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This is my physiology practical syllabus for tomorrow
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Here are your complete revision notes covering every section of your physiology practical syllabus:
PHYSIOLOGY PRACTICAL - COMPLETE REVISION NOTES
★ HEMATOLOGY
Q1 - MAJOR EXPERIMENT: RBC / WBC / DLC
RBC Count (Erythrocyte Count)
Instrument: Haemocytometer (Neubauer's counting chamber) + RBC pipette (dilution 1:200)
Diluting fluid: Hayem's solution (sodium sulphate + sodium chloride + mercuric chloride in distilled water) - prevents clumping, preserves shape
Procedure:
- Draw blood to mark 0.5 in RBC pipette
- Draw Hayem's solution to mark 101 → dilution = 1:200
- Shake for 2 minutes in figure-of-8 motion
- Discard first 3-4 drops, load Neubauer's chamber
- Let settle 2 minutes, count under high power (40x)
- Count 5 small squares of central large square (80 small squares total, count from 4 corners + center)
Formula:
RBC/mm³ = N × Dilution factor / (Area × Depth) = N × 200 / (5 × 0.0025 × 0.1) = N × 10,000
Normal values:
- Male: 4.5 - 5.5 million/mm³ (5 million average)
- Female: 3.8 - 4.8 million/mm³ (4.5 million average)
- Newborn: 6-7 million/mm³
WBC Count (Total Leucocyte Count - TLC)
Instrument: Haemocytometer + WBC pipette (dilution 1:20)
Diluting fluid: Turk's solution (1% acetic acid + gentian violet) - lyses RBCs, stains WBC nuclei
Procedure:
- Draw blood to 0.5, Turk's to 11 → dilution = 1:20
- Count all 4 corner large squares (each = 16 small squares)
Formula:
WBC/mm³ = N × 20 / (4 × 0.1) = N × 50
Normal values: 4,000 - 11,000/mm³ (average 7,000/mm³)
DLC (Differential Leukocyte Count)
Stain: Leishman's stain (combination of methylene blue + eosin in methanol)
Smear preparation:
- Place small drop of blood near one end of slide
- Place spreader at 30-45° angle, push forward smoothly
- Air dry, fix with methanol 3 min
- Flood with Leishman's stain 2 min (methanol fixes)
- Add equal volume buffer/distilled water for 7-10 min
- Wash, dry, examine under oil immersion (100x)
Differential count - Normal values:
| Cell | Normal % | Appearance |
|---|---|---|
| Neutrophils | 40-75% | Multi-lobed nucleus (2-5 lobes), pink granules |
| Lymphocytes | 20-45% | Large round nucleus, scant cytoplasm |
| Monocytes | 2-10% | Kidney-shaped nucleus, grey-blue cytoplasm |
| Eosinophils | 1-6% | Bi-lobed nucleus, large orange-red granules |
| Basophils | 0-1% | S-shaped nucleus, large dark blue granules |
Arneth's count: Neutrophil nuclear lobe index - shift left = immature cells (infection), shift right = hypersegmented (megaloblastic anaemia)
Q2 - MINOR 1: Haemoglobin / BT-CT / Blood Groups
Haemoglobin Estimation
Methods:
-
Sahli's (Acid haematin) method - most common in practicals
- Add 0.1N HCl to Sahli's tube to lower mark (10)
- Add exactly 20 µL blood via Sahli's pipette
- Mix and wait 10 minutes (Hb → acid haematin = brown)
- Add distilled water drop by drop, compare with standard brown glass colour
- Read value directly in g/dL
-
Cyanmethemoglobin method - most accurate (reference method)
- Drabkin's solution converts Hb to stable cyanmethemoglobin
- Measured by colorimetry at 540 nm
Normal values:
- Male: 13-17 g/dL (average 15 g/dL)
- Female: 11-15 g/dL (average 13.5 g/dL)
- Newborn: 17-20 g/dL
Colour index = (Hb%/RBC%) × 2 - normal = 1; <1 hypochromic, >1 hyperchromic
Bleeding Time (BT) and Clotting Time (CT)
Bleeding Time:
- Duke's method: Prick ear lobe / fingertip with lancet. Blot every 30 sec with filter paper (don't touch wound). Time from prick to stop of bleeding.
- Normal: 2-5 minutes (Duke's)
- Tests: platelet function and capillary integrity
- Prolonged in: thrombocytopenia, von Willebrand disease, aspirin use
Clotting Time:
- Capillary tube / Lee-White method: Blood drawn, tilted every 30 sec in capillary tube until it doesn't flow (clot formed)
- Normal: 5-11 minutes (capillary tube method); Lee-White: 5-15 min
- Tests: intrinsic coagulation pathway (factors VIII, IX, XI, XII)
- Prolonged in: haemophilia A & B, heparin therapy, severe liver disease
| Test | Measures | Normal |
|---|---|---|
| BT | Platelet + vessel | 2-5 min |
| CT | Coagulation factors | 5-11 min |
| PT | Extrinsic + common | 11-13.5 sec |
| APTT | Intrinsic + common | 25-35 sec |
Blood Groups (ABO & Rh)
ABO System - Karl Landsteiner (1901)
| Blood Group | Antigen on RBC | Antibody in Plasma | Can donate to | Can receive from |
|---|---|---|---|---|
| A | A | Anti-B | A, AB | A, O |
| B | B | Anti-A | B, AB | B, O |
| AB | A & B | None | AB only | All (Universal recipient) |
| O | None | Anti-A & Anti-B | All (Universal donor) | O only |
Tile/Slide method:
- Anti-A serum (blue) + drop blood → if agglutination = A antigen present
- Anti-B serum (yellow) + drop blood → if agglutination = B antigen present
- Anti-D serum + drop blood → if agglutination = Rh positive
Rh System:
- Rh+: 85% population (antigen D present)
- Rh-: 15% (no D antigen)
- Significance: erythroblastosis fetalis - Rh- mother, Rh+ fetus, second pregnancy risk
- Rhogam (Anti-D immunoglobulin) given within 72 hrs of delivery to prevent sensitization
Q3 - MINOR 2: Problem Based Questions
Common PBQ topics:
- Patient with low Hb, low RBC count → identify type of anaemia (normocytic/microcytic/macrocytic)
- Patient with prolonged BT → platelet disorder or aspirin use
- Rh incompatibility scenario - management
- Blood transfusion compatibility
★ CLINICAL
Q1 - MAJOR: CVS / Respiratory / Motor System / Sensory System
CVS Examination
Pulse:
- Sites: Radial (most common), carotid, brachial, femoral, popliteal, dorsalis pedis
- Assessment: Rate, rhythm, volume, character, vessels wall feel, radio-radial/radio-femoral delay
- Normal rate: 60-100 bpm; Bradycardia <60; Tachycardia >100
- Pulse deficit = apical rate - radial rate (seen in AF, multiple ectopics)
Key pulse characters:
- Pulsus paradoxus: exaggerated fall in systolic BP (>10 mmHg) on inspiration → pericardial tamponade, severe asthma
- Corrigan's (Water hammer) pulse: rapid rise and fall → aortic regurgitation
- Pulsus parvus et tardus: slow rising, plateau → aortic stenosis
- Dicrotic pulse: double peak → septic shock, severe heart failure
Heart Sounds:
- S1 (lub): closure of mitral + tricuspid valves; marks start of systole
- S2 (dub): closure of aortic + pulmonary valves; marks start of diastole
- S3: pathological in adults - ventricular filling gallop → heart failure, dilated cardiomyopathy
- S4: atrial gallop → stiff ventricle, hypertension, aortic stenosis
Auscultation areas:
- Mitral: apex (5th ICS, MCL)
- Tricuspid: lower left sternal border (4th ICS)
- Pulmonary: 2nd ICS, left parasternal
- Aortic: 2nd ICS, right parasternal
Respiratory System Examination
Inspection: Rate (normal 12-20/min), rhythm, depth, symmetry, use of accessory muscles, chest shape (barrel chest in COPD, pigeon chest, funnel chest)
Palpation: Tracheal deviation, chest expansion (both sides), tactile vocal fremitus (TVF)
Percussion:
- Resonant: normal lung
- Dull: consolidation, pleural effusion (stony dull), pneumonia
- Hyperresonant: pneumothorax, emphysema
Auscultation - Breath sounds:
- Vesicular: normal (heard over lung parenchyma)
- Bronchial: tubular, harsh → consolidation over the area
- Bronchovesicular: over 1st/2nd ICS anteriorly
Added sounds:
- Crepitations (crackles): fluid in alveoli/bronchioles → pulmonary oedema, pneumonia
- Rhonchi (wheeze): airway narrowing → asthma, COPD
- Pleural rub: pleuritis
Vocal resonance: Say "99" - increased over consolidation, decreased over effusion
Normal respiratory values:
- TV: 500 mL, TLC: 6L, FRC: 2.5L, RV: 1.5L, VC: 4.5L
- FEV1/FVC: >80% (obstructive <70%)
Motor System Examination
Sequence: Inspection → Tone → Power → Reflexes → Coordination
Inspection:
- Wasting/atrophy (LMN lesion), fasciculations (LMN), involuntary movements, posture
Muscle Tone:
- Normal, hypotonia (LMN, cerebellar), hypertonia
- Spasticity: velocity-dependent resistance, clasp-knife, UMN lesion
- Rigidity: constant throughout range, lead-pipe or cogwheel (Parkinson's)
Muscle Power (MRC Grading):
| Grade | Movement |
|---|---|
| 0 | No contraction |
| 1 | Flicker of contraction |
| 2 | Movement with gravity eliminated |
| 3 | Movement against gravity |
| 4 | Movement against resistance (reduced) |
| 5 | Normal power |
UMN vs LMN Lesion:
| Feature | UMN | LMN |
|---|---|---|
| Wasting | Disuse only | Marked |
| Tone | Increased (spastic) | Decreased |
| Power | Reduced (pyramidal pattern) | Reduced |
| Reflexes | Exaggerated | Diminished/absent |
| Plantar | Extensor (Babinski +) | Flexor |
| Fasciculations | Absent | Present |
Sensory System Examination
Types of sensation:
Superficial:
- Touch: cotton wool
- Pain: pin-prick
- Temperature: hot/cold tubes
Deep:
- Proprioception/Joint position sense (JPS)
- Vibration: 128 Hz tuning fork on bony prominences
- Deep pain: squeeze Achilles tendon
Cortical:
- Two-point discrimination (normal: 5mm fingertip)
- Stereognosis (identify object by touch)
- Graphesthesia (number written on palm)
- Point localization
Sensory pathways:
- Dorsal column (posterior): vibration, proprioception, fine touch → ipsilateral → crosses at medulla
- Spinothalamic (anterior/lateral): pain, temperature, crude touch → crosses 1-2 segments above entry → contralateral
Sensory level:
- Lesion of spinal cord → loss below the level
- Brown-Sequard syndrome: ipsilateral proprioception loss + contralateral pain/temp loss
Q2 - MINOR 1: Cranial Nerves + BP
Cranial Nerves 1-6
| CN | Name | Type | Function | Test |
|---|---|---|---|---|
| CN I | Olfactory | Sensory | Smell | Coffee/cloves to each nostril (not ammonia) |
| CN II | Optic | Sensory | Vision | Visual acuity (Snellen), fields, fundus |
| CN III | Oculomotor | Motor | EOM (SR, IR, MR, IO), levator palpebrae, pupil constriction | Eye movements, pupil light reflex |
| CN IV | Trochlear | Motor | Superior oblique (SO) - depression in adduction | "Down and in" movement test |
| CN V | Trigeminal | Mixed | Sensation face (3 divisions), mastication | Facial sensation V1/V2/V3, corneal reflex (afferent limb), jaw movements |
| CN VI | Abducens | Motor | Lateral rectus - abduction | Lateral gaze |
Pupillary reflexes (CN II afferent, CN III efferent):
- Direct reflex: light in one eye → that pupil constricts
- Consensual reflex: light in one eye → opposite pupil constricts
- Accommodation reflex: near object → convergence + miosis + lens bulging (CN III)
Cranial Nerves 7-12
| CN | Name | Type | Function | Test |
|---|---|---|---|---|
| CN VII | Facial | Mixed | Expression muscles, taste ant 2/3 tongue, lacrimation, stapedius | Forehead wrinkling, eye closure, smile, puffing cheeks, taste |
| CN VIII | Vestibulocochlear | Sensory | Hearing, balance | Tuning fork (Weber, Rinne), Romberg's |
| CN IX | Glossopharyngeal | Mixed | Taste post 1/3, pharyngeal sensation, parotid | Gag reflex (afferent), taste post 1/3 |
| CN X | Vagus | Mixed | Pharynx/larynx/autonomic viscera, palate, gag | Gag reflex (efferent), voice (hoarseness), palate elevation, swallowing |
| CN XI | Accessory | Motor | SCM, trapezius | Turn head against resistance (SCM), shrug shoulders (trapezius) |
| CN XII | Hypoglossal | Motor | Tongue movements | Tongue protrusion - deviates to side of lesion in LMN |
Upper vs Lower motor neuron facial palsy (CN VII):
- UMN (central): contralateral lower face only, forehead spared (bilateral cortical representation of forehead)
- LMN (Bell's palsy): ipsilateral entire face, forehead involved, Bells phenomenon (eyeball rolls up on closing)
Tuning fork tests (CN VIII):
- Rinne's: Compare AC vs BC at mastoid. AC > BC = Rinne positive (normal or SNHL); BC > AC = Rinne negative (conductive hearing loss)
- Weber: Placed at vertex midline. Lateralizes to better ear in SNHL; lateralizes to worse ear in conductive loss
Blood Pressure - Positions, Exercise, Posture
Standard method (Korotkoff sounds, auscultatory):
- Patient seated, arm at heart level, cuff 2.5 cm above antecubital fossa
- Inflate 20-30 mmHg above disappearance of radial pulse
- Deflate at 2-3 mmHg/sec
- K1 (first sound) = Systolic BP
- K5 (disappearance) = Diastolic BP; K4 (muffling) in pregnancy/aortic regurgitation
Normal BP: 120/80 mmHg
Hypertension: ≥140/90 mmHg
Hypotension: <90/60 mmHg
Effect of Sitting/Lying/Standing:
- BP is highest lying, slightly lower sitting, slightly lower standing in healthy individuals
- Postural (orthostatic) hypotension: Fall of ≥20 mmHg systolic or ≥10 mmHg diastolic on standing from lying
- Causes: dehydration, autonomic neuropathy (diabetes), medications (antihypertensives, diuretics)
- Mechanism: On standing, venous pooling in legs → ↓ venous return → ↓ CO → baroreceptors trigger compensatory sympathetic response (normally)
Effect of Exercise on BP:
- Systolic BP rises significantly (up to 180-200 mmHg during intense exercise)
- Diastolic BP remains same or slightly decreases (vasodilation in exercising muscles)
- Pulse pressure widens
- Heart rate increases (↑ sympathetic activity)
- After exercise: BP rapidly returns to normal (within minutes) due to accumulated vasodilators (adenosine, CO2, lactic acid) in muscles
Korotkoff phases:
- Tapping sound (systolic)
- Swishing/murmur
- Crisp, louder tapping
- Muffling (used for diastolic in special cases)
- Silence (diastolic)
Superficial and Deep Reflexes
Deep Tendon Reflexes (DTR):
| Reflex | Spinal Level | Technique |
|---|---|---|
| Biceps jerk | C5, C6 | Tap biceps tendon, arm semiflexed |
| Triceps jerk | C6, C7 | Tap triceps tendon, arm at 90° |
| Supinator/Brachioradialis | C5, C6 | Tap brachioradialis at wrist |
| Knee jerk (patellar) | L2, L3, L4 | Tap patellar tendon, leg hanging |
| Ankle jerk (Achilles) | S1, S2 | Tap Achilles tendon, foot dorsiflexed |
Grading of reflexes:
- 0 = Absent (LMN, peripheral neuropathy)
- 1+ = Diminished
- 2+ = Normal
- 3+ = Exaggerated (UMN, anxiety)
- 4+ = Clonus (UMN lesion)
Superficial Reflexes:
| Reflex | Level | Stimulus | Response |
|---|---|---|---|
| Corneal | CN V (aff), CN VII (eff) | Touch cornea | Eye closure |
| Abdominal (upper) | T8, T9, T10 | Stroke skin outward from umbilicus | Umbilicus moves toward stimulus |
| Abdominal (lower) | T10, T11, T12 | Same, below umbilicus | Same |
| Cremasteric | L1, L2 | Stroke inner thigh | Ipsilateral testis rises |
| Plantar | S1, S2 | Stroke outer sole, foot firmly | Normal: plantar flexion (toes curl down) |
| Babinski sign | - | As above | Dorsiflexion of big toe, fanning = UMN lesion (normal in <1 year) |
| Conjunctival | CN V, CN VII | Touch conjunctiva | Blink |
Special reflexes:
- Hoffman's sign: flick middle finger distal phalanx → thumb/index flex = UMN of upper limb
- Clonus: rapid dorsiflexion of ankle → rhythmic beats = UMN, >5 beats sustained = significant
Q3 - MINOR 2: Amphibian Charts
Frog heart experiments (in-situ or isolated frog heart)
Stannius Ligature experiment - demonstrates automaticity and hierarchy of pacemakers:
| Ligature | Position | Result |
|---|---|---|
| 1st (between sinus venosus and atrium) | Sinoatrial junction | Sinus venosus beats fast; atria + ventricle stops then resumes at slower intrinsic rate |
| 2nd (between atrium and ventricle) | Atrioventricular junction | Atria beats at sinus rate; ventricle stops then beats at slower idioventricular rate |
Vagal stimulation effects on frog heart:
- Vagal stimulation → ↓HR, ↓conduction, ↓contractility
- Prolonged stimulation → vagal escape (ventricle resumes beating despite vagal tone)
- Vagal escape mechanism: intrinsic pacemaker takes over due to hyperpolarization tolerance
Effect of ions on frog heart (Ringer's solution modifications):
- Excess K+ → cardiac arrest in diastole (depolarization block)
- Excess Ca²+ → cardiac arrest in systole (spastic contraction)
- Na+ deficiency → cardiac arrest (lost action potential propagation)
- Adrenaline → ↑HR, ↑force
- Acetylcholine → ↓HR (muscarinic)
- Pilocarpine (muscarinic) → ↓HR
- Atropine → blocks vagal slowing, ↑HR
Effect of temperature:
- Warm Ringer's → ↑HR (Bowditch staircase effect at faster rates)
- Cold Ringer's → ↓HR (useful to study heart at rest)
Refractory period of heart:
- Absolute refractory period: no stimulus can cause contraction (corresponds to plateau phase of AP)
- Relative refractory period: strong stimulus may cause extra contraction
- Extrasystole followed by compensatory pause
Frog nerve-muscle preparation:
- Used to study: threshold stimulus, summation, tetanus, fatigue
- Sciatic nerve + gastrocnemius muscle
- Single stimulus → single twitch; Rapid stimuli → summation → tetanus
★ SPOTTERS (10)
Endocrine charts + experiment apparatus + CNS/Respiratory/Renal charts
Endocrine Charts/Diagrams to Identify:
- Hypothalamo-pituitary axis - portal blood supply, releasing hormones
- Insulin secretion - beta cells, glucose stimulus, mechanism
- Thyroid hormone synthesis - iodination, coupling, T3/T4
- Adrenal cortex layers - Zona glomerulosa (aldosterone), Zona fasciculata (cortisol), Zona reticularis (androgens) - "GFR"
- Feedback loops - negative feedback in HPA axis, HPT axis
Experiment Apparatus to Identify:
| Apparatus | Used For |
|---|---|
| Haemocytometer (Neubauer's chamber) | RBC/WBC counting |
| Sahli's haemoglobinometer | Hb estimation |
| Sphygmomanometer | BP measurement |
| Stethoscope | Auscultation |
| Spirometer | Lung function tests |
| Tuning fork (128 Hz, 256 Hz, 512 Hz) | Hearing tests |
| Reflex hammer | DTR testing |
| Ophthalmoscope | Fundus examination |
| Snellen's chart | Visual acuity |
| Ishihara chart | Colour vision |
| Perimeter | Visual field |
CNS Charts:
- Ascending tracts: dorsal column, spinothalamic, spinocerebellar
- Descending tracts: corticospinal (pyramidal), extrapyramidal
- Cerebellum: DAMNIT mnemonic (Dysdiadochokinesia, Ataxia, Muscle hypotonia, Nystagmus, Intention tremor, past pointing/Titubation)
- Circle of Willis diagram
- Motor homunculus / Sensory homunculus (Penfield's)
Respiratory Charts:
- Spirometry trace: TV, IRV, ERV, RV, IC, FRC, VC, TLC
- Oxygen dissociation curve (sigmoidal) - right shift: ↑Temp, ↑CO2, ↑2,3-DPG, ↓pH (Bohr effect); left shift: opposite
- Lung volumes and capacities table
Renal Charts:
- Nephron diagram: glomerulus, PCT, LOH (thin descending, thin ascending, thick ascending), DCT, collecting duct
- Countercurrent mechanism in Loop of Henle
- Starling forces across glomerular capillary (GFR determination)
- Tubular reabsorption sites: Na, glucose, amino acids (PCT - 65%), water reabsorption
★ OSCE
Common OSCE stations in physiology:
- Identify a slide (blood smear, stained cells)
- Identify apparatus
- Calculate RBC/WBC from given count
- Interpret spirometry/ECG values
- State normal value of a given test
★ THEORY VIVA - KEY POINTS
| Topic | Must Know |
|---|---|
| Normal Hb | M: 13-17, F: 11-15, NB: 17-20 g/dL |
| Normal RBC | M: 4.5-5.5 M, F: 3.8-4.8 M/mm³ |
| Normal WBC | 4,000-11,000/mm³ |
| DLC % order | N > L > M > E > B (Never Let Monkeys Eat Bananas) |
| BT | 2-5 min (Duke's) |
| CT | 5-11 min |
| Normal BP | 120/80 mmHg |
| Pulse pressure | 40 mmHg (= systolic - diastolic) |
| Normal pulse rate | 60-100 bpm |
| Respiratory rate | 12-20/min |
| Korotkoff phases | 5 phases, K1=systolic, K5=diastolic |
| Babinski sign | Extensor plantar = UMN lesion |
| Stannius ligatures | 1st: SA junction, 2nd: AV junction |
| Vagal escape | Ventricle resumes despite vagal stimulation |
Good luck for your practical tomorrow! Work through the hematology calculations, make sure you know the normal values cold, and rehearse the cranial nerve testing sequence. The viva will likely focus on "why" - why does vagal escape occur, why does BP change with posture, what is the significance of BT vs CT.
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