Lecture 3: How CVS fails

Question 1

What are the two types of stroke?

Answer 1

Haemorrhagic: cerebral blood vessel rupture

Ischaemic: cerebral blood vessel blockage

Question 2

What is a stroke?

Answer 2

Rapid loss of brain function due to loss of perfusion to parts of the brain

Question 3

What causes a blood vessel to burst?

Answer 3

Stresses:

• High pressure
• Turbulent flow
• Large diameter (high wall tension)
• Low compliance

Damage:

• Trauma
• Atherosclerosis
• Diabetes

Question 4

What is the relationship between vessel size and wall tension?

Answer 4

The larger the vessel the greater the wall tension

Wall tension proportional to Pxradius

Question 5

What is compliance?

Answer 5

Change in volume as a result of change in pressure

Question 6

What are the activities of the endothelium?

Answer 6

Blood vessel tone

Fluid filtration

Haemostasis

White cell recruitment

Angiogenesis

Hormone trafficking

Question 7

What is coronary artery disease?

Answer 7

Disease process resulting in obstruction of the arteries supplying the heart tissue

Symptoms: angina or asymptomatic

Cause: atherosclerosis

Question 8

What are the two forces on water in the capillary?

Answer 8

Osmotic pressure in: constant 25mmHg

Hydrostatic pressure out: varies from 32mmHg at arterial end to 12mmHg at venous end

Net goes from outward at arterial end to in at the venous end

Question 9

What causes pulmonary oedema?

Answer 9

Left heart failure

Impaired gas exchange and O2 diffusion lengthened

Symptoms: dyspnoea

Question 10

What is ascites?

Answer 10

Accumulation of fluid in the peritoneal cavity

Causes: heart failure

Question 11

What is compensation?

Answer 11

Maintaining homeostasis of a physiological function despite stressors or malfunctions – happens via endogenous physiological feedback

Question 12

What is decompensated heart failure?

Answer 12

A medical emergency

The failure of the heart to maintain adequate blood circulation, after long-standing (previously compensated) vascular disease

Respiratory distress

Question 13

What are the two types of cardiac remodelling?

Answer 13

Hypertrophy:
eccentric and concentric

Dilatation

Question 14

What is ADH?

Answer 14

Causes kidneys to reabsorb more water - decreases diuresis

From posterior pituitary

Peptide

Question 15

What is aldosterone?

Answer 15

Causes kidneys to reabsorb more NaCl - directly decreases naturesis which decreases diuresis

From adrenal cortex

Steroid

Question 16

What is angiotensin 2?

Answer 16

Causes vasoconstriction

Increases fluid retention:
increases aldosterone and ADH secretion

Contributes to ventricular hypertrophy and remodelling

Question 17

Where is angiotensinogen made?

Answer 17

Liver

Question 18

Where is renin made?

Answer 18

Kidneys

Question 19

Where is ACE made?

Answer 19

Lungs

Question 20

What are the three types of diuretics?

Answer 20

Thiazide and thiazide like: blocks reabsorption at DCT e.g. indapamide

Loop: blocks reabsorption in the thick loop e.g. furosemide

K+ sparing: inhibits aldosterone receptors in the cortical collecting duct e.g. spironolactone

Question 21

How does the SNS compensate for heart failure?

Answer 21

Increase HR and PR

Question 22

What are the signs and symptoms of heart failure?

Answer 22

Fatigue esp during exertion

Peripheral oedema

Dyspnoea

Question 23

Describe the positive feedback system that fuels cardiogenic shock.

Answer 23

Heart doesn’t pump enough, not enough blood to heart, heart doesn’t have enough nutrients to function properly, so the heart pumps even less

Question 24

What is the treatment for cardiogenic shock?

Answer 24

Aggressive IV fluid, oxygen, airway maintained

Question 25

What are the treatments for chronic heart failure?

Answer 25

ACE inhibitors

Diuretics

Beta blockers