Common Requirements of living things - ANIMALS – Chapter 5 Pt B.
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Transcript of Common Requirements of living things - ANIMALS – Chapter 5 Pt B.
The Circulatory System an Internal Transport System
• Distributes :– 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• 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.
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.
The human circulatory system– 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
Red blood cells• Biconcave • Very flexible• No nucleus • Packed with haemoglobin• Main function is transporting gases
• Oxygenated blood• Deoxygenated Blood
White blood cells
• 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.
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.
Arteries• 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.
• 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.
Veins
Capillaries• 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 HeartFour 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 Circulation2 Circulatory pathways-– Pulmonary:To and from
the lungs. – Systemic :To and from
the rest of the body.
The heartVeins and arteriesPulmonary vesselsSystemic vesselsCapillariesBlood
Blood flow animation
Circulatory animations various
Blood Flow in heart
Pulmonary and System Circulation
Blood pressure
• 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• Blood pressure is described by these two limits. • Normally this is 120/80mmHg, so that is the systolic pressure/diastolic
pressure.
Right Atria receives
deoxygenated blood from body
Right Ventricle pumps
deoxygenated blood to lungs
Left Atria receives oxygenated blood
from lungs
Left Ventricle pumps out aorta
to the body
Vena cavae Aorta