Download - Pitchero

P5 Assessment
To achieve P5 you need to describe:
•
•
•
The different structures within the heart (i.e. atria, ventricles and so forth).
The different types of blood vessels (such as the arteries) outlining their structure
and function, i.e. thick walls and taking blood away from the heart.
The role of the circulatory system both at rest and during exercise, i.e. delivery of
oxygen to the muscles and removal of waste products.
To achieve M2 you need to explain the
function of the cardiovascular system:
• How does it work?
• How is each part of the system designed to
meet its function?
The Blood Vessels
Introduction
We have a variety of different vessels within the cardiovascular system to
deliver and remove nutrients and waste products.
Blood in the arteries is bright red, as it is carrying oxygen. It drops off the
oxygen and picks up carbon dioxide as it moves through the capillaries. By
the time it reaches the veins and venules it is a much darker blue/red
colour.
5 main blood vessels
Arteries - Arterioles
Carry blood away
from the heart
Capillaries
Where gas
exchange takes
place
Venules - Veins
Carry blood back to
the heart
Artery
Arteriole
Venule
Capillary
Vein
Arteries & Arterioles
• Arteries are large blood
vessels, that carry blood
away from the heart.
•Thick Elastic muscular walls
Artery walls contain elastic
cartilage and smooth muscle,
This allows the arteries walls
to contract and relax to send
blood to all parts of the body
•Carry Oxygenated blood
This process is known as
–Apart from the pulmonary artery,
peristalsis, and is how smooth
which carries deoxygenated blood to
muscle contracts
the lungs to get Oxygen
Arteries & Arterioles
• Small round lumen
• Operate under high pressure
• Arteries don’t contain valves, as
the blood is moving quickly under
high pressure, so there is no
chance of backflow.
Aorta - Main artery leaving the heart
It soon splits into smaller vessels –
Arterioles
–Arterioles deliver the blood to
the capillaries
Capillaries
Smallest blood vessels
– Found in all cells of the body
Just one cell thick
• Very thin walls
– Allows oxygen and other nutrients to diffuse through the cell walls.
Blood flows very slowly through the capillaries so that this can happen
- In the capillaries, the blood unloads the Oxygen and picks up carbon
dioxide and lactic acid (the waste products of metabolism)
Veins & Venules
•The blood flows from the capillaries to the venules
and then the veins and back to the heart
• Large lumen
– Means blood flows
at lower speed and
pressure.
• Thinner and less
muscular than arteries
– Have some smooth
muscle
• Contracts to help
sent the blood
back to the
heart
Veins & Venules
• Carry blood back to the heart
– Generally working against gravity
• Particularly blood that is going back to the
heart from the legs or arms, as it is below
the heart.
– Valves
• Prevents the blood from flowing back once
the smooth muscle relaxes.
• Prevents pooling, particularly in the legs
Deoxygenated blood
– Apart from pulmonary vein which carries oxygenated
blood from the lungs back to the heart.
Task…
- Complete the table below
ARTERIES
FUNCTION
TYPE OF BLOOD
BLOOD PRESSURE
WALL THICKNESS
VALVES?
LUMEN
VEINS
CAPILLARIES
Blood
Transport nutrients and Oxygen (O2) to the cells
of the body.
It carries:
Made up of 4
- Oxygen, Glucose, Proteins, Fats, Vitamins,
components:
Hormones, Enzymes, Platelets, Carbon Dioxide
and Electrolytes.
- Red blood cells
- White blood cells
- Platelets
- Plasma
Plasma: straw coloured liquid
that all solids are carried within.
Blood
Every cell in your body gets it’s nutrients from your
blood.
You have 5 litres / 8-9 pints of blood in your body.
This makes up 7-8% of your total body weight.
In children – most of the bones produce blood
In adults – vertebrae, sternum, ribs, pelvis,
humerus & femur
Red Blood Cells
Red blood cells make up 99% of the all the blood cells in the body
Red blood cells ‘live’ for 120 days
They are RED in colour because they
contain HAEMOGLOBIN which attracts &
carries OXYGEN
Making RED blood cells sole purpose to transport OXYGEN!
Cells
They are colourless and
transparent and fewer in
number to red blood cells
(1:700)
These ‘live’ for 3-4 days
The role of White blood cells is
to fight infection as they are
part of the immune system.
They destroy bacteria and other dangerous
organisms… fighting potential infection.
Platelets
They act by stopping
blood loss through
clotting
They become sticky when in
contact with air to form the initial
stage of repair to the damaged
tissue…
Functions of the blood
Blood has three main functions:
1 - Transport of Oxygen & carbon dioxide,
nutrients, hormones and waste
2 - Regulation of water in the body and body
temperature
3 - Protection against infection and blood loss.
Functions of the blood: transport
• The blood transports:
– oxygen from the lungs to the body cells
– carbon dioxide from the cells to the lungs
– nutrients from digestive system to the cells
– waste products from the cells, to be excreted
– hormones from endocrine glands, to regulate cells
– medication from the blood to the cells.
Functions of the blood: heat regulation
Blood picks up heat when it passes
through the liver
and distributes it around the body.
Body heat
Blood vessels near the skin’s surface
will expand when the body is hot.
This allows heat to be lost through
the skin.
Blood vessels will constrict
when the body is cold. This
retains heat within the core
of the body, where the vital
organs are.
Functions of the blood: water
regulation
The blood will retain more or less water according to
the current water content of the cells
Water content of cells
When the blood passes through the kidneys, if there is too much water
content, the kidneys retain the water and it is excreted
If there is not enough water, the kidneys pass water back into the
blood to be passed to the body’s cells
Functions of the blood: Protection
• White blood cells – ‘soldiers’ fight invading
organisms – Virus, colds – prevent/fight
infections
• Platelets – ‘barriers’ – blood clotting to
prevent loss of blood