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Higher Biology > Structure of the Cardiovascular System > Flashcards

Structure of the Cardiovascular System Flashcards

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1
Q

What is the cardiovascular system made up of

A

-heart
-blood vessel

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2
Q

Three types of blood vessels

A

-arteries
-veins
-capillaries

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3
Q

Lumen

A

each blood vessel has a central cavity, called lumen
-the endothelium lining=the central lumen of blood vessels is surrounded by layers of tissue

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4
Q

Arteries

A

-Arteries have an outer layer of connective tissue containing elastic fibres and a middle layer containing smooth muscle with more elastic fibres.
-The elastic walls of the arteries stretch and recoil to accommodate the surge of blood after each contraction of the heart.

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5
Q

what do arteries flow into

A

arterioles

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6
Q

Veins

A

-Veins have an outer layer of connective tissue containing elastic fibres but a much thinner muscular wall than arteries.
-They contain valves to prevent the backflow of blood.

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7
Q

what vessels bring blood to the vein from capillaries

A

venules

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8
Q

Capillaries

A

-Capillaries allow exchange of substances with tissues through their thin walls.
-Capillaries connect arterioles to venules.

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9
Q

how are they all connected?

A

artery-arteriole-capillary-venule-veins

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10
Q

Vasoconstriction and vasodilation

A

To control blood flow,the smooth muscle in the arterioles can either contract (vasoconstrict) or relax (vasodilate) depending on the requirements of the body.

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11
Q

Blood

A

-Blood consists of:-
Red blood cells
White cells
Platelets
-These components of blood are found suspended in plasma, a watery yellow fluid.

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12
Q

Plasma

A

-Plasma contains dissolved substances such as glucose, amino acids, respiratory gases, plasma protein and useful ions.

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13
Q

Tissue Fluid

A

-Blood arriving at the arteriole side of a capillary bed is at higher pressure than the blood in the capillaries.
-As blood is forced into these narrow capillaries, it undergoes pressure filtration.
-This is when much of the plasma (containing small dissolved molecules) is squeezed out through the thin endothelium of the capillaries

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14
Q

Pressure Filtration

A

-Pressure filtration causes plasma to pass through capillary walls into the tissue fluid surrounding the cells.
-Tissue fluid supplies cells with glucose, oxygen and other substances. Carbon dioxide and other metabolic wastes diffuse out of the cells and into the tissue fluid to be excreted. Much of the tissue fluid returns to the blood.

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15
Q

Exchange of materials

A

-Glucose, oxygen and ions, diffuse from a high concentration in the tissue fluid into the body cells.
-At the same time, carbon dioxide and other metabolic waste diffuse out of the cells into the tissue fluid for excretion.

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16
Q

Lymphatic return

A

Lymphatic vessels absorb excess tissue fluid and return it as lymph to the circulatory system.

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17
Q

Lymphatic system and flow of lymph

A

-Flow of lymph brought about by compression when muscles contract during body movements.
-Backflow of lymph is prevented because lymph vessels have valves
-Lymph eventually returns to the blood stream via two lymphatic ducts, which enter into veins in the arms

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18
Q

Heart

A

The heart is a muscular pump made up of cardiac muscle

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19
Q

The left ventricle has a thicker muscular wall than the right ventricle

A

Blood pumped from the left ventricle must be moved all the way around the body the right ventricle pumps blood only to the lungs

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20
Q

Semi-lunar valves

A

Prevent blood flowing backward from the arteries leaving the heart into the ventricles

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21
Q

Atrioventricular valves
(Bicuspid)

A

Prevent blood flowing backward from the left ventricle into left atrium.

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22
Q

Atrioventricular valves
(Tricuspid)

A

Prevent blood flowing backward from the right ventricle into right atrium.

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23
Q

Coronary Artery

A

The coronary arteries supply the heart muscle with OXYGEN and nutrients.

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24
Q

The flow of blood around the body

A

-Blood returns back to the heart through the vena cava.
-Blood enters the right atrium
-The right atrium contracts and forces blood through the triscupid valve(AV Valve)
-Blood enters the right ventricle
-The right ventricle contracts and forces blood through the pulmonary valve (semi lunar valve).
-Blood travels in the pulmonary artery to the lungs.
-When the blood reaches the alveoli, oxygen diffuses into the blood and carbon dioxide diffuses into the alveoli.
-Blood returns back to the heart through the pulmonary vein
-Blood enters the left atrium
-The left atrium contracts and forces blood through the biscupid valve(AV Valve)
-Blood enters the left ventricle.
-The left ventricle contracts and forces blood through the aortic valve (semi lunar valve).
-Blood travels in the
aorta to the body.
-When the blood reaches the
body cells, oxygen diffuses into the cells and carbon dioxide diffuses into the blood

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25
Q

volume of blood pumped from the left and right ventricle.

A

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

26
Q

Cardiac Output

A

The volume of blood pumped out of a ventricle per minute is called the cardiac output, and depends on two factors:
the stroke volume – the volume of blood pumped by the left ventricle in each heart beat. A typical value for an adult at rest is 75 ml.
the heart rate – the number of times the heart beats per minute. A typical value for an adult at rest is 70 bpm.

27
Q

Cardiac Output formula

A

stroke volume x heart rate

28
Q

Cardiac cycle

A

-A heartbeat corresponds to one cardiac cycle.
-There are three phases to one cardiac cycle.
-During which the muscles of the atria and ventricles contract and relax, and heart valves open and close.

29
Q

The period of contraction is called…

A

Systole

30
Q

The period of relaxation is called…

A

Diastole

31
Q

Atrial Systole(approx 0.1 sec)

A

Atria contracts simultaneously, ventricles are relaxing(diastole), the AV valves open and the SL Valves are closed.

32
Q

Ventricular Systole(approx 0.3 sec)

A

Atria relax(diastole), ventricles contract simultaneously(systole), the AV valves close, the SL valves open, blood is pumped out of the heart

33
Q

Atrial and Ventricular Diastole(approx 0.4 sec)

A

Atria and Ventricles relax(diastole). The AV valves open, the SL valves are closed. During diastole blood returning to the atria flows in the ventricles

34
Q

Cardiac Cycle Summary

A

-Atrial systole transfers the remainder of the blood through the atrio-ventricular (AV) valves to the ventricles.
-Ventricular systole closes the AV valves and pumps the blood out through the semi lunar (SL) valves to the aorta and pulmonary artery
-During diastole, blood returning to the atria flows Into the ventricles.
-In diastole, the higher pressure in the arteries closes the SL valves.

35
Q

Valves in the cardiac cycle

A

Valves are controlled by pressure changes in the heart chambers:
-High pressure behind the valve forces it to open
-High pressure in front of the valve closes it

36
Q

Valves and Heart Sounds

A

-The opening and closing of the AV and SL valves are responsible for the heart sounds heard with a stethoscope.
-The LUBB – DUBB sound arises from the closing of
the two AV valves.
the two semi-lunar valves

37
Q

Valves and Heart Sounds pt.2

A

LUBB - at the beginning of Ventricular Systole when the ventricular pressure exceed atrial pressure.

DUBB - at the beginning of Ventricular Diastole arterial pressure exceeds that on the ventricles.

38
Q

Control of the Heart

A

The heart beat is brought about by the activity of the pacemaker and the conducting system of the heart

39
Q

name and location of natural pacemaker

A

Sinoatrial node found in the wall of the right atrium

40
Q

SA node function

A

The SA node sends out spontaneous electrical impulses across the walls of both atria causing them to contract simultaneously and to pump blood into the ventricles causing ATRIAL SYSTOLE

41
Q

CAS of the Auto-rhythmic cells of the SAN

A

The heartbeat originates in the heart itself. The auto-rhythmic cells of the sino-atrial node (SAN) or pacemaker, located in the wall of the right atrium, set the rate at which the heart contracts.
The timing of cardiac muscle cell contraction is controlled by impulses from the SAN spreading through the atria causing atrial systole

42
Q

Second node and location

A

Atrioventricular node found in the centre of heart

43
Q

CAS of the AV node

A

The impulses from the SAN then travel to the atrioventricular node (AVN), 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
-The action of the SAN will cause the heart to beat 60-80 beat/min without input from the nervous system.

44
Q

Nervous Control of the heart

A

-The medulla regulates the rate of the sinoatrial node through the antagonistic action of the autonomic nervous system (ANS).
-A sympathetic nerve releases noradrenaline which increases the heart rate.
-A parasympathetic nerve releases acetylcholine which decreases the heart rate.

45
Q

Nervous and hormonal control

A

Under certain circumstances (exercise or stress), the sympathetic nervous system acts on the adrenal glands, making them release the hormone adrenaline.

This hormone increases the heart rate.

46
Q

Artificial pacemakers

A

-Artificial pacemakers are devices implanted in people whose heart’s electrical conduction system is not working properly.
-Problems include the SAN not firing, and blockage or disruption of impulses between the SAN and AVN, or in the conducting fibres.
-Pacemakers monitor the heart’s electrical activity and stimulate the ventricles or atria to contract when necessary. Impulses are transmitted down electrodes implanted in the muscular walls.

47
Q

What are electrocardiograms?

A

-The electrical activity of the heart can be monitored by an electrocardiograph
-Several electrodes are attached to specific places on a person’s chest and limbs. These detect changes in the heart by measuring current at the skin surface.
-The machine then draws an electrocardiogram (ECG

48
Q

CAS of ECGs

A

-Impulses in the heart generate currents that can be detected by an electrocardiogram (ECG).
-Interpretation of electrocardiograms (ECG) should involve calculation of heart rate and linking of the waves to atrial systole, ventricular systole and diastole.

49
Q

P wave

A

Atrial Systole(sinoatrial node electrical impulses)

50
Q

QRS complex

A

Ventricular Systole

51
Q

T wave

A

Diastole(recovery)

52
Q

Pressure Changes

A

Throughout the cardiac cycle, pressure changes take place in the atria, ventricles and arteries
Pressures can be recorded and illustrated in graphical form
The graph on the next slide shows pressure changes in the left side of the heart and the aorta
A similar graph can be drawn for the right side of the heart.
Such a graph is similar in shape but all the pressures readings are of a lower value

53
Q

Pressure changes diagram

A

-At W Ventricular pressure exceeds atrial pressure and AV valves close (LUBB)
-At X Ventricular pressure exceeds aortic pressure and SL valves open
-At Y Arterial pressure exceeds Ventricular pressure and SL valves close (DUBB)
-At Z Atrial pressure exceeds ventricular pressure and AV valves open,

54
Q

Blood Pressure

A

Blood pressure increases during ventricular systole and decreases during diastole.
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. A typical blood pressure reading for a young adult is 120/80 mmHg.

55
Q

Blood Pressure values

A

-During ventricular systole (contraction) the pressure of the blood in the aorta. e.g. Normal 120 mmHg
-During ventricular diastole (relaxing) the pressure of blood in the aorta is less e.g. Normal 80 mmHg.

56
Q

Changes to blood pressure

A

There is a progressive drop in blood pressure as blood travels away from the heart, around the body, dropping to almost zero by the time it reaches the right atrium again.

57
Q

Why does Pressure Decrease

A

As blood flows through narrow blood vessels, friction occurs between the blood and vessel wall, making the wall resist blood flow.
This resistance causes a decrease in pressure.

58
Q

The Arterioles show greatest decrease in pressure, why

A

The biggest pressure drop is when blood enters arterioles as they present the greatest resistance to blood flow
This is because there are many arterioles branching from one artery which increases the surface area and so increases friction.
Their narrow diameter also mean more bloods come into contact with the walls of the arterioles and increases friction.

59
Q

Hypertension

A

Hypertension (high blood pressure) is a major risk factor for many diseases including coronary heart disease.

60
Q

Hypertension examples

A

Prolonged elevation of blood pressure when at rest.

resting BP greater than 140/90mmHg

Common in adults over the age of 35.

Associated with higher incidence of Coronary heart disease and stroke.

61
Q
A

Higher Biology (12 decks)

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