Excretory Systems Flashcards
What are the two fundamental physiological functions of the kidney?
Excretion and osmoregulation
Are avian loops of henle short or long? Why? Do all birds have these loops?
short -produce very concentrated urine.
Most birds DO NOT have loops of henle
What are the 3 routes of eliminating ammonia?
Ammonotelism
Uricotelism
Ureotelism
Describe Ammonotelism
Direct excretion of ammonia
common to animals living in water
eliminated through gill epithelium, skin &other permeable membranes
Describe Uricotelism
Excretion of uric acid
performed by birds & most reptiles
Describe Ureotelism
Excretion of urea
performed by mammals
Freshwater fish excrete?
voluminous hypo-osmotic (highly dilute) urine
Marine fish excrete? and how do they compensate?
small amounts of hyper-osmotic (very concentrated) urine.
They drink sea water to help w/ water loss. Actively transport salt out through gills
Amphibians nephrons are similar to?
Fresh water fish.
What is estivate(ing)?
dry-weather equivalent of hibernation.
Store nearly pure water to be returned to the blood when needed.
Performed by some frogs.
Reptiles excrete? And lack?
uric acid
Lack loop of henle
Which animals have salt glands?
birds & reptiles
Birds excrete?
uric acid
What is a urolith?
growth or aggregation of solid waste crystals in urine, can be found anywhere in urinary tract
A bit about urolith formation
formation of crystal nidus (embryo)
initial phase called nucleation
dependant on supersaturation of urine w/ calculogenic crystalloids
Further growth of urolith dependent on?
ability to remain in lumen
degree & duration of supersaturation of urine
physical characteristics of crystal nidus
Uroliths are named according to?
mineral composition
location
shape
Obstructions induced by urolith in include?
Urine retention
Bladder distension , abdominal pain, bladder rupture
death from uraemia or septicaemia
Which are the most common crystals that cause blockage?
struvite (Mg-ammonia-phosphate)
What are some predisposing factors to urolith formation?
high grain diet silica rich soil High Ca diet mineral composition of water Vitamin A deficiency
Uroliths commonly lodge in the….?
sigmoid flexure
What is scouring?
passage of highly fluid faecal matter, often w/ increased frequency
What is the most common cause of scouring?
E. coli.
excessive intestinal motility from irritation of intestinal wall by bacterial, viral, or protozoan infection
What animal is particularly susceptible to scours and why?
Neonates -especially those reared artificially
White or yellow scours indicate?
inadequate colostrum, overfeeding/crowding, stress, poor sanitation
Watery scours indicate?
change in diet, stress
Bloody scours indicate?
infections from salmonella or coccidia
loose, dark brown faeces indicate?
bleeding from lesions & ulers in abomasum or serious infection in GIT
Name the two viruses that can lead to diarrhoea in calves
rotavirus
coronavirus
Scouring in adult animals is associated w/?
parasite burdens
excess nutrients
poor dietary adaptation
