Comparative Anatomy of Blood Vessels

Question 1

the simplest circulatory route takes blood from

Answer 1

the heart to arteries to arterioles to the capillaries to the venules to veins and back to heart

Question 2

a portal system allows blood to

Answer 2

flow through two separate capillary networks before returning to the heart

Question 3

anastomosis

Answer 3

the union of two or more blood vessels in the same body region

Question 4

shunt allows blood to flow

Answer 4

from artery to vein and bypass capillaries

Question 5

shunts are common in

Answer 5

ears, fingers, toes

they can lead to frostbite as a consequence of exposure to extreme cold

Question 6

arterial anastomoses provide

Answer 6

collateral circulation by providing alternative routes for blood to reach a capillary network

Question 7

venous anastomoses provide

Answer 7

several routes for blood to drain from an organ

Question 8

arteries carry blood

Answer 8

away from the heart

Question 9

arteries are colored

Answer 9

red , since arteries transport oxygen rich blood

Question 10

arteries have thick walls composed of _____ layers

name them

Answer 10

3:
tunica externa
tunica media
tunica intima

Question 11

tunica externa consists of

Answer 11

loose connective tissues

Question 12

tunica media consists of

Answer 12

smooth muscle, collagen fibers, and elastic fibers

-sympathetic motor nerves innervated smooth muscle

Question 13

tunica intima consists of

Answer 13

a lining of squamous endothelium attached to basement membrane that underlies connective tissue

Question 14

the smooth surface of the endothelium of the tunica intima

Answer 14

inhibits intravascular coagulation

Question 15

intracellular clefts between endothelial cells of the tunica intima

Answer 15

allow substances to freely move in and out of blood

Question 16

endothelial cells of tunica intima can

Answer 16

replace damaged cells and also produce cells that will contribute to new blood vessels

Question 17

arteries are classified according to

Answer 17

size

Question 18

conducting (elastic) arteries are

Answer 18

large. and they help propel blood through systemic circulation while ventricles are relaxing (ex. pulmonary trunk and aorta)

Question 19

distributing (muscular) arteries are

Answer 19

smaller than conducting arteries. adjust rate of blood flow to organ or limb

Question 20

resistance (small) arteries are

Answer 20

variable and include arterioles. metarterioles are short vessels that link arterioles to capillary network

Question 21

capillaries are

Answer 21

microscopic blood vessels where gases, nutrients, and wastes are exchanged between the blood and the tissue cells

Question 22

capillary walls consist of

Answer 22

a single layer of endothelium and a basement membrane

Question 23

lumen is so narrow that

Answer 23

red blood cells must pass through capillary in single file

Question 24

blood flows through a metarteriole into

Answer 24

a capillary bed

Question 25

metarteriole passes through the capillary bed as

Answer 25

a thoroughfare channel

Question 26

flow of blood into capillary bed is controlled by

Answer 26

pre-capillary sphincters comprised of smooth muscle

Question 27

continuous capillaries

Answer 27

have endothelial cells that form an uninterrupted tube to allow passage of small solutes, but not passage of plasma proteins and formed elements

Question 28

fenestrated capillaries

Answer 28

are riddled with small holes, so they allow rapid passage of wastes and small molecules

Question 29

sinusoids

Answer 29

are large, twisted spaces with very thin walls, so they allow plasma proteins and formed elements to leave blood

Question 30

capillaries unite at

Answer 30

the distal end of a thoroughfare channel to form a venule

Question 31

veins carry blood

Answer 31

toward the heart

Question 32

most veins are colored coded

Answer 32

blue since most veins transport de-oxygenated blood

Question 33

veins have the same three layers in their walls as arteries but

Answer 33

their walls are thinner and contain less smooth muscle and elastic tissue so they expand and collapse more easily than arteries

Question 34

many veins, especially in the limbs, contain

Answer 34

one way valves that prevent blood from flowing backward against the force of gravity

Question 35

a venous sinus has

Answer 35

thin walls, a large lumen, and no smooth muscle