The cardiovascular system consists of the heart and blood vessels. The heart is a cone-shaped organ located in the thoracic cavity between the lungs. It has four chambers - two upper atria and two lower ventricles separated by valves. Blood flows from the right atrium to ventricle to lungs then left atrium to ventricle and out to the body via the aorta. The cardiovascular system transports blood to the lungs for oxygenation and throughout the body, circulating nutrients and removing waste.

1. Introduction
 The cardiovascular system consists of heart and
blood vessels
 Sends blood to
 Lungs for oxygen
 Digestive system for nutrients
 CV system also circulates waste products to
certain organ systems for removal from the
blood

2. The Heart: Structures
 Cone-shaped organ about the size of
a loose fist
 located in the thoracic cavity
between the lungs. This area is
called the mediastinum.
 Extends from the level of the second
rib to about the level of the sixth rib
 Slightly left of the midline
 Receive 5% (250cm3)of cardiac
output

3. The Heart: Structures
 Heart is bordered:
 Laterally by the lungs
 Posteriorly by the vertebral
column
 Anteriorly by the sternum
 Rests on the diaphragm
inferiorly

4. The Heart: Structures
 Heart coverings:
 Pericardium
 Covers the heart and large
blood vessels attached to the
heart, Formed of two
layers:
 Visceral pericardium
 Innermost layer
 Directly on the heart
 Parietal pericardium
 Layer on top of the
visceral pericardium
 Heart walls:
 Epicardium
 Outermost layer
 Fat to cushion heart
 Myocardium
 Middle layer
 Primarily cardiac muscle
 Endocardium
 Innermost layer
 Thin and smooth
 Stretches as the heart
pumps

6. The Heart: Structures
 Four chambers
 Two atria
 Upper chambers
 Left and right
 Separated by
interatrial septum
 Two ventricles
 Lower chambers
 Left and right
 Separated by
interventricular
septum
 Atrioventricular septum separates the atria from the
ventricles

7. The Heart: Structures
 Tricuspid valve – prevents blood from flowing back into
the right atrium when the right ventricle contracts
 Bicuspid valve – prevents blood from flowing back into
the left atrium when the left ventricle contracts
 Pulmonary valve – prevents blood from flowing back into
the right ventricle
 Aortic valve – prevents blood from flowing back
into the left ventricle

9. The Heart: Blood Flow
Deoxygenate
d blood in
from body
Oxygenated
blood in lungs
Atria Contract Ventricles Contract
Deoxygenated
blood out
to lungs
Oxygenated
blood out to
body

10. The Heart: Blood Flow (cont.)
Right
Atrium
Right
Ventricle
Pulmonary
Semilunar
Valve
Left
Atrium
Bicuspid
Valve
Left
Ventricle
Pulmonary
Valve
Tricuspid
Valve
Aortic
Semilunar
Valve
LungsBody

11. The Heart: Cardiac Cycle
 Right atrium contracts
 Tricuspid valve opens
 Blood fills right ventricle
 Right ventricle contracts
 Tricuspid valve closes
 Pulmonary semilunar valve
opens
 Blood flows into pulmonary
artery
 Left atrium contracts
 Bicuspid valve opens
 Blood fills left ventricle
 Left ventricle contracts
 Bicuspid valve closes
 Aortic semilunar valve opens
 Blood pushed into aorta
 One heartbeat = one cardiac cycle
 Atria contract and relax
 Ventricles contract and relax

12. The Heart: Cardiac Cycle (cont.)
 Influenced by
 Exercise
 Parasympathetic nerves
 Sympathetic nerves
 Cardiac control center
 Body temperature
 Potassium ions
 Calcium ions

13. The Heart: Heart Sounds
 One cardiac cycle – two heart sounds (lubb and dubb)
when valves in the heart snap shut
 Lubb – First sound
 When the ventricles contract, the tricuspid and bicuspid
valves snap shut
 Dubb – Second sound
 When the atria contract and the pulmonary and aortic valves
snap shut

14. Blood Vessels:
 3 Major types of blood
vessels
1.Arteries
2.Capillaries
3.Veins
Heart to arteries to capillaries to veins to heart

15. General characteristics of vessels
 Artery and vein walls contain three layers:
1- Tunica interna or tunica intima.
2- Tunica media.
3- Tunica externa or tunica adventitia
 Lumen is the central blood filled space

16.  Tunica interna is the inner layer that comes in contact
with blood. It consists of a smooth layer of simple
squamous epithelium known as endothelium.
 The tunica media has sheets of smooth muscle
arranged as circular, layers around the lumen; it is the
thickest layer in arteries.
 The tunica externa is the outermost layer made up of
connective tissue and a few elastic fibers

18. Smooth muscle
contraction:
vasoconstriction
Smooth muscle
relaxation:
vasodilation
Sympathetic
vasomotor
nerves of
autonomic
nervous system
regulate

19.  The arteries conduct blood away from the heart
toward the tissue. The large, elastic arteries divide
and redivide into smaller midsized muscular arteries.
 The midsized arteries divide into smaller arteries. The
smallest arteries are called arterioles, the major
function of which is to regulate blood flow to the region.
 From the arterioles, the blood moves into capillaries
where exchange between blood and tissue is possible.
 The capillaries join to form venules, and then veins,
which return blood from capillaries to the heart.

20. 3. Arterioles
Smallest: .3mm-10um .
1. Elastic arteries: act as
conduits
 2.5-1 cm diameter
 Expand with surge
of blood from heart
 Recoil and continue
the propagation of blood
 Elastin is thick in media:
dampens the surge of blood
pressure
 Aorta and its branches
2. Muscular arteries: act as
distributing arteries
 Middle sized .3mm-1cm
 Changes diameter to
differentially regulate
flow to organs as needed
 Internal as well as
external elastic lamina
 Most of what we see as
“arteries”

21. Blood Vessels: Arteries and Arterioles
 Strongest of the
blood vessels
 Carry blood away
from the heart
 According to
pressure
 Vasoconstriction
 Vasodilation
 Arterioles
 Small branches of
arteries
 Aorta
 Takes blood from the
heart to the body
 Coronary arteries
 Supply blood to heart
muscle

22. Aorta
Arise from the left ventricle.
It is the largest artery in the
body.
Start as the ascending aorta,
then continue as aortic
arch, curve downward as
descending aorta, ends in
the diaphragmatic opening
by becoming abdominal
aorta.

23. Branches of the thoracic
aorta
Branches of ascending aorta:
Rt and left coronary arteries
Branches from aortic arch
Brachicephalic, lt common
carotid, lt subclavian
arteries
Brachiocephalic artery
divides in to RT common
carotid, RT Subclavian
arteries behind Rt
sternoclavicular joint.

24. Coronary arteties
The right and left coronary arteries
They arise from ascending aorta
The right coronary give posterior
interventricular, and marginal
The left coronary give anterior
interventricular and circumflex
arteries

25. Blood Vessels: Veins and Venules
 Blood under no pressure
in veins
 Does not move very easily
 Skeletal muscle
contractions help move
blood
 Valves prevent backflow
 Venules
 Small vessels formed
when capillaries merge
 Superior and inferior
vena cava
 Largest veins
 Carry blood into right
atrium

27. Blood Vessels: Capillaries
 Branches of arterioles
 Smallest type of blood vessel
 Connect arterioles to venules
 Only about one cell layer thick
 Oxygen and nutrients can pass out of a capillary into
a body cell
 Carbon dioxide and other waste products pass out of
a body cell into a capillary

28. Circulation
 Pulmonary circuit
right atrium  right ventricle  pulmonary artery
trunk  pulmonary arteries  lungs  pulmonary
veins  heart (left atrium)
Pulmonary system pressure is only 1/6 of systemic blood pressure
 Systemic circuit
left atrium  left ventricle  aorta  arteries 
arterioles  capillaries  venules  veins  vena
cava  heart (right atrium)

29. Circulation
 Arterial system
 Carry oxygen-rich blood
away from the heart,
Except Pulmonary
arteries carry oxygen-
poor blood.
 Venous system
 Carries oxygen-poor
blood toward the
heart , Except
pulmonary veins.
 Hepatic portal system
 Collection of veins
carrying blood to the
liver

30. 27-30
Diseases and Disorders of the
Cardiovascular System
Disease Description
Anemia The blood does not have enough red blood cells
or hemoglobin to carry an adequate amount of
oxygen to the body’s cells
Aneurysm A ballooned, weakened arterial wall
Arrhythmias Abnormal heart rhythms
Carditis Inflammation of the heart
Endocarditis Inflammation of the innermost lining of the
heart, including valves

31. 27-31
Disease Description
Myocarditis Inflammation of the muscular layer of the heart
Pericarditis Inflammation of the membranes that surround
the heart (pericardium)
Congestive
Heart Failure
Weakening of the heart over time; heart is
unable to pump enough blood to meet body’s
needs
Coronary Artery
Disease (CAD)
Atherosclerosis; narrowing of coronary arteries
caused by hardening of the fatty plaque deposits
within the arteries
Diseases and Disorders of the
Cardiovascular System (cont.)

32. 27-32
Disease Description
Hypertension High blood pressure; consistent resting blood
pressure equal to or greater than 140/90 mm Hg
Leukemia Bone marrow produces a large number of
abnormal WBCs
Murmurs Abnormal heart sounds
Myocardial
Infarction
Heart attack; damage to cardiac muscle due to a
lack of blood supply
Diseases and Disorders of the
Cardiovascular System (cont.)

33. 27-33
Disease Description
Sickle Cell
Anemia
Abnormal hemoglobin causes RBCs to change
to a sickle shape; abnormal cells stick in
capillaries
Thalassemia Inherited form of anemia; defective hemoglobin
chain causes, small, pale, and short-lived RBCs
Thrombophlebitis Blood clots and inflammation develops in a vein
Varicose Veins Twisted, dilated veins
Diseases and Disorders of the
Cardiovascular System (cont.)

34. Blood
 A type of connective
tissue.
 Red blood cells
(erythrocytes)
 White blood cells
(leukocytes)
 Platelets – cell
fragments
 Plasma – fluid part of
blood
Average-sized adult
has 4 to 6 liters of blood
Amount depends on:
 Size of person
 Amount of adipose
tissue
 Concentrations of ions
 Females have less than
males

35. Blood Components
 Hematocrit
 The percentage of red blood cells
 Normal is about 45%
 White cells and
platelets = 1%
 Plasma = 55%

36. Blood Components: Red Blood Cells
 Erythrocytes
 Transport oxygen throughout the body
 Small biconcave-shaped cells
 Hemoglobin is a pigment in RBCs
 Oxyhemoglobin carries oxygen; bright red
 Deoxyhemoglobin does not carry oxygen; darker red
 Carries carbon dioxide, so also called carboxyhemoglobin
 Anemia – low RBC count
 Erythropoietin – regulates production of RBCs

37. Blood Components: Red Blood Cells

38. Blood Components: White Blood Cells
Fight infection and are
formed in the bone
marrow
Five types – neutrophils,
lymphocytes, eosinophils,
basophils, and
monocytes.

39. Blood Components: White Blood Cells
 WBC count normally 5000 to 10,000 cells per cubic
millimeter of blood
 Leukocytosis
 Elevated WBC count
 Usually due to infection
 Leukopenia
 Low WBC count
 Some viral infections and other conditions

40. Blood Components: Platelets
 Fragments of cells found in the bloodstream
 Also called thrombocytes
 Important in the clotting process of blood
 Normal count
 150,000 to 400,000 platelets per cubic millimeter of
blood

41. Blood Components: Plasma
 Liquid portion of the
blood. Contains clotting
factors, hormones,
antibodies, dissolved
gases, nutrients and
waste

42. Blood: Bleeding Control
 Hemostasis – the
control of bleeding
 Three processes of
hemostasis
 Blood vessel spasm
 Platelet plug formation
 Blood coagulation

43. Platelet plug
formation:

44. Apply Your Knowledge
What is the difference between the systolic pressure
and diastolic pressure?
ANSWER:
Systolic pressure is the result of the contraction of the
ventricles increasing the pressure in the arteries. Diastolic
pressure is the result of the relaxation of the ventricles
lowering the pressure in the arteries.

45. Multiple Choice
1. Platelets are formed
in the :
A. spleen.
B. tonsils.
C. bone marrow.
D. lymph nodes.
2. The blood volume in
a young adult is :
A. 1.5–3 liters.
B. 4–6 liters.
C. 7–8 liters.
D. 8–10 liters.

46. Apply Your Knowledge
3. In a healthy adult,
the approximate
volume of blood
pumped out by the
heart in 1 minute is :
A. 80 mL.
B. 250 mL.
C. 2 L.
D. 5 L.
4. The blood vessel(s)
that carries oxygenated
blood from the lungs to
the left atrium is the :
A. pulmonary artery.
B. pulmonary vein.
C. vena cava.
D. aorta.

47. 5. The valve that
prevents backflow of
blood into the right
atrium is the :
A. pulmonary valve.
B. mitral valve.
C. aortic valve.
D. tricuspid valve.
6. Cardiac output is
increased by all of the
following conditions
EXCEPT :
A. low body temperature.
B. exercise.
C. anxiety.
D. pregnancy.

48. Fill-In
1 . The pericardium is a serous membrane that
surrounds the heart.
2 . The first heart sound is a result of the closure of
the atrioventricular valves.
3 . The major veins that drain into the right atrium
are the inferior vena cava and superior vena cava.

49. True–False
1. Coagulation is an antigen-antibody process.
2. For clotting to occur, many factors found in the
platelets, plasma, or other tissue fluids are required.
3. The pressure in the right ventricle is more than
that in the left ventricle.
4. Systolic pressure is the pressure measured during
ventricular contraction.

50. 1. False. Clumping or agglutination is an antigenantibody
process.
2. True.
3. False. Because blood drains into the right atrium via
the veins (with low pressure), and the resistance to
outflow through the pulmonary trunk is very low, the
pressure in the right ventricle is low.
4. True.