Transport In Humans Flashcards
What is blood composed of?
Plasma - water , proteins mineral salts, food substances and waste products , platelets , red blood cells, white blood cells
What are platelets and what is its function?
Membrane-bound fragments of cytoplasm to help in blood clotting
How is the red blood cell adapted for its function?
Adaptation: filled with red pigment haemoglobin
Function: binds with oxygen to form oxyhaemoglobin
Adaptation: circular biconcave shape
Function: increases surface area to volume ratio for faster uptake of oxygen
Adaptation: elastic
Function: cells can squeeze through tiny blood capillaries
What are the functions of phagocytes
Engulf and ingests foreign particles such as bacteria (phagocytosis)
What is the function of lymphocytes
Produces antibodies that can act as antitoxins, causes agglutination or kills bacteria directly
what are the causes of coronary heart disease?
smoking, a sedentary lifestyle, emotional stress and a high-fat diet rich in cholesterol and saturated animal fats
how do you prevent coronary heart disease?
a healthy diet with reduced intake of animal fats which can be replaced with polyunsaturated plant fats and rich in vegetables and fruits, management of stress in an appropriate way, regular exercise and avoidance of smoking
what is coronary heart disease?
the build up of fatty substances on the inner walls of the coronary arteries causing the lumen of the arteries to narrow , reducing blood flow to the heart. The heart muscle cells receive reduced oxygen supply and this may lead to a heart attack
how are blood types named
Through the antigen present on the red blood cell ( A, B, no antigen or both )
what is considered during a blood transfusion?
the effect of the recipients plasma on the donors red blood cell
what are the functions of blood?
Acts as a transport medium for carrying various substances from one part of the body to the other ( excretory products, digested food substances)
- Protects the body against disease-causing organisms (wbc and platelets)
- prevents excessive blood loss by blood clotting or agglutination at wounds
How is oxygen transported to the body cells
as blood passes through the lungs ,oxygen diffuses from the air sacs into the lungs into the blood. Haemoglobin in the blood combines with oxygen to form oxyhaemoglobin. Blood transports oxygen to all tissues in the body and the oxyhaemoglobin releases oxygen to the body cells at the tissue cells
how does clotting occur\ what happens after one cuts themselves
The damaged tissues and platelets produce thrombokinase which converts inactive prothrombin to active thrombin in the presence of calcium ions. the thrombin then converts soluble fibrinogen to insoluble fibrin threads that entangle blood cells and forms a clot
how to reduce the risk of tissue rejection?
ensure there is a tissue match \ use immunosuppressive drugs
production and function of antibodies
produced by lymphocytes.
Antibodies act by destroying the bacteria ; attaching to them, causing the bacterial surface membrane to rupture
Causing the bacteria to clump together / agglutinate so that they can be easily ingested by the phagocytes
Neutralising the harmful substances (toxins) produced by bacteria
antibodies bind to bacteria and cause their surface membranes to rupture. bacterial cells clump together in the presence of antibodies and the toxins produced are neutralised by antibodies
What is the function of arteries?
transports oxygenated blood away from the heart to the rest of the body
characteristics and adaptations of arteries
Small lumen, thick muscular walls to prevent rupture during influx of oxygenated blood at high pressures.
What is the function of veins?
transports deoxygenated blood back to the heart
characteristics and adaptations of veins
thin walls with less elastic tissue as blood flowing in veins is lower. Valves to prevent backflow of blood.
function of capillaries
allows for the exchange of materials between blood and tissue
characteristics and function of capillaries?
large capillary network to increase surface area to volume ratio for faster exchange of substances between blood and cells
endothelium is one cell thick to allow permeability to H2O and other substances and increase the rate of diffusion
how is waste products removed from the cell?
waste products released by cells -> tissue fluid through diffusion -> capillary walls -> blood -> excretory organs for removal
what are the advantages of double circulation
blood enters the pulmonary circulation at a low pressure, ensuring sufficient time for blood to be fully oxygenated before returning to the heart
The heart pumps oxygenated blood at high pressure to the rest of the body so oxygenated blood is distributed to the body tissues more quickly, helping maintain high metabolic rate in mammals
what is pulmonary circulation?
blood circulation linking the heart to the lungs
what is systemic circulation?
circulation of blood linking the heart to he rest of the body , except the lungs
what is the pathway of the blood through the body?
Deoxygenated blood returns to the heart via the vena cava
the right atrium contracts and blood is forced to enter the right ventricle.
the right ventricle contracts and blood leaves through the pulmonary artery
blood leaves the heart and enters the lungs via the pulmonary artery. oxygenated blood is forced to the left atrium via the pulmonary veins.
The left ventricle contracts and blood is forced towards the aorta.
blood leaves the heart via the aorta and is pumped to the rest of the body.
which artery transports oxygenated blood to the kidney?
renal artery
which artery transports oxygenated blood to the liver?
hepatic artery
What is phagocytosis?
The process of engulfing / ingesting foreign particles like bacteria by the white blood cells
How can you prevent tissue rejection?
Ensure that there is a tissue match - > the tissues of both the donor and recipient must be as genetically close as possible.
Use immunosuppressive drugs that inhibits responses of the recipients immune system. Although this could lead to problems like
Lowering the resistance of the recipient to many kinds of infection
The recipient has to continue takin drugs for the rest of their life
What are the advantages of red blood cells changing their shape as they flow through narrow blood capillaries?
The diameter of the RBCs are reduced so it can easily pass through the lumen of the capillaries
The cell increases its surface area to speed up absorption / release of oxygen
The rate of blood flow is reduced thus giving more time for , thus increasing the efficiency of exchange of materials between the blood and the tissue cells
Why are the ventricles thicker than that of the atria?
The atria only forces blood into the ventricles and thus does not require high pressure while the ventricles have comparatively thicker muscular walls ( especially the left ventricle) as it has to pump blood around the whole body
