excretion

Question 1

metabolic waste types

Answer 1

nitrogenous, organic acids, sulfates, phosphates, CO2

Question 2

waste path out of body

Answer 2

cells, interstitial fluid, blood, lungs/kidneys/gills/liver/salt glands (mostly kidneys)

Question 3

how much body water is ECF

Answer 3

26%

Question 4

excretory and urogenital development

Answer 4

intermediate mesoderm, nephrotomes (with a nephron in each) segmented under segmented somites

Question 5

nephron

Answer 5

2-layered cup of epithelium/bowmans capsule surrounds glomerulus (ball of capillaries) = renal corpuscle. attached to epithelial tube (renal tubule uses microvilli - proximal part absorbs, distal concentrates)

Question 6

blood supply to glomerulus

Answer 6

arterioles both ways, high pressure, afferent is larger

Question 7

podocytes

Answer 7

cells with finger like extensions which wrap around capillaries for filtration, keep in larger molecules. main body = diagphragma

Question 8

mesangial cells

Answer 8

regulate blood flow in glomerulus, secrete inflammatory mediators and matrix fluid

Question 9

capillaries next to renal tubule in diff groups

Answer 9

peritubular capillaries to… efferent renal vein and renal portal vein in birds, reptiles, chondrichthyes, just portal in teleosts and amphibians, just efferent in mammals (in mammals just 1 capillary with countercurrent flow)

Question 10

nephron position thru orders

Answer 10

ammocoetes and larval amphibians - external glomeruli in coelum and filtrate is moved out by cilia; elasmobranchs, primitive teleosts, and some amphibians - internal but connected to coelum via passage; all other verts- separate compartment

Question 11

nephron differentiation thru orders

Answer 11

(order of formation) pronephros - head kidneys, 12+ in agnathans, anamniotes, amphibians. 1-3 nonfunctional as adults for amniotes but starts development of archinephric duct for waste disposal in embryos. mesonephros - nonsegmented, have a gap btwn this and pro in amniotes, join with pronephros to form opisthonephros in anamniotes (advanced in fish and amphibians, front makes sperm); metanephros- invented for amniotes, where the ureteric bud forms/end of archinephric duct, grows into renal tubules and ureter.

Question 12

mammal bladder origin

Answer 12

allantois

Question 13

osmoregulation

Answer 13

maintenance of ionic balance

Question 14

osmolarity of cell

Answer 14

300 mOsm. (1000 for seawater)

Question 15

waste fixation methods

Answer 15

bony fish/water turtles - ammonia flushed out, sharks - urea storage, reptiles - uric acid, mammals - urea

Question 16

osmoregulation in early chordates/agnathans

Answer 16

interstitial fluid is isosmotic to seawater, similar in hagfish but renal tubules flush water faster for more efficient NH3 disposal

Question 17

hypoosmotic ECF

Answer 17

not enough solutes, water enters cell

Question 18

hyperosmotic ECF

Answer 18

too many solutes, water leaves cell

Question 19

renal corpuscles purpose

Answer 19

remove excess water/solutes from tissue, craniate innovation

Question 20

osmoreg freshwater teleosts

Answer 20

gills excrete NH3, kidneys osmoregulate (hypoosmotic urine), renal corpuscle is large for flow and has cilia for movement after corpuscle and at intermediate segment. minimize water intake via mucus on skin, absorb salt via ionocytes in skin and gills

Question 21

osmoreg saltwater teleosts

Answer 21

drink water, excrete salts. smaller corpuscle with no cilia and no intermediate segment to reduce flow. (hyperosmotic urine) many ionocytes to secrete salts. fish like salmon and eels have fresh and saltwater so can do both, regulated by hormones to kidneys

Question 22

osmoreg in chondrichthyans

Answer 22

minimize water intake. cells isosmotic to seawater using urea buildup. large corpuscles to eliminate water, hyposmotic urine. rectal digitiform gland excretes salt. this urea tolerance character is seen as eggs due to lack of waste exchange, could be reason for evo.

Question 23

osmoreg in amphibians

Answer 23

as larva, like freshwater fish. as adults, convert to urea and excrete hyposmotic urine bc their tubules are massive a la fish. thus they must stay wet

Question 24

osmoreg in reptiles

Answer 24

make uric acid, urine is isosmotic to blood. renal corpuscles minimize water loss, small, no glomeruli. marine ones have salt glands. sea turtles no longer do this, they just excrete NH3

Question 25

bird and mammal common osmoreg

Answer 25

more tubules in kidneys (~1mil/per in humans), high pressure filtration, panting for thermoreg. birds have iso or hypertonic, uric acid. can have salt glands

Question 26

mammal osmoreg

Answer 26

loop of Henle in tubule for higher pressure faster filtration. hypertonic urine. have cortex, medulla, pyramids (unit), loop of Henle which contacts vasa recta (arteriole) w countercurrent flow. loop is longer in water restricted environments for more room to reuptake. ADH (anti-diuretic hormone) regulates reabsorption