Heart Function

Question 0

What is systole and diastole?

Answer 0

Systole = ventricular contraction of the heart
Diastole = relaxation of either atria or ventricles (chambers fill)

Question 1

List the facts about heart function?

Answer 1

Beats 70 per min
Complete cycle takes 0.8 sec
Norm human life span it beats 2.5 x10 to power of 9 and pumps 150 million litres from each ventricle.

Question 2

What is systolic and diastolic pressure?

Answer 2

Measure of BP in mmHg
Systolic pressure = higher measurement (blood pushing through the arteries
Diastolic pressure= lower measurement (heart resting between beats)

Question 3

What factors affect blood pressure?

Answer 3

Diet, stress, exercise, body mass ,alcohol consumption

Question 4

What is hypertension?

Answer 4

High BP (above 140/90 mmHg)
Body having to work harder to pump blood around the body.

Question 5

What is hypotension?

Answer 5

Low BP ( less than 90 syst. Or less than 60 diastolic)
Physiological state associated with shock
Can occur in fit people

Question 6

What happens during the cardiac cycle?

Answer 6

Myocardium contracts, blood flows from an area of high to low conc unless flow is blocked by a valve.

Question 7

What happens to the valves during atrial contraction and ventricular relaxation?

Answer 7

Tricuspid and mitral valve open- aortic and pulmonary valve close

Question 8

What happens to the valves during atrial relaxation and vent contraction?

Answer 8

Pulmonary and aortic valve open and tricuspid and mitral close

Question 9

What happens during diastole?

Answer 9

Ventricles relax from previous cycle, the AV valves open and blood flows passively from atria to ventricles

Question 10

What happens in atrial systole?

Answer 10

Vent relaxed
Atria contract forcing blood into ventricles
Av valve stay open due to pressure
70% blood flow into vent passively so atria don’t have to contract too much

Question 11

What happens during ventricular systole?

Answer 11

Once filled vent start contracting
Increase IV pressure closes AV valves
Blood prevented from flowing back into atria
Vent walls contract forcing blood out

Question 12

What happens during ventricular systole?

Answer 12

Rise in pressure forces semi lunar valves to open - forcing blood into aorta and pulmonary arteries

Question 13

During diastole what happens to the blood pressure?

Answer 13

It drops, semi lunar valves shut to prevent back flow into ventricles.

Question 14

What is the formula for cardiac output?

Answer 14

CO= HR X SV
CO = amount of blood pumped by each ventricle per min
HR= beats/ min
SV= ml/min

Question 15

Where is cardiac impulse initiated?

Answer 15

SAN (sinoatrial node) fires at regular intervals 60/70 beats/min
Waves spread over walls so they contract

Question 16

What fibres are responsible for ventricular contraction?

Answer 16

Purkinje fibres coming from the bundle of His located in the intraventricular septum.

Question 17

What does the AV node do?

Answer 17

Send electrical signal through the bundle branches, composed of pukinje fibres causing the ventricles to contract from the apex upwards.

Question 18

What features does a normal ECG have?

Answer 18

p wave = contraction of the atria(depolarisation)
QRS = impulse over the ventricles causing contraction
T wave= relaxation of ventricular muscle and diastole

Question 19

What is atrial fibrillation?

Answer 19

Irregular fast HR> 140
Atria contract randomly and fast so heart cannot relax properly
Symptoms: dizzy, SOB, palpitations

Question 20

What is ventricular fibrillation ?

Answer 20

Uncoordinated contraction of the cardiac muscle of the ventricles ( quiver)
Arrhythmia associated with cardiac arrest