5.6 Circulatory System 3 - Blood Flashcards
What is blood?
Blood is a tissue, consisting of many similar cells working together. These cells are red blood cells, white blood cells and platelets, and they’re suspended in a liquid called plasma.
What is plasma?
It’s basically blood minus the blood cells. Plasma is a pale yellow liquid which carries just about everything that needs transporting around your body.
What are red blood cells?
Red blood cells transport oxygen from the lungs to all the cells in the body.
How are red blood cells adapted for their role? (4)
- Red blood cells are small and have a biconcave disc shape to give a large surface area to volume ratio. This increases the rate at which oxygen can diffuse into and out of the cell.
- They are packed with haemoglobin, which is what gives the red colour - it contains a lot of iron. In the lungs, haemoglobin combines with oxygen to become oxyhaemoglobin. In body tissues, the reverse happens to release oxygen to the cells.
- Red blood cells don’t have a nucleus - this frees up space for more haemoglobin, so they can carry more oxygen.
- As they are small and very flexible, they can easily pass through the tiny capillaries close to the body cells.
What are the three ways that white blood cells defend us against pathogens?
- Phagocytosis: where a white blood cell will engulf a microorganism
- Producing antibodies: which can bind onto pathogens and help destroy them
- Producing antitoxins: which neutralise any toxins that the pathogens produce.
Do white blood cells have a nucleus?
Yes - unlike red blood cells
What are platelets and what is their role?
They are small fragments of cells and they float about in the blood waiting until we get a cut, and they then rush to the wound and patch up the hole. This is called ‘clotting’.
What are the two reasons why we need platelets?
- They stop us from bleeding out
- They stop microorganisms from getting in and causing us an infection
What are 8 examples of substances that plasma transport around the body?
- Red blood cells, white blood cells and platelets.
- Water.
- Digested food products like glucose and amino acids from the small intestines to all the body cells.
- Carbon dioxide from the body cells to the lungs.
- Urea from the liver to the kidneys (where it’s removed in the urine).
- Hormones - these act like chemical messengers.
- Antibodies - these are proteins involved in the body’s immune response.
Why can a low number of red blood cells make you feel tired?
This is because less oxygen can be transported around the body, and so there is less aerobic respiration taking place to produce ATP.
What are the two different types of ‘new blood’ that can be given to a patient?
- Artificial blood: blood substitute that consists of salt water. The main benefit is that it adds volume to our circulatory system, which keeps our vessels full and allows the heart to keep pumping. The downside is that it doesn’t contain any red blood cells, so it doesn’t actually allow us to transport any more oxygen. This means we can only replace 1/3 of our blood with it.
- Blood transfusion: real blood that has been donated by blood donors. This comes with red blood cells which are the key to surviving blood loss.
How do antibodies help defend against pathogens?
They bind to pathogen and help immune cells destroy them.
