L15 Cardiovascular Pressures and Capacitance

Question 1

Which blood vessels are associated with the phenomenon known as ‘pressure reservoir’?

Answer 1

Elastic (conducting) arteries.

Propel blood while ventricles are relaxing (pressure reservoir). As blood is ejected from the heart into elastic arteries, their walls stretch, easily accommodating the surge of blood. As they stretch (elastic fibres) they store mechanical energy, functioning as a pressure reservoir.

Question 2

Which blood vessel is used to transport blood over a long distance, with little drop in BP?

Answer 2

Muscular (distributing) arteries

These are medium-size arteries

Question 3

The term ‘resistance vessel’ usually refers to which type of blood vessel?

A) Elastic artery
B) Muscular artery
C) Arteriole
D) Capillary

Answer 3

C) Arteriole

Arterioles are important because by vasoconstriction or vasodilation, they can greatly influence peripheral resistance and so modify the flow of blood from arteries into the capillaries, called resistance vessels.

Question 4

The terminal end of the arteriole is the __?__

Answer 4

metarteriole

Question 5

The proximal end of the metarteriole is called the __?__

Answer 5

metarteriole-capillary junction

Question 6

Which end of the metarteriole contains smooth muscle cells?

Answer 6

The proximal end: metarteriole-capillary junction

Question 7

The distal end of the metarteriole is called the __?__

Answer 7

thoroughfare channel

Question 8

True or false: Flow of blood from the metarteriole to the capillary bed is pulsatile

Answer 8

True

Occurs about 5-10 times per minute and is called vasomotion

Question 9

What is vasomotion?

Answer 9

Vasomotion is the spontaneous oscillation in tone of blood vessel walls, independent of heart beat, innervation or respiration.

This intermittent contraction and relaxation results in pulsatile blood flow from the metarteriole to the capillary bed.

Question 10

Which type of blood vessel commonly has a tunica interna only?

Answer 10

Capillary

Question 11

Which type of blood vessel is called an ‘exchange vessel’?

Answer 11

Capillary

Question 12

What are the three types of capillary?

Answer 12

1. Continuous (most common)
2. Fenestrated
3. Sinusoid

Question 13

True or false: Veins have a thinner wall and narrower lumen than arteries

Answer 13

False.

Veins have a thinner wall and larger lumen than arteries

Question 14

Which type of vessels are ‘capacitance vessels’?

Answer 14

Veins

Question 15

In what way are the veins and venules blood reservoirs?

Answer 15

The have the greatest reserve of blood - The venous system contains 64% of the body volume of blood

Question 16

Large, hydrophilic molecules are normally transported out of capillaries via __?__

Answer 16

transcytosis

Question 17

Which pressures promote filtration (flow of fluid and solutes out of capillary)?

Answer 17

1. Blood hydrostatic pressure (BHP)

2. Interstitial fluid osmotic pressure (IFOP)

Question 18

Which pressures promote reabsorption (flow of fluid and solutes into a capillary)?

Answer 18

1. Blood colloid osmotic pressure (BCOP)

2. Interstitial fluid hydrostatic pressure (IFHP)

Question 19

True or false: Blood colloid osmotic pressure is the same in the arterial system and in the venous system

Answer 19

True

Colloid doesn’t leave the vessel, so it’s effects of filtration/reabsorption remain constant throughout

Question 20

What causes oedema?

Answer 20

When filtration greatly exceeds reabsorption this leads to increase in the interstitial fluid volume

Question 21

Which of the following could result in oedema?

A) Increased capillary blood pressure
B) Increased capillary wall permeability to solutes
C) Decreased concentration of plasma proteins
D) Kidney disease
E) A, B and D only
F) All of the above

Answer 21

F) All of the above

↑ BP and ↑ cap. wall permeability result in excess filtration

↓ plasma proteins and kidney disease result in inadequate reabsorption

All of these factors can lead to oedema