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The Cardiovascular System

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Title: The Cardiovascular System


1
The Cardiovascular System
  • The Heart and Related Blood Vessels

2
Introduction
  • The major function of the cardiovascular system
    is to transport substances throughout the body.
  • The heart and blood vessels are the major
    components of the cardiovascular system.

3
Introduction
  • The nutrients and waste products of the body are
    transported through the blood vessels with a push
    from the heart.
  • The blood is connective tissue transported
    through the blood vessels which act as highways
    for the blood (vehicles).

4
Introduction
  • Cardiology is the study of the heart and diseases
    associated with it.

5
The Heart
  • The heart is located in the thoracic cavity
    behind the sternum.
  • The size of a persons heart is approximately the
    same size as their closed fist.
  • On average it weighs about 300g.

6
The Heart
  • The base of the heart is the wide superior
    portion.
  • The apex is the inferior point.

7
The Heart
  • The heart is covered by a sac made up of two
    layers.
  • 1.) Serous Pericardium
  • 2.) Fibrous Pericardium

8
The Heart
  • The serous pericardium is made up of the visceral
    and parietal pericardium which are delicate
    layers of epithelial and connective tissue which
    aid in lubrication of the heart.

9
The Heart
  • The fibrous pericardium is an outer tough layer
    of connective tissue that prevents the heart from
    over stretching.

10
The Heart
  • The wall of the heart is composed of three
    layers
  • 1.) epicardium, outer most layer
  • 2.) myocardium, middle layer made up of cardiac
    muscle(bulk of heart)
  • 3.) endocardium, inner layer and smooth inner
    wall of heart

11
The Heart
  • The heart is made up of four chambers.
  • The top chambers are atria.
  • The bottom chambers are ventricles.

12
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13
The Heart
  • The atria are broken up into the right and left
    atria which are separated by the interatrial
    septum.
  • The atria receive blood from veins.
  • They are very thin walled.

14
The Heart
  • The ventricles are divided into the right and
    left ventricle which are separated by the
    interventricular septum.
  • Ventricles are responsible for pumping blood from
    the heart into arteries.
  • They have much thicker walls because of their
    active role in pumping blood.

15
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16
The Heart
  • The major blood vessels associated with the heart
    are veins and arteries.
  • Arteries carry blood away from the heart.
  • Veins carry blood to the heart.

17
Blood Vessels
  • Arteries carry blood that is high in oxygen and
    low in carbon dioxide away from the heart.
  • - The aorta carries blood from the left
    ventricle to the body.
  • The pulmonary arteries carry blood from the right
    ventricle to the lungs.
  • The coronary arteries carry blood to the
    myocardium.

18
Blood Vessels
  • Veins carry blood that is high in carbon dioxide
    and low in oxygen into the heart.
  • - The superior vena cava brings blood from the
    head and upper limbs and the inferior vena cava
    brings blood from the trunk and lower limbs.
  • - The coronary sinus brings blood back from the
    myocardium.
  • - The pulmonary veins bring blood from the lungs
    into the left atrium.

19
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20
Valves of the Heart
  • The general function of heart valves is to
    prevent the back flow of blood.

21
Valves of the Heart
  • Atrioventricular valves are valves within the
    heart that separate the atria and the ventricles.
  • The tricuspid valve lies between the right atrium
    and ventricle.
  • The bicuspid valve lies between the left atrium
    and ventricle.

22
Valves of the Heart
  • These valves are opened and closed with the help
    of muscles called papillary muscles.
  • The valves are held in place by tendon like cords
    called chordae tendineae.

23
Valves of the Heart
  • The semilunar valves are valves located near the
    end of the major blood vessels into and out of
    the heart.
  • The pulmonary semilunar valve is found in the
    pulmonary trunk.
  • The aortic semilunar valve is found in the aorta.

24
Valves of the Heart
  • These valves can become damaged or diseased
    requiring them to be changed.
  • Heart Valves
  • Heart Valve Surgery

25
Pathway of Blood
  • The general path taken by all blood is the same
  • 1.) The heart pumps oxygenated blood out of the
    left ventricle to aorta which branches out into
    arteries.
  • 2.) The arteries are then branched and funneled
    into arterioles.

26
Pathway of Blood
  • 3.) The arterioles are then in turn branched out
    and funneled into capillaries which are located
    in the tissues of your body.
  • This is where gas exchange occurs, which is
    the swapping of oxygen and carbon dioxide by
    the blood.
  • 4.) The capillaries then begin to get larger and
    branch together into venules.

27
Pathway of Blood
  • 5.) The venules branch together into veins and
    the veins then come together to form the vena
    cava.
  • 6.) The vena cava then enter the heart in the
    right atrium.

28
Pathway of Blood
  • The pathway of blood through the heart and lungs
    is known as the pulmonary circuit.
  • 1.) It begins in the right atrium with
    deoxygenated blood entering the heart.
  • 2.) The tricuspid valve then opens and the blood
    rushes into the right ventricle

29
Pathway of Blood
  • 3.) The pulmonary semi-lunar valve opens the
    pulmonary trunk and the deoxygenated blood
    travels into the pulmonary arteries.
  • 4.) The blood then gets funneled into the
    capillaries in the lungs, which run along side
    alveoli.
  • 5.) The blood in the alveoli picks up oxygen from
    the walls of the lungs and the blood is
    transferred to the pulmonary veins.

30
Pathway of Blood
  • 6.) The pulmonary veins then take the oxygenated
    blood into the left atrium
  • 7.) The tricuspid valve of the left atrium then
    opens and the blood is forced into the left
    ventricle.
  • 8.) The aortic semi-lunar valve then opens and
    the left ventricle pumps the blood into the aorta
    which transports blood throughout the body.

31
Pathway of Blood
  • The supply of blood for the heart is carried to
    the myocardium by the coronary artery and sinus.
  • 1.) Coronary circulation begins in the ascending
    aorta with oxygenated blood.
  • 2.) The blood travels down one of two paths the
    right or left coronary artery.

32
Pathway of Blood
  • The presence of multiple pathways for blood is
    common throughout the body, they are known as
    anastosomes.
  • 3.) The capillaries within the myocardium then
    undergo gas exchange.
  • 4.) The cardiac veins then transport blood to
    the coronary sinus which takes the blood back to
    the right atrium.

33
Heart Disorders and Diseases
  • Blood clots, fatty atherosclerotic plaques, and
    smooth muscle spasms within the coronary vessels
    lead to most heart problems.

34
Heart Diseases and Disorders
  • Go to the following link
  • http//www.wisc-online.com/objects/OTA1604/OTA160
    4.swf
  • Make a list outlining the basic causes and
    severity of the four disorders found there.
  • Make predictions based on your knowledge of the
    heart on how easily these disorders can be
    treated.

35
Heart Disorders and Diseases
  • Common heart disorders include
  • 1.)An ischemia is a reduction of blood
    flow.
  • 2.) Hypoxia is a reduced oxygen supply due to
    an ischemia.
  • 3.) An angina pectoris is severe pain that
    accompanies an ischemia.
  • -A crushing pain radiating down the left
    arm.

36
Heart Disorders and Diseases
  • 4.) A myocardial infarction is a heart attack.
  • - A heart attack is the death of a portion
    of myocardium due to a thrombus (blood clot).
  • 5.) Reperfusion damage occurs when oxygen
    deprived tissue has its blood supply
    regenerated, the formation of oxygen free
    radicals in the blood damages cardiac tissue.

37
Cardiac Conduction System (CSC)
  • There are specialized portions of cardiac muscle
    tissue that are autorhythmic or self exciting.
  • This autorhythmic property of portions of cardiac
    tissue is what generates the electrical signal
    causing the heart to beat.

38
Cardiac Conduction System (CSC)
  • The sinoatrial node is located in the right
    uppermost atrial wall.
  • This node generates an electrical signal that is
    passed throughout atrial muscle fibers causing
    them to contract.
  • This pacemaker generates an electrical signal 60
    to 100 times per minute in a resting state.

39
Cardiac Conduction Systems (CSC)
  • The atrioventricular node (A-V Node) is located
    in the interatrial septum.
  • - It acts as a delay mechanism which
    allows for the ventricles to fill by holding up
    the electrical signal.

40
Cardiac Conduction System (CSC)
  • The atrioventricular bundle acts as the only
    electrical transfer station between the atria
    and ventricles.
  • The right and left bundle branches lead downward
    toward the apex of the heart allowing the
    electrical signal to propagate.

41
Cardiac Conduction System (CSC)
  • Throughout the heart the electrical signal makes
    contact with the muscle fibers due to the
    purkinje fibers, which are primarily responsible
    for the large scale contraction of the
    ventricles.
  • Electrical Signals of Beating Heart

42
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43
Physiology of a Cardiac Muscle Contraction
  • The contractile fibers of the heart have a
    resting potential of -90mV and the opening of Na
    channels depolarizes them and drops the potential
    to -70mV.
  • This rapid depolarization causes the release of
    Ca2 ions which are a part of the muscle
    contraction.

44
Physiology of a Cardiac Muscle Contraction
  • The K channels are then opened triggering a
    repolarization of the muscle fibers.
  • After the contraction is complete there is a
    refractory period in which no contraction can
    occur.
  • - This is the time that calcium, sodium and
    potassium levels are resupplied.

45
Electrocardiogram (ECG or EKG)
  • An ECG is a recording of the electrical changes
    that occur in the myocardium during the cardiac
    cycle.
  • There are three waves per heart beat.
  • ECG Tutorial

46
Electrocardiogram(ECG or EKG)
  • The first small upward wave is called the p wave.
  • This wave represents atrial depolarization.

47
Electrocardiogram(ECG or EKG)
  • The QRS Complex is a grouping of waves consisting
    of a downward deflection followed by a large up
    sweep and ending as a small downward wave.
  • - This wave is the start of the ventricular
    contraction.

48
Electrocardiogram(ECG or EKG)
  • The t wave is the dome shaped upward deflection.
  • - This wave represents the repolarization of
    the ventricles.

49
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50
Cardiac Cycle
  • The cardiac cycle is made up of alternating
    contractions and relaxations.
  • The contractions are known as systole.
  • The relaxations are known as diastole.
  • There is a systole and diastole for both atria
    and ventricles.

51
Cardiac Cycle
  • When taking a blood pressure there are two
    numbers measured.
  • The first number is systole and the second is
    diastole.
  • The perfect healthy blood pressure is 120/80,
    these numbers are pressures calculated based on
    readings done with a blood pressure cuff.

52
Cardiac Output
  • A persons cardiac output is the volume of blood
    pumped by each ventricle in one minute.
  • CO heart rate ? stroke volume
  • Stroke volume is the amount of blood pumped out
    by a ventricle with each beat.
  • The normal CO is 5 liters.

53
Blood Vessels
  • Blood vessels are made up of three layers.
  • 1.) tunica interna, is the inside layer of the
    vessel
  • 2.) tunica media, is the middle layer
  • 3.) tunica externa, is the outer layer

54
Blood Vessels
  • The tunica media is much thinner in the walls of
    veins than it is in arteries.
  • Artery walls are thicker so it is easier for
    oxygen and nutrients to diffuse out where they
    are supposed to.

55
Blood
  • Blood is a liquid tissue that flows through the
    blood vessel.
  • Blood consists of plasma, blood cells and
    platelets

56
Blood
  • In the average human man there are over 5,000,000
    red blood cells (rbc) per cubic millimeter of
    blood.
  • In the average human woman there are over
    4,500,000 rbc per cubic millimeter of blood.

57
Blood
  • The primary function of rbcs is to carry oxygen
    which is picked up by and attached to the bloods
    hemoglobin.
  • Hemoglobin is a protein containing iron which is
    bright red in the presence of oxygen and burgundy
    without oxygen.

58
Blood
  • The white blood cells of the body act as a line
    of defense in the blood.
  • They are macrophages which are responsible for
    attacking and destroying foreign bodies in the
    blood.

59
Blood
  • There are far less wbcs in the blood,
    approximately 5000-9000 per mm3.
  • There are two types of wbcs
  • 1.) granular, grainy exterior texture
  • 2.) agranular, smooth exterior texture
  • The major difference between the two is the type
    of foreign bodies they are responsible for
    destroying.

60
Blood
  • When a vessel opens to the outside the
    coagulation of the blood by the formation of a
    platelet plug occurs.
  • Platelets are small pieces of cellular material
    which originate by breaking off pieces of bone
    marrow.

61
Blood
  • Plasma is the liquid in which all blood particles
    are suspended.
  • Plasma is where nutrients, salts and hormones are
    transported throughout the body.
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