Ch. 44 - Osmoregulation and Excretion

Question 1

what is osmoregulation?

Answer 1

the regulation of the solutes of body fluids [maintaining salt / water concentration]

Question 2

what is excretion?

Answer 2

the removal of metabolic wastes from body fluids

Question 3

what is osmolarity?

Answer 3

the measure of the solute concentration in a volume of solvent

Question 4

what is an osmoconformer?

Answer 4

an organism in which the osmolarity varies with its environment

Question 5

what traits are common of osmoconformers?

Answer 5

-live in places with constant osmolarity
-spend little energy maintaining ion gradients

Question 6

what are osmoregulators?

Answer 6

organisms that maintain their solute concentration around a set point

Question 7

what osmoregulation happens in a hypoosmotic environment?

Answer 7

-water diffuses in, so salts must be pumped in

Question 8

what osmoregulation occurs in a hyperosmotic environment?

Answer 8

-water diffuses out, so salts must be pumped out
-must spend energy to maintain constant osmolarity

Question 9

how does shark osmoregulation differ from marine fish?

Answer 9

shark cells have a salt concentration typical to fish, but they concentrate urea = slightly hyperosmotic = water moves into sharks

Question 10

what osmoregulatory strategies do marine animals use?

Answer 10

-water is constantly moving out & salts in
-fish need to conserve water & remove salts
-active transport of Cl- out of gills, Na follows, urine is very concentrated

Question 11

what osmoregulatory strategies do freshwater animals use?

Answer 11

-water is constantly moving in & salts out
-fish need to conserve salts & remove water
-pump Cl- into gills, Na+ follows, urine is very dilute

Question 12

what osmoregulatory strategies do terrestrial animals use?

Answer 12

body coverings [skin/fur]
kidneys to conserve water
-behavior [avoiding heat]

Question 13

what are the three main types of nitrogenous waste?

Answer 13

ammonia/NH3, urea, and uric acid

Question 14

how is ammonia eliminated from fresh water fish?

Answer 14

ammonia is not converted into any other compound, it is diluted with water and excreted as is

Question 15

how is ammonia removed from mammals and amphibians?

Answer 15

ammonia is converted to urea, which is then eliminated through excretion

Question 16

how is ammonia eliminated in reptiles and birds?

Answer 16

ammonia is converted to uric acid, which is then eliminated in waste

Question 17

what are the three portions of the kidney?

Answer 17

the outer cortex, inner medulla, and renal pelvis

Question 18

what kidney component is found in the outer cortex?

Answer 18

the glomerulus of the nephron

Question 19

what kidney components are found in the inner medulla?

Answer 19

-the nephron loop and collecting ducts which form the renal pyramids

Question 20

what is the nephron?

Answer 20

the smallest functional unit of a kidney, which produces urine

Question 21

what are the five main structures found in the nephron?

Answer 21

1. glomerulus
2. proximal convoluted tubule
3. nephron loop
4. distal convoluted tubule
5. collecting duct

Question 22

what is the function of the glomerulus?

Answer 22

-to collect fluid filtered from the blood
-also begins formation of the filtrate [what becomes urine]

Question 23

what is the function of the proximal convoluted tubule?

Answer 23

-where reabsorption of nutrients and water begins
-some wastes and things not filtered from the glomerulus are secreted here

Question 24

what is the function of the nephron loop?

Answer 24

to establish a concentration gradient and further remove water and ions from the nephron

Question 25

what is the function of the distal collecting loop?

Answer 25

-to be the “last chance” to reabsorb water/nutrients/ions as well as secrete waste products

Question 26

what are the four main steps of urine formation?

Answer 26

1. filtration of blood plasma
2. reabsorption of filtrate
3. secretion of wastes
4. concentration of the urine

Question 27

where does filtration of blood plasma occur in the kidneys?

Answer 27

within the glomerulus

Question 28

where does filtrate reabsorption occur in the kidneys?

Answer 28

within the proximal convoluted tubule

Question 29

where does waste secretion occur in the kidneys?

Answer 29

within the proximal & distal convoluted tubules

Question 30

where does urine concentration occur in the kidneys?

Answer 30

within the DCT and collecting duct, due to the concentration gradient established by the nephron loop

Question 31

what are cortical nephrons?

Answer 31

-nephrons that do not create an osmotic gradient in the medulla (85%)