Circulatory system and blood flow

Question 1

describe order of systemic bloodflow from heart

Answer 1

1. left ventricle ejection into aorta
2. arteries
3. arterioles
4. caplillaries

Question 2

arteries

Answer 2

low resistance vessels that serve as pressure reservoirs to maintain blood flow during diastole

have muscular walls

responds to pressure, paracrines and nervous activity

contracts to reduce vessel diameter

Question 3

arterioles

Answer 3

highest ratio of smooth muscle to lumen size

increase or decrease local perfusion

Question 4

capillaries

Answer 4

gas, solute and fluid exchange between blood and tissues

Question 5

describe order of pulmonary bloodflow to the heart

Answer 5

1. venules
2. veins
3. vena cava

Question 6

venules

Answer 6

receive blood draining out of capillaries

Question 7

veins

Answer 7

1. venules converge into larger veins
2. large veins have valves to prevent backflow
3. contractions shorten vein length

Question 8

describe basal tone in circulatory system

Answer 8

smooth muscle partialy contracted at all times

maintained by sympathetic nervous system

Question 9

smooth muscle contraction modulated by

Answer 9

ligands (neural transmitters, hormones and paracrines)

stretch

Question 10

bulk flow

Answer 10

movement of blood from high pressure to lower pressure

P2-P1

Question 11

aortic pressure

Answer 11

ossilates between SP and DP

120mmHg and 80mmHg

Question 12

afterload

Answer 12

pressure in aorta and atrial system

Question 13

to eject blood

Answer 13

heart develops pressure equal too or greater than afterload

Question 14

hydrostatic pressure

Answer 14

pressure on vessel walls caused by fluid in vessel

Question 15

pulse pressure

Answer 15

SP-DP=PP

120-80=40mmHg

Question 16

resistance occurs when

Answer 16

as fluid flows through system pressure decreases because energy is lost through friction from vessel walls and blood cells

Question 17

blood flow

Answer 17

Q (with dot above it)

volume per time (ml/min)

Question 18

MAP

Answer 18

mean arterial pressure

driving pressure

MAP=DP + 1/3 (PP)

eg SP 120 of DP of 80 = MAP of 93mmHg

Map closer to diasole (diastole lasts longer)

Question 19

MAP rises when

Answer 19

flow into arteries greater than flow out

Question 20

TPR (refer to p148)

Answer 20

total peripheral resistance

determines blood flow out

CO x TPR = MAP - P vena cava

Question 21

hypotention

Answer 21

blood pressure falls

Question 22

hypertension

Answer 22

> 139 SP or >89 DP

leads to hemeorrhage

Question 23

TPR determined by

Answer 23

length of vessel
radius of vessel
viscosity of blood

Question 24

distribution of blood flow regulated by

Answer 24

changes in vascular resistance

arterioles primary site

Question 25

arteriole resistance regulated by

Answer 25

sympathetic system (reflex control) and

local mechanisms (paracrines, metabolites) to match flow with metabolic needs of tissue

Question 26

Local control of BP

Hyperemia

Answer 26

increased blood flow to organs

paracrine factors increases CO2, H+ and K+ in IF

Question 27

active hyperemia

Answer 27

due to increased metabolism

Question 28

reactive hyperemia

Answer 28

due to reperfusion

Question 29

myogenic response

Answer 29

contraction or dilation in smooth muscle in responce to stretch

Question 30

Reflex Control of BP

Answer 30

mediated by epinephrine (Epi) and Norepinephrine (NorEpi).

Question 31

norepinephine causes

Answer 31

vasoconstriction by acting on androgenic receptors (AR) of blood vessels

sympathetic stimulation

Question 32

epinephrine or vasopressin cause

Answer 32

vasoconstriction

Hormonal stimulation