Heart

Question 1

In terms of flow, describe Systole & Diastole

Answer 1

During Systole - Flow is low
During Diastole - Flow is high

Thus most of perfusion of myocardium occurs during diastole

Main mechanism of coronary flow - metabolic vasodilation (active hyperaemia)

Question 2

What is active hyperaemia?

Answer 2

Increase in perfusion related to an increase of metabolic activity

Question 3

How does Atherosclerosis cause vasoconstriction?

Answer 3

You get turbulent flow - which leads to disruption of the endothelium - inhibits the NO2 pathway

Question 4

What are the 2 different types of myocytes?

Answer 4

Neonatal cardiomyocytes - can divide once or twice in the first 5 days

Adult myocytes - Terminally differentiated
Can no longer divide or multiply
If cells get damaged - then they become scarred

Question 5

What is calcification?

Answer 5

Stiff arteries

Deposition of bone-like minerals in walls of artery

Also due to increased amount of collagen & reduction in amount of elastic fibres

Note: If artery is stiffer –> Pulse pressure will be larger

Question 6

What is the process of Calcification?

Answer 6

Mediated by cells that migrate into medial layer of wall of artery - which differentiate into Osteoblast-like cells

Osteoblast-like cells:

• lay down bone-mineral
• Secrete calcium phosphate

Osteoclast-like cells
- Dissolves calcium phosphate

Question 7

What is Hypertrophic remodelling?

Answer 7

Where the myocardium tries to adapt by growing muscle

Early consequence of the response of MI, Ischemia or Heart disease

Question 8

What is Cardiac hypertrophy?

Answer 8

Thickening of the myocardium

Results in a decrease or increase in chamber size of the heart

Common causes Hypertension leading to pressure overload or heart valve stenosis

Question 9

What are the 2 types of Heart Failure?

Answer 9

HFPEF - HF with Preserved Ejection Fraction

HFPEF - HF with Reduced Ejection Fraction

Increased CVP favours right atrial filling & hence right ventricular filling

Question 10

What is Heart failure?

Answer 10

Heart fails to produce an adequate cardiac output

Venous return is reduced by increased CVP

• Results in blood pooling in lower limbs
• Thus symptom of HF - lower limb oedema

Question 11

What are the signs of Heart Failure?

Answer 11

Shortness of breath/coughing

Increased jugular vein pressure

Oedema of lower limbs

Grossly dilated left ventricle

Question 12

Is Ventricular Tachycardia Reversible or Irreversible?

Answer 12

Reversible

Question 13

Is Ventricular Fibrillation Reversible or Irreversible?

Answer 13

Irreversible