Vascular Shunt + Venuos Return

Question 1

What is the Vascular shunt mechanism?

Answer 1

The process of increasing blood flow to the muscles during exercise

Question 2

Name the 3 receptors and each of their purposes DURING exercise:

Answer 2

Chemoreceptors- Detect an increase in CO2 or decrease in O2
Baroreceptors- Detect an increase in blood pressure
Proprioceptors- Detect an increase in muscle activity
(These do the OPPOSITE during recovery)

Question 3

Where do the 3 receptors send the information - and what does it do?

Answer 3

The information is sent the the VCC or vasomotor control centre which uses the sympathetic nervous system to increase - or decrease - sympathetic stimulation to the arterioles and pre-capillary sphincters

Question 4

Name the 2 issues the body must overcome during venous return:

Answer 4

The blood pressure in the veins that returns blood to the heart is exactly zero
Most cardiac output (Q) is found in the legs so has to travel against gravity to return to the heart

Question 5

List AT LEAST 3 solutions for the problems faced during venous return:

Answer 5

1. Pocket valves occur in larger veins preventing back flow of blood 2. Skeletal muscle pump-when the lower leg muscles contract, they get wider pressing against vein walls squeezing blood up toward the heart 3. Smooth muscle-a thin layer of smooth muscle in vein walls allows venoconstriction to move blood up to the heart 4. Respiratory pump-during inspiration the diaphragm flattens, decreasing volume and increasing pressure in the abdomen to below the pressure in the thoracic cavity 5. Gravity from above the heart aids blood returning to the heart from upper body