heart as a pump

Question 1

describe the right side of the heart

Answer 1

thin muscular wall

works at low pressure

RV pumps blood into the pulmonary circulatory system whet oxygen taken up, carbon eliminated

Question 2

describe left side of the heart

Answer 2

thicker muscular wall

higher blood pressure

LV pumps blood into the systemic circulatory system for delivery to the limbs and organs

Question 3

resting state amount of blood circulating

Answer 3

about 5 litres per minute

Question 4

define

1. myocardium
2. pericardium
3. endothelium

Answer 4

1. cardiac muscle
2. covered by epithelial sac called pericardium
3. inner surface facing the blood

Question 5

conducts blood away from the heart

Answer 5

aorta and pulmonic artery

Question 6

returns blood to the heart

Answer 6

pulmonary veins and vena cava

Question 7

describe function pulmonic and aortic valves

Answer 7

respond passively to pressure gradients

prevent backflow from arteries into relaxing ventricles

Question 8

describe AV valves

Answer 8

mitral: 2 leaf, higher pressure left ventricle
tricuspid: 3 leaf, lower pressure right ventricle

tethered to ventricle wall by tendon like cords and papillary muscle

Question 9

systole

Answer 9

period of contraction

Question 10

diastole

Answer 10

period of relaxation

Question 11

cardiac cycle begins at

Answer 11

diastole

ventricles relax and fill with blood

Question 12

AV valves are

Answer 12

open

Question 13

following stage of heart cycle (4 parts)

Answer 13

P wave
depolarisation of atria
contraction
blood ejected from ventricles

Question 14

when ventricular pressure exceeds atrial pressure AV valves

Answer 14

close

Question 15

last 20% of ventricular filling cause by

Answer 15

contraction of atria

Question 16

systole begins with

Answer 16

QRS complex

depolarisation of ventricles

Question 17

1. when ventricles start to contract all valves are….
2. this causes…
3. this is called
4. does blood volume change?

Answer 17

1. closed
2. increased ventricle pressure
3. isovolumic contraction
4. no

Question 18

1. increased pressure opens

2. this causes

Answer 18

1. pulmonic and aortic arteries

2. blood to be ejected

Question 19

following ejection of blood from ventricles

Answer 19

1. myocardium relaxes

2. pressure falls

Question 20

pulmonic and aortic arteries close when

Answer 20

ventricular pressure is less than that in the pulmonic and aortic arteries

Question 21

describe what happens during isovolumic relaxation

Answer 21

1. with all 4 valves closed ventricles relax further

2. with pressure in ventricles less that atria, AV valves open and blood flows passively into ventricles.

Question 22

EDV

Answer 22

end diastolic volume

volume of blood left in the ventricles at the end of ventricular relaxation

about 125ml (LV)

Question 23

SV

Answer 23

stoke volume

volume of blood ejected from the ventricles

about 70ml

Question 24

ESV

Answer 24

end systolic volume

blood remaining in the vetricle at the end of ventricular contractin

about 55ml

Question 25

CO

Answer 25

Cardiac output volume of blood ejected by ventricle over a period of time CO= SVxHR for example CO 5L= SV 70ml per beat xHR 70 beats per min

Question 26

EF

Answer 26

ejection fraction efficiency of the heart SV / EDV x 100 = EF (%)

Question 27

force of cardiac contraction increased by

Answer 27

1. cardiac muscle fibre length at beginning of contraction | 2. contractility of muscle fibre

Question 28

Frank-Starling relationship 1. length of cardiac muscle fibre dependent upon 2. stretch ....

Answer 28

1. volume of blood in ventricle | 2. increases overlap of actin and myosin to optimal length and contractile force increases

Question 29

Preload

Answer 29

degree of stretch in myocardium before contraction

Question 30

an increase in preload filling will

Answer 30

1. Raise EDV | 2. increase pressure generated (systolic pressur)

Question 31

4 factors that can increase venous return (EDV)

Answer 31

1. Skelatal Muscle Pump 2. Respiratory Pump 3. Sympathetic Nervous System 4. Increase in blood volume (doping)

Question 32

and inotropic agent... examples of inotopic agents

Answer 32

affect cardiac contractility epinephrine norepinephine