Overview of cardiovascular system

Question 1

describe varying vessel function

Answer 1

vessels can redirect or store blood

Question 2

what do arterioles act as?

Answer 2

‘the taps’ controlling resistance (and therefore flow) to each vascular bed

Question 3

what is the flow equation

Answer 3

flow = difference in pressure/resistance

Question 4

classification of aorta

Answer 4

elastic arteries

wide lumen, elastic wall, damp pressure variations

Question 5

classification of arteries

Answer 5

wide lumen, strong non-elastic wall

low resistance conduit (channel)

Question 6

describe arterioles

Answer 6

resistance vessels

narrow lumen, thick contractile, muscular wall

can control resistance and therefore flow

allow regional redirection of blood

Question 7

classification of capillaries

Answer 7

exchange vessels

narrow lumen, thin wall

Question 8

classification of venules

Answer 8

capacitance vessels

wide lumen, distensible wall (capable of being dilated)
low resistance conduit (channel), & reservoir
allows fractional distribution of blood between veins & rest of circulation (esp. heart)

Question 9

classification of veins

Answer 9

capacitance vessels

wide lumen, distensible wall
low resistance conduit, & reservoir
allows fractional distribution of blood between veins & rest of circulation (esp. heart)

Question 10

what is carried in the blood (6)

Answer 10

O2 and CO2 
nutrients
metabolites 
hormones
heat

Question 11

describe blood storage in vessels

Answer 11

at any one time about 2/3 of the blood in our bodies is stored in vessels called capacitance vessels

these allow fractional distribution of blood-blood being stored can be ejected back to the heart if needed

Question 12

what does it mean to have equal output

Answer 12

all the blood that goes through the right side of the heart must go through the left

Question 13

what does the blood leave the heart through and where does it go?

Answer 13

Blood leaves the heart then through the aorta from which it is distributed to major organs by large arteries

Question 14

describe what is meant when you say the major organs are in parallel

Answer 14

they all receive oxygenated blood from the heart at the same time

Question 15

why is being ‘in parallel’ a good thing

Answer 15

all tissues get oxygenated blood at the same time

allows for regional redirection of blood ie send it to another vascular bed- there are some exceptions to this though

Question 16

give examples of parallel circulation

Answer 16

lungs 
hypothalmus
head
legs
arms

Question 17

what happens with the gut and the liver to make them only partly in series?

Answer 17

blood moves from the gut directly to the liver and then the liver processes the blood and breaks down, balances, and creates the nutrients.

Question 18

what does the hypothalmus do

Answer 18

produces releasing factors that affect the anterior pituitary gland

Question 19

what is the resting cardiac output

Answer 19

5000 ml/min

Question 20

why does the kidney receive a large cardiac output but not use up a lot of O2?

Answer 20

it takes a lot of blood because its function is to filter it

Question 21

what is weird about the heart’s own cardiac output?

Answer 21

it has a very small cardiac output

Question 22

why does the skin receive quite a lot of blood from the heart

Answer 22

for thermoregulation - body sends hot blood to the skin

Question 23

what is the central venous pressure

Answer 23

blood pressure in the venae cavae

amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system

Question 24

how can you change direction of flow?

Answer 24

by reducing flow and increasing the resistance to flow

Question 25

what does in series mean

Answer 25

happens successively

2 sides of the heart are ‘in series’

Question 26

what is the septum

Answer 26

muscular layer that divides the heart in 2

Question 27

what is the myocardium

Answer 27

muscular wall around heart. It is thicker on L ventricle as it has to push blood through the whole systemic circulation so needs high pressure
R only to pulmonary so needs less muscle

Question 28

what is the mitral valve

Answer 28

on the left side

allows blood to move from L atrium to L ventricle

Question 29

what is the tricuspids valve

Answer 29

3 cusps to it
on the right

prevents back flow of blood from the right ventricle into the right atrium.

Question 30

what is chordae tendinae

Answer 30

tendinous chords

stop valves inverting turning inside out – they stop the valves at the right time when shutting

Question 31

what are the papillary muscles?

Answer 31

muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae

when they contract they keep tension on the chordae tendinae and prevent inversion or prolapse of these valves on systole