Overview of function of CVS

Question 1

function of CVS

Answer 1

bulk flow system carrying oxygen, co2, nutrients, metabolites, hormones, heat

Question 2

significance of vascular beds being arranged in parallel

Answer 2

all tissues get oxygenated blood, allows regional redirection of blood - head legs arms

Question 3

significance of vascular beds being arranged in series

Answer 3

two sides of heart and liver, gut in series.

Question 4

significance of pressure of blood

Answer 4

when u exercise you stop pumping more blood into the arteries and you build up a bigger mean arterial pressure so that pushes blood through all vascular beds. you can turn on and off taps to decide what parts get the blood eg turn off liver and gut and turn on legs

Question 5

arterioles are

Answer 5

Taps that control resistance and therefore flow to each vascular bed

Question 6

venules and veins are

Answer 6

capacitance vessels of the circulation- able to store a lot of blood and move very slowly back to heart but when you want to use it they give it back to the heart. control the fractional distribution of blood

Question 7

left heart deals with

Answer 7

systemic circulation

Question 8

right heart deals with

Answer 8

pulmonary circulation

Question 9

The pumping chambers on the left and right sides of the heart are in series. What is the physiological significance of this?

Answer 9

The output of each side of the heart must be equal, otherwise blood will accumulate in the pulmonary or systemic circulations.

Question 10

if the pressure gradient across a vascular bed is increased, what happens to blood flow through it?

Answer 10

Darcy’s law tells us that flow is proportional to the pressure gradient, ie blood flow will increase.

Question 11

If blood vessels supplying a particular vascular bed constrict, what happens to blood flow through it?

Answer 11

Blood flow will decrease. Darcy’s law tells us that flow is inversely proportional to the resistance, and the major thing affecting that resistance is the radius of the vessel.

Question 12

What does “regional distribution of blood” describe?

Answer 12

the ability of the body to constrict and dilate arterioles supplying different vascular beds to redirect blood flow to different body regions.

Question 13

What does “fractional distribution of blood” describe?

Answer 13

the ability of the body to constrict and dilate venules and veins to expel some of the spare capacitance of blood they contain forwards, towards the heart.

Question 14

function of elastic arteries

Answer 14

aorta and pulmonary trunk. wide lumen, low resistance, thick wall which is full of elastic fibres that help to pump the blood effectively

Question 15

function of muscular arteries

Answer 15

wide lumen, strong non elastic wall, low resistance, try to get blood out to where its going as easily as it can and as little drop it pressure as possible

Question 16

function of resistance vessels

Answer 16

arterioles, narrow lumen, thick contractile wall, allow regional redirection

Question 17

function of capacitance vessels

Answer 17

venules and veins, wide lumen, distensible wall, allows fractional distribution of blood between veins and rest of circulation

Question 18

exchange vessels

Answer 18

capillaries. narrow lumen, thin wall for gas exchange

Question 19

structure of the heart

Answer 19

two sides separated by septum, wall of heart is myocardiu- thicker on left, upper area is atria, lower area is ventricles

Question 20

structure of the heart

Answer 20

two sides separated by septum, wall of heart is myocardium- thicker on left, upper area is atria, lower area is ventricles

Question 21

systemic ciruclation

Answer 21

left side. out through aorta, oxygenated blood to tissues where exchange will occur then the deoxygenated blood will come back to the right side of the heart to then vena cava inferior and superior. then to right atrium and right ventricle and get pumped through the right ventricle into the pulmonary circulation

Question 22

pulmonary circulation

Answer 22

through the right ventricle into pulmonary trunk which splits into pulmonary arteries taking the blood to the two lungs then it will get oxygenated and come back through the pulmonary veins to the left atrium and left ventricle and go round again

Question 23

semi lunar valves

Answer 23

half moon shape allowing blood to go up the way but not back the way, aortic and pulmonary valves. passive

Question 24

mitral valve

Answer 24

separates the left atrium from the left ventricle. passive. held in place by cordae tendinae

Question 25

tricuspid valve

Answer 25

separates the right atrium from the right ventricle. passive. held in place by cordae tendinae

Question 26

papillary muscles

Answer 26

contract and keep cordae tendinae at the appropriate length to stop the valve from converting and opening back the way