2Blood 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)
3The Circulatory System The circulatory system is made up of:BloodArteriesVeinsCapillariesThe Heart
4Why Does Our Heart beat?To pump blood around the body.
5Why do we need to pump blood around the body? To get oxygen to all the organs and tissues in our bodies.
6What happens when we run out of oxygen? We need to get more
7How do we get more? The blood is pumped back to our lungs. Where it is oxygenated again.
11This is often shown in a diagram like this What happens at each section?See animation in Go Science 2 p14/15
12Double CirculationSo 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.
134 Chambers Each side has two chambers: Atria at the top, Ventricles are the bottom.
14What are their functions? Atria – Let blood pour into heart and down into ventricles.Ventricles - Blood from ventricles pumped out of heat when muscle contracts.
15How 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.
16TASKTASK : Label the diagram of the heart with all the key words.
20The HeartThe 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.
21Structures of the heart Boardworks GCSE Separate Sciences 2009The HeartStructures of the heartTeacher notesThe left and right labels on the diagram are the ‘wrong’ way around because the diagram shows the heart as you’d see it if you were looking at it within a person. The labels indicate the right and left side of the person whose heart it is.The bicuspid valve contains two cusps, or flaps, and the tricuspid valve contains three.
22What are the stages in the cardiac cycle? Boardworks GCSE Separate Sciences 2009The HeartWhat are the stages in the cardiac cycle?
23The blood systemThis is the system which carries the dissolved food and oxygen around the body. This includes the heart and the lungs.
24Blood cells provide oxygen and the plasma in the blood carries dissolved food to ALL the cells in the body.
25Role of BloodTransport gases around the body (oxygen and carbon dioxide)Transport nutrients (i.e. Glucose) around the body
27Red Blood CellRed 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.
28There 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.
29HaemoglobinHaemoglobin 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.
30White Blood CellsThere 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.
31PlasmaPlasma is the liquid part of blood. It contains many important substances which must be carried around the body.Products of Digestion (Glucose)Carbon DioxideHormonesVitaminsThe plasma is a slightly yellowish in colour.
32Platelets 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