the heart

Question 1

septum

Answer 1

thick muscle that seperarates deox and ox blood from mixing

Question 2

features of the cardiac muscle

Answer 2

-carrying on own contraction and rhythm
-has a good blood supply
-contains myoglobin as store of oxygen

Question 3

how does the cardiac muscle have a good blood supply

Answer 3

-coronary arteries bring ox blood to the tissue

Question 4

role of inferior vena cava

Answer 4

collects deox blood from lower parts of the body

Question 5

superior vena cava

Answer 5

-receives deox blood from head neck arms and chest and delivers to right atrium

Question 6

what happens when right atrium fills with blood

Answer 6

-pressure builds and tricuspid valve opens so right ventricle starts to fill with blood

Question 7

what happens when atrium is full

Answer 7

contracts and forces blood into the ventricles

Question 8

features of the atrium

Answer 8

-think muscle walls because receives blood at low pressure
-one way semilunar valves at entrance of atrium to stop backflow of blood

Question 9

features of the tricuspid valve

Answer 9

made of 3 flaps
-known as the atrioventricular valve
-separates atrium from ventricle

Question 10

role of tricuspid valve

Answer 10

-allows blood to pass from the atrium to the ventricle but not other way

Question 11

role of right ventricle

Answer 11

-filled with blood as right atrium contracts
-muscular walls produce pressure needed to force blood out of heart to pulmonary arteries

Question 12

blood returning from lungs to left side of heart

Answer 12

-through pulmonary veins
-low pressure after passing through capillaries
-blood returns to left atrium
-contracts to force blood into left ventricle
-backflow prevented by bicuspid valve

Question 13

role of left ventricle

Answer 13

-pumps blood out of heart into aorta
-carries blood away from heart at even higher pressures

Question 14

why muscle on left side of heart thicker than right

Answer 14

right side pumps blood to lungs- close so low pressures
-left side needs pressures to give blood to all of body and overcome elastic recoil of arteries
-semilunar valves prevent back flow of blood from aorta into ventricle

Question 15

foramen ovale

Answer 15

in embryo
-gap between septum
-blood from two sides of heart can mix
-doesnt matter because lungs of fetus dont function and little blood flows to them

Question 16

patent foramen ovale

Answer 16

when foramen ovale doesnt close and causes hole in heart

Question 17

how beating sounds produced

Answer 17

-made by blood hitting heart valves

Question 18

first sound of the heart

Answer 18

-comes as blood is forces against the atrioventricular valves when ventricles contract

Question 19

second sound of heart

Answer 19

-comes as backflow of blood hits the semilunar valves in pulmonary artery and aorta as ventricles relax

Question 20

what does rate of heart beat show

Answer 20

how fast your fast is contracting

Question 21

atrial systole

Answer 21

when atria contact forcing blood in the ventricles

Question 22

ventricular systole

Answer 22

when ventricles contract

Question 23

order of systole

Answer 23

ventricular systole after atrial systole
-forces blood out of ventricles into pulmonary artery and aorta
-relaxation diastole

Question 24

myogenic heart

Answer 24

cardiac muscle contracts without any external stimulus from the nervous system

Question 25

features of the sinoatrial node

Answer 25

-group of cells in right atrium -has fastest intrinsic rhythm -acts as hearts own pacemaker

Question 26

role of sinoatrial node in the cardiac cycle

Answer 26

-sets up wave of electrical excitation (depolarisation) that causes the atria to start contracting

Question 27

role of annulus fibrous in cardiac cycle

Answer 27

-prevents the excitation from the atria spreading directly the ventricles

Question 28

annulus fibrous

Answer 28

-region of non conducting tissue between the atrium and the ventricle

Question 29

atrioventricular node role in cardiac cycle

Answer 29

-depolarisation from SAN spreads through atria as they contract -cant pass through annulus fibrous so stimulates AVN

Question 30

atrioventricular node

Answer 30

-region of conducting tissue between atrium and ventricle

Question 31

bundle of his role in the cardiac cycle

Answer 31

-AVN stimulated but delay before it passes wave of depolarisation to bundle of His -ensures atria have stopped contracting before ventricles start

Question 32

bundle of His

Answer 32

-group of conducting fibres in the septum of the heart

Question 33

what does His split into

Answer 33

-splits into two branches and carries wave of excitation into purkyne tissue

Question 34

role of purkyne tissue in cardiac cycle

Answer 34

-as depolarisation travels through the tissue it sets off the contraction of the ventricles starting at the apex and squeezing blood out of heart

Question 35

purkyne tissue

Answer 35

-conducting fibres that penetrate down through the septum spreading around the ventricles

Question 36

whats is measured in ECGs

Answer 36

-the electrical changes measured

Question 37

what causes a repeating cardiac cycle

Answer 37

-changes in electrical excitation of the heart

Question 38

what makes sure the atria have stopped contracting before the ventricles start

Answer 38

the speed at which the depolarisation spreads through the heart, with the hesitation before the AVN stimulates the bundle of His

Question 39

whats an ECG used for

Answer 39

to investigate the rhythms of the heart by producing a record of the electrical activity of the heart

Question 40

how to take an ECG steps

Answer 40

12 electrodes and leads attached to body -skin wiped with alcohol to remove sweat and grease to make sure electrodes stick

Question 41

gel applied with ECG

Answer 41

-special gel applied to electrodes to make sure they conduct electricity as efficiently as possible

Question 42

fast heartbeat

Answer 42

tachycardia

Question 43

slow heartbeat

Answer 43

bradycardia

Question 44

PR interval

Answer 44

atrial depolarisation

Question 45

QRS interval

Answer 45

ventricular depolarisation

Question 46

QT interval

Answer 46

ventricular repolarisation

Question 47

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