Transcript - Your Best Wellness Tips

THE HUMAN
CIRCULATORY SYSTEM
PowerPoint by:
Reynaldo Thomas
The Limitation of Simple Diffusion

Very small organisms obtain their oxygen and nutrients by diffusion from
the outside.

When the volume of an organism is large, the surface area ratio to its
volume becomes smaller.

Simple diffusion cannot cope and a transport system is needed.

Human have a large volume in relation to their body surface.

Sufficient oxygen cannot
diffuse quickly to supply
all body organs.
Purpose of a Circulatory System

Transport substances from one part of the body to another.

Removal of waste from body parts.
Substances include:

Oxygen

Nutrients

Carbon dioxide

Urea

Heat
Parts of The Circulatory System


The heart
Blood

Blood Components
The Heart

The human heart consists almost entirely of cardiac muscle tissue.

This specialized muscle can contract about 70 times per minute without
tiring easily.
External view
Internal view
Questions
1.
Why does man need a circulatory system while a
bacterium does not?
2.
What is the heart muscle called?
3.
Give the name of two useful substances and
two waste substances that the circulatory
system transport.
Flow of Blood Through The Heart

blood from all over the body enters the right atrium.

Blood from upper body parts is taken by superior vena cava

Blood from lower body
parts by the inferior
vena cava.

This blood lacks
oxygen.

The body cells have
Used the oxygen for respiration
(deoxygenated).

When right atrium contracts, blood is forced through the
tricuspid valve to the right ventricle.

Tricuspid valve close to
prevent back flow of
blood to right atrium

The right ventricle
contracts and force
blood.

Pulmonary artery take
Blood to both lungs.

Blood becomes oxygen rich in lungs (oxygenated).

Oxygenated blood then enters the left atrium by the
pulmonary vein.

Blood is then force
through the bicuspid
valve into left ventricle.

Left ventricle then
contract and force
blood to aorta.
Types Of Circulation

There are two types

Blood passes through the heart twice on its way
around the body once.
Pulmonary Circulation
This is the passage of blood around from the
heart to the lungs and back to the heart.
Systemic Circulation
This is the passage of blood around the rest of
the body, and its return to the heart.
The cardiac Cycle

This is the complete sequence of events during
one beat of the heart.

Contractions of the heart chambers are called
systole.

When the chamber relax it is called diastole.
The Blood

Also called erythrocytes

Are the most numerous calls in the blood

Red blood cells have no nuclei.

They are made in bone marrow.

Vitamin b12 is
needed to make
red blood cell

After 120 days the red blood cells are destroy in the liver and spleen.

Red blood cells transport oxygen round the
body.

Oxygen from the alveoli combines with
haemoglobin to form oxyhaemoglobin.

Haemoglobin can also combine with carbon
dioxide for transport.

It has a bi-concave shape.

The bi-concave shape of the red blood cell
increase its surface area.

This increase the amount of oxygen it transport.
Questions
1.
List the components of the blood.
2.
What is the advantage of the red blood cell bi-concave shape?
3.
Which type of circulation allows blood to move between the heart and
lungs?
4.
White Blood Cell

Also called leucocytes

Have a nucleus

White blood cells destroys bacteria

Two types phagocytes and lymphocytes

Phagocytes engulf microorganisms in a process called phagocytosis.

Lymphocytes produce
antibodies which kill
microorganisms.
Plasma

The liquid part of the blood.

It is 90% water and 10% solutes.

Transport nutrients from the small intestine.

Carries nitrogenous waste from cells to the kidneys.

Carries hormones from endocrine gland to the organ where it is needed.

Help blood carry heat around the body
Mechanism of Blood Clotting
1.
Platelets and damaged blood vessels release
the protein thromboplastin.
2.
Thromboplastin then turns the protein
prothrombin into
thrombin.
3. Thrombin acts on
fibrinogen and turns
it into fibrin.
4. The
fibrin forms the fibres in the clot.
5. Red blood cells and platelets become trapped in
the fibres forming the clot.
NB
Prothrombin, essential
for clotting, is made in
the liver.
Vitamin K help to make
prothrombin.
The Pacemaker


The heart does not need to be told to contract by the
brain.
In the wall of the right atrium are some specialized
cardiac muscle cells.

The cells act as the heart’s
pacemaker.

These cells send out pulses
of electricity that instruct
the atria and then the
ventricles to contract.
Pulse rate

The pumping of the heart causes the surges of
blood in arteries.

This is detected as the pulse where an artery lies
above a bone near the surface of the body.

The beating pulse can be seen at the temple and
wrist.
Blood Pressure

Blood in the blood vessels is under pressure.

This is the pressure needed to pump blood round
all parts of the body.

The pressure is the force exerted on the walls of
arteries.
The Heart as a Double Pump
The heart function as a double pump because it
send deoxygenated blood to the lungs while it is
pumping oxygenated blood to the rest of the
body at the same time.
Serum
The clear liquid that can be separated from clotted
blood. Serum differs from plasma, the liquid
portion of normal unclotted blood containing the
red and white cells and platelets. It is the clot
that makes the difference between serum and
plasma.
Circulatory diseases
Coronary thrombosis
 The heart is surrounded by three coronary arteries
that supply it with blood and oxygen.

If a blood clot develops in one of these arteries, the
blood supply to that area of the heart muscle will
stop.

This is known as a heart attack, or in medical terms
a coronary thrombosis .
Circulatory diseases
Heart attack

When blood stops flowing to part of the heart
muscle.

Because a blockage occurs in one of the coronary
arteries.

When this happens, the muscles does not get the
oxygen it needs to keep it working.
It stops contracting, and parts of
it may die.


In severe cases, the whole heart stops beating. This
is cause cardiac arrest.

In severe cases, the whole heart stops beating. This
is cause cardiac arrest.

The person will have no pulse, and they rapidly
become unconscious.

Without immediate treatment, they will die.
Atherosclerosis

This is when fats with high cholesterol build up
in the arteries.

The fat laid down on the walls of the arteries
and reduces their internal diameter.

This causes high blood pressure (hypertension).

This blockage is called thrombosis
Arteriosclerosis

This is when the walls of the arteries harden and become less elastic.

This also increases blood pressure and so hypertension.

The nicotine in cigarette smoke also increases the risk of arteriosclerosis.
Hypertension (High Blood Pressure)

Systolic pressure should be 100 to 139.

Diastolic pressure 60-89.

Excessive high blood pressure, called
hypertension, occurs when these figures are
exceeded.

This is when the force of the blood against the
artery walls is high .

The narrower your arteries are , the higher your
blood pressure.

It is linked to genetic, poor diet, lack of exercise
and obesity.
Artificial Pacemakers

Can be inserted into the chest.

It contains a small battery that makes regular
shocks to stimulate and control normal
heartbeat.