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What is this sound? g
Blood and the Heart Learning Objective: To label and describe the roles of the main parts of the heart (C) To explain the route of blood through the transport system. (B) To describe double circulation (A)
The Circulatory System The circulatory system is made up of: Blood Arteries Veins Capillaries The Heart
Why Does Our Heart beat? To pump blood around the body.
Why do we need to pump blood around the body? To get oxygen to all the organs and tissues in our bodies.
What happens when we run out of oxygen? We need to get more
How do we get more? The blood is pumped back to our lungs. Where it is oxygenated again.
Where does it go from here? Back to the heart.
Where does it go from here? To the rest of the body.
body’s cells body’s cells lungs Double circulatory system
This is often shown in a diagram like this What happens at each section? See animation in Go Science 2 p14/15
Double Circulation So we have two things going on in the heart, this is known as double circulation. The blood is being pumped to the body to give it oxygen AND the blood is being pumped to the lungs to get more oxygen. So we say that the heart is spilt into two sections, the left and the right.
4 Chambers Each side has two chambers: 1.Atria at the top, 2.Ventricles are the bottom.
What are their functions? Atria – Let blood pour into heart and down into ventricles. Ventricles - Blood from ventricles pumped out of heat when muscle contracts.
How do we stop the blood from flowing backward? Valves stop the flow of blood once it has entered the ventricles. And also once the blood has been pumped out the valves stop it from coming back into the heart.
TASK TASK : Label the diagram of the heart with all the key words.
In the Boxes: From Body To Lungs To Body From Lungs Other: Right Atrium Right Ventricle Left Atrium Left Ventricle Valves
A real heart
The Heart The heart is made of very special muscle, CARDIAC muscle. It must keep beating all the time for the rest of a persons life! If you tried to do the same action repeatedly (like the heart) your muscles would get tired and, after a while, they would stop working. For example if you clench and unclench your hand continuously, it will get tired, and may even start to cramp.
Structures of the heart
What are the stages in the cardiac cycle?
The blood system This is the system which carries the dissolved food and oxygen around the body. This includes the heart and the lungs.
Blood cells provide oxygen and the plasma in the blood carries dissolved food to ALL the cells in the body.
Role of Blood Transport gases around the body (oxygen and carbon dioxide) Transport nutrients (i.e. Glucose) around the body
Red Blood Cells White Blood Cells PlateletsPlasma Description Diagram Function
Red Blood Cell Red blood cells have a perfect biconcave shape for absorbing and releasing oxygen. Red blood cells are red only because they contain a protein chemical called haemoglobin which is bright red in colour. Haemoglobin contains the element Iron, making it an excellent vehicle for transporting oxygen. They also have no nucleus so they can transport as much oxygen as possible.
There are approximately five million red blood cells per cubic millimetre of blood, slightly more in men and less in women. The number of red blood cells is higher in people who live at high altitudes. Red blood cells do not have nuclei.
Haemoglobin Haemoglobin is an amazing chemical because if you warm it slightly and add a bit of acid, it will give up all its oxygen. As blood passes through the lungs, oxygen molecules attach to the haemoglobin. As the blood passes through the body's tissue, the haemoglobin releases the oxygen to the cells.
White Blood Cells There are usually a few thousand white blood cells per cubic millimetre of blood. Their jobs are to produce antibodies and to engulf bacteria, i.e. they fight disease.
Plasma Plasma is the liquid part of blood. It contains many important substances which must be carried around the body. Products of Digestion (Glucose) Carbon Dioxide Hormones Vitamins The plasma is a slightly yellowish in colour.
Platelets To stop the loss of blood from wounds Platelets form a clot which dries up into a scab. This is quite a good thing because it prevents any more blood from getting out and it prevents germs from getting in
Components of Blood red blood cells -transport of oxygen white blood cells -defence plasma -transport of food/waste platelets -blood clotting