49 terms

IGCSE Topic 25: Blood

Transport of nutrients and oxygen; immunity and clotting.
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AIDS
Acquired immunodeficiency syndrome. Caused by HIV.
Anaemia
Lack of red blood cells caused by a shortage of iron in the diet.
Antigen
A chemical on the surface of a pathogen that is recognised as foreign by the body's immune system, and that can be targeted by antibodies.
Arterial blood
Blood found in an artery - usually high pressure and well-oxygenated.
Arteriole
Small branches of main arteries.
Artery
A major blood vessel carrying blood, usually oxygenated, under pressure from the heart.
Bacterium (bacteria)
Type of microorganism without a nucleus or any membrane-bound organelles. Many types can cause disease.
Blood
Liquid tissue that is the main transport medium in animals.
Blood serum
The liquid portion of the blood left after it has clotted
Capillary
The very fine blood vessels that permeate all the tissues in the body to supply oxygen and nutrients as well as remove waste products.
Carbon dioxide
Gas produced by respiration that is essential for photosynthesis
Carbon monoxide
Gas produced by incomplete combustion. Causes asphyxiation by combining irreversibly with haemoglobin.
Carboxyhaemoglobin
Compound forms when carbon monoxide binds very tightly to haemoglobin.
Clot
Mass of blood and fibres that forms at the site of a wound preventing loss of blood and entry of microorganisms.
Deoxygenated
Blood that is low in oxygen and high in carbon dioxide.
Diffusion
The net movement of a substance from an area of high concentration to one of lower concentration.
Fibrin
Fibrous substance formed from fibrinogen when blood clots.
Fibrinogen
Soluble plasma protein that is converted to a mesh of insoluble fibrin during the blood clottin process.
Haemoglobin
The iron-containing protein in red blood cells that carries oxygen.
Haemophilia
Genetic disease affecting the ability of the blood to clot
Heart
Pump responsible for circulation of the blood in animals.
Hormone
A chemical messenger that is transported in the blood stream as part of the endocrine system. Similar molecules are found in plants and are known as plant growth substances.
Lymph
Fluid found in the lympahtic system.
Lymphatic system
System of vessels that collect excess tissue fluid and drain it back into the blood. Plays an important role in collecting the products of fat digestion from the gut, and in defence against infection.
Lymphocyte
White blood cell that produces antibodies.
Memory cells
Special type of lymphocyte that remains after an infection to remember that the infection has taken place. Allows a more rapid response to further infection by the same organism.
Oxygen
Gas required by most living things. Allows energy to be released from food molecules by the process of aerobic respiration.
Oxygen debt
Respiration in the absence of sufficient oxygen leads to a build up of lactic acid that has to be cleared when sufficient oxygen is available.
Oxygenated
Blood that is high in oxygen and low in carbon dioxide.
Oxyhaemoglobin
The form in which oxygen is carried in red blood cells; bound to haemoglobin.
Passive immunity
When the body is protected from a pathogen or toxin by receiving antibodies from another source not involving the body's own cells.
Pathogen
A microorganism that can infect and harm a pant or animal.
Period
Another term for the release of blood from the vagina during menstruation.
Phagocyte
Type of white blood cell that helps fight nfection by engulfing and destroying microorganisms.
Phagocytosis
The process by which phagocytes ingest material by engulfing it.
Plasma
The liquid portion of the blood after all the cells have been removed.
Platelet
A small blood cell fragment that is important in the clotting process.
Red blood cell
A small and flexible cell without a nucleus that carries oxygen around the body. Also called an erythrocyte.
Sickle cell anaemia
Inherited condition caused by a mutation in one of the genes for haemoglobin. Heterozygous individuals have some resistance to malaria.
Tissue
Groups of the same type of cell with the same function
Tissue fluid
Watery solution of salts and glucose. Leaks from capillary walls and drains back into capillaries and the lymphatic system.
Toxin
A substance produced by a microorganism that can damage or kill another organism by poisoning cells.
Urea
An organic form of nitrogen that is excreted by organisms and can be formed by decay, Readily converted into ammonia in the soil
Vaccine
Inactive form of a pathogen that can be used to give protective immunity to a disease: e.g. genetically engineered bacteria can be used to produce a vaccine against the hepatitis B virus.
Venous blood
Blood found in a vein - low pressure and usually poorly oxygenated.
Viruses
Not truly living as they need to infect a living cell in order to reproduce. Can only be seen using an electron microscope.
Vitamin
A type of nutrient required in the diet in small amounts because the body cannot make them itself. Lack of these leads to deficiency disease.
Warfarin
A drug that is used to reduce the risk of blood clot formation in people who are prone to them
White blood cell
A type of blood cell involved in defence against infection.