Vertebrate Kidneys and Osmoregulation

What is the tripartite concept of kidney organization?

The concept describes the three regions of nephric tubules that develop in the nephric ridge during embryonic development: Pronephros, Mesonephros, and Metanephros.

Where does the pronephros arise from?

anterior nephric ridge

Where does the Mesonephros arise from?

middle part of the nephric ridge

Where does the Metanephros arise from?

posterior nephric ridge

How does osmoregulation work for freshwater fishes and amphibians?

Minimize water intake to prevent dilution of internal fluids, Actively excrete excess water to maintain osmotic balance, Absorb salts from their surroundings to counteract water influx

How does osmoregulation work for marine bony fishes?

Drink seawater to compensate for water loss, which introduces a salt load, Use chloride cells in gills to actively excrete salt, Produce minimal, highly concentrated urine to conserve water and eliminate excess salts

How does osmoregulation work for cartilaginous fishes?

Retain urea in the blood to maintain osmotic balance, Use a rectal gland to secrete concentrated salt solutions to remove excess salt, Exchange ions through the gills, Obtain some water and ions through their diet and drink little seawater

How does osmoregulation work for reptiles?

• Terrestrial reptiles: Excrete uric acid as a semisolid paste to conserve water.

• Marine reptiles: Have specialized salt glands near the eyes or nostrils to eliminate excess salt.

• Freshwater reptiles: Have low permeability to sodium and rapid water turnover, mainly exchanging water across the skin and mouth.

How does osmoregulation work for birds?

Kidneys filter blood and modify renal output in the lower gastrointestinal tract and Salt glands help eliminate excess salt, usually sodium chloride, and produce free water

How does osmoregulation work for mammals?

Kidneys filter blood, reabsorb essential water and solutes, and excrete waste in urine, Antiduretic hormone promotes water reabsorption in kidneys, Aldosterone increases sodium reabsorption in kidneys, promoting water retention

What is an Osmoregulartor?

able to maintain a different ion concentration than that of their environment

What is a osmoconformer?

Have blood that has the same ion concentration as the water they live in

What does the pronephros turn into?

become the adult kidney in some fishes

What does the mesonephros turn into?

adult kidney in fishes and amphibians

What does the metanephros turn into?

ureter and the adult kidney in mammals

What vertebrates have a pronephros kidney?

some jawless fish

What vertebrates have a mesonephros kidney?

amphibians and most fish

What vertebrates have a metanephros kidney?

reptiles, birds, and mammals

What vertebrates have an opisthonephros (modified mesonephros) kidney?

amphibians and fishes

What vertebrates have an Archinephros (or Holonephros) kidney?

Not found in any living vertebrates

The adult kidney forms as a result of sebsequent loss, merger, or replacement of these ______

tubules

What is the name for the pronephros if it is retained?

head kidney

How does the pronephric duct form?

distal ends of the tubules unite

What type of kidney is only found during the embryonic stage?

pronephros