Cardio physiology

Question 1

How does acidosis cause low BP?

Answer 1

Acidosis causes relaxation of precapillary sphincter causing increased flow in capillary bed and decreased systemic BP

Question 2

Frank-Starling law

Answer 2

Increased energy causing increased contractility

Question 3

Cardiac output

Answer 3

CO = SV x HR

Question 4

Stroke volume

Answer 4

SV = EDV - ESV

Question 5

Ejection fraction

Answer 5

EJ = SV / EDV

Question 6

Normal pulse pressure

Answer 6

40mmHg

Question 7

MAP

Answer 7

MAP = diastolic + 1/3 pulse pressure

Question 8

Absent a waves

Answer 8

AF

Question 9

Large a waves

Answer 9

Pulmonary hypertension
Pulmonary stenosis

Question 10

Cannon a waves

Answer 10

Complete heart block

Question 11

Large v waves

Answer 11

Tricuspid regurgitation

Question 12

Rise in JVP on inspiration (Kussmaul’s sign)

Answer 12

Constrictive pericarditis

Question 13

Carotid body

Answer 13

Chemoreceptors
Found at bifurcation of carotids

Question 14

Carotid sinus

Answer 14

Baroreceptors
Found in adventitia of internal carotid

Question 15

% estimated blood loss

Answer 15

I - <15%
II - 15-30
III - 30-40
IV - >40

Question 16

Neurogenic shock

Answer 16

High injury
Interrupts sympathetic response - bradycardia, hypotension, hypothermia

Question 17

Spinal shock

Answer 17

Injury to cord - bruising, swelling, ischaemia
Immediate loss below injury - areflexia, flaccid paralysis

Question 18

Nerves involved in bulb-cavernosis reflex

Answer 18

S2 and S3

Question 19

Spinal injury level causing autonomic dysreflexia

Answer 19

T6 or above

Question 20

Pathophysiology of autonomic dysreflexia

Answer 20

Vasodilation above injury - flushed, bradycardia, headache
Vasoconstriction below injury - pale, cool, clammy, HTN

Question 21

Most common cervical fracture from seat belt injury

Answer 21

C2 odontoid peg

Question 22

Aortic deceleration

Answer 22

Beyond L subclavian

Question 23

Most common lumbar fracture from seat belt injury

Answer 23

L2

Question 24

Sick sinus syndrome

Answer 24

Bradycardia

Question 25

Depolarisation of cardiac cells

Answer 25

Influx of Ca 2+

Question 26

Repolarisation of cardiac cells

Answer 26

Outflux of K+

Question 27

Hyperkalaemia ECG findings

Answer 27

ST elevation Tall tented T waves Long PR Wide QRS

Question 28

Hypokalaemia ECG findings

Answer 28

Depressed ST segment Inverted T wave

Question 29

Hypercalcaemia ECG findings

Answer 29

Short QT Short ST

Question 30

Hypocalcaemia ECG findings

Answer 30

Prolonged QT Prolonged ST