| what are the three main parts of the mammalian circulatory system | blood (containing plasma, red blood cells and white blood cells)
the heart
the blood vessels |
| what does blood transport | nutrients from the digestive system and oxygen from the lungs to respiring cells
in addition it transports carbon dioxide from respiring cells to the lungs |
| what two types of cells does a mammals blood contain | red blood cells
white blood cells
(and plasma) |
| how does the structure of red blood cells make them suited to their purpose? | biconcave provides a larger surface area to absorb more oxygen
no nucleus allows more haemoglobin to be present
haemoglobin attaches to oxygen |
| what is haemoglobin | a protein molecule found in red blood cells in blood vessels |
| what is the function of haemoglobin | it can easily join with oxygen in areas of the body where there is a high oxygen concentration, like in the lung capillaries.
When haemoglobin chemically combines with oxygen, oxyhaemoglobin is produced.
When haemoglobin reaches areas of the body where the oxygen concentration is low, eg respiring cells, oxyhaemoglobin will quickly release the oxygen, which then diffuses into cells |
| What is the function of white blood cells | they are part of the immune system and are involved in destroying pathogens (disease causing micro organisms like bacteria viruses and fungi) |
| what are the two types of white blood cells that destroy pathogens | phagocytes and lymphocytes |
| what is the function of phagocytes | carry out phagocytosis by engulfing and digesting pathogens |
| what is the function of lymphocytes | some lymphocytes produce antibodies which destroy pathogens
each antibody is specific to a particular pathogen
they can also make memory cells so that if the pathogen micro organism enters the body again, it will be instantly recognised and destroyed quickly |
| name each chamber of the heart | 1 Right Atrium
2 Right Ventricle
3 Left Atrium
4 Left Ventricle |
| Why does the left ventricle have a thicker muscular wall than the right ventricle? | The left side of the heart has to pump blood around the body whereas the right side only has to pump blood to the lungs |
| how many valves are located in the heart | four |
| what is the function of valves | to ensure that blood only flows in one direction through the heart
to prevent the backflow of blood |
| where are the heart valves located | between the atria and the ventricles as well as between the ventricles and the arteries leaving the heart |
| describe the pathway of blood in the heart | deoxygenated blood from all over the body enters the right atrium of the heart in the vena cava vein
the blood is pumped into the right ventricle, through a valve and then away from the heart in the pulmonary artery. The pulmonary artery carries the deoxygenated blood to the right and left lung so that it can pick up oxygen.
The now oxygen blood returns to the left atrium of the heart in the pulmonary vein. Blood flows from the left atrium, through a valve to the left ventricle and leaves the heart in the aorta, the largest artery in the body.
The aorta artery will carry oxygen to cells in the body to be used for aerobic respiration
Deoxygenated blood will then be returned to the vena cava by the coronary vein. |
| what is the heart | a muscle made out of muscle cells
it therefore requires its own blood supply, like any other muscle |
| where does the heart get its own blood supply | iti s provided by the coronary arteries
these blood vessels branch off from the aorta and spread out over the surface of the heart, providing the heart/cardiac muscles with the glucose and oxygen they require for aerobic respiration |
| what can happen if the coronary arteries become blocked or narrowed in any way | a heart attack can occur |
| describe the structure and function of the arteries | arteries carry blood away from the heart
(carry oxygenated blood around the body - except the pulmonary artery)
they have thick muscular walls
a narrow central channel
carry blood under a high pressure away from the heart - this can be felt as a pulse |
| what is the structure and function of the capillaries | described as exchange blood vessels as all exchange of materials between living cells and the blood supply occurs here
they are thin walled - one cell thick
have a large surface area
form networks at tissues and organs to allow the efficient diffusion of materials |
| what is the structure and function of veins | carry blood towards the heart
(carry deoxygenated blood, with the exception of the pulmonary vein)
have thinner walls
a wider channel
carry blood under low pressure back towards the heart
veins contain valves to prevent the backflow of blood |
