Blood Vessels Chp. 19 (Test 2)

Question 1

What is the normal route of blood flow?

Answer 1

heart –> arteries –> arterioles –> capillary network –> venules –> veins –> heart

Question 2

What is a portal system?

Answer 2

where blood flows through two consecutive capillary beds before returning to the heart. example: liver and kidneys.

Question 3

What are the three layers of artery and vein walls and describe them?

Answer 3

tunica externa: holds blood supply for vessels.
tunica media: changes diameter of vessels.
tunica intima: exposed to blood. veins contain valves.

Question 4

What are arterioles?

Answer 4

smallest of arteries. smooth muscle is one cell thick.

Question 5

What is a metarterioles?

Answer 5

short vessels, link between arterioles and capillary beds. contains precapillary sphincter.

Question 6

What is precapillary sphincters?

Answer 6

bands of muscle. open and close based on tissues need of blood (oxygen)

Question 7

What is a capillary?

Answer 7

smallest blood vessels

Question 8

What are the three types of capillaries?

Answer 8

1) continuous capillaries- most abundant
2) fenestrated capillaries- windows/pores. quick exchange. kidneys, intestines, endocrine glands.
3) sinusoid capillaries- leaky. in liver, bone marrow, spleen, and adrenal glands.

Question 9

What is a vein?

Answer 9

carry blood from capillary beds to lungs. contain a larger lumen.

Question 10

Why do veins have valves?

Answer 10

to prevent backflow

Question 11

What is blood pressure?

Answer 11

the force that blood exerts against the wall of arteries.

Question 12

What is the systolic pressure number?

Answer 12

peak arterial pressure during ventricular systole.

Question 13

What is the diastolic pressure number?

Answer 13

lowest arterial pressure during ventricular diastole.

Question 14

What is normal blood pressure for a young adult?

Answer 14

120/80

Question 15

What is pulse pressure?

Answer 15

systolic - diastolic = pulse pressure

Question 16

What is mean arterial mean pressure(MAP)?

Answer 16

pressure that propels blood to tissues. average pressure throughout cardiac cycle. used as a risk assessment tool. influenced by gravity.
MAP = diastolic pressure + 1/3(pulse pressure)

Question 17

What is venous return?

Answer 17

flow of blood back to heart.

Question 18

What are the five ways make venous return possible?

Answer 18

1) pressure gradient
2) gravity
3) skeletal muscle pump
4) respiratory pump
5) smooth muscle

Question 19

How does pressure gradient effect venous return?

Answer 19

blood flows from high pressure to low pressure

Question 20

How does the skeletal muscle pump effect venous return?

Answer 20

veins get squeezed which pushes blood toward the heart.

Question 21

How does the respiratory pump effect venous return?

Answer 21

there is slightly higher pressure in abdominal cavity then thoracic cavity while inhaling, diaphragm contracts downward causing increase in thoracic volume, and decrease in thoracic pressure. blood flows faster from abdominal cavity to thoracic cavity.

Question 22

How does that smooth muscle effect venous return?

Answer 22

smooth muscle constricts to increase venous return. occurs under sympathetic nervous system stimulation.

Question 23

What happens if the skeletal muscle pump is idle too long while a person is upright?

Answer 23

the end diastolic volume lowers, cardiac output, decreased flow to the brain, causing syncope or fainting