Transcript File - Junior Cert Science

Learning Outcomes
On completion of this chapter students should be able to:
• OB13 describe the function and composition of blood,
and know that blood contains white blood cells, red
blood cells and platelets in a liquid called plasma
• OB14 understand the structure and function of the heart,
identify the four chambers of the heart, and explain the
difference between the left and right ventricles
• OB15 describe the passage of blood through the heart
and lungs via arteries and veins, identify the pulmonary
artery and vein, aorta and vena cava, and distinguish
between arteries, veins and capillaries
Learning Outcomes contd..
• OB16 demonstrate the effect of exercise and rest on
pulse rate and understand that a balance of each
promotes good health
• OB17 recall that the average pulse rate for an adult at
rest is 70 beats per minute, and explain why exercise
results in increased pulse and breathing rates
Lesson 1
Composition of Blood
What is the circulatory system?
The Circulatory System is responsible for
transporting materials to and from different
places in the body.
It is made up of:
Blood consists of:
Red Blood Cells
Most numerous cell in
the body
Small doughnut shape
Contain haemoglobin
which transports
oxygen around the
body
White Blood Cells
Larger than red
blood cells but also
much fewer in
number
Fights infection
by destroying
bacteria and
viruses that have
invaded the body
Platelets
Tiny fragments of
cells
Cause blood to clot
by producing tiny
fibrinogen fibres
These stretch across
a cut to stop bleeding
Plasma
It also contains
useful things like:
A strawcoloured
liquid that
carries the
cells and the
platelets
which help
blood clot.
• carbon dioxide
• glucose
• amino acids
• proteins
• minerals
• vitamins
• hormones
• waste materials
Functions of Blood
To transport food, oxygen and wastes
To transport heat to the skin to keep
the body temperature at 37°C.
To fight infection
Lesson 2
Blood Vessels
Blood vessels
There are 3 types of blood vessels found in
our body:
Veins
Veins carry blood towards the heart
They have thin walls and a
wide inner cavity which allows
blood flow to the heart easily
They also contain valves which
stops the blood flowing
backwards
Wide inner
cavity (lumen)
veins with
valves
Arteries
Arteries carry blood away from the heart
They have thick elastic walls
which allows them to stretch and
recoil at each heartbeat
These muscles contract to
push the blood along
No valves present
Narrow inner
cavity (lumen)
Thick muscular
walls
Capillaries
Capillaries link arteries and veins
Have very thin walls-just one cell
thick
Materials can be exchanged from
the blood to other body cells and
vice versa via capillaries
Wall just one
cell thick
Lesson 3
The Structure of the Heart
The Heart
The heart is a muscular pump that
transports blood around the body
It consists of 4 chambers:
Right atrium
Right ventricle
Left atrium
Left ventricle
YouTube video
The Heart
Ventricles
 The lower chambers
 Receives blood from the
atria
 Pumps blood out through
arteries
 Left ventricle has thick
walls (more strength
required to pump blood
around the body)
Atria
 The upper chambers
 Receives blood from
veins
 Pumps blood into
ventricles
 Have thin walls
Structure of the Heart
Pulmonary
artery
Vena Cava
Right Atrium
Right Ventricle
Aorta
Pulmonary
vein
Left
Atrium
Left
Ventricle
How does the heart work?
1. Deoxygenated blood enters right
atrium via vena cava
2. Blood is pumped to right ventricle
and then to the lungs via the
pulmonary artery
3. Oxygenated blood enters left
atrium via pulmonary vein
4. Blood is pumped to left ventricle
where it leaves via the aorta
Pulmonary
artery
Vena cava
Aorta
Pulmonary
Vein
Tips for remembering
VEAL
Veins Enter, Arteries Leave
LORD
Left=Oxygenated, Right=Deoxygenated
Pulmonary = related to lungs
e.g. Pulmonary vein enters from lungs
Lesson 4
The Pulse
&
How to demonstrate the effect
of exercise on the pulse
The Pulse
Every time the heart contracts, the blood surges
forward in the arteries. By placing your fingers
over an artery, you can feel this pulse
The Pulse
For an adult the average pulse rate is 70
beats per minute (b.p.m.).
Children have faster heartbeats than
adults.
What happens to our pulse rate when we
exercise?
Mandatory Practical
Title: to demonstrate the effect of exercise on the
pulse rate
Beats per minute at rest
vs.
Beats per minute after exercise
Results
Beats per
minute
At rest
Immediately
after exercise
3 minutes after
exercise
6 minutes after
exercise
Person 1
Person 2
Conclusions
When a person
exercises, the muscles
need more oxygen to get
more energy from food.
A faster heartbeat
delivers oxygen to the
muscles quicker.
Exercise increases the
pulse rate.
Why we need exercise
Exercising the heart makes it stronger and
reduces the likelihood of heart disease.
To prevent heart disease we should:
Take regular exercise
Never smoke
Eat only small amounts
of saturated (animal) fats
Assessment
The circulatory system is made up of blood,
blood vessels and the _____.
Arteries _____ the heart and ______ enter the
heart.
The capillaries ______ arteries and veins.
Blood is made up of red blood cells which carry
_____, white blood cells which fight _______,
platelets which causes blood to _____ and
______ which is the liquid part of blood.
The heart is made up of _____ chambers, 2
atria and 2 ventricles.
Solutions
The circulatory system is made up of blood,
blood vessels and the heart.
Veins enter the heart; arteries leave the heart
and
The capillaries link arteries and veins.
Blood is made up of red blood cells which carry
oxygen, white blood cells which fight infection,
platelets which causes blood to clot and
plasma which is the liquid part of blood.
The heart is made up of four chambers, 2 atria
and 2 ventricles.
Bibliography
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