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Human Circulatory System
It is a network of tubes called blood vessels, the heart which keeps the blood
flowing in blood vessels(a pump), and valves in the heart and blood vessels
to ensure the blood moves in the right direction
...
• The components of blood includes red blood cells, white blood cells,
platelets and plasma
...
• They are biconcave disc-shaped cells that transport oxygen from the lungs
to all the body cells and carbon dioxide from all the body cells to the lungs
...
• The don't have a nucleus so that they can carry more carbon dioxide and
oxygen
...
White Blood Cells:
• Also known as leukocytes
...
• Some of this do this by the process of phagocytosis
...
• Others make antibodies, the antibodies destroy the pathogens by dissolving
them
...
Platelets:
• Also known as thrombocytes
...
• Their function is to clot blood in a case of an injury to a blood vessel
...
It also
prevents excessive blood loss
...
Platelets
produce tiny fibrinogen fibres to form a net
...
Arteries:
• These blood vessels cary oxygenated blood from the heart to all the
different body cells
...
So they have an elastic tissue in their walls which can stretch
and recoil which makes the blood flow smoother
...
These are capillaries
...
No cell is very far from a capillary
...
• The wall of capillaries is only one cell thick
...
• These blood vessels cary deoxygenated blood from different body cells to
the heart
...
• If veins were narrow the blood would flow even more slowly, so the space
inside the veins called the lumen, is much wider than it is in arteries
...
The blood is
also kept moving in veins by the contraction of muscles around them
...
• It is made up of a special type of muscles called cardiac muscles
...
• The function of the atrium is simply to receive blood from the lungs (LA) or
from the body (RA) and supply it to ventricles
...
• The RV pumps the deoxygenated blood to the lungs which is very close to
the heart
...
Double Circulatory System:
• In this type, the blood passes through the heart twice in one complete
circuit of the body
...
• The pulmonary circuit includes the vessels that carry the blood to the lungs
and back
...
Single Circulation System:
• Only fish have this type of circulatory system
...
• Fish have one atria and one ventricle that pushes the blood to the gills to
get oxygenated, from the lungs it goes to all the body parts and then comes
back to the heart
...
Cardiac Cycle:
• The events that occur in one cardiac cycle take 0
...
• When the cardiac muscles contract, they push the blood to the body
...
3 seconds
...
1 seconds
...
4 seconds
...
Pulse Rate:
• The pressure that passes down an artery as a result of the heart beat can
be felt as a ‘pulse’ when the artery is near the surface of the body
...
• During exercise, body cells require more energy for respiration so the heart
beats faster and the arteries dilate (widen)
...
But this can vary from age, gender and
fitness
...
• The ‘lub’ sound is caused by the closure of the valves separating the atria
from the ventricles
...
• The sound of the heart can be heart by an instrument called stethoscope
...
A normal blood pressure is around 120/80 mmHg
...
Electrocardiogram:
• An ECG helps to find any irregularity which can be caused due to a certain
heart disease
...
Coronary Heart Disease:
• The blockage of coronary arteries is known as CHD
...
The walls of the heart are so
thick that the blood cannot diffuse through it quickly enough, hence it needs
these arteries are on the outside of the heart
...
• When a coronary artery gets blocked, the heart muscles cannot respire and
this leads to the stoppage of the heart beating
...
• The narrowing of the coronary artery due to deposition of the cholesterol
will slow down the flow of blood, is called atherosclerosis
...
• In case of a cardiac arrest death will follow unless the heart starts beating
again within minutes
...
Classifies into stable and unstable depending on its pattern of occurrence and
severity