Vessels

Question 1

What are they types of arteries?

Answer 1

1) Elastic arteries
2) Muscular arteries
3) Resistant vessels
- Terminal arteries
- Arterioles

Question 2

What are elastic arteries?

Answer 2

Elastic arteries convert pulsatile flow into smoother continuous flow (e.g high pressure) (aorta)

Question 3

What are muscular arteries?

Answer 3

They contain smooth muscle cells, but are less elastic and can be regulated by nerves

Question 4

What are resistant vessels?

Answer 4

Control blood flow downstream: terminal arteries are 100-150um and arterioles are 10-100 um and control release of blood into capillaries

Question 5

Veins characteristics

Answer 5

• Thinner walls than arteries, but a thicker media making them more muscular and able to stretch.
• Act as a reservoir with 2/3 of blood in vein
• contain valves to ensure uni-directional flow

Question 6

Venule characteristics?

Answer 6

• Smallest of veins
• diameter 50-200 um
• thinner walled, layer of endothelial cells surrounded by longitudinal smooth muscle
• carry blood away from capillaries back to heart
• contain pericytes (resident stem cells that help repair parts of vessel structure if damaged)

Question 7

What is the muscular pump?

Answer 7

Veins are located around skeletal muscle.

Movement compresses veins which carry blood at low pressure, aiding the movement of blood back to the heart

Question 8

How is blood flow to capillaries regulated?

Answer 8

Via smooth muscle rings that sit on arterioles called shunts/ sphincters

Question 9

Capillary characteristics?

Answer 9

• Smallest of all vessel
• capillary density is different in different organs
• 4-6 um wide
• transit time of 0.5-2 seconds

Question 10

What is vasomotion and what does it do?

Answer 10

Vasomotion is the cyclic change of opening and closing/ oscillation of vessel walls
It regulates the number of perfused capillaries from terminal arterioles

in resting skeletal muscle cycling is approx 15 seconds, time gets shorter with more activity