Transcript The Circulatory System

The Circulatory System
Circulatory
System
Structure of Blood
Blood is made of:
• Plasma
• Red blood cells
• White blood cells
• platelets
3 Types of Blood Cell
Plasma is the liquid part of blood and it
transports chemicals (e.g. food,
hormones, carbon dioxide, salts and urea)
and heat around the body.
Red blood cells contain a
red pigment called
haemoglobin which
transports oxygen around
the body.
White blood cells fight infection.
Platelets help to form blood
clots.
Functions of the Blood
Transports chemicals such
as food, wastes, and
hormones
Maintains body
temperature
Transports oxygen
Fights infection
Forms blood clots
Blood Vessels
Arteries
• Arteries carry blood
away from the heart
• They have a strong
flow of blood that is
under high pressure
• The walls are strong
and thick
• They have no valves
Veins
• Veins carry blood
to the heart
• The blood flow or
pressure is low
• They have thinner,
weaker walls
• They have valves
• Capillaries are
tiny blood
vessels
• They connect
arteries to veins
• Their walls are
very thin
• They allow
materials to
pass in and out
of the blood
stream
Capillaries
Arteries and Veins.
The arteries and veins carry the blood
through the heart and all the organs of the
body.
The Heart
The heart
pumps
blood
around the
body.
Structure of the Heart
•The heart contains four chambers.
•The top two are the right and left atrium.
•The bottom two are the right and left ventricle.
• The heart is made of Cardiac Muscle which
never gets tired. It is supplied with oxygen
rich blood from the coronary artery
Ventricles
• The right ventricle
pumps blood from
the heart to the
lungs, so the wall is
thin.
• The left ventricle
pumps blood from
the heart all
around the body, so
the wall is very
thick.
Blood Vessels of Heart
•Vena cava – bring blood from
body to right hand side of
heart.
•Pulmonary artery - bring
blood from right hand side of
heart to lungs.
•Pulmonary vein – brings blood
to left hand side of heart from
lungs.
•Aorta brings blood from left
hand side of heart to body.
• Oxygenated blood: Is blood in which oxygen is
attached to the haemoglobin molecules in the red
blood cells. It is bright red because the attached
oxygen makes the normally blue haemoglobin
molecules turn red.
• Deoxygenated blood: When blood has delivered
oxygen to the cells, it is described
as deoxygenated. It now looks a very dark red
because so many of the haemoglobin molecules
have turned blue again. The mixture of blue and
red molecules looks dark red to our eyes.
Heartbeat
•At rest the average rate
of an adult’s heartbeat is
70 beats per minute
(b.p.m.).
•Each heartbeat causes a
pulse of blood in the
arteries.
•Exercise, stress,
excitement and smoking
can increase the
heartbeat.
Exp: To demonstrate the effect of
exercise on the rate of `breathing
Method:
1.
Count your breaths per minute at rest.
2. Repeat step one three times, get an average
reading.
3. Exercise vigorously for two mintues.
4. Immediately after exercising count the
breaths per minute.
5. Continue to record the breaths per minute
until it returns to the average resting rate.
Results:
Conclusion:
Exercise and the
Heartbeat
• When we exercise the
cells in the body need
more food and oxygen.
• The cells also need to
get rid of carbon
dioxide and heat.
• This causes the heart
to beat faster and our
pulse rate increases.
1
Exercise
• It increases not only
the muscles of the
arms and legs but also
the muscles of the
heart.
• It reduces weight.
• A good balance
between exercise and
rest is needed for a
health heart and lungs.
Body Temperature
• The normal
temperature of the
human body is 37 °C.
• When we are ill our
body temperature
may rise, this helps
to destroy the
bacteria and viruses
that cause us to
become ill.