blood vessels pt.2

Question 1

pressure in peripheral venules are less than __ percent than ascending aorta (largest artery)

Answer 1

10

Question 2

Folds of tunica intima projecting from vessel wall pointing in direction of blood flow. Ensures one-way flow of blood toward heart, powered by contraction of skeletal muscles. Not present in arteries

Answer 2

Valves (in venous system)

Question 3

Valves permit blood flow in one direction and prevent _______ of blood toward capillaries.

Answer 3

backflow

Question 4

When valves do not work properly, blood can ______ in veins, causing _______.

Answer 4

pool, distention

Question 5

condition caused by weak or damaged vein walls and valves. causes discomfort and cosmetic problems in thighs and legs

Answer 5

varicose veins

Question 6

condition which veins or blood vessels in and around your anal canal and lower rectum become swollen and irritated

Answer 6

hemorrhoids

Question 7

Systemic venous system contains __ percent of total blood volume

Answer 7

64%

Question 8

Amount of blood circulating in venous system

Answer 8

3.5 liters

Question 9

Amount of blood carried in venous networks from digestive organs to liver, providing a blood reservoir.

Answer 9

1 liter

Question 10

Consists of a tube of endothelial cells. Comprised of delicate basement membrane. Lacking both tunica media and tunica externa. About the width of single RBC

Answer 10

capillary

Question 11

Two major types of capillaries

Answer 11

continuous and fenestrated

Question 12

capillaries in which the endothelium is a complete lining. Located throughout body in all tissues except epithelia and cartilage

Answer 12

continuous capillaries

Question 13

Capillaries permitting diffusion of water, small solutes, and lipid-soluble materials. Otherwise selective vesicular transport is used.

Answer 13

continuous capillaries

Question 14

Continuous capillaries in CNS & thymus contain _____ ______, only allowing selective vesicular transport. Important for blood-brain barrier.

Answer 14

tight junctions

Question 15

Capillaries containing “windows,” or pores, penetrating endothelial lining. Permits rapid exchange of water and larger solutes.

Answer 15

fenestrated capillaries

Question 16

Found in Choroid plexus of brain, capillaries of hypothalamus, pituitary, pineal, and thyroid glands
Absorptive areas of intestinal tract
Kidney filtration sites

Answer 16

fenestrated capillaries

Question 17

Resemble fenestrated capillaries, but more flat and irregular shape. Has gaps located between endothelial cells. Basement membrane is thin or absent.

Answer 17

sinusoidal capillaries

Question 18

Structure permitting more water and solute exchange in certain capillaries. Found on capillaries in liver, bone marrow, spleen, and many endocrine organs.

Answer 18

sinusoids

Question 19

Network of numerous interconnected capillaries. Contain several connections between arterioles and venules

Answer 19

capillary bed

Question 20

capillary beds may be supplied by more than one ____. The fusion of vessels is an example of _____. Helps deliver blood to capillary bed even when one artery is blocked or compressed.

Answer 20

artery, anastomosis

Question 21

Regulates bypass of capillary beds (arteriovenous anastomosis).

Answer 21

sympathetic innervation

Question 22

directly connects arteriole to venule

Answer 22

arteriovenous anastomosis

Question 23

Initial segment or branch of the arteriole connecting it to the capillary bed. Contains smooth muscle that can change flow rate by adjusting vessel’s diameter

Answer 23

metarteriole or precapillary arteriole

Question 24

Most direct passageway through capillary bed. Continuation of metarteriole enables blood to bypass capillary bed and flow directly into a venule

Answer 24

thoroughfare channel

Question 25

Bands of smooth muscle which contract and relax. Control flow into the capillary bed.

Answer 25

precapillary sphincter

Question 26

At any given time, ____ _____ of body’s capillaries are shut down.

Answer 26

three quarters

Question 27

When sphincters _____, capillary beds fill with blood. When sphincters ______, they stop blood to the capillary bed.

Answer 27

relax, contract