What are the components of blood
Plasma , Erythocytes , white blood cells , platelets.
Describe plasma within the blood
Plasma is mainly water and dissolved substances.
- Plasma proteins : which are Albumin and Globulins , Fibrinogens , clotting products.
Plasma proteins are retained in the bloodstream and are the main factor is maintaining osmotic pressure of the blood
- Electrolytes: Mostly Sodium and potassium, which plays an important role in the brain and Calcium.
- Nutrients: Glucose , amino acids , vitamins. Brain is heavily dependent on glucose levels.
- Waste products: Urea , creatine , Uric acid and carbon dioxide.
- Hormones : Adrenaline, Noradrenaline, ADH , Testosterone, Oestrogen
- Gases : Oxygen
Describe Erythrocytes
- Bioconcave discs Flexible plasma membrane so can squeeze through capillaries and maximise carrying capacity
- No nucleus unable to go mitosis
- Carry haemoglobin , carry oxygen
- Live for 120 days
Describe haemopoiesis
- Starts in the bone marrow as an undifferentiated pluripotent stem cell.
- Differentiates into a pro erythroblast
- Synthesis of haemoglobin and nucleus is expelled making a reticulocyte
- Reticulocyte matures over 1-2 days after leaving bone marrow making an erythrocyte.
- Erythropoiesis is stimulated by low levels of oxygen which stimulates the body to produce more RBC.
- Juxtaglomerular cells of the kidney detect low oxygen.
How are erythrocytes excreted
- As erythrocytes age their membrane becomes more fragile.
- If the erythrocytes rupture they can cause clotting , therefore they are expelled through the liver and are digested and broken down into bilirubin and secreted into bile.
- Damaged erythrocytes are excreted through the spleen, bone marrow etc.
Describe a white blood cell
A WBC plays an important function in the bodys immunity and defence system. They have a nucleus and are able to form an MHC. They detect foreign material destroy it through phagocytosis. There are two types of WBC: Agranular and granular.
What are the 3 types of granulocytes
Neutrophil, Basophil , and Eosinophil
Describe the action of a neutrophil
Neutrophils are highly mobile and are attracted in large numbers. Their numbers rise quickly in an infected tissue. They act via phagocytosis. They are multilobed and contain lysozymes to digest engulfed material.
Describe the action of a Eosinophil
An eosinophil are also capable of phagocytosis , however their specialised role is in the elimination of parasites as they are too big to be engulfed.
What are basophils
Basophils are closely associated with allergic reactions.
What are Agranulocytes
Monocytes and Lymphocytes
What are monocytes
- Monocytes are the largest white blood cells.
- Shortly after release from the red bone marrow , they migrate into the tissues and envelop into macrophages.
- Produce interleukins which act on the hypothalamus.
What are lymphocytes
Lymphocytes are smaller than monocytes and have a large nuclei.
There are so types of lymphocytes B and T lymphocytes.
