Chapter 3: Shock

Question 1

Cardiac output definition

Answer 1

Stroke volume ( volume of blood ejected by the L ventricle) x HR ( ejection cycles /minute)

Question 2

What dictates stroke volume

Answer 2

Filling volume of the ventricle( preload)
Myocardial contractility (Starling’s curve)
Systemic vascular resistance ( afterload)

Question 3

What controls the HR

Answer 3

Vagus nerve and endogenous catecholamine release

Question 4

In times of stress what happens with an infant’s Cv system

Answer 4

Infants have relatively less myocardial contractility - increased cardiac output depends on increasing the HR rather than stroke volume - bradycardia is not that well tolerated in infants

Question 5

What is microcirculatory dysfunction

Answer 5

maldistribution of capillary blood flow

Question 6

By how much does hydrostatic pressure fall by in shock states

Answer 6

30-40 %

Question 7

What does endotoxin do to capillary beds during septic shock

Answer 7

Damages vascular endothelium
Damaged cells can then generate procoagulant activity - which may explain why fibrin is deposited into the microcirculation

Question 8

Norepinephrine -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 8

Stimulus - hypovolemia and head trauma
Release by sympathetic NS
Effects - vascocontriction - B1 and B2 stimulation

Question 9

Epinephrine -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 9

Stimulus - hypovolemia and hypercapnea
Release by adrenal medullae
Effects - vascocontriction - a1 and B2 stimulation

Question 10

Angiotensin II -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 10

Stimulus - hypovolemia
Release by kidneys and brain
Effects - vascocontriction

Question 11

Leukotrienes-stimulus, sources and effects as an endogenous vasoactive mediator

Answer 11

Stimulus - tumor necrosis factor
Release by macrophages
Effects - capillary permeability

Question 12

Thromboxane A2 -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 12

Stimulus - Hypoxia
Release by Platelets
Effects - Vasoconstriction and platelet aggregation

Question 13

Prostaglandins F2 -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 13

Stimulus - Hypoxia
Release by Platelets and vascular smooth muscle
Effects -Vasoconstriction

Question 14

Prostaglandins I2 -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 14

Stimulus - Hypoxia
Release by Healthy vascular endothelium
Effects -Vasodilator counterbalances thromboxane A2

Question 15

Mycocardial depressant factor -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 15

Stimulus - Ischemia/tissue damage
Release by Pancreas
Effects -Direct negative ionotropic effects

Question 16

Opiates -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 16

Stimulus - Hypoxia
Release by Pituitary
Effects -Decreased myocardial contractility, decreased sympathetic tone
Hypotension

Question 17

Inducible Nitrous Oxide -stimulus, sources and effects as an endogenous vasoactive mediator

Answer 17

Stimulus - Inflammatory cytokines
Release by Leucocytes
Effects -Vasodilation of vascular smooth muscle

Question 18

How much ATP is produced by aerobic and anerobic respiration per mole of glucose

Answer 18

2 moles compared to 38

Question 19

What are deleterious effects of anerobic metabolism

Answer 19

Depletion of glycogen stores and accumulation of lactic and associated acidosis -
Decresed ATP lead to K efflux, Na and Ca influx with water causing cells to swell