Cardiovascular system (2) - 25%

Question 1

What is the process of homeostasis?

Answer 1

1. Elevated blood pressure
2. Reflexively causes HR and BP to decrease
3. Decreased baroreflex activation
4. Heart rate increases
5. Blood pressure levels restored

Question 2

Sympathetic nervous system

Answer 2

Epinephrine

Increase rate & force

Increase in both frequency and amplitude of action potentials

Increased heart rate

‘1.45’ https://www.youtube.com/watch?v=qqU-VjqjczE

Question 3

Parasympathetic nervous system

Answer 3

Acetylcholine

Decrease rate & amp; force

Increase in time for depolarisation to cause an action potential

Decreased heart rate

https://www.youtube.com/watch?v=0IDgBlCHVsA

Question 4

What three things is stroke volume regulated by?

Answer 4

1. End diastolic volume - volume of blood in ventricle prior to contraction
2. Average aortic blood pressure (120mmHg)
3. Strength of ventricular contraction

Question 5

What does venous return mean?

Answer 5

The amount of blood entering the right atrium

Question 6

What increases Preload?

Answer 6

The greater the venous return as it leads to increased stretch on ventricular walls

Question 7

What does Preload mean?

Answer 7

Degree of stretch before contracting

Question 8

What are three factors that affect venous return?

Answer 8

1. Vasoconstriction: reduces volume capacity of the veins to store blood.
2. Muscle pump: rhythmic skeletal muscle contractions compressing veins push blood back to the heart.
3. Respiratory pump:
   - Exhalation: increases pressure, compresses veins forcing blood through valves