Physiological systems of animals operate in a ____ environment.
Relative concentrations of ___ and ____ must be maintained within fairly narrow limits in the physiological systems of animals.
____ controls solute concentrations and balances the gain and loss of water. It is based largely on controlled movement of solutes between internal fluids and the external environment.
____ gets rid of nitrogenous metabolites and other waste products.
___ is the solute concentration of a solution; determines the movement of water across a selectively permeable membrane.
If two solutions are ____, the movement of water is equal in both directions.
If two solutions differ in osmolarity, the net flow of water is from the ____ to the ____ solution.
A ___ solution has a low solute concentration and a high water concentration.
A ___ solution has a high solute concentration and a low water concentration.
_____, consisting only of some marine animals, are isoosmotic with their surroundings and do not regulate their osmolarity.
____ expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment.
Most animals are ____-- they cannot tolerate substantial changes in external osmolarity.
____ animals can survive large fluctuations in external osmolarity (e.g. salmon).
Most marine invertebrates are ____. Most marine vertebrates and some invertebrates are _____.
Marine bony fishes are ____ to sea water. They lose water by osmosis and gain salt by diffusion and from food. They balance water loss by drinking seawater and excreting salts.
Freshwater animals constantly take in water by osmosis from their ____ environment. They lose salts by diffusion and maintain water balance by excreting large amounts of dilute urine. Salts lost by diffusion are replaced in foods and by uptake across the gills.
___ animals manage water budgets by drinking and eating moist foods and using metabolic water.
___ animals get major water savings from simple anatomical features and behaviors such as a nocturnal life style.
____ must expend energy to maintain osmotic gradients.
____ are specialized epithelial cells that regulate solute movement. They are essential components of osmotic regulation and metabolic waste disposal, and they are arranged in complex tubular networks.
An example of ____ is in salt glands of marine birds, which remove excess sodium chloride from the blood.
water balance, habitat
The type and quantity of an animal's waste products may greatly affect its ____ and ___.
proteins, nucleic acids
Among the most important wastes are nitrogenous breakdown products of ____ and ___.
Some animals convert toxic ___ to less toxic compounds prior to excretion.
Most aquatic animals, including bony fishes excrete nitrogenous wastes and need lots of water. They release ___ across the whole body surface or through gills.
The liver of mammals, most adult amphibians, most sharks, and some bony fishes converts ammonia to less toxic ___. The circulatory system carries it to the kidneys, where it is excreted. Conversion of ammonia to this is energetically expensive.
Excretion of urea requires less ___ than ammonia.
Insects, land snails, and many reptiles, birds, mainly excrete ____. It is largely insoluble in water and can be secreted as a paste with little water loss.
urea, uric acid
Conversion of ammonia to ___ is energetically expensive. However it is not as energetically expensive as producing ____ from this.
Diverse excretory systems are variations on a ____ theme.
____ regulate solute movement between internal fluids and the external environment. Systems that perform these basic functions vary widely among animal groups. They usually involve a complex network of tubules.
Most excretory systems produce ___ by refining a filtrate derived from body fluids.
filtration, reabsorption, secretion, excretion
Key functions of most excretory systems:
_____: pressure-filtering of body fluids. ____: reclaiming valuable solutes. ______: adding toxins and other solutes from the body fluids to the filtrate.
____: removing the filtrate from the system.
A ____ is a network of dead-end tubules connected to external openings. These tubules excrete a dilute fluid and function in osmoregulation.
The smallest branches of the protonephridium network are capped by a cellular unit called a ____.
Each segment of an earthworm has a pair of open-ended ____, which consist of tubules that collect coelomic fluid and produce dilute urine for excretion.
In insects and other terrestrial arthropods, ____ remove nitrogenous wastes from hemolymph and function in osmoregulation.
___ produce a relatively dry waste matter, an important adaptation to terrestrial life.
the excretory organs of vertebrates, function in both ____ and ____.
water balance, salt regulation
The mammalian excretory system centers on paired kidneys, which are also the principal site of ___ and ___.
Urine exits each kidney through ducts called ___.
Both of these drain into a common urinary bladder, and urine is expelled through a urethra.
renal cortex, renal medulla
The mammalian kidney has two distinct regions: an outer ____ and an inner ____.
The ____, the functional unit of the vertebrate kidney, consists of a single long tubule and a ball of capillaries called the ____.
____ surrounds and receives filtrate from the glomerulus.