Transport in Man Flashcards
What are the four main components of blood?
Plasma, red blood cell (erythrocytes), white blood cell (leucocytes), platelets (thrombocyte)
What is plasma and state the dissolved substances
Approximately 55% blood’s volume
90% water, 10% dissolved substances
Substances include—
Mineral ions: sodium, potassium, calcium, magnesium, chloride, bicarbonate ions
Soluble food substances: glucose, amino acids
Metabolic waste products: CO2, urea, uric acid, creatinine
Plasma proteins: fibrinogen, prothrombin, antibodies, albumin
Hormones
Function of red blood cells (erythrocytes)
Transport oxygen fro the lungs to the organs of the body
Structural features of red blood cells
Haemoglobin present: binds reversible with oxygen to form oxyhaemoglobin, transports O2 around the body
Absence of nucleus: more space available for more haemoglobin to be stored and more oxygen to be transported
Biconcave shape: increases SA:V ratio, allowing quick diffusion of oxygen in and out of the cell
Elastic and flexible membrane: allows cells to change its shape while squeezing through small capillaries
What is the effect of carbon monoxide on haemoglobin?
Carbon monoxide binds tightly with haemoglobin to form carboxyhaemoglobin
Less haemoglobin is available to bind with oxygen, so less O2 transported in the body
What is sickle cell anaemia and what are its symptoms?
Genetic disease: the gene for haemoglobin contains a mutation, producing mutant haemoglobin with a sickle shape
Symptoms include:
Cells getting stuck in blood cells, blocking them
Prevents delivery of oxygens and nutrients to cells and removal of carbon dioxide and waste from cells
May cause organ swelling or severe pain during blood vessel clogging
What is red blood cell production regulated by and what is it released by in response to?
Red blood cell production is regulated by the hormone erythropoietin, which kidneys released in response to a decrease in oxygen
What is acclimatisation?
In mountainous areas, lower partial pressures of oxygen result in an initial drop of fitness levels
Body responds by producing more red blood cells, thus more haemoglobin is available for the transport of oxygen around the body
Traits of leucocytes (white blood cells)
Colourless due to lack of haemoglobin
Irregularly shaped cells with the presence of a nucleus (phagocytes)
Mobile and able to change shape to squeeze through the gaps in capillary walls
Phagocytes are irregular, lymphocytes have a round nucleus
What is phagocytosis and what cells are involved?
Phagocytosis is the process where phagocytes engulf and digest bacteria After phagocytosis (endocytosis), these cells die and form pus
Phagocytosis by phagocytes (white blood cell, type of leucocytes)
What do lymphocytes do?
They produce antibodies and have a round nucleus, with a small amount of granular cytoplasm
What do antibodies produced by lymphocytes (leucocytes) do?
Antibodies can neutralise toxins produced by bacteria
Antibodies can bind to the surface of bacteria, causing them to rupture
Antibodies can bind to the surface of bacteria, tagging them, allowing phagocytes to recognise them and carry out phagocytosis
Antibodies can cause bacteria to clump together, so that they can be easily ingested by phagocytes
What is transplantation?
The replacement of diseased tissue or organs by healthy donor ones
What is tissue rejection?
Tissue rejection is when the recipient’s immune system may recognise the transplant organ/tissue as foreign bodies
Lymphocytes may respond by producing antibodies to destroy the transplanted organ
How to prevent tissue rejection during transplantation?
- Tissue/donor matching: ensuring donor tissue is from a donor genetically close to the recipient (close relatives)
- Using immunosuppressant drugs to inhibit the recipient’s immune system, reducing the chance of tissue rejection but increasing susceptibility to infection
Platelets and function and formation of blood clots (thrombocytes)
Not true cells, but fragments of larger bone marrow cells called megakaryocytes
When an injury first occurs, platelets gather and release substances that attract other platelets. The platelets become sticky and form a temporary platelet plug.
Blood clots defend the body by:
- Preventing the excessive loss of blood from a cut
- Preventing entry of bacteria into a cut
Describe the process of blood clotting
Damaged tissues and platelets will release the enzyme thrombokinase. Together with calcium ions in blood plasma, the thrombokinase will convert inactive prothrombin (in plasma) to active thrombin.
Thrombin will convert soluble fibrinogen to form insoluble fibrin threads, forming a blood clot consisting of a network of fibrin threads that trap blood cells
What are the antigens on rbc and antibodies in plasma for each blood type?
A: A-antigen and antibody B
B: B-antigen and antibody A
AB: A-antigen, B-antigen and no antibodies
O: no antigens and A antibody, B antibody