osmoregulation and excretion

Question 1

*

what is excretion

Answer 1

elimination of cellular metabolic waste

Question 2

what is the goal of excretion

Answer 2

removal of toxic by products and for osmoregulation

Question 3

what are the products of protein and nucleic acid metabolism

Answer 3

nitrogenous waste (toxic)

Question 4

what are 3 nitrogenous waste products from most to least toxic

Answer 4

ammonia / ammonotelic
urea / ureotelic
uric acid / uricotelic

Question 5

what animals secrete ammonia

Answer 5

aquatic invertebrates and teleosts

Question 6

what animals secrete urea

Answer 6

mammals, amphibians, cartilagous fish

Question 7

what animals secrete uric acid

Answer 7

birds, insects and reptiles

Question 8

how is ammonia secreted

Answer 8

as gas and mainly excreted passively across gill membrane
some can also be exchanged across gill membrane with sodium-potassium pump

Question 9

what are the results of ammonia accumulation

Answer 9

nervous system toxicity

Question 10

what animals use high amounts of ammonia beneficially and how is it used

Answer 10

some shrimp and squid use it in their coelomic cavities to control buoyancy

Question 11

3 adaptations for urea retention

Answer 11

very low urine flow rates,
active reabsorption by kidney,
urea tolerance

Question 12

where is urea synthesised and excreted

Answer 12

synthesised in liver
excreted via kidneys

Question 13

name a specific animal that excretes uric acid and why

Answer 13

kangaroo rat - to conserve water

Question 14

why do birds and reptiles secrete uric acid

Answer 14

prevents toxicity in eggs

Question 15

what type of feedback system manages urine production

Answer 15

negative feedback system

Question 16

what are the 2 portions of the kidney

Answer 16

medulla (central) and cortex

Question 17

what is the kidney made up of

Answer 17

nephrons

Question 18

what happens at the glomerulus

Answer 18

filters small solutes from blood

Question 19

how does filtration work within the Bowans capsule

Answer 19

arteriole blood pressure forces water, salts, urea and other solutes out into the space within the Bowmans capsule

Question 20

what happens in the descending loop of Henle

Answer 20

aquaproins allow water to pass from the filtrate into the interstitial fluid
water permeable, ion impermeable

Question 21

what happens in the ascending loop of Henle

Answer 21

Na+ and Cl- are reabsorbed from filtrate into interstitial fluid
water impermeable, ion permeable

Question 22

what is the role of the distal tube

Answer 22

selectively secrett and absorb ions to maintain blood pH and electrolyte balance

Question 23

what is the osmolarity of the kidney and how does it change towards the medulla

Answer 23

cortex is iso-osmotic with blood
gets more salty as you move through the medulla

Question 24

where in the kidney is the loop of Henle found

Answer 24

descending down into the medulla

Question 25

what type of exchange is occuring in the loop of Henle

Answer 25

countercurrent exchange

Question 26

what is the role of antidiuretic hormone

Answer 26

increase permeability by adding aquaporins to the distal tubule and collecting duct reduce blood flow to body's extremities

Question 27

what does the juxtaglomerular apparatus (JGA) secrete

Answer 27

rennin

Question 28

what 2 hormones in the renin-angiotensin system increase Na+ and water reabsorption

Answer 28

angiotensin and aldosterone

Question 29

how do you calculate pH

Answer 29

pH = log(1/[H+])

Question 30

what is the pH of pure water at 37C

Answer 30

6.81

Question 31

what is the pH of mammalian blood at 37C

Answer 31

7.4

Question 32

3 mechanisms for pH regulation

Answer 32

cellular buffering, respiration, renal excretion

Question 33

what 2 molecules can be used in pH regulation in the kidney

Answer 33

H+ and HCO3-

Question 34

are smaller or larger animals able to produce more concentrated urine

Answer 34

smaller

Question 35

what is the difference in kidney structure found in animals who need to conserve water

Answer 35

longer loop of Henle thin cortex and large thick medulla

Question 36

what do insects excrete

Answer 36

uric acid

Question 37

what special strcuture has developed in insects for excretion

Answer 37

malpighian tubules

Question 38

what are malpighian tubules

Answer 38

closed projections which move around freely in the animal, constantly exposed to fresh medium

Question 39

what is the role of malpighian tubules

Answer 39

reabsorb salts, water and waste from haemolymph via active transport

Question 40

how are the malpighian tubules emptied

Answer 40

movement of animal empties tubules into hind gut for excretion

Question 41

detail steps that are carried out by the malpighian tubule

Answer 41

active transport of Na+, K+ and H+ into lumen creates electrochemical gradient driving secondary transport of water and small solutes via osmosis

Question 42

what occurs in the insect gut

Answer 42

active ion transport (Na+ / K+ ATPase) back into haemolymph water and solutes recycles

Question 43

how is uric acid excreted in insects

Answer 43

crystals in the faeces