L: Excretion

Question 1

Excretion

Answer 1

The removal of the waste products of metabolism

Question 2

Kidney

Answer 2

One of two organs in humans which extract impurities from the blood

Question 3

Metabolic waste

Answer 3

Harmful by-products of metabolic processes

Question 4

Renal artery

Answer 4

Carries blood to the kidneys

Question 5

Renal vein

Answer 5

Takes blood away from the kidney

Question 6

Urea

Answer 6

Produced from the breakdown (deamination) of excess amino acids in the liver

Question 7

Glomerular filtrate

Answer 7

The fluid forced out of the glomerulus under high pressure. It contains water, glucose, urea, ions and other small molecules, but NOT blood cells and large molecules such as proteins

Question 8

Selective reabsorption

Answer 8

The process where the substances we need, e.g. glucose, are reabsorbed from the tubules back into the blood stream

Question 9

Collecting duct

Answer 9

The tubule that receives urine from numerous nephrons. The permeability of its wall to water is controlled by ADH.

Question 10

Bowman’s capsule

Answer 10

A cup-shaped receptacle in the vertebrate kidney that is the initial, expanded segment of the nephron where filtrate enters from the blood

Question 11

Ultrafiltration

Answer 11

The process where fluid (called glomerular filtrate) is forced out of the glomerulus under high pressure

Question 12

Urine

Answer 12

The liquid waste filtered from the blood by the kidney and stored in the bladder pending elimination through the urethra

Question 13

Glomerulus

Answer 13

A dense network of capillaries where water, ions, glucose and urea are filtered from the blood into the tubules

Question 14

Pituitary gland

Answer 14

A small gland in the brain that releases several hormones, including ADH

Question 15

Active transport

Answer 15

The transport of a substance across a biological membrane against a concentration gradient. Energy from respiration is required

Question 16

Proximal convoluted tubule

Answer 16

Site where the majority of the glomerulus filtrate is reabsorbed. All of the glucose is reabsorbed back into the blood here by active transport

Question 17

Osmoregulation

Answer 17

The hormonal control of water levels in the blood

Question 18

Ureter

Answer 18

Transports urine out of the body

Question 19

Negative feedback

Answer 19

Any mechanism which reverts a change in a system back to its normal value

Question 20

Urethra

Answer 20

Transports urine out of the body

Question 21

Nephron

Answer 21

Functional filtering until of the kidney, also knowns as kidney tubules. Each kidney contains about a million of these units

Question 22

Loop of Henlé

Answer 22

A U-shaped loop that runs down into the medulla of the kidney. It has a complicated role in concentrating the fluid in the tubule to allow more water to be reabsorbed into the blood

Question 23

Anti-diuretic hormone (ADH)

Answer 23

The hormone which increases the permeability of the collecting ducts, allowing more water to be reabsorbed back into the blood

Question 24

Hypothalamus

Answer 24

A region of the brain that contains special receptor cells which are sensitive to the solute concentration of the blood. It has several other roles, e.g. it also contains the thermoregulatory centre which detects blood temperature