CARDIOLVASCULAR PRES

1. CARDIOVASCULAR SYSTEM
PRESENTERS:
BRIDGETTE TEMU
BASILISA KALANGA
FACILITORS : DR NDILE
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2. THE CARDIOVASCULAR SYSTEM
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3. OBJECTIVES
At the end of this session everyone should be able to
define :
 Cardiovascular, heart and blood vessels
 Understand briefly the Anatomy of the heart
 Explain the anatomy and physiology of blood vessels
 Describe the blood circulatatory system based
pulmonary, coronary and systemic circulation
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4. INTRODUCTION
 Heart is relatively small, roughly the same size (but
not the same shape) as your closed fist. It is about
12 cm long, 9 cm wide at its broadest point, and
6 cm thick, with an average mass of 250 g in adult
females and 300 g in adult males.
 The heart rests on the diaphragm, near the midline
of the thoracic cavity.
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5. DEFINITION OF TERMS
 The cardiovascular system is composed of the heart
and a closed system of vessels including the arteries,
veins, and capillaries.
 The heart is a hollow muscular organ that is situated
between the lungs in the middle of the mediastinum
and enclosed within the pericardium.
 Blood vessels is the flexible tubular canals through
which blood circulates in the body. Arteries, veins, and
capillaries are all kinds of blood vessels.
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6. ANATOMY OF THE HEART
 The human heart is mascular organ containing four chambers that
situated just the left of the midline of the thoracic cavity.
 It lies obliquely in the chest, behind the body of the sternum, just
left of the midline, and above the diaphragm.
 The heart is conical in shape and approximately the size of a
clenched fist. It rhythmically pumps 5 to 6 liters of blood per
minute throughout the body.
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7. CONT….
Heart is responsible for the following
functions:
 Maintaining homeostasis
 Providing a means of exchanging
nutrient- rich blood for waste products
 Oxygenating tissue throughout the body
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8. LAYERS OF THE HEART
The heart muscle has three layers and they are as follows:
 Epicardium. The epicardium or the visceral and
outermost layer is actually a part of the heart wall.
 Myocardium. The myocardium consists of thick bundles
of cardiac muscle twisted and whirled into ring like
arrangements and it is the layer that actually contracts.
 Endocardium. The endocardium is the innermost layer
of the heart and is a thin, glistening sheet of endothelium
that lines the heart chambers.
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9. • PERICARDIUM • outer membrane of the heart
• 2 layers 1. Parietal pericardium: external (outer) layer
2. Visceral pericardium (epicardium): part of the
heart wall
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10. • Functions: • protection – physical barrier
• anchors heart to other structures
• provides lubrication to reduce friction – allows
the heart to beat easily
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11. 1. Epicardium: outer portion (visceral
pericardium)
• 3 layers
• THE HEART WALL
EPICARDIUM
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12. 2. Myocardium: middle layer consists
of twisted cardiac muscle
• THIS IS THE LAYER THAT ACTUALLY
CONTRACTS
MYOCARDIUM
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13. 3. Endocardium: inner layer made of
epithelial tissue
ENDOCARDIUM
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14. CHAMBERS OF THE HEART
 Chambers of the Heart
 The heart has four hollow chambers, or cavities: two atria and two
ventricles.
 Receiving chambers. The two superior atria are primarily the
receiving chambers, they play a lighter role in the pumping activity of
the heart.
 Discharging chambers. The two inferior, thick-walled ventricles are
the discharging chambers, or actual pumps of the heart when they
contract, blood is propelled out of the heart and into the circulation.
 Septum. The septum that divides the heart longitudinally is referred to
as either the interventricular septum or the interatrial septum,
depending on which chamber it separates.
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15. CONT……
 The two AV valves, tricuspid and mitral, prevent the
backflow of blood into the atria during ventricular
contraction. The tricuspid valve, located between the right
atrium and right ventricle, consists of three somewhat
triangular cusps.
 The mitral valve is located between the left atrium and left
ventricle and is formed by only two cusps. The tricuspid
and mitral valves open when the ventricles relax,
permitting blood to enter the ventricles from the atria.
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16. CONT…
 The semilunar valves, each of which has three cusps, are
the pulmonic and aortic valves. The semilunar valves
open during ventricular contraction, allowing the
forward flow of blood into the pulmonary artery and
aorta. During ventricular relaxation, the valves close,
preventing the backflow of blood into the ventricles.
 The pulmonic valve is positioned between the right
ventricle and the pulmonary artery. The aortic valve is
located between the left ventricle and the aorta.
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17. • HEART CHAMBERS
• 4 chambers
• Atrium (left/right atria) • divided by the INTERATRIAL SEPTUM
• Function of Atria: receives blood from veins
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18. • RIGHT ATRIA • receives blood from superior & inferior
vena cava
• blood that’s been used
• oxygen poor – high in CO2
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19. • receives blood from pulmonary veins
• LEFT ATRIA
• coming from lungs
• rich in oxygen
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20. • Ventricles (left/right) • muscular pumps – divided by INTERVENTRICULAR
SEPTUM
(pig heart)
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21. • RIGHT VENTRICLE • receives blood from the right atria (O2 poor)
• pumps blood to the lungs through the PULMONARY
ARTERIES
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22. • LEFT VENTRICLE • receives blood (O2 rich) from the left atrium
• pumps blood to the body through the AORTA
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24. BLOOD VESSSELS
 5 main types
 Arteries – carry blood
AWAY from the heart
 Arterioles
 Capillaries – site of
exchange
 Venules
 Veins – carry blood TO
the heart
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25. CONT…
There are 3 layers or tunics in the blood
vessels
 Tunica interna (intima)
 Tunica media
 Tunica externa
Modifications account for 5 types of blood
vessels and their structural/ functional
differences
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26. CONT…
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27. STRUCTURE AND FUNCTION
 Tunica interna (intima)
 Inner lining in direct contact with blood
 Endothelium continuous with endocardial lining of heart
 Active role in vessel-related activities
 Tunica media
 Muscular and connective tissue layer
 Greatest variation among vessel types
 Smooth muscle regulates diameter of lumen
 Tunica externa
 Elastic and collagen fibers
 Vasa vasorum
 Helps anchor vessel to surrounding tissue
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28. ARTERIES
Arteries are tough, tensile, and less distensible than veins.
The tough and tensile walls protect the arteries against
damage as the arterial pressure increases after
ventricular contraction
layers of typical blood vessel
- Thick muscular-to-elastic tunica media
- High compliance – walls stretch and expand in
response to pressure without tearing
- Vasoconstriction – decrease in lumen diameter
Vasodilation – increase in lumen diameter
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29. CONT…
 Elastic artery
-Largest arteries
-Largest diameter but walls relatively
thin
-Function as pressure reservoir
-Help propel blood forward while
ventricles relaxing
-Also known as conducting arteries –
conduct blood to medium-sized arteries
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30. CONT…
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31. ARTERIOLES
 Abundant microscopic vessels
 Metarteriole has precapillary sphincter which
monitors blood flow into capillary
 Sympathetic innervation and local chemical
mediators can alter diameter and thus blood
flow and resistance
 Resistance vessels – resistance is opposition to
blood flow into cappillary bed
 Vasoconstriction can raise blood pressure
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32. CAPILLARIES
Capillaries
 Smallest blood vessels connect arterial outflow and venous return
 Microcirculation – flow from metarteriole through capillaries and into
post capillary venule
 Exchange vessels – primary function is exchange between blood and
interstitial fluid
 Lack tunica media and tunica external
 Substances pass through just one layer of endothelial cells and basement
membrane
 Capillary beds – arise from single metarteriole
 Vasomotor – intermittent contraction and relaxation
 Throughfare channel – bypasses capillary bed
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33.  Capillaries
 Smallest blood vessels
connect arterial outflow
and venous return
 Microcirculation – flow
from metarteriole
through capillaries and
into post capillary
venule
 Exchange vessels –
primary function is
exchange between
blood and interstitial
fluid
 Lack tunica media and
tunica external
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34. CONT..
 There are 3 types of capillaries
1. Continuous
 Endothelial cell membranes from
continuous tube
2. Fenestrated
 Have fenestrations or pores
3. Sinusoids
 Wider and more winding
 Unusually large fenestrations
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35. VEINS
Blood vessels are tubes forming blood circulation system of body
carrying in most cases oxygen-depleted blood toward the heart.
Structural changes not as distinct as in arteries
 In general, very thin walls in relation to total diameter
The also have same 3 layers
I. Tunica interna thinner than arteries
II. Tunica interna thinner with little smooth muscle
III. Tunica externa thickest layer
 Not designed to withstand high pressure
 Valves – folds on tunica interna forming cusps
 Aid in venous return by preventing backflow
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36. VENULES
Venules
 Thinner walls than arterial counterparts
 Postcapillary venule – smallest venule
 Form part of microcirculatory exchange unit with
capillaries
 Muscular venules have thicker walls with 1 or 2 layers
of smooth muscle
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37. CONT…
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38. BLOOD CIRCULATION
 Pulmonary circulation
 Systemic circulation
 Coronary circulation
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39. Unoxygenated
blood comes in
from the top of the
body through the
superior vena
cava and
Unoxygenated
blood comes in
from the lower
body though the
inferior vena cava.
UNoxygenated
blood enters the
atrium on the right
side of the heart.
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40. The
atrium
contracts
and the
tricuspid
valve
opens,
forcing
the blood
down into
the
ventricle.
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41. The ventricle
contracts.
This forces
the
unoxygenated
blood through
the
pulmonary
valve and into
the
pulmonary
arteries.
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42. The right pulmonary
artery takes the
unoxygenated blood
to the right lung.
The left pulmonary
artery takes the
unoxygenated blood
to the left lung.
THE PULMONARY
ARTERIES ARE THE
ONLY ARTERIES
THAT CARRY
UNOXYGENEATED
BLOOD.
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43. Oxygenated blood
from the right lung
returns to the heart
through the right
pulmonary vein.
Oxygenated blood
from the left lung
returns to the heart
through the left
pulmonary vein.
THE PULMONARY
VEINS ARE THE
ONLY VEINS THAT
CARRY
OXYGENATED
BLOOD.
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44. Oxygenated
blood then
enters the left
atrium.
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45. The left atrium
contracts.
This forces
the
oxygenated
blood through
the mitral
(bicuspid)
valve into the
left ventricle.
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46. Left ventricle
contracts and
Oxygenated
blood is forced
into the aorta
to be carried
to the rest of
the body.
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47. PULMONARY CIRCULATION
 Pulmonary circulation moves blood between the
heart and the lungs. It transports deoxygenated
blood to the lungs to absorb oxygen and release
carbon dioxide.
 The oxygenated blood then flows back to the
heart.
 Systemic circulation moves blood between the
heart and the rest of the body. It sends oxygenated
blood out to cells and returns deoxygenated blood
to the heart.
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48. CONT….
 The heart pumps oxygenated blood out of the left
ventricle and into the aorta to begin systemic circulation.
After the blood has supplied cells throughout the body
with oxygen and nutrients, it returns deoxygenated blood
to the right atrium of the heart.
 The deoxygenated blood shoots down from the right
atrium to the right ventricle.
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49. CONT…
 The heart then pumps it out of the right ventricle and into
the pulmonary arteries to begin pulmonary circulation. The
blood moves to the lungs, exchanges carbon dioxide for
oxygen, and returns to the left atrium.
 The oxygenated blood shoots from the left atrium to the left
ventricle below, to begin systemic circulation again.
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50. CONT…….
 The circulatory and respiratory systems work together to
sustain the body with oxygen and to remove carbon
dioxide.
 Pulmonary circulation facilitates the process of external
respiration: Deoxygenated blood flows into the lungs.
 It absorbs oxygen from tiny air sacs (the alveoli) and
releases carbon dioxide to be exhaled.
 Systemic circulation facilitates internal respiration:
Oxygenated blood flows into capillaries through the rest
of the body. The blood diffuses oxygen into cells and
absorbs carbon dioxide.
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51. CONT….
 In the pulmonary loop, deoxygenated blood exits the right ventricle of
the heart and passes through the pulmonary trunk.
 The pulmonary trunk splits into the right and left pulmonary arteries.
These arteries transport the deoxygenated blood to arterioles and
capillary beds in the lungs.
 There, carbon dioxide is released and oxygen is absorbed. Oxygenated
blood then passes from the capillary beds through venues into the
pulmonary veins.
 The pulmonary veins transport it to the left atrium of the heart. The
pulmonary arteries are the only arteries that carry deoxygenated blood,
and the pulmonary veins are the only veins that carry oxygenated blood.
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52. SYSTEMIC CIRCULATION
 The largest part of the circulatory system in which oxygen-rich
blood flows to all organs and body tissues, except the heart, and
lungs
 In the systemic loop, oxygenated blood is pumped from the left
ventricle of the heart through the aorta, the largest artery in the
body.
 The blood moves from the aorta through the systemic arteries,
then to arterioles and capillary beds that supply body tissues.
Here, oxygen and nutrients are released and carbon dioxide and
other waste substances are absorbed.
 Deoxygenated blood then moves from the capillary beds
through venues into the systemic veins.
 The systemic veins feed into the inferior and superior venae
cavae, the largest veins in the body.
 The venae cavae flow deoxygenated blood to the right atrium
of the heart.
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53. PATH OF BLOOD FLOW THROUGH
HEART
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54. CORONARY CIRCULATION
 Coronary circulation are movement of blood through the
tissues of the heart [cardiac muscle only]
 The coronary arteries is branch from the ascending aorta
and encircle the heart like a crown encircles the head.
While the heart is contracting, little blood flows in the
coronary arteries.
Two coronary arteries, the right and left coronary arteries,
branch from the ascending aorta and supply oxygenated
blood to the myocardium
 The left coronary artery passes inferior to the left auricle
and divides into the
-anterior interventricular
- circumflex branches.
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55. CONT…
 The anterior interventricular branch or left
anterior descending (LAD) artery is in the anterior
interventricular sulcus and supplies oxygenated
blood to the walls of both ventricles.
 The circumflex branch lies in the coronary sulcus
and distributes oxygenated blood to the walls of
the left ventricle and left atrium.
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56. CONT…
 After blood passes through the arteries of the coronary
circulation, it flows into capillaries, where it delivers oxygen
and nutrients to the heart muscle and collects carbon
dioxide and waste, and then moves into coronary veins.
 Most of the deoxygenated blood from the myocardium
drains into a large vascular sinus in the coronary sulcus on
the posterior surface of the heart, called the coronary
sinus.
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57. CONT….
 There are principal tributaries carrying blood into the
coronary sinus are the following:
a]Great cardiac vein in the anterior interventricular
sulcus, which drains the areas of the heart supplied by the
left coronary artery (left and right ventricles and left
atrium) •
b] Middle cardiac vein in the posterior
interventricular sulcus, which drains the areas supplied by
the posterior interventricular branch of the right coronary
artery (left and right ventricles)
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58. CONT…
 c] Small cardiac vein in the coronary sulcus,
which drains the right atrium and right ventricle •
Anterior cardiac veins, which drain the right
ventricle and open directly into the right atrium
 d]Anterior cardiac veins which drain the right
ventricle and open directly into the right atrium
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60. OTHER MAJOR ARTERIES OF THE SYSTEMIC
CIRCULATION
 Arterial Branches of the Ascending Aorta
 The aorta springs upward from the left ventricle of heart
as the ascending aorta.
 Coronary arteries. The only branches of the ascending
aorta are the right and left coronary arteries, which serve
the heart.
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61. CONT….
Arterial Branches of the
Ascending Aorta
 The aorta springs upward
from the left ventricle of
heart as the ascending aorta.
 Coronary arteries. The only
branches of the ascending
aorta are the right and left
coronary arteries, which
supply to the heart muscles.
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62. CONT…
 Arterial Branches of the Aortic Arch
 The aorta arches to the left as the aortic arch.
 Brachiocephalic trunk. The brachiocephalic trunk, the
first branch off the aortic arch, splits into the right
common carotid artery and right subclavian artery.
 Left common carotid artery. The left common carotid
artery is the second branch off the aortic arch and it
divides, forming the left internal carotid, which serves
the brain, and the left external carotid, which serves the
skin and muscles of the head and neck.
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63. CONT…
 Left subclavian artery. The third branch of the aortic
arch, the left subclavian artery, gives off an important
branch- the vertebral artery, which serves part of the
brain.
 Axillary artery. In the axilla, the subclavian artery
becomes the axillary artery.
 Brachial artery. the subclavian artery continues into the
arm as the brachial artery, which supplies the arm.
 Radial and ulnar arteries. At the elbow, the brachial
artery splits to form the radial and ulnar arteries, which
serve the forearm
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64. CONT…
 Arterial Branches of the Thoracic Aorta
 The aorta plunges downward through the thorax,
following the spine as the thoracic aorta.
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66. REFERENCES
 Anatomy and physiology saladin firth edition
 Principles of Anatomy and physiology 13th-Tortora
_Gerald J
 Anatomy and physiology of the cardiovascular system by
Jones and Bartlette
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