L10 - structure & function of blood vessels and control of blood pressure

Question 1

name the 3 layers of blood vessels

Answer 1

1. tunica intima (inner)
2. tunica media (middle)
3. tunica adventitia (outer)

Question 2

describe tunica intima

Answer 2

innermost layer of blood vessel

single layer of flattened endothelial cells

Question 3

what lies under tunica intima (in bigger vessels)

Answer 3

subendothelial connective tissue layer

Question 4

describe tunica media

Answer 4

middle layer

mostly smooth muscle

Question 5

describe tunica adventitia

Answer 5

outer layer

mainly collagen and elastin fibres arranged longitudinally

Question 6

where is internal elastic lamina located

Answer 6

in muscular arteries/arterioles beneath the subendothelial layer

Question 7

where is external elastic lamina found

Answer 7

between the Tunica media and tunica adventitia

Question 8

describe layers of blood vessels including connective layers

Answer 8

Tunica intima 
subendothelial connective tissue
internal elastic lamina
tunica media 
external elastic lamina
tunica adventitia

Question 9

is the TA thicker in arteries or veins?

Answer 9

veins

Question 10

what happens to aorta &elastic arteries during systole

to withstand pressure

Answer 10

they expand so pressure doesnt increase too much

Question 11

what happens to aorta &elastic arteries during diastole (to withstand pressure)

Answer 11

elastic recoil keeps arterial pressure from dropping too low

Question 12

what is vasa vasorum and its function?

Answer 12

blood vessels that supply larger arteries with blood because larger arteries walls are to thick to rely on diffusion

Question 13

order of arteries

Answer 13

aorta - elastic arteries - muscular arteries - arterioles - capillaries - post capillary venules - collecting venules - muscular venules - small veins - medium veins - large veins

Question 14

describe structure of muscular arteries

Answer 14

thick tunica media

Question 15

feature of muscular arteries

Answer 15

can constrict to direct blood flow

Question 16

describe structure of arterioles

Answer 16

dont always have internal elastic lamina

very thin TA

Question 17

feature of arterioles

Answer 17

can constrict/relax to alter blood flow

Question 18

what effect does reducing tube radius have
downstream
upstream

Answer 18

downstream - reduces flow and pressure

upstream - increases pressure

Question 19

define MABP

Answer 19

MABP = CO x TPR

Question 20

what is the main determinant of pulse pressure

Answer 20

CO

Question 21

what is the main determinant of diastolic blood pressure

Answer 21

TPR

Question 22

what happens to blood when it flows from arteries to arterioles

Answer 22

pressure in arterioles decreases
flow in decreases in arterioles
TPR in arterioles increases

Question 23

what reflex controls MABP short term

Answer 23

baroreceptor

Question 24

how do baroreceptors respond to increased b.p

Answer 24

increase APs

Question 25

how do baroreceptors respond to decreased b.p

Answer 25

decrease APs

Question 26

where are baroreceptor sensors

Answer 26

chemoreceptors in carotid sinus & aortic arch

Question 27

what are the effectors in the baroreceptor reflex and what nerves innervate them

Answer 27

SA node - vagus nerve and SNS nerves | arterioles - SNS nerves

Question 28

explain process of baroreceptor reflex

Answer 28

1. increased MABP leads to increased baroreceptor APs 2. signal sent to medulla via carotid sinus nerve 3. decreased SNS to SA node/arterioles/heart muscle 3. increased PSNS to SA node 4. HR decreased 4. reduced vasoconstriction 4. reduced contractility 5. reduced CO and TPR 6. reduced MABP

Question 29

describe structure of capillaries

Answer 29

1 layer of endothelial cells | surrounded by pericytes

Question 30

function of pericytes

Answer 30

involved in contraction

Question 31

how is capillary specialised for gas exchange

Answer 31

thin walled for diffusion large SA slow blood flow

Question 32

name the 3 types of capillary

Answer 32

continuous discontinuous fenestrated

Question 33

features of continuous capillaries and where theyre found

Answer 33

continuous basal lamina, no gaps between cells brain, muscle, thymus, bone, lung

Question 34

features of discontinuous capillaries and examples of where they're found

Answer 34

large gaps between endothelial cells and discontinuous basal lamina liver, spleen (blood needs to be close contact with tissues)

Question 35

features of fenestrated capillaries

Answer 35

many gaps between cells but continuous basal lamina

Question 36

where are fenestrated capillaries found

Answer 36

tissues where fluid is being transported (filtration) kidney , villi

Question 37

what are the two pressures acting on capillaries

Answer 37

capillary osmotic pressure - forcing fluid out | plasma protein osmotic pressure - water follows in

Question 38

describe baroreceptor reflex in veins

Answer 38

1. SNS and NA constrict veins when MABP decreases 2. increase in venous pressure 3. helps push blood back up to heart 4. improved venous return

Question 39

features of lymph vessels

Answer 39

1 cell thick | valves

Question 40

what are the main lymph channels

Answer 40

thoratic duct | lymphatic duct