This presentation provides a clear understanding of the physiology of the circulatory system. It focus lies on the division and component of the circulatory system, the three major function of the circulatory system, blood composition, structure of the heart, blood circulation; pulmonary and systemic circuit, valves of the heart, the pathway of blood flow through the heart, the cardiac cycle, pressure changes during the cardiac cycle; systole and diastole, cardiac output, heart sounds among others.
This presentation was designed by Fasama H. Kollie and presented by Benetta N. Kekulah, Cordelia Capehart and Abraham Peters.
2. Presentation Outline
โข Overview of the circulatory system
โข Function of the Circulatory system
โข Transportation
โข Regulation
โข Protection
โข Major components of the
circulatory system
โข Cardiovascular system
โข Lymphatic system
โข Blood Composition
โข Structure of the Heart
โข Blood Circulation
โข Pulmonary and Systemic circuit
โข Valves of the Heart
โข Pathway of Blood flow through the
heart
โข The cardiac cycle
โข Pressure changes during the
cardiac cycle: Systole & Diastole
โข Cardiac Output
โข Heart sounds
โข Cardiac Conduction System
3. Presentation Outline
โข Blood vessels
โข Arteries and Arterioles
โข Capillaries and Types
โข Veins and Venules
โข Lymphatic System
โข Conclusion
4. Circulatory System Overview
โข The circulatory system consists of
โข Blood
โข Blood vessels
โข The Heart
โข Lymphatic vessels
โข It works together with other systems in maintaining Homeostasis
โข Respiratory
โข Urinary
โข Digestive
โข Endocrine, and
โข Integumentary systems
5. Function of The Circulatory System
โข Transportation โ transport substances essential for cellular metabolism
These substances can be categorized as follows:
โข Respiratory โ Oxygen (RBC), Carbon dioxide (blood)
โข Nutritive - absorbed products of digestion (blood, lymphatics)
โข Excretory - Metabolic wastes (such as urea), excess water and ions, etc. (blood into
kidneys = urine)
โข Regulation - contributes to both hormonal and temperature regulation
โข Hormonal โ hormones (blood)
โข Temperature - diversion of blood from deeper to more superficial cutaneous
vessels or vice versa
6. Function Contโdโฆ
โข Protection โ protects against blood loss from injury and against
pathogens, including foreign microbes and toxins introduced into the
body.
These substances can be categorized as follows:
โข Clottingโ prevents blood loss when blood vessels are damaged
โข Immune function - protect against many disease-causing agents
(pathogens). Performed by leukocytes (white blood cells).
7. Major Components of the Circulatory System
๏ฑCardiovascular system consist
of:
โข Heart
โข Blood vessels: form a tubular
network that permits the
flow of blood
โข Arteries, arterioles, veins,
capillaries
๏ฑLymphatic system consists of:
โข Lymphatic vessels
โข Lymphoid tissues
โข Found in the spleen, thymus,
tonsil and lymph nodes
โข The circulatory system is divided into two major subdivisions:
โข The Cardiovascular system and the Lymphatic system
8. Composition of the Blood
โข It consist of formed elements that are suspended and carried in fluid
know as plasma
โข The formed element of the blood consist of:
โข Erythrocyte (RBC)
โข Leukocyte (WBC)
โข Platelets
โข Hematopoiesis is the formation of blood cells
โข Hematopoietic stem cells
9. The Constituents of
Blood
โข Figure 1.1 The constituents of blood. Blood cells become packed at the
bottom of the test tube when whole blood is centrifuged, leaving the fluid
plasma at the top of the tube.
10. Blood Composition Contโdโฆ
โข Erythropoiesis refers to the formation of erythrocytes
โข Leukopoesis refers to the formation of leukocytes
โข These processes occur in two classes of tissues after birth
โข Myeloid and lymphoid
11. The Heart Structure
โข Located in the thoracic cavity in
the mediastinum, between the
lungs and deep to the sternum
โข Contains four chamber
โข Its about the size of a fist, the
hollow, cone-shaped
โข There is a layer of dense
connective tissues b/t the atria
and ventricle
Figure 1.5. The Structure of the Heart
12. Blood Circulation
โข Movement of blood through the vessels of the body that is induced
by the pumping action of the heart and serves to distribute oxygen to
and remove wasted products from all parts of the body
โข Two (2) types:
โข Pulmonary circulation
โข Systemic circulation
13. Blood Circulation Contโdโฆ
โข Pulmonary circuit carries deoxygenated
blood away from the heart to the lungs
and returns oxygenated blood to the heart
โข Systemic circuit carries oxygenated blood
away from the heart to body system and
returns deoxygenated blood to the heart
โข Pulmonary circuit begins in the right
ventricle and ends in the left atrium
โข Systemic circuit beings in the left ventricle
and ends in the right atrium
Figure 1.6 A Diagram of the circulatory system.
14. Valves of the Heart
โข Two (2) main types:
โข Atrioventricular Valves
โข Semilunar Valves
Figure 1.7 The heart valves
15. Valves of the Heart: Atrioventricular Valves
โข Found between the atria and ventricles
โข Constitutes;
โข Tricuspid valve
โข Bicuspid valve
โข Tricuspid valve: right AV valve that
prevents blood from flowing back into the
right atrium when the right ventricle
contract. It has three flaps of tissues
โข Bicuspid valves: left AV valve that prevents
blood from flowing back into the left
atrium when the left ventricle contract.
Tricuspid
valve
Bicuspid
valve
AV Valves
16. Valves of the Heart: Semilunar Valves
โข Shaped like half moons
โข Constitutes;
โข Pulmonary valve
โข Aortic valve
โข Pulmonary valve: beginning of the
pulmonary truck. Prevents blood from
flowing back into the right ventricle
โข Aortic valve: beginning of the aorta.
Prevents blood from flowing back into
the left ventricle
Aortic
valve
Pulmonary
valve
18. The Cardiac Cycle
โข Cardiac cycle refers to the repeating patterns of contraction and relaxation of the heart.
The phase of contraction is called systole, and the phase of relaxation is called diastole
โข One heartbeat = one cardiac cycle
๏ง Atria contract and relax
๏ง Ventricles contract and relax
โข Right atrium contracts (1st Diastole)
โข Tricuspid valve opens
โข Blood fills right ventricle
โข Right ventricle contracts (1st Systole)
โข Tricuspid valve closes
โข Pulmonary semilunar valve opens
โข Blood flows into pulmonary artery
โข Left atrium contracts (2nd Diastole)
โข Bicuspid valve opens
โข Blood fills left ventricle
โข Left ventricle contracts (2nd Systole)
โข Bicuspid valve closes
โข Aortic semilunar valve opens
โข Blood pushed into aorta
19. Cardiac cycle
Figure 1.9 The cardiac cycle of ventricular systole and diastole. Contraction of the atria occurs in the last 0.1
second of ventricular diastole. Relaxation of the atria occurs during ventricular systole. The durations given for
systole and diastole relate to a cardiac rate of 75 beats per minute.
20. Pressure Changes During The
Cardiac Cycle: Systole
โข Has 2 phases:
1. Isovolumetric contraction โ the both ventricles contract to
increase the pressure in the ventricles. As the ventricles begin
their contraction, the intraventricular pressure rises, causing the
AV valves to snap shut and produce the first heart sound (LUB). At
this time, the ventricles are neither being filled with blood
(because the AV valves are closed) nor ejecting blood (because the
intraventricular pressure has not risen sufficiently to open the
semilunar valves).
21. Systole Contโdโฆ
โข 2. Ejection โ blood is pumped out
of the ventricles. When the
pressure in the left ventricle
becomes greater than the
pressure in the aorta, the
phase of ejection begins as
the semilunar valves open.
22. โข Has 3 phases:
1. Isovolumetric relaxation โ both atria and ventricles are
relaxed. As the pressure in the ventricles falls below the pressure
in the arteries, the back pressure causes the semilunar valves to
snap shut and produce the second heart sound (DUB). During
this phase, the AV and semilunar valves are closed. This phase
lasts until the pressure in the ventricles falls below the pressure
in the atria.
Pressure Changes During The
Cardiac Cycle: Diastole
23. Diastole Contโdโฆ
2. Rapid filling โ rapid inflow of blood into
the ventricles. When the pressure in the
ventricles falls below the pressure in the
atria, the AV valves open and a phase of
rapid filling of the ventricles occurs.
3. Atrial contraction (atrial systole) โ the
atria contract to deliver the final amount of
blood into the ventricles immediately prior
to the next phase of isovolumetric
contraction of the ventricles.
24. Cardiac Output
โข Defined as the amount of blood each ventricle pumps out per minute.
โข Determined by:
โข Stroke volume โ amount of blood that each ventricle pumps out
per beat
โข Heart rate โ number of times the heart beats in one minute
โข Cardiac Output = Heart rate X Stroke volume
25. Cardiac Output Contโdโฆ
โข Normal resting stroke volume = 70 mL of blood
โข Normal resting heart rate = 70-72 beats per minute
โข When one factor changes, the body regulates the other factor to enhance the cardiac output.
โข Normal cardiac output = 4.9-5.4 L/min (based on the body size of an
individual)
โข Normal physiological Resting Cardiac Output โ 5 L/min
โข When the body begins to move, the cardiac output increases so as to
enhance blood flow to the muscles.
26. Heart Sounds
โข There are 4 heart sounds, 3 normal, 2 of which are easily
heard
โข The 4th heart sound may normally be heard in a young
child, but is abnormal in adults
โข The 1st and 2nd heart sounds are associated with the
closure of valves
27. Heart Sound Contโdโฆ
๏ฑ 1st Heart Sound (Lubb)
โข When the ventricle contract, the tricuspid and bicuspid valves
snap shut
๏ฑ 2nd Heart Sound (Dubb)
โข When the atria contract and the pulmonary and aortic valves
snap shut
28. Heart Sound Contโdโฆ
๏ฑ 3rd Heart Sound
โข Produced during diastole
โข Heard when the two inlet valves opens
โข Not usually audible, may be heard in young child
๏ฑ 4th Heart Sound
โข Caused by contraction of both atria
โข Itโs heard when there is atrial hypertrophy
โข Thickening of the wall of the atria
29. The Heart: Cardiac Conduction System
โข Group of structures that send electrical impulses through the heart
โข Sinoatrial node (SA node)
โข Wall of right atrium
โข Generates impulse
โข Natural pacemaker
โข Sends impulse to AV node
โข Atrioventricular node (AV node)
โข Between atria just above ventricles
โข Atria contract
โข Sends impulse to the bundle of His
โข Bundle of His
โข Between ventricles
โข Two branches
โข Sends impulse to
Purkinje fibers
โข Purkinje fibers
โข Lateral walls of ventricles
โข Ventricles contract
30. Cardiac Conduction
System
Figure 1.10 The conduction system of the
heart. The conduction system consists of
specialized myocardial cells that rapidly
conduct the impulses from the atria into the
ventricles.
31. Blood Vessels
โข Blood vessels form a tubular network throughout the body that
permits blood to flow from the heart to all the living cells of the body
and then back to the heart
โข Blood leaving the heart passes through vessels of progressively
smaller diameters, referred to as arteries, arterioles, and capillaries
โข Blood returning to the heart from the capillaries passes through
vessels of progressively larger diameters, called venules and veins.
32. Blood Vessels: Arteries and Arterioles
โข Strongest of the blood vessels
โข Carry blood away from the
heart
โข Under high pressure
โข Vasoconstriction
โข Vasodilation
โข Arterioles
โข Small branches of arteries
โข Aorta
โข Takes blood from the heart
to the body
โข Coronary arteries
โข Supply blood to heart
muscle
33. The
Microcirculation
Figure 1.12 The microcirculation. Metarterioles
(arteriovenous anastomoses) provide a path of least
resistance between arterioles and venules. Precapillary
sphincter muscles regulate the flow of blood through
the capillaries.
34. Blood Vessels: Capillaries
โข The arterial system branches extensively to deliver blood to over 40 billion
capillaries in the body.
โข The tiny capillaries provide a total surface area of 1,000 square miles for
exchanges between blood and tissue fluid.
โข The amount of blood flowing through a particular capillary bed depends
primarily on the resistance to blood flow in the small arteries and arterioles
that supply blood to that capillary bed.
โข Vasoconstriction in these vessels thus decreases blood flow to the capillary
bed, whereas vasodilation increases blood flow
35. Types of Capillaries
โข In terms of their endothelial lining, these capillary types include those that
are continuous, those that are fenestrated, and those that are
discontinuous.
โข Continuous capillaries are those in which adjacent endothelial cells are
closely joined together. These are found in muscles, lungs, adipose tissue,
and the central nervous system.
โข Fenestrated capillaries occur in the kidneys, endocrine glands, and
intestines. They are characterized by wide intercellular pores that are
covered by a layer of mucoprotein, which serves as a basement membrane
over the capillary endothelium
โข Discontinuous capillaries are found in the bone marrow, liver, and spleen
36. Blood Vessels: Veins and Venules
โข Most of the total blood volume is contained in the venous system.
โข Unlike arteries, which provide resistance to the flow of blood from the
heart, veins are able to expand as they accumulate additional amounts of
blood.
โข Average pressure in the veins is only 2mmHg compared to a much higher
arterial pressure of about 100mmHg
โข The low venous pressure is insufficient to return blood to the heart,
particularly from the lower limbs. Veins, however, pass between skeletal
muscle groups that provide a massaging action as they contract.
37. The Action of The
One-way Venous
Valves
Figure 1.13 The action of the one-way venous valves. Contraction of skeletal muscles helps to pump blood toward the
heart, but the flow of blood away from the heart is prevented by closure of the venous valves.
38. Lymphatic System
โข Lymphatic vessels absorb excess interstitial fluid and transport this
fluidโnow called lymphโto ducts that drain into veins.
โข The lymphatic system has three basic functions:
โข It transports interstitial (tissue) fluid, initially formed as a blood
filtrate, back to the blood
โข It transports absorbed fat from the small intestine to the blood
โข It cellsโcalled lymphocytes โhelp provide immunological
defenses against disease-causing agents
39. Lymphatic System Contโdโฆ
โข The smallest vessels of the
lymphatic system are the
lymphatic capillaries.
โข Microscopic closed-ended tubes
that form vast networks in the
intercellular spaces within most
organs
โข Once fluid enters the lymphatic
capillaries, it is referred to as
lymph.
Figure 1.14 The relationship between blood capillaries and lymphatic capillaries
40. Lymphatic System Contโdโฆ
โข Before the lymph is returned
to the cardiovascular system,
it is filtered through lymph
nodes
โข Lymph nodes contain
phagocytic cells, which help
remove pathogens, and
germinal centers, which are
sites of lymphocyte
production.
Figure 1.15 The relationship between the circulatory and lymphatic systems
41. Location of Lymph
Node Along the
Lymphatic Pathways
Figure 1.16 The location of lymph nodes
along the lymphatic pathways. Lymph nodes
are small bean shaped bodies, enclosed
within dense connective tissue capsules.
42. In Summary
โข The circulatory system consists of the cardiovascular system and the lymphatic system.
โข Blood transports oxygen and nutrients to all the cells of the body and removes waste
products from the tissues.
โข Plasma is the fluid part of the blood, containing dissolved ions and various organic molecules.
โข The right and left sides of the heart pump blood through the pulmonary and systemic
circulations, respectively.
โข Lymphatic capillaries are blind-ended but highly permeable. They drain excess tissue fluid
into lymph ducts. Lymph passes through lymph nodes and is returned by way of the lymph
ducts to the venous blood.
43. Reference
Fox, Stuart Ira., HUMAN PHYSIOLOGY, 12th Edition. Copyright ยฉ 2011
by The McGraw- Hill Companies, Inc. Published by McGraw-Hall, a
business unit of the McGraw-Hill Companies, Inc., 1221 Avenue of the
Americas, New York, NY 10020.
44. What counts in life is not the mere fact that we have lived. It is
what difference we have made to the lives of others that will
determine the significance of the life we lead.โ
THE END
Nelson Mandela