transport
These vessels carry blood back towards the heart and contain valves to prevent backflow.
veins
The general name for any disease-causing organism.
pathogen
The dome-shaped muscle below the lungs that flattens during inhalation.
diaphragm
Respiration releases this from glucose for muscle contraction, growth and warmth.
energy (ATP)
A chemical messenger secreted by a gland into the blood, carried to a target organ.
hormone
This chamber has the thickest muscular wall because it pumps blood all around the body. (ventricle etc)
left ventricle
This type of white blood cell engulfs and digests pathogens.
phagocyte
The tiny air sacs that are the site of gas exchange.
alveoli
Anaerobic respiration in yeast produces carbon dioxide and this alcohol.
ethanol
Receptor → sensory neurone → relay neurone → motor neurone → effector describes this pathway.
reflex arc
The half of the double circulatory system that carries blood from the heart to the lungs and back.
pulmonary circulation
These proteins, produced by lymphocytes, have a shape complementary to a specific antigen.
antibodies
Rings of this tissue keep the trachea open.
cartilage
Built up during vigorous exercise, this substance creates an oxygen debt.
lactic acid
The junction between two neurones, crossed by neurotransmitter diffusing across the gap.
synapse
These vessels supply the heart muscle itself; their blockage causes a heart attack.
coronary arteries
A vaccine containing a weakened pathogen stimulates the body to make its own antibodies and memory cells, giving this type of immunity.
active immunity
These cells sweep mucus and trapped particles away from the lungs.
ciliated cells
Excess amino acids are broken down in the liver by this process, forming urea.
deamination
Secreted by the pancreas, it lowers blood glucose by making the liver convert glucose to glycogen.
insulin
The soluble plasma protein converted into insoluble fibrin during clotting.
fibrinogen
Cholera toxin causes chloride ions to be secreted into the small intestine, so water leaves the blood and tissues by this process, causing watery diarrhoea.
osmosis
When the ribs move up and out and the diaphragm flattens, thorax volume increases and this decreases, so air rushes in.
(air) pressure
The kidney process in which glucose, some water and some ions are taken back into the blood.
selective reabsorption
the maintenance of a constant internal environment
homeostasis