Anatomy and physiology of cardiovascular

1. Cardiovascular System Anatomy and Physiology
part one
Mohamed Shukri Elmi Lecturer kmtc
Garissa campus

2. OBJECTIVES
At the of this lecture you should be able :
State major function of the heart
Describe structure of the heart
Discuss blood vessel and it is main branches
Describe the physiology of the hear
Explain circulatory and conductivity system of heart
Describe capillary exchange physiology

3. Introduction

4. Functions of the Heart
The functions of the heart are as follows:
1. Managing blood supply. Variations in the rate and force of
heart contraction match blood flow to the changing metabolic
needs of the tissues during rest, exercise, and changes in body
position.
2. Producing blood pressure. Contractions of the heart produce
blood pressure, which is needed for blood flow through the
blood vessels

5. 3. Securing one-way blood flow. The valves of the heart secure
a one-way blood flow through the heart and blood vessels.
4. Transmitting blood. The heart separates the pulmonary and
systemic circulations, which ensures the flow of oxygenated
blood to tissues

6. Anatomy of the Heart
The cardiovascular system can be compared to a muscular pump
equipped with one-way valves and a system of large and small
plumbing tubes within which the blood travels.
 Weight. Approximately the size of a person’s fist,
the hollow, cone-shaped heart weighs less than a pound.
Mediastinum. Snugly enclosed within the inferior mediastinum,
the medial cavity of the thorax, the heart is flanked on each side
by the lungs

8. • Apex. It’s more pointed apex is directed toward the left hip and
rests on the diaphragm, approximately at the level of the fifth
intercostal space.
• Base. Its broad posterosuperior aspect, or base, from which the
great vessels of the body emerge, points toward the right
shoulder and lies beneath the second rib.
• Pericardium. The heart is enclosed in a double-walled sac
called the pericardium and is the outermost layer of the heart.

9. • Fibrous pericardium. The loosely fitting superficial part of this
sac is referred to as the fibrous pericardium, which helps protect
the heart and anchors it to surrounding structures such as the
diaphragm and sternum.
• Serous pericardium. Deep to the fibrous pericardium is the
slippery, two-layer serous pericardium, where its parietal layer
lines the interior of the fibrous pericardium

10. 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 ringlike 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 hat lines the
heart chambers.

11. 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

12. • Discharging chambers. The two inferior, thick-
walled ventricles are the discharging chambers, or actual
pumps of the heart wherein 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

13. Associated Great Vessels
• The great blood vessels provide a pathway for the entire
cardiac circulation to proceed.
• Superior and inferior vena cava. The heart receives
relatively oxygen-poor blood from the veins of the body
through the large superior and inferior vena cava and pumps it
through the pulmonary trunk

14. • Pulmonary arteries. The pulmonary trunk splits into the right
and left pulmonary arteries, which carry blood to the lungs,
where oxygen is picked up and carbon dioxide is unloaded.
• Pulmonary veins. Oxygen-rich blood drains from the lungs
and is returned to the left side of the heart through the four
pulmonary veins.
• Aorta. Blood returned to the left side of the heart is pumped out
of the heart into the aorta from which the systemic arteries
branch to supply essentially all body tissues

15. Heart Valves
The heart is equipped with four valves, which allow blood to flow
in only one direction through the heart chambers
• Atrioventricular valves. Atrioventricular or AV valves are
located between the atrial and ventricular chambers on each
side, and they prevent backflow into the atria when the
ventricles contract.
• Bicuspid valves. The left AV valve- the bicuspid or mitral
valve, consists of two flaps, or cusps, of endocardium

17. • Tricuspid valve. The right AV valve, the tricuspid valve, has
three flaps.
• Semilunar valve. The second set of valves, the semilunar
valves, guards the bases of the two large arteries leaving the
ventricular chambers, thus they are known as the pulmonary
and aortic semilunar valves

18. Cardiac Circulation Vessels
• Although the heart chambers are bathed with blood almost
continuously, the blood contained in the heart does not nourish
the myocardium.
• Coronary arteries. The coronary arteries branch from the base
of the aorta and encircle the heart in the coronary sulcus
(atrioventricular groove) at the junction of the atria and
ventricles, and these arteries are compressed when the
ventricles are contracting and fill when the heart is relaxed.
• Cardiac veins. The myocardium is drained by several cardiac
veins, which empty into an enlarged vessel on the posterior of
the heart called the coronary sinus

19. Blood Vessels
• Blood circulates inside the blood vessels, which form a closed
transport system, the so-called vascular system.
• Arteries. As the heart beats, blood is propelled into large
arteries leaving the heart.
• Arterioles. It then moves into successively smaller and smaller
arteries and then into arterioles, which feed the capillary
beds in the tissues.
• Veins. Capillary beds are drained by venules, which in turn
empty into veins that finally empty into the great veins entering
the heart

20. Tunics
• Except for the microscopic capillaries, the walls of the blood
vessels have three coats or tunics
• Tunica intima. The tunica intima, which lines the lumen, or
interior, of the vessels, is a thin layer of endothelium resting on
a basement membrane and decreases friction as blood flows
through the vessel lumen

21. • Tunica media. The tunica media is the bulky middle coat which
mostly consists of smooth muscle and elastic fibers that
constrict or dilate, making the blood pressure increase or
decrease.
• Tunica externa. The tunica externa is the outermost tunic
composed largely of fibrous connective tissue, and its function
is basically to support and protect the vessels

22. Major Arteries of the Systemic Circulation
• The major branches of the aorta and the organs they serve are
listed next in sequence from the heart
• 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

23. 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 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

24. • 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

25. Arterial Branches of the Thoracic Aorta
• The aorta plunges downward through the thorax, following the
spine as the thoracic aorta.
• Intercostal arteries. Ten pairs of intercostal arteries supply the
muscles of the thorax wall

26. Arterial Branches of the Abdominal Aorta
• Finally, the aorta passes through the diaphragm into the
abdominopelvic cavity, where it becomes the abdominal aorta.
• Celiac trunk. The celiac trunk is the first branch of the
abdominal aorta and has three branches: the left gastric
artery supplies the stomach; the splenic artery supplies the
spleen, and the common hepatic artery supplies the liver

27. • Superior mesenteric artery. The unpaired superior mesenteric
artery supplies most of the small intestine and the first half of
the large intestine or colon.
• Renal arteries. The renal arteries serve the kidneys.
• Gonadal arteries. The gonadal arteries supply the gonads, and
they are called ovarian arteries in females while in males they
are testicular arteries

28. • Lumbar arteries. The lumbar arteries are several pairs of
arteries serving the heavy muscles of the abdomen and trunk
walls.
• Inferior mesenteric artery. The inferior mesenteric artery is a
small, unpaired artery supplying the second half of the large
intestine.
• Common iliac arteries. The common iliac arteries are the final
branches of the abdominal aorta

29. Major Veins of the Systemic
Circulation
Major veins converge on the venae cavae, which enter the right
atrium of the heart.
• Veins Draining into the Superior Vena Cava
• Veins draining into the superior vena cava are named in a
distal-to-proximal direction; that is, in the same direction the
blood flows into the superior vena cava

30. • Radial and ulnar veins. The radial and ulnar veins are deep
veins draining the forearm; they unite to form the deep brachial
vein, which drains the arm and empties into the axillary vein in
the axillary region.
• Cephalic vein. The cephalic vein provides for the superficial
drainage of the lateral aspect of the arm and empties into the
axillary vein

31. • Basilic vein. The basilic vein is a superficial vein that drains the
medial aspect of the arm and empties into the brachial
vein proximally.
• Median cubital vein. The basilic and cephalic veins are joined
at the anterior aspect of the elbow by the median cubital vein,
often chosen as the site for blood removal for the purpose of
blood testing.
• Subclavian vein. The subclavian vein receives venous blood
from the arm through the axillary vein and from the skin and
muscles of the head through the external jugular vein

32. • Vertebral vein. The vertebral vein drains the posterior part of
the head.
• Internal jugular vein. The internal jugular vein drains the dural
sinuses of the brain.
• Brachiocephalic veins. The right and left brachiocephalic
veins are large veins that receive venous drainage from the
subclavian, vertebral, and internal jugular veins on their
respective sides.
• Azygos vein. The azygos vein is a single vein that drains the
thorax and enters the superior vena cava just before it joins the
heart

33. Veins Draining into the Inferior Vena Cava
• The inferior vena cava, which is much longer than the superior
vena cava, returns blood to the heart from all body regions
below the diaphragm.
• Tibial veins. The anterior and posterior tibial veins and
the fibular vein drain the leg; the posterior tibial
veins becomes the popliteal vein at the knee and then
the femoral vein in the thigh; the femoral vein becomes
the external iliac vein as it enters the pelvis

34. • Great saphenous veins. The great saphenous veins are the
longest veins in the body; they begin at the dorsal venous
arch in the foot and travel up the medial aspect of the leg to
empty into the femoral vein in the thigh.
• Common iliac vein. Each common iliac vein is formed by the
union of the external iliac vein and the internal iliac vein which
drains the pelvis

35. • Gonadal vein. The right gonadal vein drains the right ovary in
females and the right testicles in males; the left gonadal veins
empties into the left renal veins superiorly.
• Renal veins. The right and left renal veins drain the kidneys.
• Hepatic portal vein. The hepatic portal vein is a single vein
that drains the digestive tract organs and carries this blood
through the liver before it enters the systemic circulation.
• Hepatic veins. The hepatic veins drain the liver