chapter 20: blood vessels

Question 1

what are the 3 tunics of blood vessels from superficial to deep?

Answer 1

externa, media, intima

Question 2

what is each tunic composed of?

Answer 2

intima: simple squamous endothelium
media: smooth muscle + elastic fibers
externa: areolar CT w/ elastic and collagen fibers

Question 3

what are the 3 types of arteries?

Answer 3

elastic, muscular, arterioles

Question 4

order the 3 types of arteries from smallest to biggest, along with their sizes

Answer 4

arteriole (0.3mm - 10 micrometers), muscular (1cm - 0.3mm), elastic (2.5cm - 1 cm)

Question 5

what do elastic arteries do?

Answer 5

conduct blood from heart to muscular arteries

Question 6

the _______ arteries allow for stretch and recoil to help propel blood during diastole

Answer 6

elastic

Question 7

what are examples of elastic arteries?

Answer 7

aorta, pulmonary trunk, common carotid, common iliac

Question 8

which arteries distrubute blood to specific body regions?

Answer 8

muscular arteries

Question 9

the slightly contracted state of arterioles is called _____________

Answer 9

vasomotor tone

Question 10

what are the 3 types of capillaries from least to most permeable?

Answer 10

continuous, fenestrated, sinusoidal

Question 11

why are the capillaries optimal for blood and tissue fluid exchange?

Answer 11

their thin walls and small diameter

Question 12

______ particles aren’t allowed to pass through continuous capillaries

Answer 12

large (like cells and proteins)

Question 13

fenestrated capillaries allow for movement of ______ plasma proteins but not _________ (cells)

Answer 13

small; formed elements

Question 14

what passes through sinusoid capillaries?

Answer 14

large elements (formed elements and large plasma proteins) and plasma

Question 15

what does each capillary look like?

Answer 15

continuous: endothelial cells form a continuous lining
fenestrated: form a continuous lining with fenestrations
sinusoid: basement membrane is incomplete or absent and endothelial cells form an incomplete lining

Question 16

what is the path of blood through the capillary bed?

Answer 16

metarteriole > true capillaries > thoroughfare channel > postcapillary venule

Question 17

what is vasomotion?

Answer 17

the cycle of contracting and relaxing of precapillary sphincters; only 1/4 of capillary beds are open at a given time

Question 18

how do arteries and veins differ?

Answer 18

• arteries are more narrow and thicker than veins
• tunica media is thickest in the artery and tunica externa is thickest in veins

Question 19

how much blood is at rest in pulmonary and systemic circulation?

Answer 19

pulmonary: about 18%
systemic: about 70%

Question 20

which area has the greatest amount of blood at rest in systemic circulation?

Answer 20

systemic veins (about 55%)

Question 21

________ refers to the movement of fluids down a pressure gradient

Answer 21

bulk flow

Question 22

direction of bulk flow depends on __________ of opposing forces (_______ pressure vs ___________ pressure)

Answer 22

net pressure; hydrostatic; colloid osmotic

Question 23

how does hydrostatic pressure change from atrial to venous end?

Answer 23

35mmHg to 16mmHg

Question 24

what is the difference between hydrostatic and osmotic pressure?

Answer 24

HP is force exerted by fluid on a structure, OP is the pull of water back into tissue

Question 25

HPb is greater in the _________ end than the _________ end; osmotic pressure is greater in the __________ end than the _________ end

Answer 25

atrial, venous; venous, atrial

Question 26

HPb promotes _________; COPb promotes _____________

Answer 26

filtration; reabsorption

Question 27

positive NFP = _____________
negative NFP = _____________

Answer 27

filtration; reabsorption

Question 28

blood __________ pressure does not change along the capillary (26-28 mmHg)

Answer 28

colloid osmotic

Question 29

how is net filtration pressure calculated?

Answer 29

NFP = (HPb-HPif) - (COPb-COPif)

Question 30

HPb is 35 mmHg, and HPif is 0 mmH. COPb is 26 mmHg and COPif is 5 mm Hg. what is the NFP? will filtration or reabsorption occur?

Answer 30

14 mmHg; filtration will occur

Question 31

what 3 factors influence resistance?

Answer 31

viscosity (directly) vessel length (directly)
vessel radius (inversely)

Question 32

what is a blood pressure gradient?

Answer 32

change in pressure from one end of a vessel to the other

Question 33

pulse pressure = ________ - _________

Answer 33

systolic; diastolic

Question 34

mean arterial pressure = ________ pressure + 1/3 ________ pressure

Answer 34

diastolic; pulse

Question 35

if a pt has a bp of 155/95, what is their pulse pressure and MAP?

Answer 35

pp: 155-95= 60
MAP: 95 + 60/3 = 115 mmHg

Question 36

what is a good range of perfusion?

Answer 36

MAP = 70-110 mmHg

Question 37

what is the capillary blood pressure from atrial to venous end?

Answer 37

about 40 mmHg to <20 mmHg

Question 38

how is the small pressure gradient in veins overcome?

Answer 38

skeletal and respiratory pumps are used; skeletal: assists venous return from limbs, respiratory: assists venous return in thorax

Question 39

what factors increase total blood flow?

Answer 39

increased caridac output (= steeper pressure gradient), vasodilation (= less resistance)

Question 40

what factors decrease total blood flow?

Answer 40

decreased cardiac output (= smaller gradient), vasoconstriction (= greater resistance)

Question 41

Angiotensin II and ADH (in high doses) ________ peripheral resistance and blood pressure; and angiotensin II, aldosterone, and ADH _________ urine output to help maintain blood volume and blood pressure. ANP stimulates __________, which decreases _________________ and increases _____________, which decreases blood _________. The net effect is a decrease in blood _________.

Answer 41

increases; decreases; vasodilation; peripheral resistance; urine output; volume; pressure

Question 42

where is each hormone formed?

Answer 42

angiotensin ii: lungs
ADH: posterior pituitary
aldosterone: adrenal cortex
ANP: atria

Question 43

blood flow is ________ related to pressure gradient and _______ related to resistance

Answer 43

directly; inversely