Blood as a Transport Medium Flashcards
Outline the composition of blood.
55% plasma
41% red blood cells
4% White blood cells and platelets
What is the normal temperature and pH of blood?
38 degrees celsius and pH of 7.35.
What important substances does blood carry?
Blood distributes heat around the body. It transports nutrients, gases and wastes, as well as hormones, antibodies and clotting factors.
Describe the structure and function of red blood cells.
The main function of red blood cells is to transport oxygen. They lack a nucleus to contain more haemoglobin. They are small cells, diameter of around 7 micrometers. They are round, bioconcave and slightly flattened at the centre to increase SA:V. This shape also makes them more elastic to fit through capillaries.
Where are RBC’s formed, and what is the normal concentration of RBC’s in blood?
Red blood cells (and WBC’s) are formed in bone marrow. There are approximately 4-6 million red blood cells per mL of blood.
Describe the structure and function of white blood cells.
The main role of white blood cells (leucocytes) is the defence of the body against foreign bodies. They compose part of the immune system. There are several types of white blood cells. They are around 50% bigger than RBC’s. They all have nuclei.
Describe the structure and function of platelets.
Platelets are fragments of specialised cells. They are crescent shaped, and are about half the size of RBC’s. Their main function is to clot blood in case of a wound. They stick to each other and release an enzyme to block the open wound.
Describe the structure and function of blood plasma.
Plasma is the yellow, watery fluid in blood. It is made of 90% water. It makes up most of the blood volume. Along with blood cells, it carries: proteins, nutrients, gases, wastes, ions, hormones, and vitamins.
