Fellowship of the Royal College of Anaesthetists (FRCA) Physiology and Biochemistry Syllabus

Physiology and Biochemistry syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Physiology and Biochemistry in Fellowship of the Royal College of Anaesthetists (FRCA), not a summary of it.

1. 1

   Cardiovascular Physiology

   6 topics

   • Cardiac cycle and pressure-volume relationships
     • Wiggers diagram and valve events
     • Ventricular pressure-volume loops and contractility
     • Determinants of stroke volume: preload, afterload, contractility
   • Cardiac output and its regulation
     • Starling's law of the heart
     • Measurement: thermodilution, Fick principle, oesophageal Doppler
   • Systemic and regional circulation
     • Coronary, cerebral, hepatic and renal blood flow regulation
     • Autoregulation and metabolic control
   • Control of blood pressure
     • Baroreceptor and chemoreceptor reflexes
     • Renin-angiotensin-aldosterone system
   • Microcirculation and capillary fluid exchange
     • Starling forces and the revised glycocalyx model
   • Cardiovascular changes at altitude, exercise and haemorrhage
2. 2

   Respiratory Physiology

   6 topics

   • Mechanics of breathing
     • Compliance, elastance and surfactant
     • Airway resistance and work of breathing
   • Lung volumes and spirometry
     • FRC and closing capacity
     • Flow-volume loops in obstructive and restrictive disease
   • Gas exchange and diffusion
     • Ventilation-perfusion matching and the V/Q ratio
     • Shunt, dead space and the alveolar gas equation
   • Oxygen and carbon dioxide transport
     • Oxyhaemoglobin dissociation curve and shifts
     • Bohr and Haldane effects
   • Control of ventilation
     • Central and peripheral chemoreceptors
     • Hypoxic and hypercapnic ventilatory responses
   • Hypoxia, hyperoxia and oxygen toxicity
3. 3

   Renal, Fluids and Acid-Base

   5 topics

   • Glomerular filtration and renal clearance
     • GFR measurement and autoregulation
     • Concept of renal clearance
   • Tubular function and concentration of urine
     • Counter-current multiplier and exchanger
     • Sodium, potassium and water handling
   • Body fluid compartments and osmolality
   • Acid-base balance
     • Henderson-Hasselbalch and buffer systems
     • Metabolic and respiratory disturbances with compensation
     • Anion gap and base excess interpretation
   • Electrolyte physiology and disorders
4. 4

   Neurophysiology and Special Senses

   6 topics

   • Resting membrane and action potentials
     • Ionic basis and the Nernst/Goldman equations
     • Saltatory conduction and nerve fibre classification
   • Synaptic transmission and neurotransmitters
   • Cerebral blood flow, ICP and CSF
     • Monro-Kellie doctrine and ICP-volume curve
     • Regulation of cerebral perfusion pressure
   • Pain pathways and nociception
     • Ascending tracts and descending modulation
     • Gate control theory and central sensitisation
   • Autonomic nervous system
     • Sympathetic and parasympathetic organisation
     • Receptor types and reflex arcs
   • Muscle physiology and neuromuscular junction
5. 5

   Endocrine, Metabolic and GI Physiology

   6 topics

   • Hypothalamic-pituitary axis
   • Thyroid, adrenal and pancreatic hormones
     • Cortisol and the stress response to surgery
     • Insulin, glucagon and glucose homeostasis
   • Calcium, phosphate and bone metabolism
   • Gastrointestinal secretion and motility
     • Gastric emptying and aspiration risk
   • Liver function and metabolism
     • Bilirubin handling and synthetic function
   • Nutrition, energy balance and metabolic rate
6. 6

   Blood, Immunity and Physiology of Extremes

   6 topics

   • Haematopoiesis and red cell physiology
   • Haemostasis and the coagulation cascade
     • Platelet function and fibrinolysis
     • Anticoagulant and procoagulant balance
   • Blood groups and transfusion physiology
   • Immune system and inflammatory response
   • Physiology of pregnancy
     • Cardiovascular, respiratory and haematological changes
     • Aortocaval compression and uteroplacental flow
   • Physiology of the neonate and the elderly

Physiology and Biochemistry flashcards for Fellowship of the Royal College of Anaesthetists (FRCA)

23 of 52 cards from the Physiology and Biochemistry deck — real questions with worked answers.

1. Define stroke volume and give its normal resting value in a healthy adult.

   Stroke volume (SV) is the volume of blood ejected by a ventricle in one contraction: $SV = EDV - ESV$. Normal $\approx 70\ \text{mL}$ (EDV $\approx 120$ mL, ESV $\approx 50$ mL).

2. Write the equation for cardiac output and state its normal resting value.

   $CO = HR \times SV$. Normal resting $CO \approx 5\ \text{L·min}^{-1}$ ($70\ \text{min}^{-1} \times 70\ \text{mL}$).

3. On the left ventricular pressure-volume loop, name the four phases in order starting from the end of diastole.

   1) Isovolumetric contraction, 2) Ejection, 3) Isovolumetric relaxation, 4) Filling (diastole). The loop area equals stroke work; width equals stroke volume.

4. State the Frank-Starling law of the heart.

   The energy/force of ventricular contraction increases with the initial fibre length (end-diastolic volume/preload). Greater venous return raises EDV, increasing stroke volume to match output to inflow.

5. How is ejection fraction calculated and what is its normal value?

   $EF = \dfrac{SV}{EDV} = \dfrac{EDV-ESV}{EDV}$. Normal $EF \approx 0.55\text{–}0.70$ (55–70%).

6. Define afterload and preload for the left ventricle.

   Preload = ventricular wall tension/stretch at end-diastole (related to EDV, LVEDP). Afterload = the load/wall tension the ventricle must overcome to eject (related to aortic/systemic vascular resistance and LaPlace wall stress).

7. Give the equation for systemic vascular resistance (SVR).

   $SVR = \dfrac{MAP - CVP}{CO}$. By Poiseuille, resistance $R = \dfrac{8\eta L}{\pi r^{4}}$, so radius dominates (fourth-power dependence).

8. What is mean arterial pressure and how is it estimated from systolic and diastolic pressures?

   $MAP = DBP + \tfrac{1}{3}(SBP - DBP)$, equivalently $MAP = \dfrac{SBP + 2\,DBP}{3}$. Also $MAP = CO \times SVR + CVP$.

9. Describe the baroreceptor reflex response to a fall in arterial pressure.

   Reduced stretch of carotid sinus/aortic arch baroreceptors lowers afferent firing (via CN IX and X). The medulla increases sympathetic and decreases parasympathetic output, raising HR, contractility, SVR and venous return to restore MAP.

10. State the Starling equation for capillary fluid exchange.

    $J_v = K_f\,[(P_c - P_i) - \sigma(\pi_c - \pi_i)]$, where $K_f$ is the filtration coefficient, $\sigma$ the reflection coefficient, $P$ hydrostatic and $\pi$ oncotic pressures.

11. How does the cardiovascular system acutely adapt to high altitude hypoxia?

    Hypoxia drives a sympathetic-mediated tachycardia and raised cardiac output; hypoxic pulmonary vasoconstriction raises pulmonary artery pressure; over days plasma volume falls and erythropoietin-driven polycythaemia raises haematocrit and oxygen-carrying capacity.

12. List the classes of haemorrhagic shock (ATLS) by percentage blood loss.

    Class I: <15%; Class II: 15–30%; Class III: 30–40%; Class IV: >40%. HR, RR and reduced pulse pressure rise progressively; hypotension and reduced urine output mark Class III–IV.

13. Give the compliance equation of the respiratory system and normal lung compliance.

    $C = \dfrac{\Delta V}{\Delta P}$. Normal lung compliance $\approx 200\ \text{mL·cmH}_2\text{O}^{-1}$; total respiratory system compliance $\approx 100\ \text{mL·cmH}_2\text{O}^{-1}$.

14. State the Laplace law for an alveolus and explain the role of surfactant.

    $P = \dfrac{2T}{r}$ for a sphere/bubble with two surfaces. Surfactant lowers surface tension $T$, more so in smaller alveoli, preventing collapse and equalising pressures between alveoli of differing radii.

15. Define functional residual capacity (FRC) and give its normal value.

    FRC = volume remaining in the lungs after a normal tidal expiration $= ERV + RV$. Normal $\approx 2.5\text{–}3.0\ \text{L}$ (~30 mL·kg⁻¹). It is the lung's oxygen reservoir and cannot be measured by spirometry.

16. Distinguish obstructive from restrictive patterns by the $FEV_1/FVC$ ratio.

    Obstructive: $FEV_1/FVC < 0.7$ (reduced $FEV_1$). Restrictive: $FEV_1/FVC$ normal or increased ($\geq 0.7$) with reduced FVC and total lung capacity.

17. Write the alveolar gas equation.

    $P_AO_2 = P_iO_2 - \dfrac{P_aCO_2}{R}$, where $P_iO_2 = F_iO_2\,(P_{atm} - P_{H_2O})$ and $R$ (respiratory quotient) $\approx 0.8$.

18. State Fick's law of diffusion as applied to the alveolar membrane.

    $\dot{V}_{gas} \propto \dfrac{A \cdot D \cdot (P_1 - P_2)}{T}$, where $A$ = area, $T$ = thickness, $(P_1-P_2)$ = partial pressure gradient, and $D \propto \dfrac{\text{solubility}}{\sqrt{MW}}$ (Graham's law).

19. Describe the key features of the oxyhaemoglobin dissociation curve and its $P_{50}$.

    Sigmoid curve; $P_{50}$ (50% saturation) $\approx 3.5\ \text{kPa}$ (26.6 mmHg). $SaO_2 \approx 90\%$ at $P_aO_2 \approx 8\ \text{kPa}$. Right shift (raised $H^+$, $CO_2$, temperature, 2,3-DPG) reduces affinity and aids tissue unloading.

20. Give the oxygen content equation for arterial blood.

    $CaO_2 = (1.34 \times Hb \times SaO_2) + (0.0225 \times P_aO_2)$, in mL·dL⁻¹ (with Hb in g·dL⁻¹, $P_aO_2$ in kPa). The dissolved term is small under normal conditions.

21. Name the three forms in which $CO_2$ is carried in blood and their approximate proportions.

    As bicarbonate $\approx 70\%$ (via carbonic anhydrase, $\ce{CO2 + H2O <=> H2CO3 <=> H+ + HCO3-}$), as carbamino compounds $\approx 23\%$, and dissolved $\approx 7\%$.

22. What is the Bohr effect and what is the Haldane effect?

    Bohr effect: increased $CO_2$/$H^+$ reduces haemoglobin's $O_2$ affinity (right shift), aiding $O_2$ release in tissues. Haldane effect: deoxygenated haemoglobin carries more $CO_2$, aiding $CO_2$ loading in tissues and unloading in lungs.

23. Which receptors control ventilation and what are their primary stimuli?

    Central chemoreceptors (medulla) respond to CSF $H^+$/$P_aCO_2$ (dominant drive). Peripheral chemoreceptors (carotid and aortic bodies) respond to low $P_aO_2$ (mainly <8 kPa), raised $P_aCO_2$ and $H^+$.

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