Unit 1, Module 2 Glossary

Question 0

Metabolic waste

Answer 0

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

Question 1

Excretion

Answer 1

The removal of metabolic waste from the body.

Question 2

Deamination

Answer 2

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

Question 3

Urea

Answer 3

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

Question 4

Hepatocytes

Answer 4

Liver cells

Question 5

Hepatic portal vein

Answer 5

It is an unusual blood vessel that has capillaries at both ends - it carries blood from the digestive system to the liver

Question 6

Kupffer cells

Answer 6

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

Question 7

Bilirubin

Answer 7

One of the waste products from the breakdown of haemoglobin

Question 8

Ornithine cycle

Answer 8

The process in which ammonia is converted to urea. It occurs partly in the cytosol and partly in mitochondria, as ATP is used.

Question 9

Detoxification

Answer 9

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

Question 10

Nephrons

Answer 10

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.

Question 11

Glomerulus

Answer 11

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.

Question 12

Bowman’s capsule

Answer 12

The cup-shaped end of the nephron tubule.

Question 13

Selective reabsorption

Answer 13

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

Question 14

Ultrafiltration

Answer 14

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.

Question 15

Podocytes

Answer 15

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

Question 16

Afferent vessels

Answer 16

Bring blood into the organ

Question 17

Efferent vessels

Answer 17

Carry blood away from the organ.

Question 18

Microvilli

Answer 18

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

Question 19

Co-transporter proteins

Answer 19

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.

Question 20

Facilitated diffusion

Answer 20

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

Question 21

Sodium-potassium pumps

Answer 21

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

Question 22

Hairpin countercurrent multiplier

Answer 22

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.

Question 23

Osmoregulation

Answer 23

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.

Question 24

Antidiuretic hormone (ADH)

Answer 24

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

Question 25

Osmoreceptors

Answer 25

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.

Question 26

Hypothalamus

Answer 26

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

Question 27

Neurosecretory cells

Answer 27

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.

Question 28

Posterior pituitary gland

Answer 28

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

Question 29

Half life

Answer 29

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

Question 30

Dialysis

Answer 30

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

Question 31

Dialysis membrane

Answer 31

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

Question 32

Dialysis fluid

Answer 32

A complex solution that matches the composition of body fluids.

Question 33

Haemodialysis

Answer 33

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

Question 34

Peritoneal dialysis

Answer 34

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

Question 35

Human chorionic gonadotrophin (hCG)

Answer 35

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

Question 36

Monoclonal antibodies

Answer 36

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

Question 37

Anabolic steroids

Answer 37

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

Question 38

Gas chromatography

Answer 38

A technique used to separate substances in a gaseous state.

Question 39

Chromatogram

Answer 39

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