Key Definitions - Excretion

Question 1

define antidiuretic hormone (ADH).

Answer 1

a hormone produced by the pituitary gland that increases the reabsorption of water in the collecting duct of the kidney

Question 2

define bladder.

Answer 2

the organ that collects and holds urine before it is excreted

Question 3

define bowman’s capsule.

Answer 3

structure at the start of the nephron where the glomerular filtrate enters from the glomerulus and connects to the proximal convoluted tubule

Question 4

define collecting duct.

Answer 4

final part of the nephron which connects to the ureter where water is reabsorbed, how much is determined by its permeability which is controlled by ADH

Question 5

define convoluted tubules.

Answer 5

tubes in the nephron (PCT and DCT) where the filtrate flows through, substances (glucose, ions, amino acids) from the filtrate are reabsorbed by active transport into the blood from these tubes

Question 6

define excretion.

Answer 6

the removal of metabolic waste from the body (co2 for example)

Question 7

define glomerulus.

Answer 7

a bundle of capillaries where ultrafiltration occurs

Question 8

define loop of henle.

Answer 8

part of the nephron after the PCT where water and salts are reabsorbed

Question 9

define nephron.

Answer 9

functional unit of the kidney that contains the bowman’s capsule, PCT, Loop of Henle, DCT and collecting duct

Question 10

define organs of excretion.

Answer 10

any organ that removes metabolic waste, the lungs removing carbon dioxide and water vapour produced from respiration, the kidneys removing water, urea and salts and the skin excreting water and salts

Question 11

define osmoregulation.

Answer 11

regulation of the volume of water in body fluids by the use of the hormone ADH

Question 12

define selective reabsorption.

Answer 12

the selective uptake of useful substances such as glucose, water and ions back into the blood from the nephron. Selective reabsorption in the PCT involves the active transport of glucose out of the PCT back into the blood

Question 13

define stomata.

Answer 13

small holes found in the lower epidermis that open and close thanks to the guard cells. Control the loss of water by closing during the night but open during the day thanks to the guard cells to allow the diffusion of carbon dioxide and oxygen

Question 14

define ultrafiltration.

Answer 14

the filtration of blood at the glomerulus under high pressure to form the glomerular filtrate. Contains water, ions, glucose, urea and other molecules. Does not contain proteins and blood cells as they are too large and cannot leave due to the basement membrane

Question 15

define ureter.

Answer 15

tubes that carry urine from the kidneys to the bladder

Question 16

define urethra.

Answer 16

tube that carries urine from the bladder out of the body

Question 17

define urine.

Answer 17

waste product of the kidney that contains water, urea and ions