Osmoregulation Flashcards
What is deamination?
deamination is the process of an amino group (NH3) being released from a protein as-well as H20. occurs in the liver, goes into bloodstream, kidneys filter it out.
How do birds deal with NH3?
- ammonia turns into uric acid
- low toxicity
- high amount of water needed
How do mammals deal with NH3?
- ammonia (NH3) turns into urea and CO2
- medium toxicity
- medium amount of water needed
How to fish deal with NH3?
- fish remove it easily
- Ammonia (NH3) isn’t turned into anythings, remains
as ammonia - extremely toxic, must be removed quickly
- low amount of water needed.
How to mammals gain water?
- drinking and metabolism
How to mammals lose water?
1) urine
2) faeces
3) evaporation from the body surface and respiratory tract
Solubility of mammalian waste in water, toxicity and energy needed.
- medium solubility in water
- medium toxicity
- medium energy needed to make waste
Amphibian how do they gain water.
Cutaneous respiration allows the animal to absorb water through their skin directly into their bloodstream
Amphibian how do they lose water.
Their skins are permeable to water. On land amphibians are liable to lose water very rapidly by evaporation. In fresh water they suffer entry of water by osmosis, which is counteracted by the excretion of a large volume of dilute urine.
Amphibian type of nitrogenous waste released.
urea (NH2CONH2 + H20 + heat -> 2NH3 + CO2)
Amphibian, solubility of waste in water, toxicity of waste and energy used to make waste.
Solubility of waste in water for fish.
high
What needs to be considered when discussing osmoregulation in an animal?
- type of animal
- example of this type of animal
- animals environment
- how do they gain water
- how do they lose water
- type of nitrogenous waste produced
- solubility of waste in water
- toxicity of waste
- energy used to make waste
Define osmoregulation.
active regulation of organism’s water content, maintained fluid balance and concentration of electrolytes and other solutes so the fluids don’t become too diluted or too concentrated.
How is water regulation recepted?
by recepter cells in the hypothalamus (osmoreceptors).
When is a cell described as turgid?
a cell into which water has diffused so that the walls are stretched and the cells is fairly rigid is described as turgid.
What does isotonic mean?
when the surrounds are of equal concentration to the cellular contents and there is no net movement of water.
Hypertonic meaning.
when the surroundings are move concentrated than the environment. when solutions separated by a semipermeable barrier are of different concentrations, water will move across the barrier via osmosis in order to equalise the concentrations.
Hypotonic meaning.
when the surroundings are less concentrated than the cellular contents.
Functions of the kidneys.
- removal of nitrogenous wastes
- regulation of water concentration in the blood
- maintaining ion levels in the blood.
Why must ammonia be removed.
build of amonia is cells can affect their pH, making them more basic, which can denature enzymes and compromise their function. this can reduce metabolic activity.
Which animals secrete ammonia.
most aquatic animals, including many fishes and juvenile amphibians, can afford to lose water
Which animals secrete urea.
mammals, most adult amphibians, sharks, some bony fish, need to conserve water
Which animals secrete uric acid.
birds, insect, many reptiles, land snails, need to conserve water.
How do marine bony fish gain water and salt?
- gain of water and salt ions from drinking seawater
- gain of water and salt ions from food
How do marine bony fish lose water and salt?
- excretion of salt ions from gills
- excretions of salt ions and small amounts of water in scanty urine from kidneys
- osmotic water loss through gills and other parts of body surface
How do freshwater bony fish gain water and salt?
- uptake of water and some ions in food
- uptake of salt ions by gills
- osmotic water gain through gills and other parts of body surface
How do freshwater bony fish lose water and salt?
excretion of large amounts of water in dilute urine from kidneys.
What are the problems that marine bony fish face
loses too much water via osmosis across the skin. gains too many salts by drinking seawater and eating food
What are the problems that freshwater bony fish face?
gains too much water via osmosis across the skin and when eating food containing water. loses too many salts via diffusion and in urine.
What are the adaptations that marine bony fish have for water balance?
- constantly drinks seawater
- eats food containing water
- high levels of reabsorption in kidneys
- excretes a low volume of highly concentrated urine
What are the adaptations that marine bony fish have for salt balance.
- excretes highly concentrates urine, ridding the body of excess salts.
- active transport of salts from salt-secreting cells in gills to the seawater.
What are the adaptations that freshwater bony fish have for water balance?
- does not drink water (fish swim with the mouth open so that water passes by their gills for gas exchange, but they do not swallow.)
- low level of reabsorption in kidneys
- excretes high volumes of dilute urine.
What are the adaptations that freshwater bony fish have for salt balance?
- gains salts when eating food
- active uptake of salts from seawater across gills.
What hormone maintains water balance in mammals?
Antidiuretic hormone (ADH)
What does osmoregulation achieve?
osmosregulation is used to keep the bodily from being too diluted or too concentrated.
What happens when bodily fluids are too concentrated?
when bodily fluids are too concentrated, there are high levels of solutes and a low water contents. This leads to high osmotic pressure and the risk of cells losing too much water via osmosis.
What happens when body cels are too dilute?
when body cels are too dilute, there are relatively low levels of solutes and high water content. when this level exceeds the tolerance range, cells are at risk of absorbing too much water, which can result in theme lysing (bursting) in the cast of animal cells.
State the negative feedback loop for needing to drink water.
as a response to an increase in solute concentration in the blood (less water in the blood), the hypothalamus signals the urge to drink and also sends a nerve signal to the pituitary gland, instructing it to release stored ADH into hte blood. tihs hormones increases the permeability of the collecting duct walls to allow water to flow back into the bloodstream. this increaes the water content of the blood and reduces water loss though the urine.
Define osmoregulators.
organism that regulate their solute concentration to be either higher or lower than that of their external environment.
Define osmoconformers.
organisms that allow their solute concentration to be equal to the concentration of the external enviornment
Structural features of dingos.
dingos pant, losing water vapour from the tongue, the air passages and the lining of hte month.
Why do sweat pores aid in thermoregulation?
other animals have high densities of sweat pores in certain areas, which are exposed as the temperature rises. these are effective cooling adaptations, but also involve water loss by evaporation.
Adaptations of animals that live in dry environments.
a waterproof or impermeable outer layer (integument) can reduce water loss. e.g. scales of reptiles, the hair of mammals, feathers of birds, the upper part of the epidermis contain keratin, a protein that hardens and waterproofs the body surface. the waterproof surface acts as a barrier, preventing water loss via osmosis or evaporation.
Physiological process to maintain water balance.
repitles and birds reabsorb water from their cloaca,terrastrial vertebrates slow down the production of urine by reducing rate of glomerular filtration. desert hopping mouse can concentrates its urine more than any known rodent, desert hopping moiuse has very long loop of henle to maximise water conservation.
Physiological process to maintain water balance.
desert hopping mouse and kangaroo mouse are able to conserve water by producing a low volume of highly concentrated urine. some animals can use water stored in fats or carbohydrates, or use the water that is generated from the metabolism of fats or carbohydrates.
Why do some animals not need to drink water?
extract enough water from the food they cosume, such as plants that store water.
Why does burrowing aid in retaining water?
burrows have lower temperatures and higher humidity than the open air, so water is reduce. the burrow also traps exhaled water vapour, so there is a lower concentration gradient of water vapour between the air and animal when it is the burrow, which leads to less evaporation and less water loss.
Why does aestivation aid in retaining water?
Behaviours for retaining water.
- burrowing
- aestivation
-
Define osmoconformers in detail.
most marine invertebrates such as cnidarians and molluscs are osmoconformers. their interstitial fluid concentration fluctuates to match that of the external environment. an organism whose body fluids are of the same concentration as the surrounding water is referred to as isotonic.
How do osmoconformers do it?
cartilaginous fish are able to concentrate uera in their bodies to maintain a high sokute concentration, thus matching the ocean’s high concentration of solutes.
Similarities between endocrine system and the nervous system.
signalling molecules are produced and released by particular cells, to signal to other cells. other cells respond to these signalling molecules and effect a change in cell functioning. they are both inextricable linked though the hypothalamus and pituitary gland.
Negative feedback loop for small volume of concentrated urine.
too much salt or sweating -> water content of the blood flow -> brain produces more ADH -> high volume of water reabsorbed by kidney -> urine output low -> water content of the blood normal
Negative feedback for large volume of dilute urine.
too much water drunk -> water content of the blood high -> brain produces less ADH -> low volume of water reabsobred by kidneys -> urine output high -> water content of the blood normal
Roots transport and transpiration lead to water loss.
roots have fine root hairs attached to them that have an extremely high surface-area-to-volume ratio. they can achieve high rates of osmosis and diffusion, as well as active transport of various substances.
How do land animals gain water and salt.
water and minerals enter the animal when it eats and drinks
How do land animals remove salt and water.
much water is lost in exhaled air. water evaporates from the skin. urine and faeces represents an important loss of both water and minerals.
How do salt water single cells gain and remove salt and water.
plasma membrane has solute pumps and adjusts sugars and proteeins in cells to control water movement.
How do freshwater signal cells gain and remove salt and water?
- pumps in plasma membrane accumulates solutes
- water diffuses in
- solutes diffuse out
- eukaryotes vacuoles physically carry water out.
How do salt water animals gain and lose salt and water?
- water and solutes are obtained in food
- salt pumps adjust solutes
- water diffuses in and out across gills
- water and solutes are lost in urine
How do freshwater animals gain and lose salt and water?
- water and some solutes enter in food
- water diffuses in through the gills
- gills pumps in solutes
- kidneys produce dilute urine
What are the problems vascular plants face?
water loss and transport happen simultaneously in vascular plants.
How to plants pull up water?
water is pulled from the roots through the xylem to the leaves due ot set of forces knwon as the transpiration pull. these forces include cohesion and adhesion
What is cohesion?
cohesion is the attracticve force that occurs between water molecules. as water evaporates from the leaves, columns of water are drawn up throuhh the xylgem vessels
What is adhesion?
adhesion is the attractive force operating between water molecules and the inner walls of the xylem vessels.
What is capillary action?
combine forces of cohesion and adhesion create capillary action. iyt is defined as the movement of water withni the spaces of pous material due to the two forces.
Why does water move in by osmosis?
as water continues to move up the column and is drawn from the root hairs (by the xylem and the water molecules it contains), this sets up a concentration gradient between the inside and outide of the root hairs, enablign water to move via osmosis.
What is root pressure?
in addition, active transport of salt ions into the roots cans cause osmotic water movement into the root hairs,balancing the salt concetnration inside and outside the root hairs. this movement of water into the root hairs causes root pressure.
What is the transpiration stream?
together, the forces of cohesion, adhesion, and root pressure produce a continuous flow of water from the roots to the leaves via the xylem. this continuous flow of water is known as the transpiration stream.
What is the importance of transpiration?
- transpiration supplies photosynthesis with the water it needs
- the evaporation of wter from the meosphyll cells in the leaves that accompanies transpiration requires energy and therefore cools the leaves in the saem way that sweating cools the skin of some mamals. heat energy is drawn out of the plant, into the water, then out into the external environment
- the transpiration stream is also necessary for distributing mineral salts throughout the plant.
How is a stomata opened and stimulated?
light stimulates opening of stomata. using active transport, potassium ions (K+) are purposely moved into guard cells, creating a concentraiton gradient. the gaurd cells then take up wate by osmosis and become turgid. because their inner walls are rigid, they are pulled apart, opening the pore. In darkness, water is lost, the guard cells become flaccid, and their inner walls move together, closing the pore.
Where does gas exchange occur in plants?
through the stomata
What is the effect of the factor of light on the rate of transpiration in plants?
an increase in sunlight leadd to an incrase in transportation due to warming the leaf and stimulating the open of stomata (actice transpoirt of ions tinto the guard cells can cause water to be absorbed via osmosis because of a concerntration gradient in the ions in solution); once the stomata are open, transpiration can start.
What is the effect of the factor of humidity on the rate of transpiration in plants?
a decrease in humidity leads to higher water vapour concentration gradient betwen the air at the surface of the leaf and the air outside the leaf. this increases diffusion of water vapour out of the lead and evaporation from the leaf surface, which leas to an increase in water loss from the plant (transpiration).
What is the effect of the factor of wind on the rate of transpiration in plants?
an increase in wind leads to an increase in the rate of evaporation, which leads to an increase in the rate of transpiration, because humid air near the stomata is being carried away, increasing the water vapour concentration gradient between the air at the surface of the leaf and the air outside the leaf.
What is the effect of the factor of temperature on the rate of transpiration in plants?
an increase in the temperature (due to heat eneggy being receive from the sun) increases the evaporation rate from the surface of the leaf, because of an increase in water vapour concentration gradient between the air at the surface of the leaf and the air outside the leaf. this leads to an increases rate of water loss from the plant (transpiration rate)
What are the mechanisms of osmoregulation in plants?
transport and transpiration
Define transport.
describes the movement of water and minerals in the xylem up the stem to the leaves, and solutes in the phloem.
Define transpiration.
transpiration stream describes the pull of water from the roots to the leaves due to cohesion, adhesion, and root pressure. transpiration is the loss of water from the leaves.
What is turgor?
turgor is a force that results from the water pressure inside plant cells and it is maintained by osmosis.
What happens as ammonia -> urea -> uric acid.
left to right = more water needed to excrete
right to left = more energy needed to produce
Do osmoregulators have a tight control of osmolarity?
Osmoregulators have tight control of the osmolarity of their body fluids, thanks to osmoregulation.
What is isn’t measured by osmoregulators?
Osmoregulators infer the amount of water in the body by measuring blood volume, blood pressure and sodium concentration. Water is not measured directly.
A mammal regulates its water and salt balance. Is this an example of homeostasis? Give reasons for your answer.
Yes, this is an example of homeostasis. Homeostasis is the maintenance of a relatively constant internal environment. Mammals maintain a relatively constant salt-water balance despite fluctuations in the external environment. They do this by using osmoregulatory mechanisms to maintain a constant internal salt-water balance.
Explain the process of osmoregulation in humans.
Receptors
The water balance of the blood is constantly monitored by specialised sensory neurons in the hypothalamus known as osmoreceptors. These monitor blood volume and pressure, as well as sodium concentration. These features reflect the body’s water balance in slightly different ways:
Increased blood volume would suggest water levels are increased, since blood has a high water content.
This increased blood volume results in increased blood pressure.
As for sodium concentration, sodium ions are found dissolved in the water in the blood. By measuring sodium concentration the body can make an estimate of the amount of water.
Control centre
Once receptors detect a change in any of these parameters, they will send a signal to the “control centre”. In humans this is the hypothalamus, and it interprets information from the receptors.
Effectors
The hypothalamus coordinates both a physiological and behavioural response to combat excessive or insufficient water levels in the blood. In terms of a negative feedback loop, this means it will activate an effector, mainly the kidney, in order to achieve a response that cancels out the original change in water levels.
Marine bony fish excrete only a small volume of urine. Explain why.
Marine body fish typically inhabit oceans, where salt concentrations are higher than the fish’s internal environment. Because fish are osmoconformers, they lose water to the external environment by osmosis. However, fish still need water in order for their cells to function. To minimise water loss, fish produce small amounts of concentrated urine.
Describe ONE mechanism by which plants maintain internal water homeostasis.
Plants can control the movement of water out of the leaf to keep a stable internal environment with respect to water by altering the size of their stomata. The opening and closing is under hormonal control. For example, abscisic acid is a stress hormone produced by plants when internal water is low, causing stomata to close thus reducing water loss.
