Download Blood pressure - SandyBiology1-2

Common Requirements of living
things - ANIMALS – Chapter 5 Pt B
The Circulatory System an Internal
Transport System
• Distributes :
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nutrients,
gases
wastes
hormones
• Blood is :
– vital in defence, immunity,
– blood clotting and
– transfer heat around the body of mammals
and birds.
Open Circulatory System
• No specialised transporting fluid.
• Instead interstitial fluid is moves freely around the body before eventually
returning to the heart.
• Very low blood pressure and long circuit times.
Closed circulatory systems
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Blood is enclosed in a system of vessels
connected to a muscular heart. Which pumps
the blood around the body.
Blood is returned very rapidly to the heart and
there is a higher blood pressure.
Blood is also separated from the interstitial fluid
vessel walls allowing the blood to be used for
transport and defence.
Small molecules like nutrients, gases, water and
waste are freely exchanged by diffusion across
capillaries.
Because larger molecules(blood proteins) can’t
diffuse out of the blood, this exerts osmotic
effect drawing water back into the blood.
Closed Circulatory System
Closed System
2 Chambered Heart
Closed System
3 Chambered Heart
Closed System
4 Chambered Heart
Mammalian Transport Systems
• There are 2 transport systems in mammals:
– The blood circulatory system- majority of the
animal’s transport needs.
– The lymphatic drainage system-open system
that maintains osmotic and fluid balance in
tissues and in immune defence.
Internal transport systems
Features of effective transport systems
• Large surface area for exchange both with the
environment and internally.
• A reliable and responsive way of moving
fluid(blood) around the body.
• A fluid that can carry the maximum amount of
material.
• A way to regulate transport according to the
needs of the body.
– A fluid material in which substances are transported; blood
– A system of blood vessels or spaces throughout the body in which
fluid moves
– A pump such as the heart that pushes through the blood vessels and
spaces.
THE CARDIOVASCULAR SYSTEM = heart and blood vessels
Blood
Red blood cells
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Biconcave
Very flexible
No nucleus
Packed with haemoglobin
Main function is transporting gases
• Oxygenated blood
• Deoxygenated Blood
• Larger than red blood cells
• About 1WBC to every 700 RBC
• Several types but all involved in
defence.
– Phagocytes: remove debris and
fight infection
– Lymphocytes: produce
antibodies.
Platelets
• Fragments of cells, important in
preventing blood loss and
promoting blood clotting.
Arteries and Veins
• Arteries carry blood away from the heart.
• Veins carry blood towards the heart.
• Arteries and veins have the same number of walls but arteries
have more muscular walls and veins more elastic walls.
• Conduct blood towards the
heart.
• Pressure in veins is much lower
than in arteries.
• Blood moves along due
muscles compressing the
veins.
• Veins have lots of one way
valves, that push the blood
towards the heart.
• In the legs the blood has to be
returned against gravitational
pressure.
• The negative pressure in the
lungs assists in drawing the
blood up from the legs.
• Conduct blood away from the
heart.
• Because of their thicker walls they
can withstand greater pressure.
• Arteries flow into arterioles that
then flow into capillaries.
• Blood pressure decreases as blood
flows further along.
Blood Movement in the Veins
• Tiny, many branched blood
capillaries provide a vast surface
for exchanging blood.
• Most cells are no more than
1mm from the nearest capillary.
• Same diameter as a red blood
cell, so they fit in one by one.
• When the wall of a red blood
cell presses on the capillary wall
there is an exchange of oxygen
and carbon dioxide.
• blood vessels
Mammalian Heart
Four chambers:
The Atria (singular: atrium):
– Two top chambers, thinner
walls.
The Ventricles:
– Two bottom chambers, thicker
walls.
One way valves ensure blood
flows in one direction.
The heart is very coordinated first
the atria contract forcing the
blood into the ventricles then
the ventricles contract.
Blood Circulation
2 Circulatory pathways– Pulmonary:To and from
the lungs.
– Systemic :To and from
the rest of the body.
The heart
Veins and arteries
Pulmonary vessels
Systemic vessels
Capillaries
Blood
Circulatory animations various
Blood flow animation
Blood Flow in heart
Pulmonary and System Circulation
Blood pressure
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Caused by the contraction of
the ventricles.
The right ventricle is much
thinner than the left so the
pressure caused by the left
ventricle is greater than the
right.
In the arteries blood pressure
changes with every heart beat,
this is the pulse you hear on
your wrist.
The higher systolic pressure
occurs when the ventricles
contract.
The lower diastolic pressure
occurs when the ventricles
relax.
• Blood pressure is described by these two limits.
• Normally this is 120/80mmHg, so that is the systolic pressure/diastolic
pressure.
Vena cavae
Right Atria
receives
deoxygenated
blood from body
Right Ventricle
pumps
deoxygenated
blood to lungs
Aorta
Left Atria receives
oxygenated blood
from lungs
Left Ventricle
pumps out aorta
to the body
Cardiac Surgury You Tube