Chapter 18 - Blood Vessels - Learning Outcomes

Question 1

What are the different layers (tunics) of a blood vessel?

Answer 1

Tunica Externa, Tunica Media, Tunica Intima

Question 2

What are each blood vessels made of, and what is the function of each?

Question 3

What are some differences between the structure of a vein and an artery?

Question 4

At rest, how is blood distributed throughout the circulatory system?

Question 5

Where is the majority of blood found?

Answer 5

Systemic Veins (55%)

Question 6

What are the similarities and differences between arterioles and arteries?

Question 7

What about venules and veins?

Question 8

What is blood pressure?

Answer 8

The amount of pressure blood exerts on blood vessels

Question 9

What factors are capable of determining blood pressure?

Question 10

In a standard blood pressure reading, what do the “top” and “bottom” numbers mean?

Answer 10

Top number is systole, bottom number is diastole

Question 11

What is “mean arterial pressure” (MAP)? And how is this calculated?

Question 12

Where in the systemic circuit is blood pressure highest? And where is it lowest?

Answer 12

The blood pressure is higher near the Aorta (heart) and lower near the venae cavae (body)

Question 13

What is the trend in blood pressure as blood moves through the systemic circuit?

Answer 13

Blood pressure decreases

Question 14

How does low pressure blood in veins still make its way to the heart (especially when it is “fighting” against gravity)?

Answer 14

The constriction of the muscles where veins are located act as a force to help propel blood upwards

Question 15

How do autonomic signalling pathways effect blood pressure?

Answer 15

Parasympathetic: dilates blood vessels which decreases blood pressure.
Sympathetic: constricts blood vessels which increase blood pressure.

Question 16

What is a baroreceptor?

Question 17

What is the baroreceptor reflex?

Question 18

What mechanisms are responsible for short-term changes in blood pressure?

Question 19

What mechanisms are responsible for long-term maintenance of blood pressure?

Question 20

How is the structure of a capillary different than an artery or vein?

Answer 20

Capillaries are much smaller (single cell thick) and have less protective layers, mostly endothelial cells.

Question 21

In what ways can substances move into and out of a capillary?

Answer 21

Cell membrane (diffusion), transcytosis (through endothelial cells, or fenestrations.

Question 22

Which is the most restrictive and least restrictive ways substances move in and out of the capillary?

Answer 22

Most restrictive is through

Question 23

How are the three types of capillaries structured?

Question 24

Where in the body would you find sinusoidal capillaries?

Answer 24

liver, bone marrow, spleen, lymphoid organs

Question 25

Which is the most permissive to exchange (“leaky”) and which is the least?

Answer 25

Sinusoidal is the most permissive, continuous is the least permissive

Question 26

Why is it important that the sinusoidal capillary is in these places?

Question 27

How is blood flow through a capillary bed regulated?

Question 28

Are capillary beds always “open”?

Answer 28

They are not always open, they are closed by the precapillary sphincters