1. Name: LEVVA SOFIA
Number: 27108
E-mail: s_levva@hotmail.com
2. Name: KOULINA ANASTASIA
Number: 27076
E-mail: tkoulina@in.com
BODY SYSTEM:
CARDIOVASCULAR
SYSTEM
Student 1: Levva Sofia
Question 1: How does the circulatory system work?
Answer:
Heart and circulatory system make up the cardiovascular system. The heart,
works as a pump that pushes blood to the organs, tissues, and cells of the body.
The one-way circulatory system carries blood to all parts of the body (including
the heart itself) and then back to the heart, through a complex network of elastic
tubes, called vessels.
The body’s circulation has two parts, with the heart acting as a double pump.
The pumping of the heart forces the blood on its journey. Blood from the right
side pump is dark red (bluish) and low in oxygen. It travels along pulmonary
artery to the lungs where it receives fresh supplies of oxygen. Then, it flows
along pulmonary veins back to the heart’s left side pump. Blood leaves the left
side of the heart and travels through arteries, which finally branch into capillaries.
Capillaries move the blood back through wider vessels called venules. Venules
eventually join to form veins. The blood then travels in veins back to the right side
of the heart, and the whole process begins again.
The body’s circulatory system has three distinct parts, as they referred below.
Each part must be working independently in order for them to all work together.
Pulmonary circulation
Pulmonary circulation is the movement of
blood from the heart, to the lungs, and then
back to the heart again. Throughout two large
veins called vena cavae, all the veins of the
body bring waste-rich blood back to the heart
entering the right atrium. The right atrium fills with the blood and then contracts,
pushing the blood through a one-way valve, the tricuspid valve, into the right
ventricle. The right ventricle fills and then contracts, pushing the blood into the
pulmonary artery which leads to the lungs. At the same time, tricuspid and mitral
valves are closed. In the lung capillaries, takes place the exchange of carbon
dioxide and oxygen. The fresh, oxygen-rich blood returns to the heart, re-entering
through the left atrium throughout the pulmonary veins. The oxygen-rich blood
then passes through mitral valve (a one-way valve) into the left ventricle where it
will exit the heart through aorta. The left ventricle’s contraction forces the blood
into the aorta and then begins its journey throughout the body.
The one-way valves are important for preventing any backward flow of blood.
The circulatory system is a network of one-way streets. If blood started flowing
the wrong way, the blood gases (oxygen and carbon dioxide) might mix, causing
a serious threat to your body.
Coronary circulation
While the circulatory system is busy providing oxygen and nourishment to
every cell of the body, heart which works hardest of all, needs oxygen-rich blood
to survive. Coronary circulation refers to the movement of blood through the
tissues of the heart. Blood is supplied to the heart by its own vascular system,
the coronary arteries.
The aorta branches off into two main coronary arteries. These branch off into
smaller arteries, which supply oxygen-rich blood to the entire heart muscle. The
heart tissue receives nourishment through the capillaries located in the heart.
The right coronary artery supplies blood mainly to the right heart. The right side
of the heart is smaller because it pumps blood only to the lungs. The left
coronary artery, which branches into the left anterior descending artery and the
circumflex artery, supplies blood to the left side of the heart. The left side of the
heart is larger and more muscular because it pumps blood to the rest of the
body.
Serious heart damage may occur if the heart tissue does not receive a normal
supply of food and oxygen.
Systemic circulation
Systemic circulation supplies nourishment to all the tissue of the human body,
with the exception of the heart and lungs. The blood vessels are responsible for
the delivery of oxygen and nutrients to the tissue. The forceful contraction of the
heart’s left ventricle forces the oxygen-rich blood into the aorta which then
branches into many smaller arteries which run throughout the body. The blood
enters the capillaries where the oxygen and nutrients are released. The waste
products are collected and the blood which transfers them flows into the veins in
order to circulate back to the heart where pulmonary circulation will allow the
exchange of gases in the lungs.
During systemic
through the
systemic
renal circulation.
kidneys filter
the blood. Blood
small intestine
circulation. This
circulation. During
from the small
portal vein which
circulation, blood passes
kidneys. This phase of
circulation is known as
During this phase, the
much of the waste from
also passes through the
during systemic
phase is called portal
this phase, the blood
intestine collects in the
passes through the liver.
Question 2: Which are the main parts of the circulatory system?
Answer:
The circulatory system includes the heart, lungs, arteries, arterioles (small
arteries), and capillaries, the blood vessels that carry oxygen-rich blood away
from the heart. It also includes venules (small veins) and veins, the blood vessels
through which blood flows as it returns to the heart and which carry oxygen-poor
blood. If all the vessels of this network in human’s body were laid end-to-end,
they would extend for about 60,000 miles!
Tubular circulation
Located throughout human’s body, blood vessels are hollow tubes that
circulate the blood. There are three varieties of blood vessels: arteries, veins,
and capillaries. During blood circulation, the arteries carry blood away from the
heart. The capillaries connect arteries to veins, and finally the veins return the
blood back to the heart.
Besides circulating blood,
the blood vessels provide two
important means of measuring
vital health statistics: pulse
and blood pressure. Heart rate
or pulse is measured by
touching an artery. The
rhythmic contraction of the
artery keeps pace with the
beat of the heart. To measure
blood pressure, we use the
blood flowing through the arteries because it has a higher pressure than the
blood in the veins. The blood pressure is measured using two numbers. The first
one, which is higher, is taken when the heart beats during the systole phase. The
second number is taken when the heart relaxes during the diastole phase.
Normal blood pressure ranges from 110 to 150 millimeters (as the heart beats)
over 60 to 80 millimeters (as the heart relaxes). It is normal for the blood
pressure to increase when people are exercising and to decrease when they are
sleeping.
Arteries
Arteries are tubes that carry blood away
from the heart. The heart pumps blood out
through one main artery called the dorsal
aorta. The main artery then divides and
branches out into smaller arteries so that
each region of the body has its own system
of arteries supplying it with fresh, oxygen-rich
blood.
An artery has three layers: an outer layer
of tissue, a muscular middle, and an inner
layer of epithelial cells. The inside layer is very smooth, allowing the blood to flow
quickly and easily without any obstacles in its path. The muscle in the middle is
elastic and very strong. Finally, the outside layer is very strong, allowing the
blood to flow forcefully. The muscular wall of the artery helps the heart pump the
blood. When the heart relaxes, the artery contracts, exerting a force in order to
push the blood along. Then, arteries deliver the oxygen-rich blood to the
capillaries.
Capillaries
Capillaries connect arteries and veins. They are thin and fragile. Capillaries are
actually one epithelial cell thick, and blood cells can only pass through them in
one single file.
The exchange of oxygen and
carbon dioxide takes place through
the thin capillary wall. The red
blood cells inside the capillary
release their oxygen which passes
through the wall and into the
surrounding tissue. The tissue
releases its waste products, like
carbon dioxide, which passes
through the wall and into the red
blood cells. Capillaries are also involved in the body’s release of excess heat.
Blood delivers the heat to the capillaries which then rapidly release it to the
tissue. The result is that the skin takes on a flushed, red appearance.
Veins
Veins are tubes that return blood to the
heart. They are not as strong as the arteries
because they transport blood at a lower
pressure. They consist of three layers: an
outer of tissue, muscle in the middle, and a
smooth inner layer of epithelial cells. The
layers are thinner than those of arteries,
containing less tissue. Veins receive blood
from the capillaries and also transport wasterich blood back to the lungs and heart. It is
important that the waste-rich blood keeps moving in the proper direction and
against the force of gravity (e.g. the blood from the foot), and not be allowed to
flow backward. This is accomplished by one-way valves that are located inside
the veins. Because it lacks oxygen, the waste-rich blood that flows through the
veins has a deep purplish color.
Heart
The heart is a muscular organ located between
the lungs in the middle of the chest, behind and
slightly to the left of the breastbone (sternum). It is
about the size of human’s fist and it pumps 4300
gallons of blood a day. A double-layered membrane
called the pericardium surrounds the heart like a
sac. The outer layer of the pericardium surrounds
the root of the heart’s major blood vessels and is
attached by ligaments to the spinal column,
diaphragm, and other parts of the body. The inner
layer of it is attached to the heart muscle. A coating
of fluid separates the two layers of membrane,
letting the heart move as it beats, yet still be attached to your body.
The heart weighs between 200 to 425 grams. It has four chambers. The upper
chambers are called the left and right atria, they receive blood from the body or
lungs. The lower chambers are called the left and right ventricles, they pumps
blood to the rest of the body. A wall of muscle called the septum separates the
left and right atria and the left and right ventricles. The left ventricle is the largest
and the strongest chamber in the heart.
A valve connects each atrium to the
ventricle below it. The mitral valve connects
the left atrium with the left ventricle. The
tricuspid valve connects the right atrium with
the right ventricle. There are also another
two valves: the pulmonary valve and the
aortic valve.
The top of the heart connects to a few
large blood vessels. Two of them are
arteries- the aorta and the pulmonary arteryand the other two are veins- the superior
and the inferior vena cava.
The heart’s structure make’s it an efficient, never-ceasing pump. The average
cardiac muscle contracts and relaxes about 70 to 80 times per minute. Nerves
connected to the heart regulate the speed with which the muscle contracts.
Blood
The blood is the transport system by which oxygen and nutrients reach the
body’s cells, and waste materials, by those cells, are carried away. In addition,
blood carries substances called hormones, which control body processes, and
antibodies to fight invading germs.
Question 3: How does the heart work?
Answer:
The role of the heart is to deliver the oxygen-rich blood to every cell in the
body. As the cardiac muscle contracts it pushes blood through the chambers into
the vessels. Blood flows continuously through the circulatory system, and the
heart muscle is the pump which makes it all possible.
How does the heart pump blood?
Heart does it by a sequence of highly organized contractions of its four
chambers. As blood collects in the upper chambers, the heart’s natural
pacemaker sends out an electric signal that causes the atria to contract. This
contraction pushes blood through the tricuspid and the mitral valves into the
resting lower chambers. This part of the two-part pumping phase (the longer of
two) is called the diastole. The second part of it begins when the ventricles are
full of blood, then the mitral and tricuspid valves are closed. The electrical signals
from the SA node cause the ventricles to contract. This is called systole.
As the tricuspid and mitral valves shut tight to prevent a back flow of blood, the
pulmonary and aortic valves are pushed open and the blood is supplied to the
lungs and the other parts of the body. Continuing, the ventricles relax, and the
pulmonary and aortic valves close. The lower pressure in the ventricles causes
the tricuspid and mitral valves to open, and the cycle begins again. This series of
contractions is repeated over and over again, and it is affected by different
factors. The human heart is a muscle designed to remain strong and reliable for
a hundred of years or longer.
The conduction system
The heart also has an electrical system which includes a permanent
pacemaker to regulate the heartbeat rate and specialized wiring to transmit the
pacemaker beat to all parts of the heart, and cause the heart to beat (contract).
The pacemaker (sinoatrial node) is located at the top of the right atrium. This
pacemaker creates a miniature electrical impulse. The signal then passes
through the atrioventricular (AV) node, which creates a short delay in the impulse
to allow the atria to contract and forces blood into the ventricles before they
contract.
The AV node checks the signal and
sends it through the muscle fibers of the
ventricles, causing them to contract. The
SA node sends electrical impulses at a
certain rate, but your heart rate may still
change depending on physical demands,
stress, or hormonal factors.
Question 4: Draw and label the major parts of the heart.
Answer:
Student 2: Koulina Anastasia
BLOOD
Question 1: What blood is made up and why is so important?
Answer:
Blood is a liquid tissue. It moves in blood vessels and is circulated by the heart,
a muscular pump. It passes to the lungs to be oxygenated and then is circulated
throughout the body by the arteries. It diffuses its oxygen by passing through the
capillaries. It then returns to the heart through the veins.
Blood is vital for life; without it the body would stop working. Its functions are:
to transport
 Oxygen from the lungs to body tissue and carbon dioxide from body tissue
to the lungs
 Nourishment from digestion throughout the body
 Hormones from glands throughout the body
 Disease fighting substances to the tissue
 Waste to the kidneys
Blood is composed of living cells (erythrocytes, leukocytes, thrombocytes
constitute about 45% of whole blood) and plasma (the other 55%).
Erythrocytes (red blood cells)
They contain a protein called
hemoglobin by which they deliver
oxygen to body tissues and carry
carbon dioxide back from the
tissues. Human erythrocytes have
a flattened ovate shape, depressed
in the centre and lack a nucleus
and organelles. They are flexible
so as to fit through tiny capillaries.
Their diameter is about 6-8 m.
Adult humans have approximately
4-6 million erythrocytes per cubic
millimeter of blood (women 4-5,
men 5-6). Erythrocytes are produced in the red bone marrow, develop in about 7
days and live about 120 days.
Leukocytes (white blood cells)
Leukocytes help to defend body against infectious disease
and foreign materials as part of the immune system. There
are normally between 4,000-10,000/μl of them at any time.
There are many types of white cells:
Granulocytes

Neutrophile: (50-70% of whole leukocytes) they are the
primary cells of acute inflammatory response and act by
phagocytosing foreign materials and pathogens.

Eosinophile: (1-2%) they have a role in the allergic
response and in defending parasites.

Basophile: (0-1%) their purpose is not clear.
Other White Cells

Lymphocytes: (20-40%) there are three types of lymphocytes, B cells
(they make antibodies that bind to pathogens and destruct them), T cells
(they co-operate the immune system) and natural killer cells (they kill cells
of the body that are infected by virus).
.

Monocytes: (3-6%) they phagocytose pathogens
Thrombocytes (platelets)
Platelets are cells that stick together to form blood
clots. They are irregularly-shaped, colorless
broken-off pieces of megacaryocyte cytoplasm
released from the red bone marrow into the blood
stream. When there is a disturbance in the blood
vessels (such as a broken vessel) they stick
together at that point and prevent blood from
coming out of the vessel. A normal platelet count
in a healthy person is between 150,000 and
300,000/μl.
Blood plasma
Plasma is mainly composed of water (90%), proteins and mineral salts (calcium,
sodium, magnesium and potassium). It serves as a transport medium for the
blood cells, glucose, lipids, hormones, products of metabolism, carbon dioxide,
oxygen and microbe-fighting antibodies.
Question 2: Conditions (3) associated with the heart and
treatments/research.
Answer:
Hypertension
It is the medical term for high blood pressure. According to new guidelines
released by the National Heart, Lung, and Blood Institute (NHGBI) in 2003,
people with a blood pressure above 140/90 mm Hg are classified within the
category “hypertension”
Category
Normal
Prehypertension
Hypertension
Stage 1
Stage 2
Systolic (mm Hg)
Lower than 120
120-139
Diastolic (mm Hg)
Lower than 80
80-89
140-159
160 or higher
90-99
100 or higher
High blood pressure results from the hardening of very small arteries, arterioles,
which regulate the blood flow through the body. It can affect the health in four
main ways:
 Hardening the arteries. Their walls thicken and they become narrower.
 Enlarged heart. The amount of heart’s work is increased, causing the
heart grow bigger. The bigger the heart is, the less able is to maintain
proper blood flow.
 Kidney damage.
 Eye damage.
About 90-95% of all cases, the real cause is not known (primary or essential
hypertension), although there is a number of risk factors associated (family
history, male, older than 60, African Americans, stress, smoking, overweight, diet
high in salt or saturated fat, alcohol, physical inactive, diabetes). The rest
patients have secondary hypertension, which is a result of other conditions
(kidney disorders, acromegaly, pregnancy, problems with the parathyroid gland,
reactions to medicines).
Symptoms: The patients usually have no symptoms, or some of them may have
a pounding feeling in their chest or head, a feeling of lightheadedness or
dizziness.
Diagnosis: It is diagnosed by a doctor during a medical check-up.
Treatment: The treatment involves lifestyle changes and, if it is necessary,
administration of medicines (diuretics, ACE inhibitors, beta blockers, calcium
channel blockers, vasodilators) which control the blood pressure.
Congestive Heart Failure (CHF)
Congestive Heart Failure is a condition in which the heart can not pump enough
blood to meet the needs of the body’s other organs. It usually develops slowly; a
patient may go for years without symptoms, and the symptoms become worse
with time. This slow onset and progression of CHF is caused by the heart’s own
efforts to deal with its graduate weakening. The heart tries to make up for this
weakening by enlarging and by forcing itself to pump faster to move more blood
through the body.
Previous heart attacks, coronary artery disease, hypertension, irregular
heartbeat, heart valve disease (especially of the aortic and mitral valves)
cardiomyopathy, congenital heart defects are considered as risk factors for CHF.
Symptoms: If the left side of the heart is not working properly, then blood and
fluid back up to the lungs and the patient feels short of breath, very tired and has
a cough.
If the right side of the heart is not working properly, fluid is built up in the veins.
The feet, legs and ankles swell (edema). Sometimes edema is spread to the
lungs, liver and stomach. The patient may need to go to the bathroom more
often, especially at night.
Other symptoms are chest pain, irregular or fast pulse, cold and sweaty skin.
Diagnosis: It is usually diagnosed by the presence of edema and shortness of
breath. The imaging techniques used are chest X-ray, electrocardiography,
echocardiography, nuclear ventriculography and angiography.
Treatment: It includes lifestyle changes, medicines (diuretics, digitalis,
vasodilators, beta blockers, ACE inhibitors, etc), transcatheter interventions
(angioplasty, stenting) and surgical procedures (pacemaker insertion, coronary
artery bypass surgery, heart valve repair or replacement, correction of congenital
heart defects, mechanical assist devices, heart transplantation).
Stroke
Stroke is a form of a cerebrovascular disease, meaning it affects the vessels that
supply blood to the brain. A stroke is caused when blood flow to the brain is
blocked, either by a blood clot or by a weaken artery that bursts in the brain.
 A blood clot or a blocked artery leading to the brain causes about 80% of
all strokes (ischemic stroke).Oxygen supply is cut off and brain cells begin
to die. The longer the brain is without blood, the more severe the damage
will be.
 The other 20% of strokes are caused by ruptured or leaky blood vessels
in or around the brain (hemorrhagic stroke). Hemorrhagic strokes cause
more deaths than ischemic ones, but patients who survive a hemorrhagic
stroke recover more fully and have fewer long-lasting disabilities.
Effects: In people who survive stroke, there may be paralysis, emotional
problems, or trouble with speech, memory or judgment. If the right side of the
brain is affected, the left side of the body may become paralyzed. The effects
may be severe or mild, short-term or permanent.
Diagnosis: Tests that show images of the brain (CT scan, MRI), measure the
brain’s electrical activity (electroencephalography) and show the blood flow to the
brain (carotid duplex scan) are used to find out the type and severity of stroke.
Treatment: Treatment includes anti-clotting drugs, hospital care, hospital care,
rehabilitation and, rarely, surgery.
Question 3: How can we maintain a healthy circulatory system?
Answer:
In order to keep a healthy circulatory system, people should:
 Get plenty of exercise
 Follow a good diet and manage their weight
 Control risk factors
Physical activity
Daily physical activity reduces the risk of heart
disease and keeps weight under control. Other
benefits are that it improves blood cholesterol
levels, prevents and manages high blood
pressure.
A successful exercise program involves exercises
that are rhythmic, repetitive, challenge the
circulatory system and use large muscles (aerobic
exercises). It must increase the blood flow to the
muscles for an extend period of time. Some aerobic exercises are walking,
hiking, jogging, bicycling, swimming, jumping rope and roller skating.
(http://www.nvo.com/upandmoving/benefits)
Diet
In order to maintain a healthy cardiovascular
system and reduce the risk for heart diseases,
people should follow a balanced diet. A
balanced diet excludes foods that are rich in
fat, especially saturated fat. These foods add
many useless calories (obesity contributes to
heart diseases) and can raise the level of
cholesterol in the blood –which can lead to risk
for heart diseases.
On the contrary, a suitable diet includes:
 6-11 servings from the Bread, Cereal, Rice and Pasta Group
 at least 3-5 servings from the Vegetable Group
 2-4 servings from the Fruit Group
 2-3 items from Milk, Yoghurt and Cheese
 2-3 servings from the Meat, Poultry, Fish, Dry Beans, Eggs and Nuts
 small quantities from Fats, Oils and Sweets
(http://www.apronstringsbabythings.com/make_your_own_baby_food.htm)
Risk factors
Smoking, alcohol and drug abuse, and stress are the main
risk factors.
Stress is the body’s response to change. Great range of
stress can lead to habits like smoking, drinking, overeating
or drug abuse. Even if someone does not feel stress at all,
the body suffers from it.
Smoking, taking drugs or drinking alcohol excessively give
heart extra work, which the heart is not able to handle for a
long period of time. Smokers have double risk of having a heart attack, even
quadruple risk of sudden cardiac death and high risk of developing chronic
disorders, such as atherosclerosis. Additionally, the ratio of high-density
lipoprotein (or good) cholesterol to low-density lipoprotein (or bad) cholesterol is
lower in smokers than in nonsmokers. Former smokers can completely lower
their risk of sudden cardiac death within ten years of quitting.
Drinking alcohol in large quantities poses a serious hazard to the heart, because
the blood cannot nourish the heart properly. The moderate intake of alcohol is an
average of one or two drinks per day for men and one drink per day for women.
(http://www.mankao.msus.edu/healthsv)
List of academic words
TERM
Example in
context
Major
The
major
factor
that
affects
heart’s
function is…
Affect
The
blood
oxygen
affects
heart’s pulse.
Phase
This phase of
systemic
circulation….
Medium
Layer
Treatment
Word class Dictionary
information
definition
Adjective
Very large or
important
’serious
Greek
translation
Μεγαλύτερος,
κύριος
Verb
To have an Επηρεάζω
influence on
sb/sth
Noun
a stage in a Φάση
process
of
change
or
development
In the middle Μέτριος,
between two μεσαίος
sizes,
amounts,
lengths, etc.
The medium Adjective
layer
of
arteries
is
consisted of
muscular
fibers.
An artery has Noun
three layers:
an outer layer
of tissue
…he
is Noun
receiving
treatment for
sock
Techniques
…teachers
Noun
learn various
techniques
for
dealing
with problem
students.
Abuse
...what
she Noun
did was an
abuse of her
position as a
manager.
A level or part Στιβάδα,
within
a στρώμα
system
Something
that is done
to cure an
illness
or
injury, or to
make sb feel
good
A particular
way of doing
sth,
especially
one in which
you have to
learn special
skills
The use of
sth in a way
that is wrong
or harmful
Θεραπευτική
αγωγή
Τεχνικές
Κατάχρηση
Challenge
Obesity
…he
is Noun
looking
forward to the
challenge of
his new job
…obesity can Noun
increase the
risk of heart
disease.
List of medical words
TERM
Example
in Word class
context
information
Tissue
…pushes
Noun
blood to the
organs,
tissues,
and
cells of the
body.
Renal
(circulation)
Aorta
Pulse
This phase of Adjective
systemic
circulation
is
known
as
systemic
circulation.
The
aorta Noun
branches off
two...
..measuring
Noun
vital
health
statistics:
pulse
and
blood
pressure.
A new or Προκαλώ
difficult task
that tests sb’s
ability
and
skill
The condition Παχυσαρκία
of being very
fat, in a way
that is not
healthy
Dictionary
Definition
Collection of
cells organized
in
a
cooperative
arrangement
for
the
purpose
of
performing a
particular
function
Something
that ha to do
with the kidney
Greek
translation
Ιστός
Νεφρικός
The main trunk Αορτή
of the systemic
arteries.
The rhythmical Σφυγμός,
expansion and παλμός
contraction of
an
artery
produced
by
waves
of
pressure
caused by the
ejection
of
blood from the
left ventricle of
the heart as it
contracts.
Intestine
Blood
also Noun
passes
through
the
small intestine
during
systemic
circulation.
Diuretics
…diuretics
Noun
help rid your
body of water
and sodium
Hormones
...oestrogen is Noun
a female sex
hormone
…angioplasty
noun
is used
to
open arteries
narrowed
by
fatty
plaque
buildup
Atherosclerosis …a diet rich in noun
saturated fats
may
cause
atherosclerosis
Angioplasty
Edema
…ankles begin Noun
to swell if fluid
is built up in
the veins; this
The section of Έντερο
the alimentary
canal from the
stomach to the
anus.
It
includes
the
small intestine
and the large
intestine.
A substance or Διουρητικά
drug that tends
to increase the
discharge
of
urine
A
chemical Ορμόνες
substance
produced
in
the body that
encourages
growth
or
influences how
the cells and
tissues
function
The
surgical Αγγειοπλαστική
repair of a
blood vessel
A
type
of αθηροσκλήρωση
arteriosclerosis
characterized
by
the
deposition of
plaques
containing
lipids
and
cholesterol on
the inner layer
of the walls of
arteries
An excessive Οίδημα
accumulation
of serous fluid
in
tissue
swelling
is
called edema
spaces or
body cavity
a
Websites consulted:
http://en.wikipedia.org/wiki/
http://sln.fi.edu/biosci/
http://texasheartinstitute.org/
http://www.rcpg.com/
http://www.tmc.edu/thi/
http://www.americanheart.org/presenter.jtml?identifier=4598
http://www.accessexcellence.org/AE/AEC/CC/heart_graphics/ Human_Heart.gif
http://www.accessexcellence.org/AE/AEC/CC/heart_graphics/ Open_Heart.gif
http://www.jhbmc.jhu.edu/cardiology/rehab/healthy.heart.html