Unit 1, Module 2 Glossary Flashcards Preview

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Flashcards in Unit 1, Module 2 Glossary Deck (40):
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Excretion

The removal of metabolic waste from the body.

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Metabolic waste

It consists of waste substances that may be toxic or are produced in excess by the reactions inside cells.

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Deamination

The removal of the amine group from an amino acid to produce ammonia.

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Urea

An excretory product formed from the breakdown of excess amino acids.

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Hepatocytes

Liver cells

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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

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Kupffer cells

Their primary function appears to be the breakdown and recycling of old red blood cells.

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Bilirubin

One of the waste products from the breakdown of haemoglobin

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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.

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Detoxification

The conversion of toxic molecules to less toxic or non-toxic molecules.

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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.

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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.

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Bowman's capsule

The cup-shaped end of the nephron tubule.

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Selective reabsorption

Where useful substances are reabsorbed from the nephron into the bloodstream while other excretory substances remain in the nephron.

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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.

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Podocytes

Specialised cells that make up the lining of the Bowman's capsule.

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Afferent vessels

Bring blood into the organ

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Efferent vessels

Carry blood away from the organ.

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Microvilli

Microscopic folds of the cell surface membrane that increase the surface area of the cell.

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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.

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Facilitated diffusion

Diffusion that is enhanced by the action of proteins in the cell membrane.

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Sodium-potassium pumps

Special proteins in the cell surface membrane that actively transport sodium and potassium ions against their concentration gradients.

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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.

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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.

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Antidiuretic hormone (ADH)

Released from the pituitary gland and acts on the collecting ducts in the kidneys to increase their reabsorption of water.

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Osmoreceptors

Receptor cells that monitor the water potential of the blood. If the blood has a low water potential then water is moved out of the osmoreceptor cells by osmosis, causing them to shrink. This causes stimulation of the neurosecretory cells.

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Hypothalamus

A part of the brain that contains neurosecretory cells and various receptors that monitor the blood.

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Neurosecretory cells

Specialised cells that act like nerve cells but release a hormone into the blood. ADH is manufactured in the cell body and passes down the axon to be stored in the terminal bulb. If an action potential passes down the axon the ADH is released from the terminal bulb.

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Posterior pituitary gland

The hind part of the pituitary gland, which releases ADH.

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Half life

The time taken for its concentration to drop to half its original value.

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Dialysis

The use of a partially permeable membrane to filter the blood.

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Dialysis membrane

A partially permeable membrane that separates the dialysis fluid from the patient's blood in a dialsysis machine.

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Dialysis fluid

A complex solution that matches the composition of body fluids.

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Haemodialysis

Where blood is taken from a vein and passed through a dialysis machine so that exchange can occur across an artificial partially permeable membrane.

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Peritoneal dialysis

Where dialysis fluid is pumped into the body cavity so that exchange can occur across peritoneal membrane.

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Human chorionic gonadotrophin (hCG)

A hormone released by human embryos; its presence in the mother's urine confirms pregnancy.

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Monoclonal antibodies

They are identical because they have been produced by cells that are clones of one original cell.

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Anabolic steroids

Drugs that mimic the action of steroid hormones that increase muscle growth.

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Gas chromatography

A technique used to separate substances in a gaseous state.

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Chromatogram

A chart produced when substance are separated by movement of a solvent along a permeable material such as paper or gel.