intro to cardiovascular system

Question 1

what do we need the CVS for

Answer 1

1) Transport for respiratory gases and nutrients.
2) temperature regulation
3) as a signalling system for distributing hormones, information molecules etc to target tissues
4) male hydraulic device

Question 2

what is t proportional to

Answer 2

x2 (distance squared)

Question 3

what does the CVS use a combination of

Answer 3

convection and diffusion

Question 4

what is convection

Answer 4

movement by pressure gradient

Question 5

how does the heart create this convection current

Answer 5

by creating a pressure difference between arteries and veins

Question 6

heart cycle

Answer 6

1) superior and inferior vena cave deposits deoxygenated blood into the right atrium
2) blood then goes into the right ventricle
3) blood is then pushed out of the right ventricle via the pulmonary artery into the lungs (under lower pressure to allow good gaseous exchange)
4) - blood gets oxygenated by diffusion -
5) it then comes back to the heart and enters into the left atrium via the pulmonary vein
6) blood is then pumped to left ventricle
7) finally pumped out of left ventricle to the rest of the body under high pressure via the aorta.

Question 7

what do the opening and closing of the valves depend on

Answer 7

pressure gradients

Question 8

systole =

Answer 8

contractions (ventricles being emptied of blood)

Question 9

diastole =

Answer 9

relaxations (ventricles being filled with blood)

Question 10

What is Cardiac output

Answer 10

volume of blood ejected from the ventricles per minute

Question 11

cardiac output equation =

Answer 11

SV X HR

Question 12

what organ’s oxygen supply is relatively in line with how much they need? (they’re output) (3)

Answer 12

• liver
• GI
• muscles

Question 13

what organ is well perfused

Answer 13

Kidney

Question 14

what organs are underperfused (2)

Answer 14

• myocardium
• brain
  (becomes an issue when there is a clinical problem such as angina e.g. angina / myocardium

Question 15

CO at rest =

Answer 15

70bpm + 70ml = 5litres/min

Question 16

CO after exercise =

Answer 16

180bpm + 120ml = 20 litres/min

Question 17

what are the three main factors controlling cardiac output

Answer 17

1) filling pressure - starling’s law
2) sympathetic/parasympathetic nerves
3) chemical factors

Question 18

what do sympathetic nerves release and what receptors do they act on (causes increase in heart rate and contractility so CO increases)

Answer 18

NA acting at beta-1-adrenoceptors

Question 19

what do parasympathetic nerves release and what receptors do they act on (decrease in heart electrical activity at the SAN reducing HR)

Answer 19

Ach acting at M2 receptors

Question 20

what is blood flow proportional to

Answer 20

pressure across blood vessels - greater pressure means greater flow

Question 21

what is blood flow is inversely proportional to

Answer 21

resistance - greater resistance means less flow

Question 22

what is darcey’s law

Answer 22

Blood flow = (pa - pv) / resistance

Question 23

systemic circulation =

Answer 23

high pressure system

Question 24

pulmonary circulation =

Answer 24

low pressure system

Question 25

how do arterioles control arterial BP

Answer 25

by determining total peripheral resistance which changes blood flow

Question 26

what is parallel circulation

Answer 26

when cardiac output is split up to supply individual areas with blood. - getting first hand oxygenate blood

Question 27

what is series ‘portal’ circulation

Answer 27

where same blood supply is used between organs e.g. liver receives second hand blood from intestines (contains various nutrients and chemicals from intestines that have been digested)

Question 28

what are the 4 main functional groups of blood vessels

Answer 28

• elastic vessels
• resistance vessels
• exchange vessels
• capacitance vessels