overview of the CVS

Question 1

what is the function of the CVS

Answer 1

bulk flow system

Question 2

what does the CVS transport

Answer 2

oxygen and carbon dioxide
nutrients
metabolites
hormones
heat

Question 3

how is the CVS flexible?

Answer 3

pump can vary output
vessels can redirect blood
vessels can store blood

Question 4

describe the structure of the CVS

Answer 4

heart –> lungs –> heart –> body –> heart

the pumps are in series

Question 5

what is important about the pumps being in series

Answer 5

output must be equal

Question 6

most vascular beds are in …

Answer 6

parallel - blood goes to all of them at the same time

Question 7

what is important about vascular beds being in parallel

Answer 7

all tissues get oxygenated blood
allows regional redirection of blood
there are some exceptions

Question 8

what are the 2 exceptions to parallel vascular beds

Answer 8

hypothalamus and anterior pituitary
liver
these are known as portal systems

Question 9

describe the hypothalamus and pituitary vascular bed

Answer 9

blood goes to the hypothalamus first then the anterior pituitary

Question 10

describe the vascular bed in the liver

Answer 10

blood from the gut goes directly to the liver

the liver also has its own direct blood supply

Question 11

CO vs oxygen consumption of the brain

Answer 11

13 vs 18

Question 12

CO vs oxygen consumption of the heart

Answer 12

4 vs 10

Question 13

CO vs oxygen consumption of the skeletal muscle

Answer 13

20 vs 20

Question 14

CO vs oxygen consumption of the skin

Answer 14

9 vs 2

thermoregulatory functions

Question 15

CO vs oxygen consumption of the kidneys

Answer 15

20 vs 6

recieves a lot more blood than it needs, necessary for pressure filtration

Question 16

CO vs oxygen consumption of the abdominal organs

Answer 16

24 vs 30

Question 17

how is blood redirected during exercise

Answer 17

pressure difference = mean arterial pressure - central venous pressure
this affects all tissue

Question 18

what is the equation relating flow, pressure difference and resistance

Answer 18

flow = pressure difference / resistance

Question 19

what is the equation for pressure difference

Answer 19

pressure difference = mean arterial pressure - central venous pressure

Question 20

resistance is controlled by …

Answer 20

radius ^4

this selectively redirects flow

Question 21

why are arterioles called resistance vessels

Answer 21

they act as the taps controlling resistance and therefore flow to each vascular bed

Question 22

elastic arteries

Answer 22

aorta
wide lumen
elastic wall with lots of elastic fibres
dampen pressure variations

Question 23

muscular arteries

Answer 23

wide lumen
strong, non-elastic wall
low resistance conduit

Question 24

resistance vessels

Answer 24

arterioles
narrow lumen 
thick, contractile, muscular wall 
control resistance and therefore flow 
allow regional redirection of blood

Question 25

exchange vessels

Answer 25

capillaries narrow lumen thin wall - one cell thick, small barrier to diffusion

Question 26

capacitance vessels

Answer 26

``` venules and veins wide lumen distensible wall low resistance conduit and reservoir allows fractional redistribution of blood between the veins and the rest of the circulation ```

Question 27

define fractional distribution

Answer 27

how much of the total blood volume is sitting in the capacitance vessels

Question 28

what is the role of the septum in the heart

Answer 28

divides the left and right side to separate oxygenated and deoxygenated blood

Question 29

how is the myocardium different on the L and R side of the heart

Answer 29

heart muscle | thicker on the L

Question 30

atrium

Answer 30

recieveing chamber

Question 31

ventricle

Answer 31

pumping chamber

Question 32

aorta

Answer 32

blood leaving LV to the body

Question 33

vena cava

Answer 33

blood entering RA from the body | divided into inferior and superior

Question 34

pulmonary trunk

Answer 34

artery taking blood away from RV to the lungs

Question 35

pulmonary veins

Answer 35

vein taking blood into the LA from the lungs

Question 36

aortic valve

Answer 36

semi-lunar valve | stops blood re-entering LV

Question 37

pulmonary valve

Answer 37

semi-lunar | stops blood re-entering RV

Question 38

mitral valve

Answer 38

L AV valve | bicuspid

Question 39

tricuspid valve

Answer 39

R AV valve

Question 40

chordae tendinae

Answer 40

tendinous chords attached to the valves to hold them in place

Question 41

papillary muscles

Answer 41

muscles attached to the chords | allows the chords to shorten at the right time and prevents the valves inverting when the pressure is high

Question 42

what causes valves to open/close

Answer 42

pressure in the heart | all the valves are passive