Chapter 16: Vascular

Question 1

arteries

Answer 1

carry blood away from the heart

Question 2

veins

Answer 2

return blood to the heart

Question 3

capillaries

Answer 3

connect the smallest arteries to the smallest veins

Question 4

tunica intima

Answer 4

• innermost layer of a vessel
• composed of endothelium
• smooth surface
• produces chemicals that cause dilation or constriction

Question 5

tunica media

Answer 5

• middle layer of a vessel
• thickest layer in arteries
• smooth muscle and elastic tissue
• allows vessels to change diameter
• innervated by ANS

Question 6

tunica externa

Answer 6

• outer layer of a vessel
• fibrous connective tissue
• supports and protects
• thickest layer in veins

Question 7

aneurysm

Answer 7

if a portion of the arterial wall weakens, the blood inside will push against the area and cause it to bulge

Question 8

conducting arteries

Answer 8

• largest arteries
• can expand and recoil
• elastic fibers in tunica media
• also called “elastic arteries”
• ex. aorta, common carotid artery

Question 9

distributing arteries

Answer 9

• carry blood farther away from the heart to specific organs/areas
• also called “muscular arteries”
• smaller than elastic arteries
• ex. brachial & femoral arteries

Question 10

arterioles

Answer 10

• smallest arteries
• also called “resistance vessels”
• can resist flow of blood
• help control blood pressure
• control how much blood enters an organ
• too numerous to be names

Question 11

metarterioles

Answer 11

short vessels that connect arterioles to capillaries

Question 12

characteristics of veins

Answer 12

• thinner walls than arteries
• great ability to stretch
• can carry varying amounts of blood with almost no change in pressure
• sometimes called “capacitance vessels”
• can constrict extensively
• lie closer to the skin’s surface than arteries

Question 13

large veins

Answer 13

• formed as medium-sized veins converge
• thick tunica externa
• ex. vena cavae, pulmonary veins, internal jugular veins

Question 14

medium-sized veins

Answer 14

• formed by the convergence of venules on their way toward the heart
• thicker, more elastic walls
• contain one-way valves that keep blood moving toward the heart and prevent backflow
• ex. radial, ulnar, saphenous veins
• veins in the legs have the most valves because they have to fight gravity when transporting blood back up to the heart

Question 15

venules

Answer 15

• smallest veins
• collect blood from capillaries
• thin walls
• porous; exchange fluid with surrounding tissues

Question 16

capillaries

Answer 16

• microscopic, very thin walls
• barely wide enough for blood cells to pass
• link arterioles to venules
• “exchange vessels” of the circulatory system
• transfers nutrients, wastes, and hormones between blood and tissues

Question 17

distribution of capillaries

Answer 17

• unevenly distributed
• tissues with high metabolic rates contain more (ie. liver, kidneys)
• fibrous connective tissues (lower metabolic rate) contain fewer (ie. tendons)

Question 18

distribution of capillaries

Answer 18

• unevenly distributed
• tissues with high metabolic rates contain more (ie. liver, kidneys)
• fibrous connective tissues (lower metabolic rate) contain fewer (ie. tendons)c

Question 19

distribution of capillaries

Answer 19

• unevenly distributed
• tissues with high metabolic rates contain more (ie. liver, kidneys)
• fibrous connective tissues (lower metabolic rate) contain fewer (ie. tendons)

Question 20

capillary organization

Answer 20

• capillaries organized into networks (capillary beds)
• form the microcirculation

Question 21

precapillary sphincters

Answer 21

• at beginning of each capillary bed
• regulates flow of blood into network
• open during exercise
• close during periods of rest

Question 22

sinusoid

Answer 22

• unique capillary
• irregular, blood filled spaces
• more permeable
• allow for passage of large substances (ie. blood cells, proteins)
• ex. allows blood cells formed in bone marrow and proteins formed in the liver to enter the bloodstream

Question 23

capillary exchange

Answer 23

• two-way exchange
• release chemicals to be used by surrounding tissues
• take up waste and substances that need to be transported to other parts of the body
• water moves in and out

Question 24

diffusion

Answer 24

• substances move from area of greater to lesser concentration
• oxygenated blood flows into the capillaries
• oxygen moves out of capillaries and into surrounding fluid
• CO2 diffuses into the capillary simultaneously

Question 25

filtration

Answer 25

• occurs close to the arterial side of the capillary bed
• blood enters capillary through metarteriole
• higher pressure in the capillary pushes plasma and dissolved nutrients through the capillary wall and into surrounding tissue

Question 26

colloid osmotic pressure

Answer 26

• happens when blood pressure inside the capillary drops
• albumin in the blood pulls tissue fluid and waste products into the capillaries

Question 27

edema

Answer 27

water filters out of the capillaries faster than it is absorbed and it accumulates in the surrounding tissues

main causes:
- increased capillary filtration
- reduced capillary reabsorption
- obstructed lymphatic drainage