intro to VC

Question 1

what vein is blood normally taken from in the arm and what does this do

Answer 1

medial cubital vein

blood traveling to sup vena cava

Question 2

pressure in vena cava (lying and standing)

Answer 2

lying: 3-8mmHg

standing - 0

Question 3

composition of blood - fluid and cells

Answer 3

55% fluid

45% cells (mainly RBS)

Question 4

how much protein is in the blood and in what form

Answer 4

70g/L

mainly albumin

Question 5

partial pressure of venous gases O2 and CO2

Answer 5

pO2 = 40mmHg (150ml/L)
pCO2 = 46mmHg (520ml/L)

Question 6

what occurs a the Q point on an ECG

Answer 6

depolarisation through AV node (slow)

Question 7

what does an increased after load do on a frank-starling curve and why

Answer 7

shifts curve down

increased resistance

Question 8

what effect does increasing activity of cardiac sympathetic nerve fibres have on a frank starling curve and why

Answer 8

shifts up
increase CVP, stretchRV, inc pulmonary pressure, increase LV pressure, stretches and beats more forcefully
increases CO

Question 9

why is low vascular resistance important for venous system

Answer 9

creates large surface area for gas exchange in alveoli

Question 10

link poiseuilles law to pulmonary vessels

Answer 10

arteries are shorter and have a larger radius

lower resistance

Question 11

what’s the pressure in the aorta

Answer 11

120/80mmHg

Question 12

how much of the SV in the aorta is pushed into smaller arteries (forwards)

Answer 12

25%

75% stored in aorta

Question 13

how is flow maintained during diastole from the aorta

Answer 13

stored energy in the elastic walls = arterial recoil and pushes blood forwards

Question 14

what happens to pressure across areas of high resistance

Answer 14

falls steeply

Question 15

what’s the flow rate

Answer 15

5L/min= CO

Question 16

what is the microcirculation made out of

Answer 16

terminal arterioles, capillaries, post-capillary venules

Question 17

diameter of microcirculation

Answer 17

3-10 micron

Question 18

what controls terminal arterioles and what does it so

Answer 18

• local factors

- controls flow through capillary set

Question 19

what do capillaries and post-capillary venules lack

Answer 19

no smooth muscle

Question 20

what is the role of lymphatic capillaries

Answer 20

• absorb fluid and protein and return these to the blood

- take up and transport microorganisms to lymph glands

Question 21

what are the receptors involved in autonomic regulation of the vascular system, and what branch are they from

Answer 21

• SNS - a1 receptors

- PNS - muscarinic and NANC (non-adrenergic, non-cholinergic e.g. NO)

Question 22

what circulating hormones regulate vascular system

Answer 22

-adrenaline
angiotensin II (vasoconstriction. increase aldosterone synthesis)
vasopressin (anti-diuretic)

Question 23

what is atherosclerosis

Answer 23

build up of cholesterol rich plaque

cause stenosis of artery

Question 24

what can thrombosis lead to if uncreated

Answer 24

unstable angina

myocardial infarction: NSTEMI (v narrow artery) or STEMI (completely blocked)

Question 25

what can cause acute coronary syndromes

Answer 25

sudden decrease in coronary flow

Question 26

what is an incisor due to (BP graph)

Answer 26

closure of aortic valve)

Question 27

how much blood is in the venous system and why is this important

Answer 27

70%

contraction of veins = redistribute to arteries to maintain BP

Question 28

what valves does blood flow through during atrial systole

Answer 28

tricuspid and mitral

Question 29

what is the end diastolic volume (plus value)

Answer 29

vol at end of systole(in ventricles)

120ml

Question 30

what is the end systolic volume

Answer 30

70ml blood

ventricles eject

Question 31

ejection fraction

Answer 31

60%

Question 32

what receptors/pumps are involved in cardiac relaxation in a myocyte

Answer 32

Na/Ca exchanger (NCX) - pump out excess Ca

ATPase - reputare of Ca into SR