Download The Circulatory System - Ms Barry Home Economics

The Circulatory System
Junior Certificate Home Economics
Ms. Barry
The Circulatory System
The circulatory system transports blood
around the body
It is made up of three parts:
1. The Heart
2. The Blood
3. The Blood Vessels
The Heart
• Acts as a pump, which pumps blood around the
body
• Is found in the chest cavity, between the lungs
• It is hollow inside and is divided in two by a wall
of muscle called the septum
• It has four chambers – left & right atria at the top
and the left & right ventricles on the bottom
• The walls of the ventricles are stronger than the
atria
• It contains valves to make sure the blood flows
in one direction only
Pulmonary
Artery
Vena Cava
Right Atrium
Aorta
Pulmonary Vein
Left Atrium
Valve
Right Ventricle
Left Ventricle
Blood flow through the Heart
• Impure blood flows into the right atrium
through the vena cavae
• Flows through a valve into the right
ventricle
• Heart muscle contracts  blood flows to
the lungs  carbon dioxide is exchanged
for oxygen
• The pure blood flows back to the heart,
into the left atrium.
Blood flow through the Heart
• It flows through a valve into the left
ventricle.
• Muscle contracts  blood flows through
the aorta (largest artery) around the body
• Blood gives out its oxygen and picks up
carbon dioxide
• It returns to the right atrium and the cycles
begins again
Blood Flow
through the Heart
Blue – blood with
CO2 (impure)
Red – blood with
O2 (pure)
The Blood
• Adult – 4 or 5 litres of blood
• Made up of plasma
Plasma contains:
- Red blood cells
- White blood cells
- Platelets
Red Blood Cells
• Contain a red pigment called
haemoglobin
• This carries oxygen around the body
• Iron is needed to make haemoglobin
White Blood Cells
• Less white than red blood cells in
blood
• They attack and kill harmful germs
• Prevent infection & disease
Platelets
• Cause blood to clot
• Prevent severe blood loss
Functions of Blood
1. Blood transports:
– nutrients, heat and oxygen around the body
– carbon dioxide to the lungs
– hormones to where they are needed
– waste products to the kidneys
2. Fights bacteria & infection
3. Prevents blood clotting
Blood Vessels
• Arteries
• Veins
• Capillaries
Arteries
•
•
•
•
Largest blood vessel
Carry blood AWAY from heart
Blood is usually rich in oxygen
Artery walls are thick and elastic
PULSE: heart forcing blood around the body
can be felt in arteries under the skin
Veins
• Carry blood BACK to the heart
• Blood is usually rich impure (high in
carbon dioxide0
• Artery walls are thinner (less pressure)
• Veins have VALVES to prevent backflow
Capillaries
• Thin walls
• Allow oxygen and nutrients to pass
between blood & cells
• Carbon dioxide and waste from body pass
into the blood to be removed
• They come together to form veins