excretory system (exam 3)

Question 1

carbon waste from sugar breakdown (by animals) is removed by

Answer 1

breathing

Question 2

nongaseous waste must be removed by

Answer 2

excretory system

Question 3

osmoregulation

Answer 3

controlling internal water and solute concentrations

Question 4

osmolarity

Answer 4

total solute concentration

Question 5

where does nitrogen waste come from?

Answer 5

breaking amino acids or nucleic acids down for energy

Question 6

nitrogenous wastes must be eliminated in…

Answer 6

a solution (by peeing it out)

Question 7

most efficient method of eliminating nitrogen and why?

Answer 7

ammonia; since no conversion is needed
(very toxic and must be highly diluted to be safe)

Question 8

urea must be converted from

Answer 8

from ammonia, requiring energy

Question 9

urea gets rid of __ nitrogens per one molecule. and it is not toxic, so…

Answer 9

2; requires less water to excrete

Question 10

urea is used in

Answer 10

mammals, amphibians, sharks, and some bony fish

Question 11

uric acid requires more/less energy than urea to convert?

Answer 11

more

Question 12

uric acid eliminates __ nitrogen per uric acid molecule

Answer 12

4

Question 13

uric acid is..

Answer 13

-not toxic
-not very soluble
-requires very little to excrete

Question 14

excretion basics: 1. filtration

Answer 14

internal pressure pushes water and small solutes into an internal tube
- called the filtrate
-almost everything is thrown away

Question 15

excretion basics: 2. reabsorption

Answer 15

water and useful solutes are moved back into the body from the tube

Question 16

excretion basics: 3. secretion

Answer 16

additional wastes are actively transported into filtrate

Question 17

excretion basics: 4. excretion

Answer 17

filtrate is excreted from the body as urine

Question 18

creating filtrate

Answer 18

-large ball of capillaries called the glomerulus is surrounded by glomerular capsule (beginning of tubule)

Question 19

in the filtrate, epithelial cells are

Answer 19

selectively permeable
-allows: water, ions, small solutes
-does not allow: blood, blood proteins

Question 20

filtrate flow steps

Answer 20

o Proximal tubule
o Descending limb of nephron loop
o Ascending limb of nephron loop
o Distal tubule
o Collecting duct

Question 21

ways to eliminating nitrogen:

Answer 21

ammonia, urea, or uric acid

Question 21

ammonia is excreted by what ?

Answer 21

most aquatic animals and most bony fish

Question 22

excretory systems are all based on

Answer 22

tubes

Question 22

excretory basics: order

Answer 22

filtration, reabsorption, secretion, excretion

Question 22

1. proximal tubule: is the beginning of

Answer 22

reabsorption

Question 22

1. proximal tubule: ____ is actively transported out of the tubule, resulting in…

Answer 22

Na+ is actively transported out of tubule
(Cl- passively follows Na+ and water passively follows NaCl)

Question 22

1. proximal tubule: unwanted molecules are actively secreted into tubule, such as

Answer 22

drug metabolites; toxins, H+

Question 22

2. descending nephron loop: ____ reabsorption

Answer 22

water

Question 22

2. descending nephron loop: important for

Answer 22

water reabsorption

Question 22

2. descending nephron loop: epithelial cells have many

Answer 22

aquaporin channels (passive water transport) that are impermeable to salt and other solutes

Question 22

2. descending nephron loop: the filtrate loses water down the entire length of the loop, …

Answer 22

becoming increasingly concentrated

Question 22

3. ascending nephron loop: important for

Answer 22

ion reabsorption

Question 22

3. ascending nephron loop: epithelium has many ion channels that are completely impermeable to

Answer 22

water

Question 22

3. ascending nephron loop: where are the passive and active NaCl transports?

Answer 22

• Passive NaCl transport near bottom
  of tubule
  -Active NaCl transport near top of tubule

Question 22

3. ascending nephron loop: filtrate becomes….

Answer 22

less concentrated as ions leave

Question 22

4. distal tubule

Answer 22

-active NaCl reabsorption
-active K+ secretion
-controls levels in the body (crucial for proper nerve function)

Question 22

5. collecting duct: important for..

Answer 22

reabsorption of water and ions via diffusion

Question 22

5. collecting duct: controls

Answer 22

body osmotic balance (makes urine more or less concentrated AND changes if aquaporins are in ducts)

Question 22

5. collecting duct: not enough internal water…

Answer 22

water is then reabsorbed from duct

Question 22

5. collecting duct: too much internal water…

Answer 22

water is NOT reabsorbed from duct

Question 22

the collecting duct sends urine…

Answer 22

to bladder for excretion

Question 22

nephron loop creates osmolarity gradient in

Answer 22

medulla

Question 23

collecting duct uses ___ to ___ reabsorb water

Answer 23

gradient; passively

Question 24

length of nephron loop determines ability to

Answer 24

concentrate urine