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Primary FRCA MCQ > Physiology > Flashcards

Physiology Flashcards

1
Q

Define flow

A

Volume per unit time

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2
Q

Define Reynolds number

A

Reynolds number is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces.

Basically predicts when flow through a tube is likely to change from laminar to turbulent

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3
Q

Which Reynold’s number is the turning point where laminar flow become turbulent

A

2000

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4
Q

What is the formula for Reynolds number

A

Re = pvD/μ

Reynolds number = Fluid density x Velocity x pipe diameter / dynamic viscosity of fluid

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5
Q

Why is turbulent flow useful in trachea

A

Droplets fly off in all directions hitting mucosa which allows them to be cleared

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6
Q

Define ohms law

A

V = IR

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7
Q

Describe course of RCA

A

Arises from anterior aortic sinus of aortic root and runs between right atrium and right ventricle

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8
Q

Describe course of LCA

A

Arises from left posterior sinus of aortic root then devides into circumflex and LAD.

Circumflex runs between left atrium and left ventricle

LAD runs between left and right ventricles

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9
Q

What percentage of CO goes to coronary blood flow

A

5%

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10
Q

Describe why exercise can trigger angina in terms of blood flow

A

CO can increase 4-7 fold during exercise whilst coronary blood flow only increases 3-4 fold

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11
Q

Why is turbulent flow important in the aortic root

A

Blood moving through aortic valve becomes turbulent which causes back flow into sinus valsalve and therefore into coronary arteries.

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12
Q

Describe the major venous drainage of the heart

A

Great and small cardiac veins coalesce into coronary sinus and drain into right atrium

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13
Q

Which vessels play a minor part in venous drainage of the heart

A

Thebesian veins- very small veins impeded in the myocardium which drain directly into each chamber separately

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14
Q

Which equation is used to calculate the transmembrane potential considering only 1 ion

A

Nernst equation

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15
Q

Which equation is used to calculate the transmembrane potential considering multiple ions

A

Goldman-hodgkin-katz equation

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16
Q

What is the Nernst equation

A

Pd = nRT/F X Ln (Ion o/ Ion i)

Potential difference = (Valence X Universal gas constant X Absolute temperature/ Faraday constant.) X Ln (outside conc./ Ion inside conc.)

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17
Q

What is the resting membrane potential of a neuron

A

-70mv

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18
Q

How long does an action potential last in a neuronal cell

A

1msec

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19
Q

How long does an action potential last in a cardiac myocyte

A

300msec

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20
Q

How do action potentials spread between cardiac myocytes

A

GAP junctions

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21
Q

Describe the 4 phases of the cardiac myocyte action potential

A

0- Na+ influx through fast channels and CA2+ influx through T-type channels - causing membrane depolarisation

1- Potassium outflow acts to repolarise

2- More Ca2+ influx via L-type channels prolongs action potential

3- Ca2+ channels close causing re-polarisation

4- Membrane stabilised at -85mV

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22
Q

How do pacemaker cells in SAN and AVN fire automatically

A

Continuous slow leak of ions causing action potentials to be triggered

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23
Q

Describe 3 phases of action potential in pacemaker myocyte

A

Phase 4- Slow Na+ inflow causing slight depolarisation to -40mV the threshold potential

Phase 0- Ca2+ influx via T-type channels causing depolarisation

Phase 3- K+ outflow repolarises membrame

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24
Q

Which ECG leads show inferior infarct (RCA)

A

Leads II, III, AVF

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25
Q

Which ECG leads show anterior infarct (LAD)

A

Leads V1 and V2

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26
Q

Which ECG leads show Lateral infarct (Circumflex)

A

Leads I, AVL, V5, V6

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27
Q

How is MAP calculated

A

MAP = Diastolic pressure + 1/3 pulse pressure

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28
Q

What causes dichrotic notch in aortic pressure wave

A

Aortic valve closing

Backflow around aortic valve

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29
Q

What is the normal pressure in the right atrium

A

< 5mmHg

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30
Q

What is the normal pressure in the right ventricle

A

<25/5 mmHg

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31
Q

What is the normal pressure in the pulmonary artery

A

<25/10 mmHg

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32
Q

What is the normal pressure in the Left atrium/ Pulmonary wedge pressure

A

< 12 mmHg

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33
Q

What is the normal pressure in the left ventricle

A

<130/10 mmHg

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34
Q

What is the normal pressure in the Aorta

A

<130/90 mmHg

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35
Q

Which 2 metabolic factors have largest impact on coronary artery vasoconstriction

A

increased PO2
Decreased PCO2

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36
Q

Define Hagen-pouseuille’s law

A

The volumetric flow rate of a fluid through a pipe is directly proportional to the fourth power of the diameter and the pressure difference, and inversely proportional to the pipe length and the fluid’s dynamic viscosity.

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37
Q

Give the Hagen-pouseuille’s equation

A

Q = △P π r⁴/8 η L

Flow = pressure difference X π X radius ⁴ / 8 X Viscosity of liquid X length of tube

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38
Q

Which 2 cranial nerves transmit action potentials from baroreceptors in heart

A

Glossopharyngeal (IX)
Vagus (X)

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39
Q

How do you calculate average weight of a child over 5 years old

A

Weight (kg) = (Age x3) + 7

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40
Q

Which agent is used to measure total body water

A

Deuterium Oxide (D2O)

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41
Q

Explain the Cushing’s reflex in acute head injury

A

Triad of: Hypertension, bradycardia, irregular respiration.

Caused by increased inter cranial pressure. Sign indicates imminent brain herniation

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42
Q

In what form is the majority of CO2 transported in the blood

A

Bicarbonate (90%)

Carbamino compound (5%)

Dissolved in plasma (5%)

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43
Q

Which 4 cranial nerves carry parasympathetic outflow

A

CN III
CN VII
CN IX
CN X

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44
Q

What are some of the signs of CNVII palsy (cerebellopontine tumour)

A

Ipsilateral facial weakness
Ipsilateral loss of taste
Ipsilateral loss of tear production and sweating

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45
Q

Explain how hypermagnesaemia (magnesium overdose) can cause muscle weakness

A

Magnesium competes for voltage gated calcium channels and prevents ACh vesicle exocytosis from presynaptic terminal

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46
Q

How does Zollinger Ellison disease cause gastric ulcers

A

Neuroendocrine gastrin producing tumour of G cells in pyloric region of stomach. Gastrin leads to HCL production by parietal cells which when unregulated causes multiple ulcers.

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47
Q

What do G cells produce in stomach

A

Gastrin ( causes parietal cells to produce HCL)

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48
Q

What do parietal cells produce in stomach

A

HCL

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49
Q

What do D cells produce in stomach

A

Somatostatin (acts to decrease gastrin production)

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50
Q

What do Chief cells produce in stomach

A

Pepsinogen- inactive pepsin which is a proteolytic enzyme involved in protein digestion

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51
Q

What do Enterochromafin cells produce in stomach

A

Histamine (triggers parietal cells to produce HCL)

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52
Q

Which 2 factors lead to closure of the ductus arteriosus

A

Increased oxygen tension as foetus takes a breath.

Dropping PGE2 levels as placenta is removed.

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53
Q

Which drug can be used to maintain patency of ductus arteriosus in babies with a ductal dependant congenital cardiac disease

A

PGE1

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54
Q

Define respiratory quotient

A

Dimensionless number that is the ratio of carbon dioxide produced to oxygen consumed in respiration. It can be used to calculate basal metabolic rate.

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55
Q

What Is the respiratory quotient of carbohydrates

A

1

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56
Q

What Is the respiratory quotient of fat

A

0.7

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57
Q

What Is the respiratory quotient of protein

A

0.8

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58
Q

What Is the respiratory quotient of amino acids

A

0.8

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59
Q

What is the role of foetal renin in maternal-foetal circulation

A

Renin converts angiotensinogen to angiotensin I. Angiotensin I is converted to angiotensin II by ACE.

Angiotensin II regulates uteroplacental vascular resistance and blood flow.

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60
Q

What is a delta ratio in acid-base disorder

A

The ratio of change in anion gap to the ratio of change in bicarbonate

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61
Q

What does a delta ratio in acid- base disorder of <0.4 tell you

A

Normal anion gap acidosis

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62
Q

What does a delta ratio in acid- base disorder of 0.4-0.8

A

Combination of normal and high anion gap metabolic acidosis

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63
Q

What does a delta ratio in acid- base disorder of 1-2 tell you

A

High anion gap metabolic acidosis

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64
Q

What does a delta ratio in acid- base disorder of >2 tell you

A

Metabolic acidosis with co-existing metabolic alkalosis

or a compensated respiratory acidosis

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65
Q

How many molecules of ATP does one cycle of the Kreb’s cycle produce

A

15

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66
Q

Describe what the relative refractory period is in the cardiac myocyte action potential

A

The Na+ channels can’t be re-activated until they have returned to their resting potential to avoid tetany. Na+ channels start to reach this point at phase 3 and fully reach it by phase 4. In phase 3 a supra maximal stimulus may trigger an action potential as some of the Na+ channels are available already.

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67
Q

Why should tracheostomy tube cuff pressure be kept between 20-25mmHg

A

Excessive cuff pressure can compromise blood flow to tracheal mucosa by branches of the inferior thyroid artery.

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68
Q

What are the signs of anterior spinal cord syndrome

A
  • Bilateral loss of temperature and pain sensation.
  • Complete motor paralysis. - Proprioception intact (dorsal columns supplied by posterior spinal artery)
  • Caused by damage/occlusion to anterior spinal artery.
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69
Q

What are the signs of posterior spinal cord syndrome

A

Bilateral loss of proprioception and vibration sense. Pain and temperature sensation intact. Caused by damage to posterior spinal artery.

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70
Q

Which artery is affected in locked-in syndrome

A

Basilar artery

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71
Q

Where is the narrowest part in a child’s airway

A

At the level of the cricoid cartilage

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72
Q

Describe temperature control of hypothalamus

A

Posterior hypothalamus sets temperature set point and responds to cold stimulus. Acetylcholine Is main neurotransmitter.

Anterior hypothalamus senses warming of blood. Main neurotransmitters include dopamine, 5HTP, norepinephrine, prostaglandins

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73
Q

What are cold receptors in the skin also known as

A

Bulbs of krause

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74
Q

What are warm receptors in the skin also known as

A

Bulbs of Ruffini

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75
Q

Describe the Gibbs- Donnan effect

A

The Gibbs-Donnan effect is the unequal distribution of charged permeant ions across a semi-permeable membrane due to the effect of presence of charged unpermeant ions.

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76
Q

Damage to which nerve during radical mastectomy causes winging of the scapula

A

Long thoracic nerve C5, C6, C7

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77
Q

Mutation of which gene causes primary polycythaemia

A

JAK2

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78
Q

What are the levels of neuromuscular blockade

A

Complete (PTC = 0)
Deep (PTC >=1 TOF count 0)
Moderate (TOF count 1-3)
Shallow block ( TOF count 4, TOF ratio < 0.4)
Minimal block (TOF count 4, TOF ratio 0.4-0.9)
Acceptable recovery (TOF ratio >0.9)

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79
Q

Give signs and symptoms of hypermagnesemia

A

ECG: Prolonger PR and wide QRS. In severe cases complete heart block
Hyporeflexia
Double vision
nausea and vomiting
Respiratory depression

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79
Q

How do you calculate osmolality

A

Osmolality = Glucose + urea + 2(Na+)

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80
Q

What is normal serum osmolality in mOsmol/kg

A

280-305 mOsmol/kg

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81
Q

Define Pasteur point

A

The partial pressure of oxygen at which oxidative phosphorylation ceases.

Around 1mmHg

(mitochondria no longer able to carry out aerobic respiration)

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82
Q

How can a fast insufflation rate of intra-abdominal CO2 cause bradycardia

A

Peritoneal stretch receptors trigger vagal response causing increased parasympathetic and reduces sympathetic drive to heart.

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83
Q

Describe ventilation and perfusion in West zone 1 of lung

A

Apical alveoli are more distended here and have high intra-alveolar pressure which compresses blood vessels.

Good ventilation
Poor perfusion
High V/Q (deadspace)

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84
Q

Describe ventilation and perfusion in West zone 3 of lung

A

Alveoli at lung bases are compressed due to weight of lung (gravity). The venous pressure is higher than alveolar pressure.

Poor ventilation
Good perfusion
Low V/Q (shunt)

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85
Q

Describe ventilation and perfusion in West zone 2 of lung

A

Alveolar pressure is lower than arterial pressure but higher than venous pressure. This are has optimal V/Q matching

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86
Q

What is the resting membrane potential of a cardiac myocyte

A

-90mV

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87
Q

What is the resting membrane potential of the SAN

A

-60mV

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88
Q

At what level does the spinal cord terminate and become cauda equina in adults

A

L1

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89
Q

Why can glycosuria be normal in pregnancy

A

During pregnancy there is increased renal vasodilation causing GFR and renal blood flow to increase. This reduces threshold for glucose to be filtered out.

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90
Q

What is the chemotactic trigger zone also known as

A

Area postrema

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91
Q

Which drug is used to treat MuSK (muscle specific tyrosine kinase) myasthenia gravis

A

Rituximab

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92
Q

Where is aldosterone secreted

A

Zona glomerulosa in adrenal cortex

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93
Q

How does aldosterone act on the kidney

A

Acts on ENaC coupled channel in principal cells of DCT. This causes increased Na+ reabsorption and increased K+ excretion.

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94
Q

Which Aquaporins are present in descending loop of Henlé

A

AQP1

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95
Q

Which Aquaporins are always present in basement membrane of loop collecting duct

A

AQP3 and AQP4

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96
Q

Which Aquaporins are inserted into tubular cell wall of collecting duct in response to ADH

A

AQP2

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97
Q

Where are V2 (vasopressin) receptors found

A

Collecting duct of nephrons.

Trigger AQP2 insertion into luminal membrane

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98
Q

Where are V1 (vasopressin) receptors found

A

peripheral arterioles

Cause vasoconstriction

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99
Q

Where are V3 (vasopressin) receptors found

A

CNS

Trigger ACTH release

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100
Q

What effect does ANP have on kidneys

A

Promotes Na+ and H20 excretion.

Increases GFR by causing vasodilation of afferent renal arteriole and efferent arteriole vasoconstriction.

Inhibits renin and aldosterone release

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101
Q

What is the Cockcroft-Gault equation

A

Equation used to estimate creatinine clearance

(140-age) x lean body weight) / (Creatinine (mg/l) X 72)

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102
Q

Why does Uncal herniation cause fixed dilated pupils

A

Parasympathetic nuclei in the midbrain become compressed causing unopposed sympathetic enervation to Iris causing dilation and loss of light reflex.

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103
Q

What is the formula for Cerebral Perfusion Pressure (CPP)

A

Cerebral perfusion pressure = MAP - ICP/CVP (Whichever is higher)

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104
Q

Outline CSF flow

A

Produced by ependymal cells in choroid plexus in lateral ventricle.

Flows through foramen of Monroe into 3rd Ventricle

Flows through aqueduct of Sylvius into 4th Ventricle

Flows through foramen of magendie into cisterna magna to supply spinal cord

Also flows through and foramen of Luschka into subarachnoid space to supply brain

Re-absorbed by arachnoid vili.

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105
Q

Define Huffner’s constant

A

The volume of oxygen that can be bound to 1g of adult Hb.

1.34

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106
Q

What is the formula for arterial oxygen content

A

Arterial oxygen content = [Hb x Sa02 X 1.34] + [0.003 X PaO2]

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107
Q

Define pulmonary hypertension

A

Pulmonary artery systolic pressure > 30mmHg or mean pressure > 20mmHgh.

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108
Q

How is anion gap calculated

A

anion gap =
(Na+ + K+) - (Cl- + HC03-)

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109
Q

Give 8 causes of raised anion gap metabolic acidosis

A

MUDPILES

Metformin
Urea
DKA
Paracetamol
Isoniazid
Lactate
Ethylene glycol
Salicilate

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110
Q

Describe features of Type Ia sensory nerve fibres

A
  • Primary afferent sensory fibres for stretch receptors in muscle known as muscle spindle
  • Myelinated large diameter
  • fast conduction speeds 80- 120 m/s
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111
Q

Describe features of Type Ib nerve fibres

A
  • Primary afferent sensory fibres for stretch receptors in muscle known as Golgi tendon organ
  • Myelinated large diameter
  • fast conduction speeds 80- 120 m/s
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112
Q

Describe Golgi Tendon Reflex

A

An inhibitory reflex stimulated by stretch of Golgi tendon organ in muscle.

Synapse in Doral columns with interneurons that inhibit the same muscle contraction or cause contraction of antagonising muscle.

Avoids over stretching muscle

Uses Type 1b afferent nerve fibres

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113
Q

Describe features of Type II nerve fibres

A

Primary afferent sensory fibres for cutaneous mechanoreceptors in skin

Myelinated

Fast conduction speeds

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114
Q

Describe features of Type III nerve fibres

A

(aka Type A-delta) Primary afferent sensory fibres for nociceptors. Temperature and sharp pain sensation.

Lightly myelinated

Moderate conduction speeds

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115
Q

Describe features of Type B nerve fibres

A

Preganglionic autonomic nerve fibres

lightly myelinated

smaller diameter than type A nerves and slower conduction speeds

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116
Q

Describe features of Type C nerve fibres

A

Primary afferent sensory fibres for pain and temperature sensation

Unmyelinated

Slow conducting speed

Responsible for neuropathic pain. Poorly localised

E.G DOMS

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117
Q

rupture of aneurysm of which artery is most commonly implicated in subarachnoid haemorrhage

A

Anterior communicating artery

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118
Q

What is the Anrep effect

A

Increased after load causes increased contractility of the heart

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119
Q

What is the Bowditch effect

A

Increased heart rate causes increased contractility of the heart

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120
Q

Describe double Bohr effect

A

CO2 in foetal blood diffuses down its concentration gradient into maternal circulation at placenta. Lower CO2 shifts oxygen dissociation curve to left increasing affinity of Hb for oxygen

Loss of CO2 makes foetal blood relatively more alkaline which shifts oxygen dissociation curve to the left. Increasing Hb affinity for oxygen

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121
Q

What are the 5 parts of the brachial plexus

A

RTDCB - Read that damn cadaver book

Roots
Trunks
Divisions
Cords
Branches

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122
Q

Which part of the brachial plexus is blocked during inter scalene block

A

Trunks

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123
Q

Define abdominal compartment syndrome

A

Intra-abdominal pressure >20mmHg with organ compromise

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124
Q

How can abdominal compartment syndrome cause acute renal failure

A

Reduced renal arterial pressure due to compression of great vessels

Increased pressure causes renal outflow obstruction which causes back pressure.

Reduces filtration gradient in glomerulus

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125
Q

How do you calculate target tidal volume when ventilating a patient

A

Ideal body weight X 6ml/kg

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126
Q

What is the saturated vapour pressure of water at 37C

A

6.3kPa

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127
Q

What is the diagnostic criteria for ARDS

A

1- Acute onset with identifiable condition
2- Bilateral pulmonary infiltrates + oedema on XR
3- Pulmonary wedge pressure <18 mmHg
4- Reduced PaO2/FiO2 ratio

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128
Q

Give 4 conditions associated with a Transudative pleural effusion

A

CCF
Liver cirrhosis
Nephrotic syndrome
Severe hypoalbuminaemia

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129
Q

Give 4 conditions associated with a exudative pleural effusion

A

Malginancy
Infection - empyema
P.E
Pulmonary infarction
Trauma

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130
Q

Describe Light’s criteria for pleural effusions

A

Pleural fluid is considered an exudate if any of the following are present:

1- The ratio of pleural fluid to serum protein is greater than 0.5

2-The ratio of pleural fluid to serum LDH is greater than 0.6

3- The pleural fluid LDH value is greater than two-thirds of the upper limit of the normal serum value

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131
Q

Describe the Bainbridge reflex

A

Increase in heart rate in response to increased venous return to right atrium in high volume states. Triggered by atrial stretch receptors

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132
Q

At how many weeks gestation does surfactant production begin

A

20 weeks

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133
Q

At how many weeks gestation does surfactant production reach an adequate level

A

35 weeks

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134
Q

What is the L:S (Lecithin: sphingomyelin) ratio in mature foetal lungs

A

2

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135
Q

What is the L:S (Lecithin: sphingomyelin) ratio in immature foetal lungs

A

<2

136
Q

What is the purpose of surfactant

A

Reduce alveolar surface tension

137
Q

Outline puppilary reflex

A

Afferent nerve CNII carries action potential to pretectal nucleus in brain. Nasal fibres decussate at optic chiasm on the way

From pretectal nucleus afferent nerves go to Edinger westphal nucleus.

Parasympathetic fibres of CNIII go to Cilliary ganglion. From here 2 efferent limbs to puppilary muscle- 1 ipsilateral and 1 contrallateral

Causes Miosis in response to light

138
Q

List endogenous compounds that are metabolised by the lungs

A

Bradykinin
Noradrenaline
Adenosine
Serotonin (5HTP)
PGE2
Leukotrienes

139
Q

Name a hormone that is activated in the lungs

A

Angiotensin 1 to angiotensin 2

140
Q

Which nerve fibres enter via Dorsal ramus

A

Sensory nerves from skin
Motor nerves to deep muscles of the back

141
Q

Which nerve fibres enter via Ventral ramus

A

Mainly motor nerves

142
Q

Which nerve roots make up the Cervical plexus

A

C1-C4

143
Q

Which nerve roots make up the Brachial plexus

A

C5-T1

144
Q

Which nerve roots make up the Lumbar plexus

A

L1-L4

145
Q

Which nerve roots make up the Sacral plexus

A

L4-S4

146
Q

Define allodynia

A

Pain sensation from a stimulus that does not normally cause pain

147
Q

How do you manage patients with adrenal insufficiency during major surgery

A

100mg hydrocortisone intra-operatively

200mg in 24hr infusion post operatively

148
Q

How do you calculate Cerebral Perfussion Pressure (CPP)

A

CPP = MAC - ICP or CVP (whichever is highest)

149
Q

What is the target range of cerebral percussion pressure (CPP) in traumatic head injury?

A

50-70mmHg

150
Q

Summarise central chemoreceptors that control breathing

A
  • Found on ventral surface of medulla
  • Stimulated by increased H+ ions in CSF (indirectly by increased CO2)
151
Q

What are the 2 types of peripheral chemoreceptors and which nerves are their afferents

A

Aortic bodies- Vagal afferents

Carotid bodies- glossopharyngeal afferents

(Both sense increased PCO2, increased H+ AND LOW PO2)

152
Q

What proportion of renal blood flow goes to medulla and cortex

A

Cortex 90%
Medulla 10%

153
Q

Name the capillaries that run along the loop of Henle into the medulla of the kidney

A

vasa recta

154
Q

Which technique uses nitrous oxide inhalation to estimate cerebral blood flow

A

Kety-Schmidt technique

Inhale 10% Nitrous oxide for 10 minutes and measure jugular venous concentration which is assumed to be the same as cerebral conc.

155
Q

Does ICP affect rate of CSF production

A

No

CSF production is indépendant of ICP

156
Q

What volume of CSF is produced in one day

A

500ml

157
Q

Where is CSF absorbed

A

Dural venous sinuses via arachnoid vili

158
Q

What conc. of K+ is normal in CSF

A

2.5-3.5mmol/L

159
Q

What conc. of glucose is normal in CSF

A

2.7-4.2 mmol/L

160
Q

Which 2 ions are found at a higher conc. in CSF compared to plasma

A

Magnesium and Chloride

161
Q

What is the formula to calculate pH

A

pH = - Log(H+)

162
Q

Describe the Haldane effect

A

Haemoglobin can carry increased amounts of CO2 in its deoxygenated compared to oxygenated state

(Venous blood carries more CO2)

This is because Carbon dioxide binds to amino groups of Hb forming carbamino compounds. But oxygen reduced Hbs affinity to bind CO2.

163
Q

Describe the Bohr effect

A

Affinity of Hb for oxygen decreases in acidic pH or high CO2

Haemoglobin buffers H+ ions by dissociating oxygen to bind H+ ions. Therefore increased acidity causes reduced oxygen affinity and right shift of oxygen dissociation curve

164
Q

What is the normal anion gap range

A

8-16mmol/L

165
Q

What effect does hypoalbuminaemia have on calculated anion gap

A

Under-estimates anion gap

metabolic acidosis could be due to lactic acidosis or DKA despite normal anion gap

166
Q

List 4 causes of normal anion gap metabolic acidosis

A

ABCD

Addisons
Bicarbonate loss ( GI tract/ renal)
Chloride excess (lots of NaCL fluids)
Diuretics (acetazolamide)

167
Q

What is the pKa of carbonic anhydrase

A

6.1

168
Q

Where is the majority of HC03- Reabsorbed in the kidney

A

PCT

169
Q

List the fat soluble vitamins

A

ADEK

Vitamin A, D, E, K

170
Q

Outline the swallowing reflex

A
  • Food is voluntarily pushed into pharynx by raising tongue
  • Swallowing receptors (in tonsil pillars) in pharynx trigger autonomic pharyngeal muscle contractions
  • Soft palate elevates to stop food entering nasal cavity
  • Palatopharyngeal folds pull medially so well masticated food can pass posteriorly
  • Vocal cords close and epiglottis pulls upwards by neck muscles
  • Upper pharyngeal sphincter relaxes to allow masticated food to enter oesophagus
171
Q

Where is calcitriol produced

A

PCT of nephrons

172
Q

Where is calcitonin produced?

A

Parafollicular cells (C-cells) of thyroid gland

173
Q

Where is glucagon produced

A

alpha cells in pancreas

174
Q

Where is CCK produced

A

Duodenal mucosal cells

175
Q

Where are oxytocin and ADH released from

A

Posterior pituitary

176
Q

Which hormones are released from anterior pituitary

A

GH
prolactin
ACTH
MSH (melanocyte stimulating hormone)
TSH
FSH
LH

177
Q

How many molecules of oxygen can be carried by one Hb

A

4

178
Q

Describe cooperative binding in Hb

A

Binding to first molecule of oxygen causes change in shape of Hb which increases its affinity for further oxygen binding of the other globing chains

179
Q

Which glial cells make up the blood brain barrier (BBB)

A

Astrocytes

180
Q

Which lung volumes can’t be measured with a spirometer

A

FRC
Total lung capacity
residual volume

181
Q

How can FRC be measured

A

Helium dilution
Body plethysmograph

182
Q

Which method is used to measure anatomical dead space

A

Fowler’s method

Breathing in 100% oxygen and exhaled gas analysed by nitrogen analyser. As deadspace slowly replaced with oxygen the nitrogen volume increases until a plateau is reached.

183
Q

Which method is used to measure physiological dead space

A

Bohr’s method

184
Q
A
185
Q

Which glial cells are the macrophages of the central nervous system

A

Microglia

186
Q

Which glial cells insulate neurones in the CNS

A

Oligodendrocytes

187
Q

Which glial cells insulate neurones in the peripheral nervous system

A

Schwann cells

188
Q

Which glial cells form an epithelial layer that lines the ventricles and central canal of spinal cord

A

Ependymal cells

189
Q

What is another name for the cell body of a neurone

A

Soma

190
Q

What is the function of dendrite in a neuronal cell

A

Receive information from other cells

191
Q

What is the resting potential of a neuronal cell

A

-70mV

192
Q

What is meant by saltatory conduction

A

Saltatory conduction is the propagation of action potentials along myelinated axons from one node of Ranvier to another.

Depolarisation only occurs at nodes of Ranvier which speeds up the transmission of the AP

193
Q

What are the signs of spinal cord hemisection (Brown Squared syndrome)

A

Ipsilateral motor and proprioception loss

Contralateral loss of pain and temperature sensation

194
Q

What are the signs of complete cord transection

A

Loss of motor function and sensation below level of injury

  • Some reflexes recover and can become hyperactive
195
Q

What are the signs of central cord syndrome

A

Motor impairment worse than sensory loss

upper limbs and distal muscles more affected than lower limbs and proximal muscles

196
Q

What can cause central cord syndrome

A

Trauma that causes hyper extension of neck

Especially in elderly patients with narrow spinal cord e.g spinal canal stenosis or spondylosis

197
Q

At which level does the sympathetic trunk start and end

A

T1- L2/3

198
Q

Which artery supplies the anterior 2/3 of spinal cord

A

Anterior spinal artery

199
Q

Which arteries supplies the posterior 1/3 of spinal cord

A

2 X posterior spinal arteries

200
Q

What is the role of the radicular arteries in the spine

A

Support blood supply to spinal cord by feeding into anterior and posterior arteries

201
Q

Which artery is a major contribution to the blood supply of the lower 2/3rds of the spinal cord

A

Artery of Adamkiewicz ( arteria radicularis manga)

202
Q

At what level does the artery of Adamkiewicz arise

A

T11- L3

203
Q

How many pairs of spinal nerves are there

A

31

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

204
Q

List the ascending spinal tracts

A

Dorsal columns
Lateral spinothalamic
Anterior spinothalamic
Anterior spinocerebellar
posterior spinocerebellar

205
Q

List the descending spinal tracts

A

Lateral corticospinal
Anterior corticospinal
Rubrospinal
tectospinal
reticulospinal
Vestibulospinal

206
Q

What is the role of Dorsal columns

A

Ascending tract for fine touch and proprioception

207
Q

What is the role of anterior spinothalamic tract

A

Ascending tract for crude touch and pressure sensation

208
Q

What is the role of lateral spinothalamic tract

A

Ascending tract for pain and temperature sensation

209
Q

What is the role of lateral spinocerebellar tract

A

Ascending tract for proprioception

210
Q

In which part of the dorsal columns do nerves from below the level of T6 travel

A

Medial part known as Gracile fascicle

211
Q

In which part of the dorsal columns do nerves from above the level of T6 travel

A

Lateral part known as Cuneate fascicle

212
Q

Where no neurones in dorsal columns decussate

A

Medulla

213
Q

Where do neurones in spinothalamic tracts decussate

A

At level where afferent 1st order neurone enters spinal cord

214
Q

Explain the decussation of corticospinal tracts

A

80% decussate at medulla to form lateral corticospinal tract

20% do not decussate and form the anterior corticospinal tract

215
Q

Which reflex is monosynaptic

A

Stretch reflexes e.g bicep or patella tendon

216
Q

Which spinal reflex is polysynaptic

A

Withdrawel reflex

Sensory nerve from receptor synapses with interneurone in spinal cord which synapses with motor neurone to effector organ (muscle)

217
Q

Which arteries is the basilar artery formed from

A

Left and Right vertebral artery

218
Q

Which artery supplies the posterior cerebral hemisphere and brainstem

A

Basilar artery

219
Q

What is the normal range of MAP under which cerebral blood flow is controlled by auto regulation

A

50-150 mmHg

220
Q

How does hypothermia affect cerebral blood flow?

A

In hypothermia metabolic activity in the brain reduces which reduces blood flow due to flow metabolism coupling

221
Q

How does a low PaCO2 affect cerebral blood flow

A

Causes vasoconstriction and reduced cerebral blood flow

222
Q

List 4 circumventricular organs

A

Choroid plexus
Posterior pituitary gland
Area Postrema
Pineal gland

223
Q

List 5 functions of CSF

A

1 Protect brain from trauma
2 Support weight of the brain by CSF buoyancy
3 Respiratory control via acid-base
4 Ionic homeostasis
5 Nutrition for brain tissue

224
Q

Which intrinsic muscle of the larynx is innervated by Superior Laryngeal Nerve (SLN)

A

Cricothyroid

225
Q

List the 5 intrinsic muscles of the Larynx

A

Cricothyroid
Cricoarytenoideus
Aretynoideus
Thyroaretynoideus
Thyroepiglotticus

226
Q

What happens in unilateral recurrent laryngeal nerve injury

A

Hoarseness of voice and weak cough

227
Q

What happens in bilateral recurrent laryngeal nerve injury

A

Airway obstruction or horseness of voice

(Partial injury to RLN causes more adduction of vocal cord than complete)

228
Q

Does compliance increase or decrease with age

A

Increases

229
Q

What term is used to describe how compliance varies during inspiration and expiration on a lung compliance curve

A

Hysteresis

230
Q

How does closing capacity change as a percentage of vital capacity with age

A

Young healthy person CC is 10% of vital capacity

Patient > 65 years old CC is about 40% of VC

231
Q

What happens when closing capacity is equal to FRC

A

Airway closure

Occurs in neonates and infants

40 year olds when supine

> 65 year old when standing

232
Q

How is closing capacity measured

A

Helium dilution + Fowler’s method

Phase 1: Dead space gas with no helium

Phase 2: Mixed dead space and alveolar gas with increasing helium conc.

Phase 3: Plateau of just alveolar gas containing fixed conc. helium

Phase 4: Closing volume reached, Helium conc. increases further as airways closed

233
Q

Which metabolic reaction causes production of 2,3 DPG

A

Glycolysis

234
Q

Why does stored blood’s p50 lie to the left on oxygen dissociation curve compared to normal blood

A

No 2,3 DPG in stored blood

235
Q

What does a huge V wave on CVP monitoring suggest

A

Tricuspid regurgitation

236
Q

What is the minimum MAP required to maintain auto regulation of renal blood flow to maintain constant GFR

A

MAP > 80

237
Q

Where in the kidney is aldosterone produced

A

Zona Glomerulosa

238
Q

When in the day is aldosterone release highest

A

Morning

239
Q

What does an increased strong ion difference mean in terms of Stewart’s theory of acid-base

A

Increased strong ion difference (SID) = gain of strong cations (Na+ / K+) or loss of strong anions (Cl-) this causes alkalosis

240
Q

What does a reduction in strong ion difference mean in terms of Stewart’s theory of acid-base

A

Reduced strong ion difference (SID) = loss of strong cations (Na+ / K+) or gain of strong anions (Cl-) this causes acidosis

241
Q

Which metabolic disturbance is seen in Aspirin overdose

A

Initial respiratory alkalosis followed by metabolic acidosis

242
Q

What effect does Gastrin have on gastric emptying

A

Increases gastric emptying by increasing pyloric pumping force

243
Q

Which enzyme is deficient in Gilbert’s disease

A

Glucoronyl transferase

(responsible for conjugation of bilirubin)

244
Q

Explain why post hepatic jaundice causes dark urine and pale stools

A

Increased levels of conjugated bilirubin enter blood due to not being able to drain into intestine where bacteria break it down. More filtered into urine causing dark urine.

Intestines break down conjugated bilirubin into stercobilinogen then oxidised to stercobilin which gives faeces brown colour. Absence of this causes pale stools.

245
Q

How can you calculate an estimate for osmolality

A

Osmolality = 2(Na+) + Urea + Glucose

246
Q

How is post dural puncture headache managed in first 24 hours

A

Supportive Mx- Hydration and simple analgesia e.g paracetamol

247
Q

what is the gold standard management of post dural puncture headache post 24 hours

A

Epidural blood patch

248
Q

What is the flow rate of a 14G cannula

A

360mL/min

249
Q

Which drugs can be used to increase heart rate in a transplanted heart

A

Direct acting Beta agonist drugs- Noradrenaline, adrenaline, isoprenaline

(Transplanted hearts are denervated so need direct acting catecholamines that act on SAN)

250
Q

Which physiological parameters must be checked to exclude reversible causes when doing brainstem testing

A

Na+ 115-160
Glucose 3- 20
PO2 >10kPa
temperature >34

251
Q

Why is the vocal cord more adducted in partial laryngeal nerve injury than complete

A

Recurrent laryngeal nerve supplies abductors more than adductors. During partial injury abductors are affected more than adductors.

252
Q

Which SOFA score defines sepsis

A

Sequential organ failure assessment (SOFA) score of 2 or more

253
Q

What causes the 4th heart sound

A

When during atrial systole blood hits into a non compliant left ventricle

e.g in aortic stenosis, hypertrophic cardiomyopathy

254
Q

What causes the 3rd heart sound

A

Blood flowing rapidly into the relaxing ventricles during early diastole.

Congestive cardiac failure

255
Q

What is the role of T-tubule in sarcomere

A

Extension of sarcolemma (cell membrane) that invaginates into sarcomere to transmit AP to Dihydropiridine receptor of sarcoplasmic reticulum where calcium is released

256
Q

What blocks the actin- binding site when a myocyte is at rest

A

Tropomyosin

257
Q

What does calcium bind to during myocyte contraction to cause the tropomyosin to move away from actin binding site

A

Troponin C

258
Q

What binds on the actin binding site to cause cardiac muscle contraction

A

Myosin head

259
Q

What determines the force of contraction of cardiac myocyte

A

Number of cross bridges formed - this depends on free calcium conc.

260
Q

Outline the stages of skeletal muscle contraction

A
  • AP reaches sarcomere and spreads down into T-tubules
  • Conformational change in DHP receptor on sarcoplastic reticulum
  • DHP receptor interacts with Ryanodine receptor on SR
  • Calcium induced calcium release
  • Calcium binds to troponin C
  • Troponin C moves tropomyosin out of the way so it no longer covers actin binding site
  • Myosin head binds to actin binding site and pivots to pull the actin and myosin over each other
  • Na+/Ca2+ exchange pump moves Ca2+ back into SR
  • ATP binds to myosin causing it to release from actin
261
Q

Which cranial nerve is the afferent fibre for the baroreceptors in carotid sinus

A

Glossopharyngeal (CN IX)

262
Q

Which cranial nerve is the afferent fibre for the baroreceptors in aortic arch

A

Vagus (CN X)

263
Q

What effect does adenosine have on smooth muscle

A

Causes vasodilation by reducing calcium influx

264
Q

What effect does prostaglandin E and prostacyclin have on vascular smooth muscle

A

Both are vasodilators

265
Q

How does Anti natriutic peptide (ANP) control ECV and Na+ conc.

A

ANP is released from atria in response to increased stretch of the wall during high volume state

ANP binds to receptors in collecting duct causing increased NA+ and water exertion

266
Q

Are lungs more or less compliant during inspiration compared to expiration

A

Less compliant during inspiration

267
Q

What is a normal volume for FRC

A

2.5-3L

268
Q

What effect does exercise have on pulmonary vascular resistance (PVR)

A

Reduces PVR

269
Q

What is the equation for Systemic vascular resistance (SVR)

A

SVR = (MAP-CVP)/CO X 80

270
Q

Which units are used to measure SVR

A

Dynes.s/cm5

271
Q

What does the Pentose phosphate shunt produce

A

NADPH

272
Q

Which cells produce calcitonin in the thyroid

A

Parafollicular cells

273
Q

What percentage protein bound is T3 and T4

A

99% bound to thyroxine-binding globulin

274
Q

Which adrenal cells are affected in pheochromocytoma

A

Chromafin cells

275
Q

Which drug can be used to manage carcinoid syndrome

A

Octreotide

276
Q

What causes secretin release

A

S cells in the duodenum release secretin in response to low pH (acid) and fat

277
Q

What is the effect of secretin on the pancreas

A

Causes increase in volume of pancreatic juices and HCO3- content

278
Q

What causes release of CCK

A

I cells in duodenum release CCK in response to fatty acids and protein

279
Q

What are the functions of CCK

A

Stimulates Acinar cells in pancreas to release more enzyme into pancreatic juice

Stimulates increased bile production and gall bladder contraction

Increases satiety

280
Q

What is the normal volume of CSF

A

150ml

281
Q

What effect does sympathetic stimulation have on detrusor muscle

A

Causes relaxation and urine retention

282
Q

What effect does parasympathetic stimulation have on detrusor muscle

A

Causes muscle contraction and micturition

283
Q

Which of the external and internal urinary sphincter is innervated by the pudendal nerve S2-4

A

External urinary spincter- this is under voluntary control

284
Q

How do you calculate maintenance fluids for children

A

4-2-1 rule

4ml/kg/hr for first 10kg
2ml/kg/hr for next 10kg
1ml/kg/hr for any weight after that

285
Q

How do you calculate fluid deficit in children

A

Fluid deficit = weight x %dehydration x 10

signs of 5-10% dehydration
- Reduced skin turgor, sunken eyes, tachycardia, tachypnoea, reduced UO

Signs of >10% dehydration
Skin mottled, deeply sunken eyes, markedly increased HR, RR and markedly reduced UO

286
Q

Explain how an intra-aortic balloon pump works

A

IABP inserted via femoral artery and up to descending aorta.

IABP inflates during diastole to increase coronary perfussion pressure

Deflates during systole which reduces after load

287
Q

How is FRC measured

A

Helium dilution
Body Pletysmograph

288
Q

Which gas is used in diffusion capacity testing of the lung

A

CO

carbon monoxide

289
Q

Where in the kidney is Adenosine released

A

Macula densa

290
Q

What effect does Adenosine have on renal blood flow

A

Baseline level of constriction of afferent arteriole

Reduced Adenosine release in response to reduced GFR causes less consctriction of afferent arteriole and increased GFR

291
Q

What effect does PGE2 have on renal blood flow

A

Dilated afferent arteriole to increase GFR

292
Q

Where is PGE2 released in nephron

A

DCT

293
Q

Why can NSAIDs cause reduction in GFR

A

NSAIDS inhibit PGE2 which is responsible for dilation of afferent arteriole in bowmen’s capsule

294
Q

What effect does angiotensin II have on GFR

A

Causes constriction of efferent arteriole to increase GFR

295
Q

What is the main excitatory neurotransmitter for painful stimulus where Aδ neurone synapses with second order neurone

A

Glutamate

296
Q

What are the main Inhibitory neurotransmitters for painful stimulus where Aδ neurone synapses with second order neurone

A

Gamma-amino butyric acid (GABA)

Glycine

297
Q

At what plasma conc. of Glucose do you start to get glycosuria

A

10mmol/L

298
Q

What proportion of filtered urea is reabsorbed

A

50%

299
Q

What effect does acidosis have on k+ excretion from the kidney

A

Reduced k+ excretion

300
Q

What effect does alkalosis have on k+ excretion from the kidney

A

Increased k+ excretion

301
Q

What effect does supine position have on FRC

A

Reduces FRC

302
Q

What effect does a general anaesthetic have on FRC

A

Reduces FRC

303
Q

Who has a greater FRC men or women

A

Men

304
Q

What effect does a exercise have on FRC

A

Increases FRC

305
Q

Define venous admixture

A

The amount of mixed venous blood which would have to be added to ideal pulmonary end-capillary blood to explain the observed difference between pulmonary end-capillary PO2 and arterial PO2

(Basically a volume of venous deoxygenated blood that appears to have bypassed the lungs (shunted) which has causes a lower than expected arterial PO2)

306
Q

What is the Chloride shift in red blood cells

A

When HCO3- leaves red cells CL- enters red cells to maintain electric neutrality

307
Q

Where in the stomach are chief cells found

A

Fundus

308
Q

What is the effect of secretin on the stomach

A

Inhibits gastric acid secretion

309
Q

What is the role of ADH in platelets

A

ADH has a role in platelet aggregation.

Stored in dense granules in platelet.

Binds to P2Y12 receptor on platelet causing platelet aggregation

310
Q

What is the mnemonic WET FLAG for paediatric emergencies

A

W eight (age+4) X 2
E nergy 4 x weight (energy for defib)
T ube age / 4 + 4
FL uids 20ml/kg bolus NS
A drenaline 0.1ml/kg of 1:10,000
G lucose 2ml/kg of 10% glucose

311
Q

What are the main differences in signs of neuroleptic malignant syndrome and serotonin syndrome

A

Serotonin syndrome has hyperreflexia and clonus whereas NMS has more pronounced rigidity known as lead pipe rigidity

312
Q

What is the risk of using Suxamethonium in patients with Neuromuscular disorders

A

May cause hyperkalaemia by recruiting extra-junctional Ach receptors

313
Q

What do gamma cells of the pancreas release

A

Pancreatic polypeptides

314
Q

What do Epsilon cells of the pancreas release

A

Ghrelin

315
Q

Describe the differences between type 1, type 2a and type 2b muscle fibres

A

Type 1: Slow contracting slow to fatigue, use aerobic respiration, fine movements, more mitochondria, contain more myoglobulin

Type 2a: Fast twitch, intermediate motor units, anaerobic, intermediate myoglobin

Type 2b: Fast twitch, large motor units, anaerobic, low myoglobin, high glycolytic capacity late recruitment

316
Q

How long before brainstem testing must sedatives and neuromuscular blocking drugs be held

A

48 hours

317
Q

Which cranial nerve reflexes are tested during brainstem testing

A

Pupillary reflex (CNII + CNIII)
Corneal reflex (CNV + CNVII (blink))
Pain response (pressure on supraorbital notch)
Gag reflex (CNIX + CNX)
Cough reflex( CNX- Stimulate carina with suction)

318
Q

Which 2 tests need to be carried out twice before determining brainstem death

A

Cranial nerve testing
Apnoea test

319
Q

Which ECG lead configuration is used to detect left ventricular ischaemia

A

CM5

320
Q

Describe closing capacity in the lungs

A

Closing capacity is the volume at which airway closure starts.

Closing capacity = closing volume + residual volume

Normally smaller than FRC so airway closure does not occur during tidal volume breaths

321
Q

What effect does pH have on pulmonary vascular resistance (PVR)

A

PVR decreases with more alkaline blood (increased pH)

322
Q

What effect does PaCO2 have on pulmonary vascular resistance (PVR)

A

Increased PaCO2 increases PVR

323
Q

What effect does Angiotensin have on pulmonary vascular resistance (PVR)

A

Angiotensin increases PVR by causing vasoconstriction

324
Q

What effect does Prostacyclin have on pulmonary vascular resistance (PVR)

A

Prostacyclin decreases PVR due to vasodilating effect

325
Q

What effect do volatile anaesthetic agents have on pulmonary vascular resistance (PVR)

A

All volatile anaesthetic agents reduce PVR

326
Q

What is the formula for Oxygen Flux

A

DO2 = CO X (( Hb X Sa02 X 1.34) + (PaO2 X 0.003))

DO2 = CO X Arterial oxygen content

327
Q

Which Ion Is exchanged to secrete H+ into the filtrate of the PCT

A

Na+ is reabsorbed out of filtrate in exchange for H+ which is secreted into the filtrate

328
Q

What is the function of Aα nerve fibres

A

Motor nerves to muscles and proprioception

329
Q

What is the function of Aβ nerve fibres

A

Touch and pressure sensation

330
Q

What is the function of Aγ nerve fibres

A

Innervate muscle spindles which are stretch receptors that detect changes in the length of a muscle

331
Q

What is the function of Aδ nerve fibres

A

Sharp pain sensation
Temperature sensation

332
Q

What are the 4 factors in Apfel score for PONV

A

Female gender
Previous PONV or motion sickness
Opiate use
Non-smoker

333
Q

What effect does Calcitonin have on plasma calcium levels

A

Reduces Calcium levels

Inhibits osteoclasts
Reduces calcium reabsorption in kidney

334
Q

What effect does PTH have on calcium

A

Increases Calcium levels

Stimulates Osteoclasts
Increases calcium reabsorption from kidney
Increases intestinal calcium reabsorption

335
Q

Why can TURP syndrome cause visual disturbances/ blindness

A

During TURP procedure high volumes of irrigation fluid are used most commonly 1.5% Glycine

Glycine causes direct depressant effects on CNS including visual disturbances

336
Q

Which calcium channel blocker can be used in cerebral vasospasm

A

Nimodipine

337
Q

How long does it take before proteolysis starts in starvation

A

24 hours

Primary FRCA MCQ (6 decks)

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