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Zorluk: OrtaMorphological and Physiological Adaptations to Environments

Freshwater teleost fishes live in an environment that is hypoosmotic relative to their internal body fluids, leading to continuous passive influx of water and loss of essential salts. Which of the following physiological adaptations enables these fishes to maintain osmotic homeostasis?

  1. Excreting large volumes of dilute urine while actively absorbing salts through gill chloride cellsCevap
  2. B
    Drinking large quantities of water while actively excreting salt ions through rectal glands
  3. C
    Excreting nitrogenous waste as insoluble uric acid paste to prevent water loss
  4. D
    Eliminating excess salts through Malpighian tubules while reducing renal filtration

Cevap

Excreting large volumes of dilute urine while actively absorbing salts through gill chloride cells
Freshwater teleost fishes are hypertonic to their surrounding habitat. Water constantly enters their tissues by osmosis, while electrolytes are lost by diffusion. To maintain osmoregulatory balance, their kidneys produce a large volume of dilute urine to void excess water, and specialized epithelial cells (chloride cells) in their gills actively absorb sodium and chloride ions from the dilute water into the bloodstream.

Adım Adım Çözüm

1
Analyze the environmental osmotic pressure acting on freshwater teleost fishes.
The surrounding freshwater is hypoosmotic (lower solute concentration) than the fish's body fluids, causing water to continuously enter passively across the gills and skin while body salts diffuse outward.
Determining the osmotic gradient is necessary to identify the corrective physiological mechanism.
2
Identify the required physiological adjustments to handle water influx and salt loss.
The fish must continuously expel excess water without losing too many salts, while actively acquiring replacement ions from dilute surroundings.
Maintaining internal hydromineral balance requires coordinated kidney and gill function.
3
Match the required adjustments to specific vertebrate organs and cellular adaptations.
Large renal glomeruli produce large volumes of dilute urine to void water, and specialized chloride cells in the gill epithelium actively transport sodium and chloride ions into the blood against a concentration gradient.
This dual mechanism resolves both osmotic water loading and ionic dilution.

Anahtar Kavram

Physiological Osmoregulation in Freshwater Teleost Fishes
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Konular

Morphological and Physiological Adaptations to Environments

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