Title: The Cardiovascular System
1The Cardiovascular System
- The Heart and Related Blood Vessels
2Introduction
- 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.
3Introduction
- 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).
4Introduction
- Cardiology is the study of the heart and diseases
associated with it.
5The 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.
6The Heart
- The base of the heart is the wide superior
portion. - The apex is the inferior point.
7The Heart
- The heart is covered by a sac made up of two
layers. - 1.) Serous Pericardium
- 2.) Fibrous Pericardium
8The 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.
9The Heart
- The fibrous pericardium is an outer tough layer
of connective tissue that prevents the heart from
over stretching.
10The 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
11The Heart
- The heart is made up of four chambers.
- The top chambers are atria.
- The bottom chambers are ventricles.
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13The 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.
14The 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.
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16The 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.
17Blood 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.
18Blood 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.
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20Valves of the Heart
- The general function of heart valves is to
prevent the back flow of blood.
21Valves 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.
22Valves 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.
23Valves 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.
24Valves of the Heart
- These valves can become damaged or diseased
requiring them to be changed. - Heart Valves
- Heart Valve Surgery
25Pathway 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.
26Pathway 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.
27Pathway 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.
28Pathway 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
29Pathway 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.
30Pathway 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.
31Pathway 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.
32Pathway 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.
33Heart Disorders and Diseases
- Blood clots, fatty atherosclerotic plaques, and
smooth muscle spasms within the coronary vessels
lead to most heart problems.
34Heart 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.
35Heart 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.
36Heart 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.
37Cardiac 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.
38Cardiac 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.
39Cardiac 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.
40Cardiac 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.
41Cardiac 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
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43Physiology 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.
44Physiology 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.
45Electrocardiogram (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
46Electrocardiogram(ECG or EKG)
- The first small upward wave is called the p wave.
- This wave represents atrial depolarization.
47Electrocardiogram(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.
48Electrocardiogram(ECG or EKG)
- The t wave is the dome shaped upward deflection.
- - This wave represents the repolarization of
the ventricles.
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50Cardiac 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.
51Cardiac 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.
52Cardiac 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.
53Blood 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
54Blood 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.
55Blood
- Blood is a liquid tissue that flows through the
blood vessel. - Blood consists of plasma, blood cells and
platelets
56Blood
- 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.
57Blood
- 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.
58Blood
- 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.
59Blood
- 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.
60Blood
- 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.
61Blood
- Plasma is the liquid in which all blood particles
are suspended. - Plasma is where nutrients, salts and hormones are
transported throughout the body.