the heart as a pump

Question 1

how can blood vessels regulate the amount of blood reaching each tissue

Answer 1

they are able to constrict and dilate changing the amount of blood reaching each tissue

Question 2

explain the route blood takes around the body

Answer 2

deoxy enter right atria then right ventricle. pumped to lungs via pulmonary artery and then pumped back to left side of the heart via the pulmonary vein. pumped around body via aorta. systematic pressure= much higher than pulmonary pressure

Question 3

what is systole

Answer 3

contraction and injection of blood from the ventricles

Question 4

what is diastole

Answer 4

relaxation and filling of ventricles

Question 5

how many tires of blood in the average man

Answer 5

5 L

Question 6

what is stroke volume per beta of an average man

Answer 6

70ml

Question 7

features of heart muscle

Answer 7

1 nuclei per cardiomyocyte, connected by intercalated discs which allows them to communicate for synchronised contraction. have longer length of contraction and use ca2+ for action potential. triggered by wave of excitation

Question 8

valves found on the right side of the heart and their function

Answer 8

tricuspid and pulmonary valve - prevent back flow

Question 9

valves found on the left side of the heart and their function

Answer 9

mitral (2 flaps instead of 3) and aortic valve - prevent blood back flow

Question 10

what prevents the inversion of valves in the heart

Answer 10

papillary muscles attached to chordae teninae

Question 11

explain the wave of excitation in the heart

Answer 11

starts at SAN, when reaches AVN a delay is imposed to allow the atria to finish contracting. it is then sent via the bundle of HIS to the apex of the heart where it flows up the side of the ventricles via the purkinje fibres allowing effective release of blood.

Question 12

explain the wiggers diagram

Answer 12

it is a groan which shows the changing pressure in the aorta atria, ventricles and the volume in the ventricles. usually plotted just for the left side of the heart however right would be similar just at lower pressure because act in synchrony

Question 13

stages of the wiggers diagram

Answer 13

1- atria contraction 
2- isovolumetric contraction 
3- rapid ejection 
4- reduced ejection 
5- isovoumteric relaxation 
6- rapid filling 
7- reduced filling

Question 14

what happens during atria contraction

Answer 14

partial pressure rises because of atrial systole, this is called the A wave. ventricles finish filling

Question 15

what is isovolumetric contraction

Answer 15

mitral valve closes causing a rapid increase in pressure in ventricles but there is no increase in the volume. atrial pressure shows C wave from small increase in pressure from mitral valve closing

Question 16

what happens during rapid ejection

Answer 16

aortic valve opens when ventricle pressure exceeds that in the aorta. volume in the ventricles decreases although the pressure stays the sam as they are contracting. slight decrease in pressure in the atria due to atrial base being pulled down by ventricle contraction. this is called the x descent

Question 17

what happens during reduced ejection

Answer 17

ventricle is depolarised meaning less ejection. atrial pressure starts increasing due to continued venous return - v wave

Question 18

what happens during isovolmetric relaxation

Answer 18

ventricle pressure falls and there is back flow causing aortic valve to shut. volume is same however pressure has decreased a lot in ventricles

Question 19

what happens during rapid filling

Answer 19

mitral valves opens causing drop in pressure in the atria (Y descent) and once valve is open the ventricle volume increases

Question 20

what happens during reduced filling

Answer 20

rate of filling reduced as ventricles reach their relaxed volume

Question 21

explain what is happening during the P wave in an ECG

Answer 21

onset of atrial depolarisation to allow atrial contraction. - heart is filling with blood- disatole

Question 22

explain the QRS wave

Answer 22

ventricular depolarisation. start of systole as mitral valve has shut and contraction of the ventricles begings

Question 23

explain the T wave

Answer 23

depolarisation- diastole begins and ventricles are relaxed and emptying

Question 24

where is abnormal valve function usually found

Answer 24

on the left side due to much higher pressure here

Question 25

what happens during aortic valve stenosis

Answer 25

its caused by congenial effects (bicuspid instead of tricuspid), degenerative effects or by rheumatic fever. it means that less blood gets through the valve increasing the pressure in the ventricles and therefore hypertrophy to pump blood harder and heart failure leading to syncope(fainting) and angina(not enough blood for coronary arteries meaning less energy for heart)

Question 26

what happens during mitral valve stenosis

Answer 26

mainly caused by rheumatic fever and blood flows from atria to ventricles with much more difficulty leading to higher pressure in atria. causes atrial dilation which can cause fibrillation and thrombosis formation aswelll as oesophagus compression causing dysphagia. can also cause pulmonary oedema leading to left ventricle oedema due to blood build up in lungs which can cause right ventricle hypertrophy.

Question 27

what happens during aortic valve regurgitation

Answer 27

caused by root dilation (look up if need to know) or valve damage by rheumatic fever. it means blood can flow back into ventricles meaning stroke volume and systolic pressure increase and diastolic pressure decrease. have greater PP = heading bobby and left ventricle hypertrophy to try and pump it out

Question 28

explain mitral valve regurgitation

Answer 28

caused by degeneration/ weakness of the papillary muscles after a heart attack, rheumatic fever or left heart failure which can cause valve to stretch. it means there is more blood in the atria due to back flow meaning hypertrophy to maintain cardiac output.