Unit 1, Module 2 Glossary Flashcards
Metabolic waste
It consists of waste substances that may be toxic or are produced in excess by the reactions inside cells.
Excretion
The removal of metabolic waste from the body.
Deamination
The removal of the amine group from an amino acid to produce ammonia.
Urea
An excretory product formed from the breakdown of excess amino acids.
Hepatocytes
Liver cells
Hepatic portal vein
It is an unusual blood vessel that has capillaries at both ends - it carries blood from the digestive system to the liver
Kupffer cells
Their primary function appears to be the breakdown and recycling of old red blood cells.
Bilirubin
One of the waste products from the breakdown of haemoglobin
Ornithine cycle
The process in which ammonia is converted to urea. It occurs partly in the cytosol and partly in mitochondria, as ATP is used.
Detoxification
The conversion of toxic molecules to less toxic or non-toxic molecules.
Nephrons
They are the functional units of the kidney. It is a microscopic tubule that receives fluid from the blood capillaries in the cortex and converts this to urine, which drains into the ureter.
Glomerulus
A fine network of capillaries that increases the local blood pressure to squeeze fluid out of the blood. It is surrounded by a cup - or funnel-shaped capsule which collects the fluid and leads into the nephron.
Bowman’s capsule
The cup-shaped end of the nephron tubule.
Selective reabsorption
Where useful substances are reabsorbed from the nephron into the bloodstream while other excretory substances remain in the nephron.
Ultrafiltration
Filtration at a molecular level - as in the glomerulus where large molecules and cells are left in the blood and smaller molecules pass into the Bowman’s capsule.
Podocytes
Specialised cells that make up the lining of the Bowman’s capsule.
Afferent vessels
Bring blood into the organ
Efferent vessels
Carry blood away from the organ.
Microvilli
Microscopic folds of the cell surface membrane that increase the surface area of the cell.
Co-transporter proteins
Proteins in the cell surface membrane that allow the facilitated diffusion of simple ions to be accompanied by transport of a larger molecule such as glucose.
Facilitated diffusion
Diffusion that is enhanced by the action of proteins in the cell membrane.
Sodium-potassium pumps
Special proteins in the cell surface membrane that actively transport sodium and potassium ions against their concentration gradients.
Hairpin countercurrent multiplier
The arrangement of a tubule in a sharp hairpin so that one part of the tubule passes close to another part of the tubule with the fluid flowing in opposite directions. This allows exchange between the contents and can be used to create a very high concentration of solutes.
Osmoregulation
The control and regulation of the water potential of the blood and body fluids. In humans the kidney controls the water potential of the blood.
