocytosis (cell drinking), receptor-mediated endocytosis (e.g., LDL uptake); exocytosis (release of vesicle contents, e.g., neurotransmitters, insulin); transcytosis (across the cell, e.g., IgA across gut epithelium).

Diagram tip: a two-column table comparing passive vs active transport with examples is exactly what examiners expect in a 5-mark answer.

1.8 Cell division

• Interphase (G₁ growth, S DNA replication, G₂ preparation) is where the cell spends most of its life.
• Mitosis — one cell → two identical diploid cells. Phases: prophase (chromosomes condense, spindle forms), metaphase (chromosomes line up at the equator), anaphase (sister chromatids pull apart), telophase (nuclei reform), then cytokinesis (cytoplasm splits). Used for growth and repair.
• Meiosis — one cell → four haploid gametes; happens only in gonads. Reduces chromosome number from 46 to 23.

Pharmacy link: anticancer drugs target dividing cells — antimetabolites act in S phase, vinca alkaloids block the mitotic spindle in M phase.

1.9 Cell junctions

• Tight junctions — seal neighbouring cells (gut lining, blood–brain barrier); nothing leaks between cells.
• Adherens junctions — anchor cells together with actin filaments.
• Desmosomes — strong "spot welds" using intermediate filaments; found in skin and cardiac muscle, tissues under mechanical stress.
• Gap junctions — channels (connexons) letting ions and small molecules pass directly; found in cardiac and smooth muscle, allowing them to contract as a unit.
• Hemidesmosomes — anchor cells to the basement membrane.

1.10 General principles of cell communication

Cells talk to each other in four forms named in the syllabus:

• Contact-dependent (juxtacrine) — cells touch; signal stays on the surface (e.g., immune cell recognition).
• Paracrine — signal acts on nearby cells (e.g., histamine in inflammation, neurotransmitters spilling to neighbours).
• Synaptic — signal crosses a synapse to a specific target (neurotransmission).
• Endocrine — hormone travels in blood to distant targets (e.g., insulin, thyroid hormone). (Autocrine — cell signals itself — is sometimes added.)

1.11 Classification of tissues

Four basic tissue types:

Epithelial tissue — covers surfaces, lines cavities, forms glands. Classified by layers and cell shape:

• Simple squamous — one flat layer; alveoli of lungs, endothelium of blood vessels, Bowman's capsule (filtration/diffusion).
• Simple cuboidal — kidney tubules, gland ducts (secretion, absorption).
• Simple columnar — stomach to rectum lining; often with goblet cells (mucus).
• Stratified squamous — multiple layers; keratinised (skin — protection against abrasion) vs non-keratinised (mouth, oesophagus, vagina).
• Pseudostratified columnar — looks layered but isn't; ciliated, in the trachea (moves mucus up).
• Transitional — stretches; urinary bladder.

Connective tissue — most abundant; cells scattered in a matrix:

• Connective tissue proper — loose (areolar: under skin) and dense (tendons, ligaments).
• Cartilage — hyaline (nose, trachea, articular ends), elastic (ear pinna, epiglottis), fibrocartilage (intervertebral discs, menisci).
• Bone — mineralised matrix; support and protection.
• Blood — fluid matrix (plasma); transport.

Muscular tissue — skeletal (striated, voluntary, multinucleated), cardiac (striated, branched, intercalated discs, involuntary), smooth (spindle-shaped, involuntary; walls of gut, blood vessels).

Nervous tissue — neurons (conduct impulses) + neuroglia (support).

Diagram tip: one labelled sketch per epithelial type is a classic 5-mark question. Practise drawing them from memory.

1.12 Basic principles of cell injury and adaptation

Causes of cellular injury: hypoxia and ischaemia (the most common — e.g., myocardial infarction), physical agents (trauma, heat, radiation), chemicals and drugs, infectious agents, immunologic reactions (autoimmunity, hypersensitivity), nutritional imbalance, and genetic defects.

Pathogenesis (how injury happens at molecular level):

• ATP depletion — the Na⁺/K⁺ pump fails → Na⁺ and water enter → cell swelling. Protein synthesis drops.
• Cell membrane damage — loss of phospholipids, lipid peroxidation by free radicals; membrane becomes leaky.
• Mitochondrial damage — opening of the mitochondrial permeability transition pore, release of cytochrome c → triggers apoptosis; ATP production collapses.
• Cytosolic calcium overload — activates destructive enzymes (phospholipases, proteases, endonucleases).
• Nuclear damage — DNA injury; if severe and irreparable, the cell dies.

Morphology of cell injury:

• Reversible injury: cell swelling (hydropic degeneration — first change, due to Na⁺/water entry) and fatty change (steatosis — lipid droplets in liver cells, e.g., in alcoholism). The cell recovers if the cause is removed.
• Irreversible injury → cell death by two routes:
• Necrosis — unplanned death with inflammation. Types: coagulative (most common; heart, kidney — tissue architecture preserved), liquefactive (brain, abscesses — tissue turns to liquid), caseous (tuberculosis — cheese-like), fat necrosis (pancreatitis), fibrinoid (blood vessel walls in hypertension/vasculitis), gangrenous (limb ischaemia with infection).
• Apoptosis — programmed, tidy death: cell shrinks, chromatin condenses, membrane blebs, apoptotic bodies are eaten by neighbours — no inflammation. Controlled by caspases; triggered by cytochrome c release.

Adaptive changes (cells adjusting to stress without dying):

• Atrophy — decrease in cell size (disuse atrophy of muscle in a plaster cast, denervation).
• Hypertrophy — increase in cell size (left ventricular hypertrophy in hypertension; skeletal muscle with exercise).
• Hyperplasia — increase in cell number (benign prostatic hyperplasia, endometrial hyperplasia).
• Metaplasia — one adult cell type replaced by another (smoker's bronchial epithelium changes from columnar to squamous; Barrett's oesophagus). Reversible if the stimulus stops.
• Dysplasia — disordered, abnormal growth; considered premalignant (cervical dysplasia). Note the difference from metaplasia — dysplasia is not a benign adaptation.

Intracellular accumulations: lipids (fatty liver), proteins, glycogen, pigments (lipofuscin — "wear and tear" pigment, melanin, haemosiderin in iron overload).

1.13 Commonly used medical terminologies

Learn the building blocks — they decode hundreds of terms:

• Prefixes: hyper- (excess), hypo- (deficient), a-/an- (without), dys- (abnormal/painful), brady- (slow), tachy- (fast), endo- (inside), ecto-/exo- (outside), peri- (around), sub- (below).
• Suffixes: -itis (inflammation: arthritis, dermatitis), -oma (tumour: carcinoma), -pathy (disease: neuropathy), -emia (blood condition: anaemia), -lysis (breakdown: haemolysis), -plasia (growth: hyperplasia), -rrhage (bursting forth: haemorrhage), -stasis (standing still: haemostasis).
• Examples to practise: hypertension, hypotension, tachycardia, bradycardia, dyspnoea, anaemia, gastritis, nephritis.

1.14 Integumentary system: structure and functions of skin

The skin is the largest organ (~2 m², ~16% of body weight). Layers:

• Epidermis — stratified squamous keratinised epithelium, no blood vessels. Layers from deep to surface: stratum basale (stem cells divide here), stratum spinosum, stratum granulosum, stratum lucidum (thick skin only — palms, soles), stratum corneum (dead keratinised cells, constantly shed). Cells: keratinocytes (make keratin), melanocytes (make melanin — protects against UV), Langerhans cells (immune), Merkel cells (touch).
• Dermis — connective tissue with blood vessels, nerves, hair follicles, glands. Papillary layer (dermal papillae — form fingerprints) and reticular layer (collagen, elastic fibres).
• Hypodermis (subcutaneous layer) — fat and loose connective tissue; insulation and energy store.

Appendages: hair, nails, sebaceous glands (sebum — oils the skin), sweat glands — eccrine (all over, temperature control) and apocrine (axilla, groin).

Functions of skin: protection (against microbes, UV, chemicals, water loss), temperature regulation (sweating, vasodilation/vasoconstriction), sensation (touch, pressure, pain, temperature), vitamin D synthesis (UV converts 7-dehydrocholesterol), excretion (sweat), absorption (basis of transdermal drug delivery), and immune defence.

1.15 Skin disorders: psoriasis, dermatitis, leprosy

• Psoriasis — chronic autoimmune disorder; T-cell mediated hyperproliferation of keratinocytes. Thick, red plaques with silvery scales, typically on extensor surfaces (elbows, knees), scalp. Auspitz sign (pinpoint bleeding when scale is removed), Koebner phenomenon (lesions at sites of skin trauma), nail pitting. Pharmacy link: treated with topical corticosteroids, vitamin D analogues (calcipotriol), and biologics.
• Dermatitis — inflammation of the skin; redness, itching, swelling. Types: atopic dermatitis (eczema — allergic, often in children), contact dermatitis (irritant or allergic — e.g., to nickel, cosmetics), seborrheic dermatitis (oily areas, dandruff).
• Leprosy (Hansen's disease) — caused by Mycobacterium leprae; affects skin and peripheral nerves (loss of sensation, deformities). Two poles: tuberculoid (paucibacillary) — few lesions, strong cell-mediated immunity; lepromatous (multibacillary) — many lesions, weak immunity, leonine facies. Treated with multidrug therapy (dapsone + rifampicin + clofazimine). Still relevant in India — know it well.

1.16 Basic principles of wound healing

Phases (overlap, in order):

1. Haemostasis (minutes) — vasoconstriction, platelet plug, clot formation stops bleeding.
2. Inflammatory phase (1–3 days) — neutrophils then macrophages clean debris and bacteria.
3. Proliferative phase (day 3 to ~3 weeks) — fibroblasts lay down collagen (type III), new blood vessels form (angiogenesis), granulation tissue fills the wound, epithelial cells cover the surface.
4. Remodelling/maturation (weeks to months) — collagen type III replaced by stronger type I; scar contracts and strengthens (never regains 100% of original strength).

Primary intention (clean surgical wound, edges closed — heals fast, thin scar) vs secondary intention (open wound, heals by granulation — larger scar, e.g., pressure ulcers).

Factors affecting healing: nutrition (protein, vitamin C for collagen, zinc), infection, poor blood supply, diabetes, old age, smoking, and drugs — corticosteroids and NSAIDs delay healing. Pharmacy link: this is why diabetic foot care and perioperative drug review matter.

Diagram tip: draw skin in cross-section with all three layers labelled, plus the five epidermal strata. For wound healing, a timeline strip of the four phases is enough.

Unit I — Frequently asked questions

Q. What is the difference between anatomy, physiology and pathophysiology? A. Anatomy studies body structure, physiology studies normal function, and pathophysiology studies how function changes in disease. A pharmacist needs all three: structure tells you where a drug acts, physiology tells you what it changes, and pathophysiology tells you what is broken in the patient.

Q. What are the three components of a feedback system? Give one example each of negative and positive feedback. A. Receptor, control centre, and effector. Negative feedback: blood glucose control by insulin/glucagon. Positive feedback: oxytocin-driven uterine contractions during labour.

Q. How does the sodium–potassium pump work, and why does it matter in pharmacy? A. It pumps 3 Na⁺ out and 2 K⁺ in using ATP, maintaining membrane potential and cell volume. It matters because digoxin inhibits this pump to strengthen heart contraction — a direct link between cell physiology and a drug you will study.

Q. What is the difference between necrosis and apoptosis? A. Necrosis is unplanned cell death with membrane rupture and inflammation; apoptosis is programmed, tidy cell death with no inflammation. Necrosis follows severe injury; apoptosis removes old or damaged cells routinely.

Q. Name the layers of the epidermis from deep to superficial. A. Stratum basale, spinosum, granulosum, lucidum (thick skin only), corneum. Mnemonic: "Brittany Spears Glitters Like Candy" — Basale, Spinosum, Granulosum, Lucidum, Corneum.

Q. What are the four phases of wound healing? A. Haemostasis, inflammatory, proliferative, and remodelling/maturation phases.

Unit I — Key takeaways

• Homeostasis is maintained mainly by negative feedback loops (receptor → control centre → effector).
• The Na⁺/K⁺ ATPase (3 Na⁺ out, 2 K⁺ in) is the single most exam-worthy transport protein in this unit.
• Tight junctions seal, desmosomes weld, gap junctions connect — match each junction to its tissue.
• Reversible injury = swelling + fatty change; irreversible = necrosis (with inflammation) or apoptosis (without).
• Atrophy/hypertrophy change size; hyperplasia changes number; metaplasia changes type; dysplasia is disordered and premalignant.
• Skin: 3 layers, 5 epidermal strata, and functions beyond protection — temperature, sensation, vitamin D, transdermal absorption.
• Psoriasis (autoimmune, silvery scales, Auspitz sign), dermatitis (inflammatory), leprosy (M. leprae, nerve damage, two poles).
• Wound healing: haemostasis → inflammation → proliferation → remodelling; vitamin C, protein, and good blood supply speed it; steroids and diabetes slow it.

Unit II — Skeletal System, Joints, Bones and Joint Diseases

2.1 Divisions of the skeletal system

The adult skeleton has 206 bones, divided into:

• Axial skeleton (80 bones) — skull (cranium 8 + face 14 = 22, plus 6 auditory ossicles and 1 hyoid), vertebral column (33 vertebrae), ribs (12 pairs), sternum.
• Appendicular skeleton (126 bones) — pectoral girdle (clavicle, scapula × 2), upper limbs (30 each), pelvic girdle (2 hip bones), lower limbs (30 each).

Functions of the skeleton: support, protection (skull → brain, rib cage → heart and lungs), movement (levers for muscles), mineral storage (calcium, phosphorus), blood cell formation (red bone marrow), and fat storage (yellow marrow).

2.2 Types of bones

• Long bones — longer than wide; shaft (diaphysis) + ends (epiphyses). E.g., femur, humerus. The femur is the longest and strongest bone in the body.
• Short bones — cube-shaped; carpals (wrist), tarsals (ankle).
• Flat bones — thin and curved; skull bones, ribs, sternum, scapula. Protect organs; the sternum and pelvis make blood cells.
• Irregular bones — complex shapes; vertebrae, facial bones.
• Sesamoid bones — embedded in tendons; the patella (kneecap) is the largest sesamoid.

2.3 Salient features and functions of bones of the axial skeleton

• Skull: cranium (frontal, parietal ×2, temporal ×2, occipital, sphenoid, ethmoid) protects the brain; facial bones form the orbits, nasal cavity, and jaws. The foramen magnum in the occipital bone lets the spinal cord pass. Sutures are fibrous joints between skull bones.
• Vertebral column: 7 cervical (the atlas C1 and axis C2 allow head rotation — the dens of the axis), 12 thoracic (attach to ribs), 5 lumbar (large, bear weight), 5 fused sacral, 4 fused coccygeal. Normal curves: cervical and lumbar lordosis (inward), thoracic and sacral kyphosis (outward). Intervertebral discs (fibrocartilage with nucleus pulposus) cushion the vertebrae — a slipped disc is herniation of this nucleus.
• Rib cage: 12 pairs — 7 true ribs (attach directly to sternum), 3 false ribs (attach via cartilage), 2 floating ribs (no anterior attachment). Protects heart and lungs; moves during breathing.
• Sternum: manubrium, body, xiphoid process. Site of bone marrow aspiration in adults.

2.4 Salient features and functions of bones of the appendicular skeleton

• Pectoral girdle: clavicle (collarbone — most commonly fractured bone) and scapula (shoulder blade, with acromion and coracoid processes, glenoid cavity).
• Upper limb: humerus (deltoid tuberosity, head fits into glenoid cavity), radius and ulna (forearm; radius on the thumb side), carpals (8 — scaphoid is the most fractured carpal), metacarpals (5), phalanges (14).
• Pelvic girdle: each hip bone = ilium + ischium + pubis fused at the acetabulum (hip socket). The female pelvis is wider with a broader sciatic notch — an adaptation for childbirth.
• Lower limb: femur (head fits into acetabulum; longest bone), patella, tibia (shinbone — medial, weight-bearing) and fibula (lateral, slender), tarsals (7 — calcaneus is the heel bone, largest tarsal), metatarsals (5), phalanges (14).

Diagram tip: a labelled anterior skeleton with axial vs appendicular colour-coded is the single best diagram for this unit. Practise it until you can label 20+ bones from memory.

2.5 Organisation of skeletal muscle

From outside in: whole muscle wrapped in epimysium → bundles of fibres (fascicles) wrapped in perimysium → each muscle fibre (cell) wrapped in endomysium. Tendons attach muscle to bone (dense connective tissue, mainly collagen).

A muscle fibre contains myofibrils, which contain sarcomeres — the contractile unit from one Z-disc to the next. Within a sarcomere: thin filaments (actin, with troponin and tropomyosin) slide over thick filaments (myosin). Bands: A band (thick filaments, dark), I band (thin only, light), H zone (centre of A band), M line (middle).

2.6 Physiology of muscle contraction — the sliding filament theory

1. A nerve impulse reaches the muscle; calcium ions (Ca²⁺) are released from the sarcoplasmic reticulum.
2. Ca²⁺ binds troponin, moving tropomyosin off the actin binding sites.
3. Myosin heads attach to actin, forming cross-bridges; using ATP, the myosin head pivots — the power stroke — pulling actin toward the centre.
4. New ATP binds, the head detaches, and the cycle repeats. The sarcomere shortens; I bands and H zone shrink, but the A band stays the same length.
5. When stimulation stops, Ca²⁺ is pumped back and the muscle relaxes.

Key point students miss: ATP is needed both for the power stroke and for detachment/relaxation — this is why rigor mortis (stiffness after death) happens when ATP runs out.

Muscle twitch → summation → tetanus (sustained contraction). Isotonic contraction (muscle shortens, e.g., lifting) vs isometric (length unchanged, e.g., pushing a wall).

2.7 The neuromuscular junction (NMJ)

The synapse between a motor neuron and a muscle fibre:

1. Action potential arrives at the axon terminal → voltage-gated Ca²⁺ channels open.
2. Ca²⁺ triggers release of acetylcholine (ACh) into the synaptic cleft.
3. ACh binds nicotinic receptors on the motor end plate → Na⁺ influx → end-plate potential → muscle action potential → contraction.
4. Acetylcholinesterase breaks down ACh, ending the signal.

Pharmacy links (you will meet these in pharmacology): myasthenia gravis is treated with acetylcholinesterase inhibitors (neostigmine); tubocurarine and similar neuromuscular blockers block nicotinic receptors and are used in anaesthesia.

2.8 Structural and functional classification of joints

Structural (by material binding the bones):

• Fibrous joints — bound by dense connective tissue; no movement. E.g., sutures of the skull, gomphosis (tooth in socket).
• Cartilaginous joints — bound by cartilage; slight movement. E.g., intervertebral discs, pubic symphysis.
• Synovial joints — bones separated by a fluid-filled cavity; freely movable. Features: articular cartilage, joint (synovial) cavity with synovial fluid, articular capsule, reinforcing ligaments.

Functional: synarthrosis (immovable), amphiarthrosis (slightly movable), diarthrosis (freely movable).

Types of synovial joints (with examples — a favourite exam list):

• Ball-and-socket — shoulder, hip (movement in all planes).
• Hinge — elbow, knee, ankle (flexion/extension only).
• Pivot — atlas–axis joint (rotation of the head).
• Saddle — thumb carpometacarpal joint.
• Condyloid/ellipsoid — wrist joint.
• Gliding/plane — between carpals, between tarsals.

2.9 Pathophysiology of rheumatoid arthritis (RA)

• What it is: a chronic autoimmune inflammatory disorder attacking the synovial membrane of joints — small joints of hands and feet first, symmetrically.
• Pathogenesis: unknown trigger → immune attack on synovium → synovial inflammation (synovitis) → formation of pannus (invasive granulation tissue) → destruction of cartilage and bone → joint deformity (swan-neck, boutonnière deformities; ulnar deviation).
• Markers: rheumatoid factor (RF) and anti-CCP antibodies (more specific).
• Clinical features: morning stiffness lasting more than 30–60 minutes (key difference from osteoarthritis), symmetric polyarthritis, fatigue, rheumatoid nodules.
• Contrast with osteoarthritis (useful in exams): OA is degenerative "wear and tear" of weight-bearing joints in the elderly, worse with activity and better with rest; RA is autoimmune, symmetric, worse with rest (morning stiffness).
• Pharmacy link: treated with NSAIDs, DMARDs (methotrexate is first-line), and biologics (TNF-α inhibitors).

2.10 Pathophysiology of osteoporosis

• What it is: reduced bone mineral density with deteriorated bone microarchitecture → fragile bones, fractures from trivial trauma.
• Pathogenesis: imbalance between osteoblast (bone-forming) and osteoclast (bone-resorbing) activity — resorption wins. Main driver: oestrogen deficiency after menopause (oestrogen normally restrains osteoclasts), plus ageing, low calcium/vitamin D, smoking, alcohol, corticosteroid use, immobility.
• Clinical features: often silent until fracture — classic fracture sites are the hip (neck of femur), vertebrae (compression → kyphosis, height loss), and distal radius (Colles' fracture). Back pain from vertebral crush fractures.
• Diagnosis: DEXA scan; T-score ≤ −2.5 = osteoporosis.
• Pharmacy link: calcium + vitamin D supplementation, bisphosphonates (alendronate — must be taken upright with water on an empty stomach), and the link between long-term steroid therapy and bone loss.

2.11 Pathophysiology of gout

• What it is: crystal-induced arthritis from hyperuricaemia (high blood uric acid) → monosodium urate crystals deposit in joints.
• Pathogenesis: overproduction (high purine diet — red meat, seafood, alcohol; cell turnover) or underexcretion (kidney disease, diuretics) of uric acid → crystals deposit in the joint → neutrophils attack them → sudden, severe inflammation.
• Clinical features: classic podagra — sudden agonising pain, redness, and swelling of the first metatarsophalangeal joint (big toe), often starting at night. Chronic gout forms tophi (chalky urate deposits) in ears, elbows, and joints, and urate kidney stones.
• Pharmacy link: acute attacks — NSAIDs, colchicine (watch GI toxicity); long-term — allopurinol (xanthine oxidase inhibitor, reduces uric acid production), and avoid thiazide diuretics which raise uric acid.

Diagram tip: draw a synovial joint in cross-section (articular cartilage, synovial cavity, capsule, ligaments) and a sarcomere at rest vs contracted. Both are high-yield.

Unit II — Frequently asked questions

Q. How many bones are in the axial and appendicular skeleton? A. Axial: 80 (skull, vertebral column, ribs, sternum). Appendicular: 126 (pectoral girdle, upper limbs, pelvic girdle, lower limbs). Total: 206 in an adult.

Q. Explain the sliding filament theory of muscle contraction. A. Calcium released from the sarcoplasmic reticulum binds troponin, exposing actin binding sites; myosin heads form cross-bridges and, using ATP, pull actin filaments toward the sarcomere centre. The sarcomere shortens while the A band stays constant.

Q. What happens at the neuromuscular junction, step by step? A. Nerve impulse → Ca²⁺ entry into axon terminal → acetylcholine release → ACh binds nicotinic receptors on the muscle → muscle action potential → contraction → acetylcholinesterase clears ACh.

Q. How do you differentiate rheumatoid arthritis from osteoarthritis? A. RA is autoimmune, symmetric, affects small joints, with prolonged morning stiffness (>30 min) and raised RF/anti-CCP; OA is degenerative, affects weight-bearing joints asymmetrically in the elderly, with stiffness under 30 minutes that worsens through the day.

Q. Why do postmenopausal women get osteoporosis? A. Oestrogen normally suppresses osteoclast activity; after menopause its fall lets bone resorption outpace formation, lowering bone mineral density and causing fragility fractures of the hip, vertebrae, and wrist.

Q. What causes gout, and which joint is classically affected? A. Hyperuricaemia leading to monosodium urate crystal deposition; classically the first metatarsophalangeal joint of the big toe (podagra), with sudden nocturnal pain.

Unit II — Key takeaways

• 206 bones: 80 axial + 126 appendicular; femur is longest, patella is the largest sesamoid, clavicle fractures most often.
• Sarcomere = Z-disc to Z-disc; contraction = actin slides over myosin; A band constant; ATP needed for both contraction and relaxation.
• NMJ in four steps: Ca²⁺ in → ACh out → nicotinic receptors → acetylcholinesterase clears. Links to myasthenia gravis and muscle relaxants.
• Joint types to memorise with one example each: fibrous (sutures), cartilaginous (pubic symphysis), synovial subtypes (shoulder, elbow, atlas–axis, thumb, wrist, carpals).
• RA = autoimmune synovitis → pannus → deformity; morning stiffness >30 min; RF and anti-CCP positive.
• Osteoporosis = low bone density from resorption > formation; postmenopausal oestrogen loss; hip/vertebra/wrist fractures; DEXA diagnosis.
• Gout = urate crystals from hyperuricaemia; podagra of the big toe; colchicine for acute, allopurinol for chronic control.

Unit III — Body Fluids, Blood, Lymphatic System, Inflammation, Haematological Diseases

3.1 Body fluids: distribution and compartments

Water is about 60% of body weight in an adult male (slightly less in females and the elderly, more in infants). It sits in two main compartments:

• Intracellular fluid (ICF) — inside cells; ~40% of body weight (two-thirds of total water). Rich in K⁺, Mg²⁺, phosphate.
• Extracellular fluid (ECF) — outside cells; ~20% of body weight (one-third of total water). Rich in Na⁺, Cl⁻, HCO₃⁻. Subdivided into plasma (~4–5% of body weight, the fluid part of blood) and interstitial fluid (~15%, bathing the cells), plus small volumes like lymph and CSF.

Fluid moves between compartments by osmosis and filtration (Starling forces at capillaries). Oedema is excess interstitial fluid — from increased capillary permeability, low plasma protein, or blocked lymph drainage.

3.2 Composition and functions of blood

Blood is ~5 litres in an adult (~7–8% of body weight). Components:

• Plasma (~55%) — 90% water; proteins: albumin (maintains osmotic pressure, carries drugs — hypoalbuminaemia changes drug distribution), globulins (antibodies, transport), fibrinogen (clotting); plus nutrients, hormones, gases, waste, electrolytes.
• Formed elements (~45%):
• RBCs (erythrocytes) — 4.5–5.5 million/µL; biconcave discs, no nucleus, packed with haemoglobin; carry O₂ (and some CO₂); lifespan ~120 days; destroyed in the spleen.
• WBCs (leukocytes) — 4,000–11,000/µL; defence. Granulocytes (neutrophils — phagocytosis of bacteria; eosinophils — parasites and allergy; basophils — release histamine/heparin) and agranulocytes (lymphocytes — B cells make antibodies, T cells kill infected cells; monocytes — become macrophages).
• Platelets (thrombocytes) — 1.5–4 lakh/µL (150,000–400,000); cell fragments from megakaryocytes; form the platelet plug in clotting.

Functions of blood: transport (O₂, CO₂, nutrients, hormones, waste, drugs), regulation (pH, temperature, fluid balance), and protection (clotting, immunity).

Haematocrit (PCV) — the percentage of blood volume occupied by RBCs: ~40–54% in men, ~36–46% in women. Rises in dehydration and polycythaemia; falls in anaemia.

3.3 Haemopoiesis and haemoglobin formation

Haemopoiesis (blood cell formation) happens in red bone marrow (in adults: pelvis, vertebrae, sternum, ribs, skull). All blood cells come from haematopoietic stem cells, which divide into myeloid and lymphoid lines.

• Erythropoiesis (RBC formation): stimulated by erythropoietin (EPO), made by the kidney in response to low oxygen. Needs iron, vitamin B₁₂, and folic acid. Stages run from erythroblast → reticulocyte → mature RBC (losing the nucleus along the way).
• Haemoglobin formation: each Hb molecule = 4 haem groups (each with one Fe²⁺ iron) + 4 globin chains (2 alpha + 2 beta in adult HbA). Iron is absorbed in the duodenum (helped by vitamin C), transported by transferrin, stored as ferritin and haemosiderin. Old RBCs are broken down in the spleen and liver; haem becomes bilirubin (excreted in bile — excess causes jaundice), iron is recycled.

3.4 Mechanism of blood coagulation

Haemostasis has three stages: vascular spasm (vessel constricts), platelet plug formation (platelets stick to exposed collagen via von Willebrand factor, then aggregate), and coagulation (fibrin mesh stabilises the plug).

The clotting cascade (simplified, exam-safe version):

• Extrinsic pathway — triggered by tissue injury releasing tissue factor (factor III); fast; measured by PT/INR (used to monitor warfarin).
• Intrinsic pathway — triggered by blood contacting exposed collagen; slower; measured by aPTT (used to monitor heparin).
• Common pathway — both converge: factor X → Xa → converts prothrombin (II) to thrombin (IIa) → thrombin converts fibrinogen (I) to fibrin → fibrin mesh + factor XIII cross-linking = stable clot.

Key factors to name: I (fibrinogen), II (prothrombin), III (tissue factor), VIII (antihaemophilic — deficient in haemophilia A), IX (deficient in haemophilia B), plus calcium (factor IV) and vitamin K (needed to make factors II, VII, IX, X — this is why warfarin, a vitamin K antagonist, is an anticoagulant).

Fibrinolysis: plasmin dissolves the clot when healing is done (streptokinase and alteplase work by activating plasminogen — used in MI and stroke).

Pharmacy link: this one cascade explains heparin (intrinsic/aPTT), warfarin (extrinsic/PT-INR, vitamin K dependent), and aspirin/clopidogrel (antiplatelet — they block the platelet plug stage, not the cascade).

3.5 Blood grouping, Rh factor and transfusion

• ABO system (Landsteiner): RBCs carry A and/or B antigens; plasma carries antibodies against the antigens you lack. Group A has anti-B, group B has anti-A, group AB has neither antibody (universal recipient), group O has both antibodies (universal donor for RBCs).
• Rh factor: Rh-positive RBCs carry the D antigen. Rh-negative people have no anti-D antibody naturally, but develop it after exposure (transfusion or pregnancy) — causing haemolytic disease of the newborn in a later Rh-positive pregnancy. Prevented with anti-D immunoglobulin (RhoGAM).
• Transfusion rules: always cross-match; ABO incompatibility causes acute haemolytic transfusion reaction (donor RBCs agglutinate and burst). Reactions: fever, chills, haemolysis, kidney damage, shock.

Diagram tip: a 4×4 ABO compatibility table (donor rows × recipient columns with ✓/✗) is the fastest way to learn and to answer transfusion questions.

3.6 Lymphatic organs, tissues, vessels, and lymph

• Lymphatic organs: lymph nodes (filter lymph; swell in infection), spleen (filters blood, destroys old RBCs, immune responses), thymus (T-cell maturation — most active in childhood), tonsils and Peyer's patches (MALT — guard entry points).
• Lymphatic vessels: begin as blind capillaries, drain through nodes, and return lymph to blood at the subclavian veins (via the thoracic duct on the left and right lymphatic duct on the right). One-way valves prevent backflow.
• Lymph formation: plasma filtered out of capillaries becomes interstitial fluid; the part not reabsorbed (~3 L/day) enters lymph capillaries as lymph.
• Functions: return tissue fluid to blood, absorb dietary fats (lacteals in the intestine), and immune surveillance (lymphocytes in nodes trap pathogens).

3.7 Basic mechanism of inflammation and repair

Inflammation is the vascular and cellular response to injury or infection. The five cardinal signs (Celsus + Galen): rubor (redness), tumor (swelling), calor (heat), dolor (pain), and functio laesa (loss of function).

Classification: acute (seconds to days; neutrophils; e.g., a cut, bacterial infection) vs chronic (weeks to years; macrophages and lymphocytes; e.g., TB, rheumatoid arthritis, granulomas).

Pathophysiology — vascular and cellular events:

1. Vasodilation (histamine, prostaglandins) → redness and heat.
2. Increased vascular permeability → plasma leaks out → swelling (oedema) and pain from pressure.
3. Cellular events: margination → rolling → adhesion → diapedesis (WBCs squeeze through the vessel wall) → chemotaxis (WBCs follow chemical signals to the injury) → phagocytosis of microbes/debris.

Mediators of inflammation (learn as a list — examiners love it): histamine (mast cells — immediate vasodilation), prostaglandins (pain, fever — blocked by NSAIDs), leukotrienes (bronchoconstriction in asthma), cytokines (IL-1, IL-6, TNF-α — fever, systemic effects), complement (C3a, C5a — chemotaxis), kinins (bradykinin — pain), and platelet-activating factor.

Repair: regeneration (same tissue regrows — liver, skin epithelium) vs fibrosis/scarring (connective tissue fills the gap — heart muscle after MI). Which happens depends on the tissue's regenerative capacity and the extent of damage.

Pharmacy link: NSAIDs and corticosteroids both suppress inflammation but at different points — NSAIDs block prostaglandin synthesis (COX), steroids block earlier steps (phospholipase A₂).

3.8 Pathophysiology of haematological diseases

Iron deficiency anaemia — the commonest anaemia worldwide. Cause: blood loss (menstruation, hookworm, piles), poor intake, pregnancy. Iron is needed for haem. Microcytic hypochromic RBCs (small, pale). Features: fatigue, pallor, koilonychia (spoon-shaped nails), pica (craving non-food like clay), angular cheilitis. Treated with ferrous sulphate/fumarate — tell patients it blackens stools and is best absorbed on an empty stomach with vitamin C.

Megaloblastic anaemia (vitamin B₁₂ and folic acid deficiency) — both vitamins are needed for DNA synthesis; without them RBC precursors can't divide → large, immature (megaloblastic), macrocytic RBCs. B₁₂ deficiency (pernicious anaemia — lack of intrinsic factor; strict vegetarian diets) additionally causes neurological symptoms (tingling, numbness, subacute combined degeneration of the cord) because B₁₂ maintains myelin — folate deficiency does not. Treat B₁₂ deficiency with B₁₂, never folate alone (folate masks the anaemia while nerve damage progresses).

Sickle cell anaemia — autosomal recessive; a single amino acid swap in beta-globin (glutamate → valine) makes HbS, which polymerises in low oxygen → RBCs sickle. Sickled cells block small vessels (vaso-occlusive painful crises), haemolyse early (haemolytic anaemia), and damage the spleen (infection risk). Common in central India (Madhya Pradesh, Chhattisgarh, Maharashtra tribal belts) — know it. Managed with hydroxyurea, folic acid, vaccination, and crisis care.

Thalassemia — reduced synthesis of globin chains: beta-thalassemia (beta chains low → excess alpha chains damage RBCs) and alpha-thalassemia. Microcytic hypochromic anaemia, but unlike iron deficiency the iron studies are normal/high. Severe beta-thalassemia major (Cooley's anaemia) needs lifelong transfusion → iron overload → chelation with deferoxamine/deferiprone.

Hereditary and acquired haemolytic anaemias — note: the syllabus phrase "hereditary acquired anaemia" is ambiguous; it most plausibly means hereditary haemolytic anaemias and acquired haemolytic anaemias. Hereditary spherocytosis (defective membrane proteins spectrin/ankyrin → fragile spherical RBCs destroyed in the spleen; treated by splenectomy) is the classic hereditary example; acquired examples include autoimmune haemolytic anaemia and drug-induced haemolysis.

Haemophilia — X-linked recessive bleeding disorder (males affected, females carriers). Haemophilia A: factor VIII deficiency (commonest, ~85%). Haemophilia B (Christmas disease): factor IX deficiency. Features: prolonged bleeding after injury, haemarthrosis (bleeding into joints), easy bruising; PT normal, aPTT prolonged. Treated with factor concentrates; avoid NSAIDs and IM injections.

Diagram tip: draw the clotting cascade as a flowchart (extrinsic → X, intrinsic → X, common → thrombin → fibrin) and annotate where heparin, warfarin, and aspirin act. This one diagram covers half the pharmacy questions on this unit.

Unit III — Frequently asked questions

Q. What is the difference between plasma and serum? A. Plasma is the fluid part of unclotted blood (contains fibrinogen and clotting factors); serum is the fluid left after blood clots (plasma minus fibrinogen and clotting factors).

Q. Which tests monitor heparin and warfarin therapy, and why? A. aPTT monitors heparin (intrinsic pathway); PT/INR monitors warfarin (extrinsic pathway, vitamin K–dependent factors).

Q. Why is group O the universal donor and AB the universal recipient? A. Group O RBCs carry no A or B antigens, so no recipient's antibodies attack them; group AB plasma carries no anti-A or anti-B antibodies, so it accepts any RBCs.

Q. What are the five cardinal signs of inflammation? A. Rubor (redness), tumor (swelling), calor (heat), dolor (pain), functio laesa (loss of function).

Q. How do you distinguish iron deficiency anaemia from megaloblastic anaemia in the lab? A. Iron deficiency gives microcytic hypochromic RBCs with low ferritin; megaloblastic (B₁₂/folate) deficiency gives macrocytic RBCs with hypersegmented neutrophils.

Q. Why should folate never be given alone in B₁₂ deficiency? A. Folate corrects the anaemia but lets the irreversible neurological damage of B₁₂ deficiency progress silently.

Unit III — Key takeaways

• Body water ~60%: ICF 40% (K⁺-rich), ECF 20% (Na⁺-rich) = plasma + interstitial fluid.
• Blood: plasma 55% (albumin, globulins, fibrinogen), RBCs/WBCs/platelets 45%; haematocrit ~42–50% (men), ~37–45% (women).
• EPO from the kidney drives RBC production; iron + B₁₂ + folate are the three nutrients anaemia questions revolve around.
• Clotting: extrinsic (PT/INR, warfarin) and intrinsic (aPTT, heparin) converge on factor X → thrombin → fibrin; vitamin K makes factors II, VII, IX, X.
• ABO + Rh grouping with cross-matching prevents fatal transfusion reactions; anti-D prevents haemolytic disease of the newborn.
• Inflammation: five cardinal signs, vascular events then cellular events (diapedesis → chemotaxis → phagocytosis); mediators list is a must-memorise.
• Anaemias: iron deficiency (microcytic), B₁₂/folate (macrocytic + neuro signs in B₁₂), sickle cell (HbS, vaso-occlusive crises), thalassemia (chain synthesis defect), haemophilia A (VIII) / B (IX), X-linked.

Flagged ambiguity: the syllabus lists "hereditary acquired anaemia" — this reads as a compressed phrase for hereditary haemolytic anaemias (e.g., spherocytosis) and acquired haemolytic anaemias. I have covered both interpretations above; confirm against the PCI text if your college's question bank treats it differently.

Unit IV — Peripheral Nervous System and Special Senses

4.1 Classification of the peripheral nervous system

The nervous system divides into the central nervous system (CNS — brain and spinal cord) and the peripheral nervous system (PNS — everything outside: nerves and ganglia). The PNS itself has two divisions:

• Somatic (voluntary) nervous system — sensory neurons carry information in; motor neurons carry commands out to skeletal muscle. One neuron runs from CNS to muscle; neurotransmitter is acetylcholine at the NMJ.
• Autonomic (involuntary) nervous system — controls smooth muscle, cardiac muscle, and glands. Two-neuron chain (preganglionic → ganglion → postganglionic). Further divided into sympathetic and parasympathetic (below). A third enteric division controls the gut.

4.2 Sympathetic vs parasympathetic nervous system

Pharmacy links everywhere here: beta-blockers blunt sympathetic effects on the heart; anticholinergics (atropine) block parasympathetic effects (dry mouth, dilated pupils, urinary retention — the classic side-effect list); salbutamol mimics sympathetic bronchodilation in asthma.

Diagram tip: a two-column comparison table like the one above, memorised cold, answers most autonomic pharmacology questions you will ever face.

4.3 Spinal nerves: origin and functions

31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal. Each forms from a dorsal (sensory) root and a ventral (motor) root joining at the intervertebral foramen. Named by the vertebra below their exit in the neck (C1–C7) and the vertebra above elsewhere.

Functions: carry sensory information from skin, muscles, and joints to the cord, and motor commands to skeletal muscles. A dermatome is the skin area supplied by one spinal nerve — used clinically to locate cord lesions (e.g., shingles follows a dermatome).

Important plexuses (networks where nerves regroup): cervical (phrenic nerve → diaphragm), brachial (upper limb — injuries cause Erb's palsy), lumbar (femoral nerve), sacral (sciatic nerve — the largest nerve in the body; its compression causes sciatica).

4.4 Cranial nerves: origin and functions

12 pairs, numbered I–XII, arising from the brain (mostly the brainstem). Learn with the mnemonic for names: "Oh, Oh, Oh, To Touch And Feel Very Green Vegetables, AH!" — Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory (spinal), Hypoglossal.

The high-yield ones:

• I Olfactory — smell. II Optic — vision. III Oculomotor, IV Trochlear, VI Abducens — eye movements (III also constricts the pupil and lifts the eyelid).
• V Trigeminal — face sensation + muscles of chewing. VII Facial — facial expression, taste from anterior tongue, salivary glands. VIII Vestibulocochlear — hearing and balance.
• IX Glossopharyngeal — taste from posterior tongue, swallowing, parotid gland. X Vagus — the wanderer: parasympathetic supply to heart, lungs, and most of the gut; key in the parasympathetic column above. XI Accessory — trapezius and sternocleidomastoid (shrug, head turn). XII Hypoglossal — tongue movements.

4.5 Structure and functions of the eye

• Three coats: outer sclera (white, protective; continuous with the cornea in front) → middle choroid (vascular, pigmented; continuous with ciliary body and iris — the coloured part controlling pupil size) → inner retina (photoreceptors).
• Front to back: cornea (transparent, most of the eye's focusing power) → anterior chamber with aqueous humor (drains through the canal of Schlemm — blockage raises pressure in glaucoma) → pupil → lens (fine focusing, changes shape — accommodation) → vitreous humor (gel filling the back) → retina.
• Retina: rods (dim light, black-and-white; contain rhodopsin, need vitamin A — deficiency causes night blindness) and cones (colour, sharp vision; concentrated in the fovea at the centre of the macula). The optic disc (blind spot) is where the optic nerve leaves — no photoreceptors.
• Visual pathway (brief): retina → optic nerve → optic chiasma (nasal fibres cross) → optic tract → lateral geniculate body → visual cortex (occipital lobe).
• Accessory structures: eyelids, eyelashes, lacrimal (tear) glands, and six extraocular muscles.

4.6 Structure and functions of the ear

• External ear: pinna (collects sound) → external auditory canal (wax/cerumen) → tympanic membrane (eardrum).
• Middle ear: air-filled cavity with three ossicles — malleus (hammer) → incus (anvil) → stapes (stirrup) — which amplify sound from eardrum to inner ear. Connected to the throat by the Eustachian (auditory) tube, which equalises pressure (this is why your ears "pop" and why colds lead to middle-ear infections in children).
• Inner ear: cochlea (snail-shaped; hair cells convert sound vibrations to nerve impulses — sensorineural hearing), vestibule (utricle and saccule — static balance/head position), and semicircular canals (rotational balance). The vestibulocochlear nerve (VIII) carries both signals.

Hearing loss types: conductive (external/middle ear — wax, otitis media, ossicle damage; bone conduction better than air) vs sensorineural (inner ear/nerve — ageing/presbycusis, noise, ototoxic drugs like aminoglycosides and furosemide — a pharmacy link to remember).

4.7 Structure and functions of the nose and tongue

• Nose (olfaction): olfactory receptors sit in the olfactory epithelium high in the nasal cavity; smells dissolve in mucus, bind receptors → olfactory nerve (I) → olfactory bulb → brain. The only sense that reaches the cortex without passing through the thalamus — which is why smells trigger memory so strongly. Also warms, moistens, and filters air (respiratory function).
• Tongue (gustation): taste buds sit mainly on papillae (fungiform, circumvallate, foliate). Five basic tastes: sweet, salty, sour, bitter, umami. Taste travels via facial (VII, anterior two-thirds) and glossopharyngeal (IX, posterior third) nerves. Most of "taste" is actually smell — which is why food is tasteless with a blocked nose.

4.8 Pathophysiology of special sense disorders

• Glaucoma — raised intraocular pressure (aqueous humor can't drain) damages the optic nerve → gradual peripheral vision loss ("tunnel vision"); painless, so it's caught late. Types: open-angle (chronic, commonest) and angle-closure (acute, painful emergency). Pharmacy link: treated with timolol eye drops (beta-blocker), pilocarpine, latanoprost — and note that systemic anticholinergics can precipitate angle closure.
• Cataract — clouding of the lens (ageing, diabetes, UV, steroids) → painless blurring, glare. Treated surgically (lens replacement); no drug reverses it.
• Myopia (near-sightedness) — eyeball too long or lens too powerful; distant rays focus in front of the retina. Corrected with concave lenses. (Contrast: hypermetropia — focus behind the retina, convex lenses; presbyopia — ageing lens loses accommodation.)
• Otitis externa — infection of the outer ear canal ("swimmer's ear"); pain when the pinna is pulled.
• Otitis media — middle-ear infection, common in children via the Eustachian tube; ear pain, fever, possible eardrum perforation.
• Vertigo — false sense of spinning/rotation from vestibular disturbance. Causes: BPPV (loose otolith crystals — brief episodes on head movement), Ménière's disease (endolymph buildup — vertigo + tinnitus + hearing loss). Distinguish from dizziness/light-headedness (often cardiovascular).
• Anosmia — loss of smell; causes include nasal polyps, sinusitis, head injury, viral infections, and zinc deficiency. Matters in pharmacy because it kills appetite and because intranasal drugs (and some systemic ones) list it as a side effect.

Diagram tip: draw the eye in sagittal section (three coats, lens, humors, fovea, optic disc) and the ear's three divisions with the ossicle chain. Label the drainage angle of the eye — it makes the glaucoma mechanism obvious.

Unit IV — Frequently asked questions

Q. What is the difference between the somatic and autonomic nervous systems? A. Somatic is voluntary, one neuron to skeletal muscle using acetylcholine; autonomic is involuntary, a two-neuron chain to smooth/cardiac muscle and glands, split into sympathetic and parasympathetic divisions.

Q. How do sympathetic and parasympathetic effects on the heart differ? A. Sympathetic (noradrenaline) increases heart rate and contraction force; parasympathetic (vagus, acetylcholine) slows the heart rate.

Q. Name the 12 cranial nerves in order. A. Olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal.

Q. What is the role of rods and cones? A. Rods detect dim light (night vision, need vitamin A); cones detect colour and fine detail, concentrated in the fovea.

Q. What causes glaucoma, and why is it dangerous? A. Blocked drainage of aqueous humor raises intraocular pressure, damaging the optic nerve. It is dangerous because vision loss is gradual and painless — patients notice only when damage is advanced.

Q. What is the difference between conductive and sensorineural hearing loss? A. Conductive loss is in the external/middle ear (wax, otitis media — often treatable); sensorineural loss is in the cochlea or nerve (ageing, noise, ototoxic drugs — usually permanent).

Unit IV — Key takeaways

• PNS = somatic (voluntary, skeletal muscle) + autonomic (involuntary); autonomic = sympathetic (thoracolumbar, noradrenaline, fight-or-flight) + parasympathetic (craniosacral, acetylcholine, rest-and-digest).
• 31 spinal nerve pairs; sciatic is the largest nerve; dermatomes map skin to cord levels.
• 12 cranial nerves — learn names in order; vagus (X) is the parasympathetic workhorse.
• Eye: three coats, aqueous humor drainage (glaucoma), lens (cataract), rods/cones and the fovea.
• Ear: ossicle chain (malleus–incus–stapes), Eustachian tube (otitis media route), cochlea (hearing) vs semicircular canals (balance).
• Glaucoma = pressure → optic nerve damage; cataract = cloudy lens; myopia = focus in front of retina, concave lens correction.
• Otitis externa vs media (pinna-pull test vs Eustachian route); vertigo is true spinning (BPPV, Ménière's); anosmia = smell loss.

Unit V — Cardiovascular System

5.1 Anatomy of the heart

The heart is a fist-sized muscular pump in the mediastinum, tilted left, enclosed in the pericardium (fibrous outer sac + serous layers with pericardial fluid for frictionless beating). Wall layers: endocardium (inner lining), myocardium (muscle — thickest in the left ventricle), epicardium (outer layer).

Chambers: right atrium → right ventricle → (lungs) → left atrium → left ventricle → body. Right side handles deoxygenated blood, left side oxygenated; the septum keeps them apart.

Valves (prevent backflow):

• Atrioventricular (AV) valves: tricuspid (right, 3 cusps) and mitral/bicuspid (left, 2 cusps). Held by chordae tendineae attached to papillary muscles — they stop the valves flipping inside-out during ventricular contraction.
• Semilunar valves: pulmonary (right) and aortic (left), each with 3 cusps, no chordae.

Coronary circulation: the heart feeds itself via the right and left coronary arteries (branching from the aorta just above the aortic valve); blockage here causes myocardial infarction. Deoxygenated blood drains via the coronary sinus into the right atrium.

5.2 Blood circulation

• Pulmonary circulation: right ventricle → pulmonary trunk → lungs (CO₂ out, O₂ in) → pulmonary veins → left atrium.
• Systemic circulation: left ventricle → aorta → body tissues → venae cavae → right atrium.
• Coronary circulation (above) and portal circulation (gut → liver via the hepatic portal vein before reaching the heart — this is why many oral drugs undergo first-pass metabolism in the liver; a direct pharmacy link).

Note the two exceptions students mix up: pulmonary arteries carry deoxygenated blood and pulmonary veins carry oxygenated blood — the only places where artery/vein doesn't match oxygenation.

5.3 Structure and functions of blood vessels

Three layers (tunics) in arteries and veins: tunica intima (endothelium), tunica media (smooth muscle + elastic fibres), tunica externa/adventitia (connective tissue).

• Arteries — thick muscular/elastic walls, withstand high pressure; carry blood away from the heart. Elastic arteries (aorta) stretch and recoil; muscular arteries distribute.
• Arterioles — the main resistance vessels; their constriction/dilation controls blood pressure and local flow.
• Capillaries — one endothelial cell thick; site of exchange (O₂, nutrients, waste) by diffusion and filtration.
• Veins — thin walls, large lumens, valves to prevent backflow; carry blood toward the heart; act as blood reservoirs (~60% of blood volume). Varicose veins are failed venous valves.
• Atherosclerosis begins with damage to the endothelium (tunica intima) — keep this layer in mind for section 5.10.

5.4 Conduction system of the heart and the heartbeat

The heart beats on its own (autorhythmic); nerves only adjust the rate:

1. SA (sinoatrial) node — the pacemaker, in the right atrium; fires fastest (~100/min intrinsic, slowed to ~72 by vagal tone).
2. Impulse spreads across the atria (they contract) → reaches the AV (atrioventricular) node (delays ~0.1 s so ventricles fill).
3. Down the bundle of His → right and left bundle branches → Purkinje fibres → ventricles contract from the apex upward.

Regulation by the autonomic nervous system: sympathetic (noradrenaline, β₁ receptors) → faster rate, stronger contraction; parasympathetic (vagus, acetylcholine) → slower rate. Pharmacy links: beta-blockers (propranolol, metoprolol) slow the heart; atropine blocks vagal slowing; digoxin increases vagal tone and contractility.

5.5 Cardiac cycle

One cycle (~0.8 s at 72 bpm) has three stages:

1. Atrial systole (0.1 s) — atria contract, topping up the ventricles; AV valves open.
2. Ventricular systole (0.3 s) — ventricles contract; AV valves shut (first heart sound, S₁ — "lubb"); pressure opens the semilunar valves; blood ejects into aorta and pulmonary trunk.
3. Diastole (0.4 s) — everything relaxes; semilunar valves shut (second heart sound, S₂ — "dupp"); AV valves open; ventricles fill passively (~70%) plus atrial kick (~30%).

Heart sounds: S₁ = AV valves closing (start of systole), S₂ = semilunar valves closing (start of diastole). Murmurs are abnormal sounds from turbulent flow (valve stenosis or regurgitation).

5.6 Cardiac output

Cardiac output (CO) = heart rate × stroke volume ≈ 72 bpm × 70 mL ≈ 5 L/min at rest — the entire blood volume each minute.

• Stroke volume depends on: preload (venous return / end-diastolic volume — more stretch → stronger contraction, the Frank–Starling law), afterload (resistance the ventricle pumps against — high BP reduces stroke volume), and contractility (sympathetic stimulation and drugs like digoxin increase it).
• Ejection fraction (~55–70%) = stroke volume ÷ end-diastolic volume; the key number in heart failure assessment.

Pharmacy link: diuretics reduce preload, vasodilators reduce afterload, digoxin raises contractility — the three levers of heart-failure treatment map directly onto this equation.

5.7 Regulation of blood pressure

Blood pressure = cardiac output × peripheral resistance. Normal: ~120/80 mmHg (systolic/diastolic).

Short-term regulation (seconds–minutes):

• Baroreceptors (carotid sinus, aortic arch) sense stretch → via vagus/glossopharyngeal nerves to the medulla → adjust sympathetic/parasympathetic outflow. BP rises → vagal slowing + vasodilation; BP falls → sympathetic surge.
• Chemoreceptors respond to low O₂ / high CO₂ / low pH.

Long-term regulation (hours–days) — the RAAS (renin–angiotensin–aldosterone system): low BP/renal flow → kidney releases renin → converts angiotensinogen to angiotensin I → ACE (lungs) makes angiotensin II → powerful vasoconstriction + aldosterone release (Na⁺ and water reabsorbed, K⁺ lost) → blood volume and pressure rise. Also ADH (water reabsorption) and ANP (opposes RAAS — released when atria stretch).

Pharmacy links: ACE inhibitors (-prils) block angiotensin II formation; ARBs (-sartans) block its receptor; diuretics cut volume; beta-blockers cut renin and cardiac output.

5.8 Pulse and electrocardiogram (ECG)

• Pulse — the pressure wave felt where an artery runs over bone (radial artery at the wrist is standard). Normal 60–100/min; rate, rhythm, and volume are all noted clinically. Pulse deficit (apex–radial difference) suggests atrial fibrillation.
• ECG — records the heart's electrical activity via chest/limb leads:
• P wave — atrial depolarisation (contraction follows).
• QRS complex — ventricular depolarisation (the big spike; contraction follows). Abnormally wide QRS suggests bundle-branch block.
• T wave — ventricular repolarisation (recovery).
• PR interval — AV nodal delay; prolonged in heart block. ST segment — elevation signals acute MI; depression signals ischaemia.
• Normal sinus rhythm: every P followed by a QRS, regular, 60–100/min.

Diagram tip: draw one perfect ECG complex and label P, QRS, T, PR interval, and ST segment. Then draw the heart's conduction path (SA → AV → His → Purkinje). These two diagrams together answer most Unit V short notes.

5.9 Pathophysiology of hypertension

• Definition: sustained BP ≥ 140/90 mmHg (measured on more than one occasion).
• Types: primary (essential) — ~90–95%, no single cause; risk factors are age, family history, obesity, high salt intake, smoking, alcohol, stress, physical inactivity. Secondary — ~5–10%, from kidney disease, aldosteronism, Cushing's, phaeochromocytoma, coarctation of aorta, or drugs (NSAIDs, steroids, oral contraceptives).
• Pathogenesis: increased cardiac output and/or peripheral resistance — via overactive sympathetic tone, RAAS overactivity, endothelial dysfunction, and salt/water retention.
• Why it matters ("the silent killer"): usually no symptoms until complications — stroke, myocardial infarction, heart failure, chronic kidney disease, and retinopathy (target-organ damage). Malignant hypertension can cause papilloedema and encephalopathy.
• Pharmacy link: lifestyle first; then drug classes matched to mechanism — thiazide diuretics, ACE inhibitors/ARBs, calcium-channel blockers, beta-blockers. Hypertensive emergency is treated with IV drugs (nitroprusside, labetalol).

5.10 Pathophysiology of cardiac arrhythmias

An arrhythmia is any abnormality of rate, rhythm, or conduction:

• Sinus tachycardia (>100/min) — fever, anxiety, exercise; sinus bradycardia (<60/min) — athletes, beta-blockers, hypothyroidism.
• Atrial fibrillation (AF) — chaotic atrial activity, irregularly irregular pulse, loss of atrial kick; danger is clot formation in the atria → stroke → needs anticoagulation (warfarin/DOACs).
• Atrial flutter — sawtooth pattern, fast regular atrial rate.
• Ventricular tachycardia / ventricular fibrillation — VF is chaotic ventricular quivering with no cardiac output — cardiac arrest; treated with immediate defibrillation.
• Heart blocks — AV nodal conduction fails; first-degree (long PR), second-degree (dropped beats), third-degree/complete (atria and ventricles beat independently — needs a pacemaker).
• Extrasystoles (ectopic beats) — premature beats from atria or ventricles; often benign.

Pharmacy link: antiarrhythmics (amiodarone, lidocaine, verapamil, adenosine) act on ion channels and conduction — which is why Unit V's conduction system must be learned first.

5.11 Pathophysiology of congestive heart failure (CHF)

• Definition: the heart cannot pump enough blood to meet the body's needs — not that it stops, but that it fails as a pump.
• Left-sided failure — blood backs up into the lungs: dyspnoea, orthopnoea (breathless lying flat), paroxysmal nocturnal dyspnoea, pulmonary oedema (crackles), fatigue. Causes: hypertension, MI, valve disease.
• Right-sided failure — blood backs up into the systemic veins: pedal oedema, jugular venous distension, enlarged tender liver (hepatomegaly), ascites. Often follows left-sided failure (via pulmonary hypertension) or lung disease (cor pulmonale).
• Pathogenesis: an initial insult (MI, chronic hypertension) reduces output → compensatory mechanisms kick in — sympathetic activation and RAAS activation (retain salt/water, vasoconstrict) plus ventricular remodelling (hypertrophy, dilation). These help briefly but worsen the load long-term — a vicious cycle.
• Systolic failure (reduced ejection fraction — weak squeeze) vs diastolic failure (preserved EF — stiff ventricle that can't fill).
• Pharmacy link: treatment unloads the failing heart — diuretics (reduce preload/oedema), ACE inhibitors/ARBs + beta-blockers (block the harmful compensation — proven to prolong life), digoxin (raises contractility), and ARNIs in modern guidelines.

5.12 Pathophysiology of ischemic heart disease

Atherosclerosis is the root process:

1. Endothelial injury (hypertension, smoking, high LDL, diabetes) lets LDL into the intima.
2. LDL oxidises → monocytes enter, become macrophages, gorge on lipid → foam cells → fatty streak.
3. Smooth-muscle proliferation and collagen form a fibrous plaque with a lipid core.
4. Plaque rupture exposes thrombogenic material → thrombus → vessel occlusion. Stable plaques narrow the lumen (stable angina); ruptured plaques cause sudden occlusion (MI).

Angina pectoris — chest pain from myocardial ischaemia (demand exceeds supply), relieved by rest or nitroglycerin:

• Stable angina — predictable, on exertion, relieved by rest; fixed plaque narrowing.
• Unstable angina — new, more severe, or at rest; plaque disruption without full occlusion — a warning of impending MI.
• Prinzmetal (variant) angina — coronary spasm, often at rest, can occur with normal coronaries.

Myocardial infarction (MI) — prolonged ischaemia kills heart muscle ("heart attack"). Usually plaque rupture + thrombus in a coronary artery. Features: severe crushing retrosternal chest pain radiating to the left arm/jaw, sweating, nausea, breathlessness; not relieved by rest or nitrates. Diagnosis: ECG (ST elevation in STEMI) + cardiac markers — troponin I/T (most specific, rises in 3–6 hours) and CK-MB. Complications: arrhythmias (commonest cause of early death), heart failure, cardiogenic shock, rupture. Treatment: aspirin + clopidogrel, thrombolytics (streptokinase — recall fibrinolysis from Unit III) or primary angioplasty (PCI) — "time is muscle."

Coronary artery disease (CAD) is the umbrella term for atherosclerotic disease of the coronary arteries manifesting as angina, MI, or sudden death. Modifiable risk factors — smoking, hypertension, diabetes, dyslipidaemia, obesity, inactivity — are the prevention message pharmacists counsel on.

Diagram tip: draw the atherosclerosis sequence as four panels (healthy artery → fatty streak → fibrous plaque → rupture with thrombus). It is the single most asked diagram in cardiovascular pathophysiology.

Unit V — Frequently asked questions

Q. Trace the path of blood through the heart. A. Venae cavae → right atrium → tricuspid valve → right ventricle → pulmonary valve → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → body.

Q. What is the correct order of the heart's conduction system? A. SA node → atria → AV node (delay) → bundle of His → bundle branches → Purkinje fibres → ventricles.

Q. What does each wave of a normal ECG represent? A. P wave: atrial depolarisation; QRS complex: ventricular depolarisation; T wave: ventricular repolarisation.

Q. How is blood pressure regulated in the short term and long term? A. Short term: baroreceptors and chemoreceptors adjusting autonomic outflow within seconds. Long term: RAAS (renin → angiotensin II → aldosterone), ADH, and ANP controlling blood volume over hours to days.

Q. What is the difference between stable and unstable angina? A. Stable angina is predictable exertional pain relieved by rest (fixed narrowing); unstable angina is new, severe, or rest pain from plaque disruption — a pre-infarction emergency.

Q. Why is troponin the preferred marker for MI? A. Troponin I/T is highly specific to cardiac muscle and stays elevated for days, unlike CK-MB which is less specific and normalises faster.

Q. What is the difference between left- and right-sided heart failure? A. Left-sided failure backs blood into the lungs (dyspnoea, pulmonary oedema); right-sided failure backs blood into the systemic veins (pedal oedema, raised JVP, hepatomegaly).

Unit V — Key takeaways

• Heart: 4 chambers, 4 valves (tricuspid, pulmonary, mitral, aortic); left ventricle has the thickest wall; coronary arteries feed the heart itself.
• Pulmonary circuit oxygenates; systemic circuit delivers; portal circuit explains first-pass metabolism.
• Conduction: SA node (pacemaker) → AV node (delay) → His → Purkinje; sympathetic speeds up, vagus slows down.
• Cardiac cycle: S₁ (AV valves shut) and S₂ (semilunar shut); cardiac output = HR × SV ≈ 5 L/min; Frank–Starling law links preload to contraction strength.
• BP = CO × peripheral resistance; short-term control by baroreceptors, long-term by RAAS.
• ECG: P = atrial depolarisation, QRS = ventricular depolarisation, T = ventricular repolarisation; ST elevation = MI.
• Hypertension (≥140/90): mostly essential; the silent killer — stroke, MI, heart failure, CKD.
• Arrhythmias: AF risks stroke (anticoagulate); VF means no output (defibrillate); complete heart block needs a pacemaker.
• CHF: left = lungs (breathlessness), right = body (oedema, JVP); RAAS/sympathetic compensation becomes the disease.
• Atherosclerosis sequence (injury → foam cells → plaque → rupture) underlies angina (stable/unstable/Prinzmetal), MI (troponin, "time is muscle"), and CAD.

End of BP104T notes. Suggested study order: Unit I → Unit V (heart builds on cell/tissue basics) → Unit III (blood links to circulation) → Unit II → Unit IV. Draw every suggested diagram at least once before the exam.

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