Exotics urinary system

Question 1

What is an aquatic Organisms primary form of

Nitrogenous waste?

Answer 1

Ammonia (fish, aquatic amphibians)
— relatively toxic; aquatic animals more tolerant
— 400 ml water required /gm. ammonia to secrete

Question 2

Terrestrial Organisms

What is the primary form of nitrogenous waste in mammals, terrestrial amphibians?

Answer 2

Urea— 40 ml water per/gm of urea for excretion

Question 3

What is the primary form of excretion of nitrogenous waste in birds and reptiles.

Answer 3

Uric Acid = Uricotelism
— 8 ml water per/gm to excrete
— highly insoluble

Question 4

Describe the fish Renal Anatomy?

Answer 4

Single kidney, length of coelom
. Divisions (may be separate)
— cranial: endocrine & hematopoietic
— caudal: filtration (nephrons)

Question 5

What structure is missing from a fishes nephron?

Answer 5

Loop of henle missing in fish as they don’t need to concentrate their urine. They produce a hypo-osmotic urine.

Question 6

How does water and nitrogenous movement happen in fish?

Answer 6

by osmosis across skin and gill epithelium.
Nitrogenous waste: ammonia
urine
-gills

Question 7

What happens to ion and water movement in freshwater fish (osmoregulation)?

and how does the fish compensate for this?

Answer 7

*Ion loss/water gain across gills (and skin) happens.

and therefore,

• Kidney: excrete water
• High GFR
• The gills can also actively uptake NaCL and excrete ammonia.

Question 8

What happens to ion and water movement in saltwater fish (osmoregulation)?

and how does the fish compensate for this?

Answer 8

*Loose water across gills and skin and NaCl moves in.

and therefore,

• Gills excrete Nacl
• Gills excrete ammonia.
• Kidneys remove divalent ions Mg2+

Question 9

In both saltwater and freshwater fish the Gills are the main organs responsible for?

Answer 9

Regulating salt balance.

Question 10

Terrestrial amphibians excrete …… or …… acid?

Answer 10

Urea or uric acid.

Question 11

Aquatic amphibians excrete mostly …….?

Answer 11

Ammonia.

Question 12

What kind of urine do amphibians excrete?

Answer 12

Hypo-osmotic.

Question 13

How do aquatic amphibians get water in and out of their system?

Answer 13

Skin extremely water permeable
. Passive absorption (osmosis)
. Kidney must excrete excess water
. Excrete ammonia (through gills/skin)

Question 14

What structure do terrestrial amphibians have that allows them to store water?

Answer 14

Urinary bladder to store water (reabsorb)

Question 15

How are bird and reptile kidneys divided?

Answer 15

Cranial, middle and caudal divisions.

Question 16

In avian nephrons what type makes up 70-90% of them? And what structure do they lack?

Answer 16

Reptile type:
— no loop of Henle (can’t concentrate urine)
— cortex only

Question 17

In avian nephrons what type makes up 10-30% of them?

Answer 17

mammalian type
— loop of Hen le (can do limited urine concentration)
— Run from cortex - medulla
. Limited urine concentration

Question 18

What surrounds avian kidneys?

Answer 18

Air sacs.

Question 19

What do avians lack the ability to do when stressed or polyuric?

Answer 19

sodium-linked water reabsorption (decreased

with stress,polyuria)

Question 20

The avian Renal Portal System is the second afferent blood supply from pelvic limbs (pelvic limb blood goes to renal parenchyma). What position is the renal portal valve in under influence of aCH and Adrenaline?

Answer 20

aCH— Normally closed: blood from limbs - renal
portal veins, kidney (under influence of aCH)
Adrenaline— open: blood from limbs - straight to caudal VC (under influence of adrenaline)
— Doesn’t supply glomerulus

Question 21

What happens in avians if you inject a nephrotoxic drug into the hindlimb?

Answer 21

Injecting a nephrotoxic
drug will increase its nephrotoxicity if injected
in hind limb

Question 22

In birds what clinical sign is seen in renomegaly?

Answer 22

The lumbar and sacral plexi are associated with the kidneys.Therefore renomegaly causes pressure on the nerve plexi thereby causing non weight bearing lameness.

Question 23

In terrestrial reptiles and birds:Uric acid (UA)

is made where?

Answer 23

In the liver and it is independent of urine flow rate because it is from tubular secretion. Meaning reptiles and birds can get rid of nitrogenous waste even if they are dehydrated.

Question 24

Define Hyperuricemia?And what condition can it cause?

Answer 24

An excess of uric acid in the blood.It can cause gout.

Question 25

What are some of the causes of hyperuricaemia and consequently gout?

Answer 25

. renal disease
. very high dietary protein
. Dehydration (can’t flush uric acid
out of kidney)
. nephrotoxic drugs can damage renal
tubules (e.g. gentamicin)

Question 26

Uric acid is eliminated as a suspension of?

Answer 26

Uric acid complexed with protein and

Na/K

Question 27

What are salt glands and when do they become active?

Answer 27

.Supraorbital gland that drains into nostrils
. Salt glands become active when Salt
consumption>renal clearance

Question 28

The salt gland hypertrophies with salt exposure but how do they work?

Answer 28

When a bird Drinks seawater Na in the intestine moves intot the blood. Thereby increasing solute conc. in the blood. Water then moves out of cells which increases the ECFV.
An increase in blood solute concentration and ECFV in blood stimulates salt glands to excrete.

Question 29

What animal has the caudal aspect of kidneys often fused and sometimes is +1- a bladder?

Answer 29

Lizards.

Question 30

What reptile has no bladder (store urine distal colon, ureters)?

Answer 30

Snake.

Question 31

What reptile has:
— bladder +/- accessory bladders;
— can reabsorb water from them
— buoyancy aid
. Renal portal system?

Answer 31

Chelonians.

Question 32

Which kidney is cranial in the snake?

Answer 32

The right. Both have 25-30 lobes.

Question 33

What renal anatomy summary does the below list apply to:
. No pelvis, pyramids, cortex, medulla
. Poorly developed glomeruli, few capillaries
. No loop of Henle
. Squamates: sexual segment (males)
— between distal tubule and collecting duct

Answer 33

Summary: Reptile Renal

Question 34

What is the reptilian response to dehydration?

Answer 34

— Afferent arteriole constricts, glomerulus closes,
tubule collapses, GFR decreases
— Decreased excretion
— Renal portal blood perfuses tubules
. Salt glands
— Actively excrete Na+ and K +
— High plasma osmotic concentration stimulates.