UNIT 2 - KA6 Flashcards

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1
Q

What is the heart

A

The heart is a muscular pump which keeps blood flowing continuously in one direction round the body

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2
Q

What are the four chambers through which blood flows

A

The tow upper chambers are called atria, while the lower chambers are known as ventricles

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3
Q

What do valves within the heart prevent

A

There are valves within the blood which prevent blood flowing backwards

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4
Q

In which parts of the heart does de/oxygenated blood flow through

A

Deoxygenated blood flows through the right side of the heart, while oxygenated blood flows through the left side

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5
Q

Which wall in the heart ensures deoxygenated and oxygenated blood never mix

A

Both sides of the heart beat in rhythm, but a muscular dividing wall in the centre of the heart called the septum ensures that oxygenated and deoxygenated blood never mixes

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6
Q

Describe the process of deoxygenated blood entering and leaving the heart

A

Deoxygenated blood enters the right atrium through the two main veins of the body, the vena cavae. It is then pushed through the tricuspid (atrio-ventricular or AV valve) into the right ventricle. When the right ventricle contracts blood is forced out of the heart through a semi-lunar valve into the pulmonary arteries. These arteries carry the blood to the lungs where it releases carbon dioxide and picks up oxygen.

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7
Q

Describe the process of oxygenated blood entering and leaving the heart

A

Oxygenated blood then returns to the left atrium along the pulmonary veins. Contraction of the left atrium pushes the blood through the bicuspid (atrio-ventricular or AV valve) into the left ventricle. When the left ventricle contracts, blood is forced out of the heart through a semi-lunar valve into the aorta. The aorta is the main artery of the body and it carries oxygenated blood to all the body organs.

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8
Q

Where does the right half of the heart receive blood from

A

The right half of the heart receives deoxygenated blood from all parts of the body through the veins called the VENA CAVAE

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9
Q

Where does the left side of the heart receive blood from

A

The left half receives oxygenated blood returning from the lungs via the pulmonary veins

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10
Q

What is the purpose of the Atrio-ventricular valves linking the atria to the ventricles

A

The purpose of these is to prevent back flow of blood and keep it moving in one direction

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11
Q

What is the purpose of semi lunar valves

A

Semi lunar valves open only during contraction to ensure blood flows in one direction as it leaves the heart

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12
Q

Why is the left ventricle thicker than the right

A

The left ventricle forces blood from the heart to the rest of the body so it is thicker than the right ventricle that know takes blood to the lungs

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13
Q

Cardiac output (CO)

A

Volume of blood pumped through each ventricle per minute (1/min)

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14
Q

Heart rate (HR)

A

Number of heartbeats that occur per minute (bpm)

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15
Q

Stroke volume (SV)

A

volume of blood pumped through each ventricle per contraction (ml)

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16
Q

What are the three distinct stages in the cardiac cycle

A
  • atrial systole
  • ventricular systole
  • diastole
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17
Q

Atrial systole

A

(0.1s) - when the atria contract sending blood through the bicuspid and tricuspid valves (AV valves) into the ventricles

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18
Q

Ventricular (systole)

A

(0.3s) - when the ventricles contract and blood is pushed out of the heart through the Semi-lunar valves

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19
Q

Diastole

A

(0.4s) when the heart muscles relax and atria fill with blood

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20
Q

Describe the action of the heart during atrial systole

A

During atrial systole the atria are contracting and ventricles are in diastole (relaxed) the AV valves are open and the SL valves are closed

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21
Q

Describe the action of the heart during ventricular systole

A

During ventricular systole the ventricles are contracting and the atria are in diastole (relaxed) the AV valves are closed and SL valves are open

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22
Q

Describe the action of the heart during full diastole

A

During diastole the atria are in diastole (relaxed) the ventricles are in diastole (relaxed) the AV valves are (closed) opening and the SL valves are closed

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23
Q

What valves are responsible for the heart sounds heard with a stethoscope

A

The opening and closing of the AV and SL valves are responsible for the heart sounds heard with a stethoscope

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24
Q

What is the heart beat sounds

A

‘Lubb’ ‘dupp’

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25
Q

Lubb

A
  • Lubb AV valves close (end of atrial systole start of ventricular systole)
  • SL Valves open (ventricular systole)
26
Q

Dupp

A
  • SL VALVES close (end of ventricular systole)
  • AV VALVES open (atrial and ventricular diastole)
27
Q

Heart murmur

A

Abnormal heart sounds produced by abnormal patterns of cardiac blood flow
- often caused by defective valves

28
Q

What is meant by the terms systole and diastole

A

Systole - when the heart muscles are contracting
Diastole - when the heart muscles relax and the atria fill with blood

29
Q

During which process of the cardiac cycle is the pressure greater in the ventricles

A

Systole because muscles are contracting and squeezing the blood

30
Q

Vena cava

A

Carries deoxygenated blood from the body back to the heart

31
Q

Pulmonary artery

A

Carries deoxygenated blood from the heart to the lungs

32
Q

Pulmonary vein

A

Carries oxygenated blood from the lungs to the heart

33
Q

Aorta

A

Carries oxygenated blood from the heart to the rest of the body

34
Q

How much volume of blood do the left and right ventricles pump

A

The left and right ventricles pump the same volume of blood through the aorta and pulmonary artery

35
Q

What happens during diastole

A

During diastole, blood returning to the atria flows into the ventricles

36
Q

What happens during atrial systole

A

Atrial systole transfers the remainder of the blood through the atrio ventricular valves to the ventricles

37
Q

What happens during ventricular systole

A

Ventricular systole closes the AV valves and pumps the blood out through the semi lunar valves to the aorta and pulmonary artery.

38
Q

What happens in full diastole

A

In diastole the higher pressure in the arteries closes the SL valves

39
Q

What are the sequence of events that occur during each heartbeat brought about by

A

The sequence of events that occur during each heart beat are brought about by the activity of the peacemaker and the conducting system of the heart

40
Q

Which control is the rate of the heart under

A

The heart beat originates in the heart itself but its rate is under both nervous and hormonal control

41
Q

What is the pacemaker called

A

The pacemaker is called the sino-atrial node (SAN)

42
Q

What sets the rate at which heart contracts (1st stage of cardiac conducting system)

A

The auto rhythmic cells of the sino-atrial node (SAN) or the pacemaker, located in the wall of the right atrium set the rate at which the heart contrasts,

43
Q

What is the timing of cardiac muscle cell contraction controlled by (2nd stage of cardiac conducting system)

A

The timing of the cardiac muscle cell contraction is controlled by impulses from the SAN spreading through the atria (in a wave of excitation) causing atrial systole

44
Q

Atrio ventricular node (3rd state of the cardiac conducting system)

A

They then travel to the atrio ventricular node, located in the centre of the heart. Impulses from the AVN travel down fibres in the central wall of the heart and then up through the walls of the ventricles, causing ventricular systole.

45
Q

What does the conducting system ensure

A

The conducting system ensures that atrial systole occurs before ventricular systole and that blood is efficiently pushed through the heart

46
Q

Electrocardiogram

A

P= wave of excitation across atria from SAN - atrial systole

QRS= wave of excitation passing through the ventricles - ventricular systole

T= recovery of ventricles at the end of VS - diastole

47
Q

Which part of the brain regulates heart rate

A

The medulla regulates the rate of Sino atrial node through the antagonistic action of the autonomic nervous system

48
Q

What is the antagonistic effect on heart rate

A

Two pathways are antagonistic to one another in that they have opposite effects on heart rate

49
Q

How does a sympathetic nerve affect heart rate

A

A sympathetic nerve releases noradrenaline which increases the heart rate

50
Q

How does a parasympathetic nerve affect heart rate

A

A parasympathetic nerve releases acetylcholine which decreases the heart rate

51
Q

When does blood pressure increase and decrease

A

Blood pressure increases during ventricular systole and decreases during diastole

52
Q

Which piece of equipment measures blood pressure

A

Two readings for blood pressure can be measured using a digital sphygmomanometer

53
Q

What is the process of measuring blood pressure using an sphygmomanometer

A

An inflatable cuff stops blood flow,in the artery and deflates gradually. The blood starts to flow(detected by a pulse) at systolic pressure. The blood flows freely through the artery(and a pulse is not detected) at diastolic pressure.

54
Q

What is a typical blood pressure reading for a young adult

A

A typical blood pressure reading for a young adult is 120/80 mmHg

55
Q

What goes above and beneath in the blood pressure reading

A

Systolic value on top
Diastolic value on bottom

56
Q

What is hypertension

A

Hypertension is a prolonged elevation of blood pressure when at rest

57
Q

How is hypertension indicated

A

It is normally indicated by values of systolic pressure greater than 14mmHg and diastolic pressure greater than 90mmHg

58
Q

What is hypertension a major risk factor for

A

It is a major risk factor for many diseases including coronary heart disease and strokes

59
Q

Which factors may lead to hypertension

A
  • being overweight
  • lack of excerise
  • high (animal( fat / salt diet
  • drinking alcohol
60
Q

Explain why the systolic value is greater than the diastolic value

A

Because the blood is at higher pressure due to contracting of ventricles as they are pushing blood into the arteries. Whereas the diastolic has lower blood pressure as during ventricular diastole, elastic walls recoil so blood continue to propel through