Chapter 13: Osmoregulation Flashcards
What is interstitial fluid?
Extracellular fluid; fluid in spaces surrounding cells
What is osmoregulation?
The processes by which internal water and solute concentration are maintained despite fluctuations in the external environment
What is osmotic concentration?
The measure of solute concentration
What are osmoregulators?
An organism that has specialised mechanisms for regulating internal water and solute concentration changes in the external environment
What are osmoconformers?
An organism in which the internal solute concentration changes with the concentration of solutes in the external environment
What is a euryhaline species?
An organism that can tolerate a wide change in salinity
What function do the kideneys play in osmoregulation?
Removal of nitrogenous wastes, regulation of water concentration in blood and maintaining ion levels in the blood
How does the loop of henle preserve water?
The longer the loop, the more water is absorbed and the more concentrated the urine is
What is the antidiuretic hormone (ADH)?
A hormone responsible for increase permeability of the distal tubes of the kidney, increasing water reabsorption and reducing urine volume
What is the hypothalamus’ response to dehydration?
When the hypothalamus recognises the rise in osmotic pressure of the blood, it sends a message to the pituitary gland to release an antidiuretic hormone (ADH) which goes to the kidney where it increases the permeability of cells lining the collecting ducts
What are some features that minimise water loss?
- A thick waxy cuticle on the leaf surface
- Reduced numbers of stomata of the top of the leaf and increased numbers on the bottom
- Suken stomata
- Cylindrical or rolled leaves
- Redued leaf numbers or no leaves
- Hairs on leaves
How do hairs help to maintain water loss?
They help create a microclimate, reducing transpiration through the stomata as the concentration gradient has been reduced
What is a mesophyte?
A plant that grows in an environment with medium conditions of moisture
What is a hydrophyte?
A plant that is adapted to aquatic conditions
What is a halophyte?
A plnat that is adapted to salty conditions
