Chapter 22- Blood vessels and Circulation

Question 1

blood vessels

Answer 1

• closed circuit of tubes
• arteries carry blood away from the heart
• capillaries are exchange vessels
• veins return blood to heart
• oxygen does not distinguish arteries from veins

Question 2

summary of circulation

Answer 2

heart-arteries-arterioles-capillaries-venules-veins-heart

Question 3

blood vessel tissues

Answer 3

endothelium
-smooth surface for blood flow
-simple squamous epithelium
CT
-provides elasticity to withstand BP changes
smooth muscle
-vasoconstriction
-vasodilation

Question 4

blood vessel histology: layers

Answer 4

tunica intima

• innermost
• endothelium on top of CT membrane
• internal elastic membrane
• functions:
• -separates blood flow from vessel wall
• -prevents blood clotting
• -helps regulate BP

Question 5

layers

Answer 5

tunica media

• middle
• bulk of wall
• smooth muscle and elastic CT

Question 6

layers

Answer 6

Adventitia (tunica externa)

• arteries: thin
• veins: not so thin
• outer
• made of CT, elastic and collagenous fibers
• attaches artery to surrounding tissues
• contains vasa vasorum
• -BV of BV because they are so thick

Question 7

arteries: characteristics

Answer 7

strong and elastic

-subdivided into arterioles

Question 8

differences in arteries and veins

Answer 8

-artery wall thicker
-artery lumen appears smaller
endothelium of artery can not contract

Question 9

types of arteries

Answer 9

elastic

• large diameter
• in areas of high pressure
• media:
• -high % elastic tissue,
• -less smooth muscle
• examples:
• -pulmonary trunk, aorta, carotid, subclavian, common iliacs

Question 10

types of arteries

Answer 10

muscular

• large to small diameter
• carry blood to skeletal muscles and organs
• media:
• -much smoother muscle
• -less elastic tissue
• examples
• -femoral, carotids, brachials, mesenteric

Question 11

arterioles

Answer 11

microscopic continuations of arteries-cant see them

• small diameter
• adventitia is thin
• no external elastic membrane
• no vasa vasorum

Question 12

capillaries

Answer 12

consist of
-only intima:
--basement membrane
--simple squamous epithelium
-very thin
-variable permeability
materials exchanged:
-nutrients
-dissolved gases
-wastes

Question 13

capillary permeability

Answer 13

maximized by:
-thin wall
-low BP
-slow blood flow
mechanism of permeability:
-diffusion across endothelial cells: lipids, gases
-diffusion through gaps between endothelium: water, small solutes
-diffusion through pores: water, larger solutes
-vesicular transport with pinocytes (ATP involved): large, bound solutes

Question 14

continuous capillaries

Answer 14

many:
-tight junctions
-desmosomes
-pinocytes
allow movement by:
-passive diffusion
-active transport
locations:
-CNS
-skeletal muscle
-lungs

Question 15

fenestrated capillaries

Answer 15

• swiss cheese appearance
• -pores
• allow movement of:
• -peptides
• -small proteins
• -molecules that cant make it through likes wastes, plasma components that arent cells
• locations
• -kidneys
• -intestines
• -intestines
• -endocrine glands
• -choroid plexus

Question 16

sinusoid capillaries

Answer 16

specialized for max exchange by

• large intercellular gaps
• pores
• discontinuous basement membrane
• -allows CELLS to enter/exit
• location
• -spleen and bone marrow
• -liver and adrenal glands

Question 17

capillary beds

Answer 17

network of interconnected capillaries

• connection for veins and arteries
• depreived from arterioles
• precapillary sphincters
• -manages blood flow to bed
• metarterioles
• -a direct connection through the bed
• -leads to a throughfare channel

Question 18

anastomses

Answer 18

messing with blood flow in capillaries

• collateral arteries
• -two arteries fuse
• -twice as much blood supplies the arteries
• -found in areas with high O2 demand
• -allow for variable degree of blood flow to capillary beds. can contract one tube or open both
• arteriovenous anastomosis
• -direct connectoin between arteriole and venule
• -where blood flow may be hindered by posture
• -allows to reroute blood flow if hindered in capillary bed

Question 19

venules

Answer 19

smallest veins that collect blood from capillaries

• can lack a media
• scatter, minimal amount of smooth muscles occasionally

Question 20

medium sized veins

Answer 20

2-9mm in diameter

• thin media
• few smooth muscle fibers
• thick adventitia
• low bp
• valves
• shape does not need to change, not enough pressure for lots of things that arteries do

Question 21

large sized veins

Answer 21

• great veins: superior/inferior vena cava, and tributaries
• thin media
• thcik adventitia
• low BP
• valves

Question 22

venous valves

Answer 22

flap like structures projecting inward
-folds of media
-found in extremities
veins have low BP
-valves prevent back flow of blood
movement of blood through veins
-movement of limbs and contraction of muscles
--skeletal muscle pump
--positive pressure to push blood up
-expansion of the thoracic cavity
--involves negative pressure, creating empty space to be filled, sucks blood up
--thoracoabdominal pump

Question 23

blood distribution

Answer 23

• unveven
• -oxygenated blood in the heart, arteries, and capillaries-1/3 of blood
• -deoxygenated, venous blood-2/3 of blood
• known as the blood reservoir
• -allows ability to lose fair amount of blood but still be able to survive and escape, essentially extra blood
• veins contract during blood loss

Question 24

circuits: pulmonary

Answer 24

pulmonary circuit

• deoxygenated blood goes to lungs from right ventricle
• oxygenated in alveolar capillaries of lungs
• brought to left atrium, then left ventricle
• veins=oxygenated
• arteries=deoxygenated

Question 25

circuits: systemic

Answer 25

• oxygenated blood goes from left ventricle to body
• deoxygenation occurs in systemic capillaries
• brought to right atrium, then to right ventricle
• veins= deoxygenated
• arteries= oxygenated