anatomy physiology of circulatory system

1. Aswathi T.R

4.  The heart is part of your body’s circulatory
system. It’s made up of the atria, ventricles,
valves, and various arteries and veins. The
main function of your heart is to keep blood
that’s full of oxygen circulating throughout
your body. Because your heart is crucial to
your survival, it’s important to keep it
healthy with a well-balanced diet and
exercise, and avoid things that can damage
it, like smoking.
 While you’re probably familiar with a few
heart-healthy tips, there are some fun facts
about the heart that you may not know.

5.  The average heart is the size of a fist in an adult.
 Your heart will beat about 115,000 times each day.
 Your heart pumps about 2,000 gallons of blood every
day.
 An electrical system controls the rhythm of your
heart. It’s called the cardiac conduction system.
 The heart can continue beating even when it’s
disconnected from the body.
 The first open-heart surgery occurred in 1893. It was
performed by Daniel Hale Williams, who was one of
the few black cardiologists in the United States at
the time.

6.  The first implantable pacemaker was used in
1958. Arne Larsson, who received the
pacemaker, lived longer than the surgeon who
implanted it. Larsson died at 86 of a disease that
was unrelated to his heart.
 The youngest person to receive heart surgery
was only a minute old. She had a heart defect
that many babies don’t survive. Her surgery was
successful, but she’ll eventually need a heart
transplant.
 The earliest known case of heart disease
was identified in the remains of a 3,500-year-old
Egyptian mummy.
 The fairy fly, which is a kind of wasp, has the
smallest heart of any living creature.

7.  The American pygmy shrew is the smallest
mammal, but it has the fastest heartbeat at
1,200 beats per minute.
 Whales have the largest heart of any mammal.
 The giraffe has a lopsided heart, with their left
ventricle being thicker than the right. This is
because the left side has to get blood up the
giraffe’s long neck to reach their brain.
 Most heart attacks happen on a Monday.
 Christmas day is the most common day of the
year for heart attacks to happen.
 The human heart weighs less than 1 pound.
However, a man’s heart, on average, is 2 ounces
heavier than a woman’s heart.

8.  A woman’s heart beats slightly faster than a
man’s heart.
 The beating sound of your heart is caused by the
valves of the heart opening and closing.
 It’s possible to have a broken heart. It’s called
broken heart syndrome and can have similar
symptoms as a heart attack. The difference is
that a heart attack is from heart disease
and broken heart syndrome is caused by a rush
of stress hormones from an emotional or physical
stress event.
 Death from a broken heart, or broken heart
syndrome, is possible but extremely rare.


9.  The iconic heart shape as a symbol of love is
traditionally thought to come from the silphium
plant, which was used as an ancient form of
birth control.
 If you were to stretch out your blood vessel
system, it would extend over 60,000 miles.
 Heart cells stop dividing, which means heart
cancer is extremely rare.
 Laughing is good for your heart. It reduces stress
and gives a boost to your immune system.


10.  The Aorta: this is the largest artery in the
human body. Arteries are tubular branching
elastic-walled muscle vessels that carry blood all
the way from the heart through the body. The
main function of the aorta is to take oxygenated
blood all the way from the left ventricle to the
rest of the body.
 The Pulmonary Artery: this artery is responsible
for carrying deoxygenated blood all the way
from the right ventricle to the lungs.
 Oxygenated blood: the word “oxygenated”
simply means that it carries oxygen. So,
oxygenated blood is the blood that carries
oxygen.

11.  Deoxygenated blood: the word “deoxygenated”
simply means that it carries very little or no
oxygen. So, deoxygenated blood is the blood
that carries either very little or no oxygen.
 The Right Atrium: this part of the human body is
tasked with receiving deoxygenated blood from
the rest of the body.
 The Pulmonary Vein: Veins are the tubular
branching vessels that carry blood all the way
from the capillaries and take it to the heard.
The function of the pulmonary vein is to take
oxygenated blood all the way from the lungs to
the left atrium.

12.  The Left Ventricle: A ventricle is any of the cavities
of a bodily part or organ. This ventricle, in particular,
is the chamber of the heart that gets blood from a
corresponding atrium. The left verticle is from where
the blood is forced into the different arteries. The
essential function that the left ventricle carries out is
pumping oxygenated blood into the aorta.
 The Right Ventricle: the right ventricle is tasked
with pumping deoxygenated blood into the
pulmonary artery.
 The Coronary Vessels: these vessels supply the
myocardium (the heart muscle) with the necessary
supply of blood. There is a main left coronary that
goes into the circumflex artery, supplying blood to
the left atrium. There is a right coronary vessel that
goes into the right marginal artery, supplying blood to
the right atrium and the right ventricle.

13.  The Arteries: the arteries are tasked with carrying blood away from the
heart. These blood vessels are muscular tubes. The aorta is the largest
artery. Each and every artery is lined with three layers of sooth tissue.
The three layers are the intima, which is the inner layer whose tissue is
called endothelium; then, there the media, which is a muscle layer
whose role is to allow the human heart to deal with high pressures;
finally, there is the adventitia, which connects the arteries to tissue.
 The Veins: the veins are tasked with carrying blood toward the heart.
 The Bicuspid Valve: Valves are bodily structures (such as the mitral
valve) that either shut down temporarily an orifice or passage or that
permits fluid to move, but always in only one direction. The Bicuspid
Valve is the valve located between the left ventricle and the left atrium.
Some people are born with this kind of aortic valve that is located
between the aorta and the left ventricle and has two cusps instead of the
usual three. People who are born with a bicuspid valve instead of a
tricuspid valve may be affected by it, particularly, once they become
adults. This valve often causes what is known as an aortic valve stenosis,
which is the narrowing of the aortic valve. People with a bicuspid valve
sometimes suffer from an enlarged aorta and this can increase the risk of
having an aortic dissection.

14.  The Tricuspid Valve: this is the vale that is located
between the right ventricle and the right atrium.
Most people are born with a tricuspid valve, which is
the valve with three cusps located between the aorta
and the left ventricle.
 The Vena Cava: this is the largest vein in the human
body (vena is Latin for vein). Its essential function is
to carry blood from all around the body all the way to
the heart. There is a superior vena cava and an
inferior vena cava. The superior vena cava is tasked
with carrying blood to the upper body: neck, head,
and both upper limbs back to the heart. What the
inferior vena cava does is carrying blood back from
the lower parts of the body back to the heart.

16.  The right atrium receives non-oxygenated blood from the body’s
largest veins — superior vena cava and inferior vena cava — and
pumps it through the tricuspid valve to the right ventricle.
 The right ventricle pumps the blood through the pulmonary valve
to the lungs, where it becomes oxygenated.
 The left atrium receives oxygenated blood from the lungs and
pumps it through the mitral valve to the left ventricle.
 The left ventricle pumps oxygen-rich blood through the aortic
valve to the aorta and the rest of the body.
 The coronary arteries run along the surface of the heart and
provide oxygen-rich blood to the heart muscle.
 A web of nerve tissue also runs through the heart, conducting the
complex signals that govern contraction and relaxation. A sac
known as the pericardium surrounds the heart.
 The outer layer of the pericardium surrounds the roots of the
heart’s major blood vessels, and the inner layer is attached to
the heart muscle.


17.  The heart contracts at different rates depending
on many factors. At rest, it might beat around 60
times a minute, but it can increase to 100 beats
a minute or more. Exercise, emotions, fever,
diseases, and some medications can influence
heart rate. For more information on what is
"normal," read this article.
 The left and right side of the heart work in
unison. The right side of the heart receives
deoxygenated blood and sends it to the lungs;
the left side of the heart receives blood from
the lungs and pumps it to the rest of the body.
 The atria and ventricles contract and relax in
turn, producing a rhythmical heartbeat:

18. Right side
 The right atrium receives deoxygenated
blood from the body through veins called the
superior and inferior vena cava (the largest
veins in the body).
 The right atrium contracts and blood passes
to the right ventricle.
 Once the right ventricle is full, it contracts
and pumps the blood through to the lungs via
the pulmonary artery, where it picks up
oxygen and offloads carbon dioxide.

19.  Left side
 Newly oxygenated blood returns to the left atrium via
the pulmonary vein.
 The left atrium contracts, pushing blood into the left
ventricle.
 Once the left ventricle is full, it contracts and pushes
the blood back out to the body via the aorta.
 Each heartbeat can be split into two parts:
 Diastole: the atria and ventricles relax and fill with
blood.
 Systole: the atria contract (atrial systole) and push
blood into the ventricles; then, as the atria start to
relax, the ventricles contract (ventricular systole)
and pump blood out of the heart.

20.  When blood is sent through the pulmonary artery to
the lungs, it travels through tiny capillaries on the
surface of the lung's alveoli (air sacs). Oxygen travels
into the capillaries, and carbon dioxide travels from
the capillaries into the air sacs, where it is breathed
out into the atmosphere.
 The muscles of the heart need to receive oxygenated
blood, too. They are fed by the coronary arteries on
the surface of the heart.
 Where blood passes near to the surface of the body,
such as at the wrist or neck, it is possible to feel your
pulse; this is the rush of blood as it is pumped
through the body by the heart. If you would like to
take your own pulse, this article explains how.

21.  The valves
 A diagram of the heart's valves.
Image credit: OpenStax College, Anatomy & Physiology, 2013
 The heart has four valves that help ensure that blood only flows
in one direction:
 Aortic valve: between the left ventricle and the aorta.
 Mitral valve: between the left atrium and the left ventricle.
 Pulmonary valve: between the right ventricle and the pulmonary
artery.
 Tricuspid valve: between the right atrium and right ventricle.
 Most people are familiar with the sound of a human heartbeat. It
is often described as a "lub-DUB" sound. The "lub" sound is
produced by the tricuspid and mitral valves closing, and the
"DUB" sound is caused by the closing of the pulmonary and aortic
valves.


22.  The heart's electrical system
 To pump blood throughout the body, the muscles of the heart
must be coordinated perfectly — squeezing the blood in the right
direction, at the right time, at the right pressure. The heart's
activity is coordinated by electrical impulses.
 The electrical signal begins at the sino-atrial (or sinus, SA) node
— the heart's pacemaker, positioned at the top of the right
atrium. This signal causes the atria to contract, pushing blood
down into the ventricles.
 The electrical impulse travels to an area of cells at the bottom of
the right atrium called the atrioventricular (AV) node. These cells
act as a gate; they slow the signal down so that the atria and
ventricles do not contract at the same time — there needs to be
a slight delay.
 From here, the signal is carried along special fibers called
Purkinje fibers within the ventricle walls; they pass the impulse
to the heart muscle, causing the ventricles to contract.


23.  Blood vessels
 There are three types of blood vessels:
 Arteries: carry oxygenated blood from the heart to
the rest of the body. Arteries are strong and stretchy,
which helps push blood through the circulatory
system. Their elastic walls help keep blood
pressure consistent. Arteries branch into smaller
arterioles.
 Veins: these carry deoxygenated blood back to the
heart and increase in size as they get closer to the
heart. Veins have thinner walls than arteries.
 Capillaries: they connect the smallest arteries to the
smallest veins. They have very thin walls, which
allow them to exchange compounds with surrounding
tissues, such as carbon dioxide, water, oxygen,
waste, and nutrients.

24. 
 There are many different types of heart disease.
 There are many types of heart disease that affect
different parts of the organ and occur in different
ways.
 Congenital heart disease
 This is a general term for some deformities of the
heart that have been present since birth. Examples
include:
 Septal defects: There is a hole between the two
chambers of the heart.
 Obstruction defects: The flow of blood through
various chambers of the heart is partially or totally
blocked.

25.  Cyanotic heart disease: A defect in the heart causes a
shortage of oxygen around the body.
 Arrhythmia
 Arrhythmia is an irregular heartbeat.
 There are several ways in which a heartbeat can lose its
regular rhythm. These include:
 tachycardia, when the heart beats too fast
 bradycardia, when the heart beats too slowly
 premature ventricular contractions, or additional,
abnormal beats
 fibrillation, when the heartbeat is irregular
 Arrhythmias occur when the electrical impulses in the
heart that coordinate the heartbeat do not work properly.
These make the heart beat in a way it should not, whether
that be too fast, too slowly, or too erratically.

26.  Irregular heartbeats are common, and all people experience
them. They feel like a fluttering or a racing heart. However,
when they change too much or occur because of a damaged or
weak heart, they need to be taken more seriously and treated.
 Arrhythmias can become fatal.
 Coronary artery disease
 The coronary arteries supply the heart muscle with nutrients and
oxygen by circulating blood.
 Coronary arteries can become diseased or damaged, usually
because of plaque deposits that contain cholesterol. Plaque
buildup narrows the coronary arteries, and this causes the heart
to receive less oxygen and nutrients.
 Dilated cardiomyopathy
 The heart chambers become dilated as a result of heart muscle
weakness and cannot pump blood properly. The most common
reason is that not enough oxygen reaches the heart muscle, due
to coronary artery disease. This usually affects the left ventricle.

27.  Myocardial infarction
 This is also known as a heart attack, cardiac
infarction, and coronary thrombosis. An interrupted
blood flow damages or destroys part of the heart
muscle. This is usually caused by a blood clot that
develops in one of the coronary arteries and can also
occur if an artery suddenly narrows or spasms.
 Heart failure
 Also known as congestive heart failure, heart failure
occurs when the heart does not pump blood around
the body efficiently.
 The left or right side of the heart might be affected.
Rarely, both sides are. Coronary artery disease
or high blood pressure can, over time, leave the
heart too stiff or weak to fill and pump properly.

28.  Hypertrophic cardiomyopathy
 This is a genetic disorder in which the wall of the left ventricle thickens,
making it harder for blood to be pumped out of the heart. This is the
leading cause of sudden death in athletes. A parent with hypertrophic
cardiomyopathy has a 50 percent chance of passing the disorder on to
their children.
 Mitral regurgitation
 Also known as mitral valve regurgitation, mitral insufficiency, or mitral
incompetence, this occurs when the mitral valve in the heart does not
close tightly enough. This allows blood to flow back into the heart when
it should leave. As a result, blood cannot move through the heart or the
body efficiently.
 People with this type of heart condition often feel tired and out of
breath.
 Mitral valve prolapse
 The valve between the left atrium and left ventricle does not fully close,
it bulges upwards, or back into the atrium. In most people, the condition
is not life-threatening, and no treatment is required. Some people,
especially if the condition is marked by mitral regurgitation, may require
treatment.

29.  Pulmonary stenosis
 It becomes hard for the heart to pump blood from the right
ventricle into the pulmonary artery because the pulmonary valve
is too tight. The right ventricle has to work harder to overcome
the obstruction. An infant with severe stenosis can turn blue.
Older children will generally have no symptoms.
 Treatment is needed if the pressure in the right ventricle is too
high, and a balloon valvuloplasty or open-heart surgery may be
performed to clear an obstruction.
 Symptoms
 The symptoms of heart disease depend on which condition is
affecting an individual.
 However, common symptoms include chest pain, breathlessness,
and heart palpitations. The chest pain common to many types of
heart disease is known as angina, or angina pectoris, and occurs
when a part of the heart does not receive enough oxygen.
 Angina can be triggered by stressful events or physical exertion
and normally lasts under 10 minutes.
 .

30.  Heart attacks can also occur as a result of different types of
heart disease. The signs of a heart attack are similar to angina
except that they can occur during rest and tend to be more
severe.
 The symptoms of a heart attack can sometimes
resemble indigestion. Heartburn and a stomach ache can occur,
as well as a heavy feeling in the chest.
 Other symptoms of a heart attack include:
 pain that travels through the body, for example from the chest to
the arms, neck, back, abdomen, or jaw
 lightheadedness and dizzy sensations
 profuse sweating
 nausea and vomiting
 Heart failure is also an outcome of heart disease, and
breathlessness can occur when the heart becomes too weak to
circulate blood.
 Some heart conditions occur with no symptoms at all, especially
in older adults and individuals with diabetes

31.  The term 'congenital heart disease' covers a range of conditions, but the
general symptoms include:
 sweating
 high levels of fatigue
 fast heartbeat and breathing
 breathlessness
 chest pain
 a blue tint to the skin
 clubbed fingernails
 In severe cases, symptoms can occur from birth. However, these
symptoms might not develop until a person is older than 13 years.
 Causes
 Heart disease is caused by damage to all or part of the heart, damage to
the coronary arteries, or a poor supply of nutrients and oxygen to the
organ.
 Some types of heart disease, such as hypertrophic cardiomyopathy, are
genetic. These, alongside congenital heart defects, can occur before a
person is born.

32.  There are a number of lifestyle choices that
can increase the risk of heart disease. These
include:
 high blood pressure and cholesterol
 smoking
 overweight and obesity
 diabetes
 family history
 a diet of junk food
 age

33.  a history of preeclampsia during pregnancy
 staying in a stationary position for extended periods of
time, such as sitting at work
 Having any of these risk factors greatly increases the risk
of heart disease. Some, such as age, are unavoidable. For
example, once a woman reaches 55 years of age, heart
disease becomes more likely.
 Treatment
 There are two main lines of treatment for heart disease.
Initially, a person can attempt to treat the heart condition
using medications. If these do not have the desired effect,
surgical options are available to help correct the issue.
 Medication
 A very wide range of medication is available for the
majority of heart conditions. Many are prescribed to
prevent blood clots, but some serve other purposes.

34.  The main medications in use are:
 statins, for lowering cholesterol
 aspirin, clopidogrel, and warfarin, for preventing blood
clots
 beta-blockers, for treating heart attack, heart failure, and
high blood pressure
 angiotensin-converting enzyme (ACE) inhibitors, for heart
failure and high blood pressure
 Your doctor will work with you to find a medication that is
safe and effective. They will also use medications to treat
underlying conditions that can affect the heart, such as
diabetes before they become problematic.
 Surgery
 Heart surgery is an option for people with heart disease,
but it can be debilitating.
 Heart surgery is an intensive option from which it can take
a long time to recover.

35.  However, they can be effective in treating blockages and heart
problems for which medications may not be effective, especially
in the advanced stages of heart disease.
 The most common surgeries include:
 angioplasty, in which a balloon catheter is inserted to widen
narrowed blood vessels that might be restricting blood flow to
the heart
 coronary artery bypass surgery, which allows blood flow to reach
a blocked part of the heart in people with blocked arteries
 surgery to repair or replace faulty heart valves
 pacemakers, or electronic machines that regulate a heartbeat for
people with arrhythmia
 Heart transplants are another option. However, it is often
difficult to find a suitable heart of the right size and blood type
in the required time. People are put on a waiting list for donor
organs and can sometimes wait years.

36.  Some types of heart disease, such as those that are present from birth, cannot be
prevented.
 Other types, however, can be prevented by taking the following measures:
 Eat a balanced diet. Stick to low-fat, high-fiber foods and be sure to consume five
portions of fresh fruit and vegetables each day. Increase your intake of whole grains
and reduce the amount of salt and sugar in the diet. Make sure the fats in the diet
are mostly unsaturated.
 Exercise regularly. This will strengthen the heart and circulatory system, reduce
cholesterol, and maintain blood pressure.
 Maintain a healthy body weight for your height. Click here to calculate your current
and target body mass index (BMI).
 If you smoke, quit. Smoking is a major risk factor for heart and cardiovascular
conditions.
 Reduce the intake of alcohol. Do not drink more than 14 units per week.
 Control conditions that affect heart health as a complication, such as high blood
pressure or diabetes.
 While these steps do not completely eliminate the risk of heart disease, they can
help improve overall health and greatly reduce the chances of heart complications.