The Circulatory System
The circulatory system includes the Heart, Blood Tissue
and the Blood Vessels.
The Circulatory SystemTransport
• The absorption and
circulation of
materials
throughout an
organism
What does the circulatory system do?
(What is its function?)
1. Delivers food and oxygen to body cells.
2. Carries carbon dioxide and other waste
products away from cells.
 Movement of materials into and out of cells occurs by
diffusion (from an area of high concentration to low
concentration– no energy required)
 Movement also occurs by active transport (from an area of
low concentration to high– this requires energy)
• ** In general, the blood is a fluid tissue
helping to maintain homeostasis for all
cells in the body.
• Transport of needed substances to body
cells. (oxygen, amino acids, glucose,
fatty acids, glycerol, salts, etc.)
The heart functions as a double pump
beating in unison.
1. Deoxygenated blood--relatively low in
oxygen
2. Oxygenated blood--relatively high in
oxygen
** Heartbeat is stimulated by an
electrochemical impulse.
Pacemaker - in the right atrium - initiates the
heartbeat
2. Transport of wastes from cells. (urea,
water, carbon dioxide in the form of the
bicarbonate ion)
3. Helps to maintain a constant body
temperature.
4. Aids the body in fighting disease.
The Human (Mammalian) Heart
Structure
1. septum: muscular central wall dividing
the mammalian heart into two halves
2. atria: thin walled upper heart chambers
which receive blood pump blood to the
ventricles
3. Ventricles: muscular thick walled
chambers which pump blood from the
heart -- the lower chambers
4. Valves - prevent the backward flow of
blood in the heart
A = aorta
B = pulmonary arteries
C = pulmonary veins
D = left atrium
E = valve
F = left ventricle
G = right ventricle
H = valve
I = vena cavae
J = right atrium
1. Inferior & superior vena cava
2. Right atrium
3. valve
4. Right ventricle
5. valve
6. Pulmonary arteries
(BLOOD TO THE LUNGS –
GAS EXCHANGE) …
7. Pulmonary veins
8. Left Atrium
9. valve
10. Left ventricle
11. valve
12. Aorta
Blood Vessels
1. Arteries
--carry blood away from the heart
--usually spurt blood when cut
--all except the pulmonary artery carry
oxygenated blood
--thick walled and elastic
pulse: expansion and contraction of the
artery walls in response to the heartbeat
Veins
--carry blood toward the heart
--contain valves
--closer to the body surface than the
arteries
--all except the pulmonary vein carry
deoxygenated blood
--thinner, less muscular and elastic than
arteries
--depend upon muscle and diaphragm
movements for blood flow
Capillaries
--most numerous vessels
--connect arteries to veins
--microscopic, one cell thick walls
--site of much exchange between the
blood and the intracellular fluid (lymph)
by diffusion
Lymph vessels
-have walls one cell thick
-present around all body cells
-Lymph composition is similar to that of
blood except for the absence of RBC
and some plasma proteins.
-chief site of material exchange with the
tissues
Major lymph vessels have lymph nodes
which contain phagocytic white blood cells
which filter bacteria and dead cells from the
lymph.
X = lymph nodes
Valves are present in some lymph vessels-aiding in the movement of the lymph.
Respiratory movements also aid lymph flow.
Which Way Did it Go?
Blood Pressure
Causes of HBP implicated:
1. excess sodium intake
2. stress
3. cigarettes (nicotine)
4. saturated fats
5. alcohol & caffeine
6. obesity
7. heredity & aging
No cure--may be treated by medication & diet.
"Silent killer"--millions don't know they have it
Blood
Blood = a connective tissue made up of blood cells and a
liquid called blood plasma.
 About 7 % of your body mass
 About 4.5- 5.6 Liters in an adult human
Men = 5.6 Liters
Women = 4.5 Liters
Pregnant woman = 5.0 Liters
The Functions of Blood
Delivers:
Picks Up:
- Nutrients
- waste  kidneys
- Oxygen, Water, minerals
- carbon dioxide  lungs
- Hormones and enzymes
- heat  skin
- pollutants
The Parts of Blood
1. Plasma =carries everything
2. Red Blood Cells =(RBC) gas exchange
3. White blood Cells =(WBC) fight infection
4. Platelets = clotting
Components of Blood
Blood Composition
• Plasma 55% (liquid part of the blood);
Blood Cells 45%
55%
plasma
45 %
RBC, WBC
and platelets
Plasma- nonliving
• Yellow liquid (92% H2O)
• 8 % nutrients, salts, urea, hormones
• Carries:
RBC, WBC, Platelets, Carbon dioxide, food
and waste
BLOOD CELL TYPES
• Red Blood Cells:
– most numerous
– biconcave disc shaped
– smaller than white blood cells, larger than
platelets
– no nucleus when mature
– produced in the red marrow of long bones
– destroyed in the liver and spleen
– contain the iron protein compound
HEMOGLOBIN whose chief function is to
combine with oxygen and carry it to the cells
Red Blood Cells- living
• 5 million in 1 drop of blood (most common)
• Shape = donut
Draw here:
• Made in bone marrow
• Live approximately 120-125 days
Hemoglobin = oxygen containing pigment
Binds to oxygen and carries it to the cells
Gives red blood cells its red color
White blood cells- living
• AKA- Lymphocytes or Leukocytes
• White blood cells are larger than red blood
cells, but there are less of them.
• 8000 in one drop of blood
Function of White Blood Cells
 surround and digest bacteria
Attack bacteria and viruses
**Pus = WBC + dead bacteria
YouTube - White Blood Cell Chases Bacteria
White Blood cells
--largest blood cells--several different
types
--about 8,000 per drop of blood
--most are formed in the bone marrow or
in the lymph tissue
--most protect the body against
diseases by forming antibodies or
engulfing bacteria
Main White Blood Cell Types
1. Phagocytes-- engulf bacteria and
viruses by phagocytosis
--able to leave the bloodstream
and move between the cells of
the body by squeezing through
the capillary walls
2. Lymphocytes--produce antibodies
which clump bacterial poisons or
bacteria (antigens) (antigens--foreign
substances in the body)
Platelets- living
• Bits of cells
• Live for approximately 10 days
Function of Platelets
creates fibrin = enzyme that helps clot
blood (tiny threads seal cuts)
3. Platelets
--smallest blood cells (fragments)
--150,000 to 300,000 per drop of blood
--needed for clotting
Clotting:
Involves a series
of enzyme
controlled
reactions resulting
in the formation of
protein fibers that
trap blood cells
and form a clot.
Pacemaker•Uses electrical impulses from
wire leads inserted into the Heart.
•Keeps the Heart in perfect
rhythm.
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Diseases and Disorders of the
Circulatory System
Myocardial Infarction- heart attack
Hypertension- high blood pressure
Hypotension- low blood pressure
Stroke- clot in the brain
Angina Pectoris- severe pain in chest
Sickle Cell Anemia- sickle shaped rbc’s
Pernicious Anemia- very low rbc count
MVP- prolapsed mitral valve
Pericarditis- inflammation of outer membrane covering the heart
Leukemia- cancer of the blood, elevated wbc count
Varicose veins- enlargement of veins
Arrhythmias- irregularities in heart rhythm
Endocarditis- inflammation of inner lining of heart
Cardiomyopathy- weakening of the heart muscle
Hemophilia- no clotting factor in the blood
Thalassemia- low rbc count, genetic, low hemoglobin count
Heart Disease
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Mitral Valve Surgery
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Aortic Aneurysm
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Aortic Valve Replacement
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