Ch 44 Osmoregulation and Excretion Flashcards
Osmoregulation
The maintenance of internal solute concentrations and water levels within a range that allows cellular functions to continue
Osmosis
Water moves across a membrane from where it is more concentrate (relative to solutes) to where it is less concentrated
Osmotic conformers
Animals that do no actively regulate osmotic pressure of their body fluids
Why are most marine invertebrates osmotic conformers?
They are in a stable environment
Why do most invertebrates actively osmoregulate?
They are in less stable environments
Animals can modify behavior to limit what?
Water loss
In what two kind of environments is water loss a major problem?
1) Terrestrial
2) Temporary aquatic
How do terrestrial vertebrates regulate their water balance physiologically?
1) Consuming water
2) Consuming moist foods
3) Acquiring water through metabolism
Water molecules are one of the final products of what?
The electron transport chain
What purpose do salt glands in marine reptiles serve?
Reduce osmotic pressure by removing salt from the blood
What can greatly effect an animal’s water balance?
The type and amount of its waste
What is one of the most important wastes?
Nitrogenous breakdown products of proteins and nucleic acids
Ammonia (NH4)
The primary nitrogenous waste of metabolism
Toxic except in very dilute form
Terrestrial vertebrates convert ammonia to what?
Less toxic wastes
Why do terrestrial vertebrates convert ammonia into les toxic wastes?
They can be concentrated in the body an excreted with less water
Why do sharks and rays concentrate urea in their tissues?
To increase the body’s osmotic pressure and retain water from the environment
Metanephridia
Secrets wastes and reabsorbs solutes
Possessed by terrestrial coelomates (annelids and molluscs)
Insects and spiders posses what kind of excretion?
Malphigian tubule excretion (not associated with blood circulation)
Malpighian tubule
Hydrogen ions are actively pumped into the tubules
The increased osmotic pressure draws in salts, water, and wastes which are passed into the intestine
Kidney
Primary organ regulating volume and composition of body fluids in vertebrates
Urine is formed as a result of what?
Three physiological processes that take place across the cortex and medulla of the kidney
Three physiological processes that form urine
1) Filtration
2) Reabsorption
3) Secretion
Nephron
The basic functional unit of the kidney
Glomerulus
Found in the nephron of the kidney
Water and small solutes, but no proteins and red blood cell, can pass through this structure
Proximal tubule
Found in the nephron of the kidney
Where most of the water and glucose are reabsorbed
Distal tubule
Found in the nephron of the kidney
Hydrogen, potassium, and foreign molecules (including drugs) are secreted into this structure
What process in the kidney changes osmolarity and facilitates additional water absorption?
Transport of salts from the nephron to the interstitial fluid
The mammal kidney allows for the production of urine that is what?
More concentrated than the blood
