Lecture 11 - Circulation of blood

Question 1

What is the function of the cardiovascular system?

Answer 1

Maintain an adaptable supply of blood to tissues to supply nutrients and remove waste

Question 2

What are the 5 different components of the circulatory system?

Answer 2

Brain
Adrenal glands
Kidney
Heart
Blood vessels

Question 3

Which components of the circulatory system are involved in neural regulation?

Answer 3

The brain

Question 4

Which components of the cardiovascular system are involved in hormonal regulation?

Answer 4

Adrenal glands
Kidneys

Question 5

What are the two factors that determine blood flow?

Answer 5

Pressure difference between point A and B
The resistance to flow

Question 6

What is the equation for blood flow?

Answer 6

F = ΔP/R

Question 7

What is vascular resistance?

Answer 7

Resistance caused by friction from blood contacting blood vessel walls
Determined by length and radius of the vessel and blood viscosity

Question 8

How is the pressure gradient generated?

Answer 8

From the heart contracting

Question 9

How is blood flow maintained during diastole?

Answer 9

Elastic arteries act as pressure reservoirs

Question 10

What is the cardiac cycle?

Answer 10

A series of electrical and mechanical events that determine blood flow through the heart and into circulation during one heart beat

Question 11

What is the cardiac conduction system?

Answer 11

Initiates contraction and relaxation events by rapidly carrying electrical impulses across the heart

Question 12

What is an ECG?

Answer 12

It detects electrical activity across the heart
Shows a combination of all the action potentials in the heart

Question 13

What is the P wave in an ECG?

Answer 13

Atrial depolarization -> Contraction

Question 14

What is the QRS complex in an ECG?

Answer 14

Ventricular depolarisation -> Contraction
Atrial repolarisation -> Relaxation

Question 15

What is the T wave in an ECG?

Answer 15

Ventricular repolarisation -> relaxation

Question 16

What are the main mechanical events in the cardiac cycle?

Answer 16

1. Atrial systole begins
2. Atrial systole ends and atrial diastole begins
3. First phase of ventricular systole
4. Second phase of ventricular systole
5. Early ventricular diastole
6. Late ventricular diastole

Question 17

What occurs in atrial systole?

Answer 17

Atrial contraction forces small amount of additional blood into relaxed ventricles

Question 18

What occurs in first phase of ventricular systole?

Answer 18

Ventricular contraction pushes atrioventricular valves closed but doesn’t create enough pressure to open semi-lunar valves

Question 19

What happens in second phase of ventricular systole?

Answer 19

Ventricular pressure rises and exceeds pressure in arteries
Semilunar valves open and the blood is ejected

Question 20

What happens in early ventricular diastole?

Answer 20

When ventricles relax pressure drops and blood flows back against the cusps of the semilunar valves and forces them closed
Blood flows into relaxed atria

Question 21

What happens in late ventricular diastole?

Answer 21

All the chambers are relaxed
The ventricles fill passively