Arteries, Capillaries, And Veins

Question 1

What is the function of arteries?

Answer 1

To convey blood at high pressure from the ventricles to the tissues of the body and lungs

Question 2

What is another name for tunica intima?

Answer 2

Narrow lumen

Question 3

What is the function of the tunica intima?

Answer 3

Maintains high blood pressure (80 to 120 MM Hg)

Question 4

What is the function of the tunica externa/adventitia?

Answer 4

Outer layer of collagen that prevents the artery from rupturing under high pressure

Question 5

What is the function of the tunica media?

Answer 5

Contains an inner layer of muscle in elastic fibers to maintain pulse flow (it can contract and stretch)

Question 6

What are the functions of muscle fibers?

Answer 6

Contractor near the lumen which increases pressure between pumps and maintains blood pressure

Question 7

What are the functions of elastic fibers?

Answer 7

Allow the walls of the arteries to stretch and expand upon the flow of a pulse through the lumen

Question 8

What is elastic recoil?

Answer 8

Pressure that is exerted on an arterial wall is returned to the blood when the artery returns to its normal size

Question 9

What is vasoconstriction?

Answer 9

When the circular muscles around the arteries resist the outward pressure and constrict

Question 10

What is vasodilation?

Answer 10

The smooth muscles around the arteries relax

Question 11

When does systolic blood pressure occur?

Answer 11

When the arteries experience the highest pressure during vasoconstriction

Question 12

When does diastolic blood pressure occur?

Answer 12

When the pressure in the arteries is the slowest during vasodilation

Question 13

What is the function of capillaries?

Answer 13

To exchange materials between the cells and tissues in blood traveling at low pressure (less than 10 MM Hg)

Question 14

What are the diameter of capillaries?

Answer 14

~ 5 µm

Question 15

Why is the capillary wall made of a single layer of cells?

Answer 15

To minimize the diffusion distance for permeable materials

Question 16

What other structures aid in permeability in capillaries?

Answer 16

Basement membrane and pores

Question 17

What can limit permeability of large molecules in capillaries?

Answer 17

The capillary wall maybe continuous with endothelial cells held together by tight junctions

Question 18

In what type of tissues may the capillary wall be fenestrated?

Answer 18

In tissue is specialized for absorption (ex. intestines, kidneys)

Question 19

What capillaries have open spaces between cells for permeability of large molecules?

Answer 19

Sinusoidal capillaries (ex. liver)

Question 20

What materials are force from the bloodstream into the tissue fluid due to higher hydrostatic pressure?

Answer 20

Oxygen and nutrients (cell respiration)

Question 21

What materials enter from the tissues into the bloodstream due to lower hydrostatic pressure?

Answer 21

Carbon dioxide and urea (cell waste)

Question 22

What is the function of veins?

Answer 22

To collect blood from tissues and transport it to the atria of the heart

Question 23

What is the function of the valves in veins?

Answer 23

Prevents backflow into stop blood from pulling at the lowest extremities

Question 24

Why do veins have very wide lumen in their tunica intima?

Answer 24

To maximize blood flow for more effective return

Question 25

Why are valves in the veins necessary to prevent backflow?

Answer 25

Since blood is that very low pressure in the veins, it can make blood transportation very difficult as blood hast to move against the downward force of gravity