Theme 4 Part 1 Flashcards
What is the purpose of homeostasis
To maintain a steady internal environment in a specific narrow range
Then environment shapes the temp ph concentration of solutes, of the animist which also effects the metabolism
How do cells protect from the external environment
The cells have an external layer facing the environment , this layer is full of dead cells to protect the organism
And the internal layer has the external facing cells that can’t die. These are what is being protected and is protecting the rest of the body from the external environment (through secretions
The internal cells are protected though homeostasis (bathed in extracellular fluids like blood plasma or interstitial fluid)
What do extracellular fluids do
They connect the all the internal cells in the body to the external environment.
So wherever the cell is it can exchange info and get what they need from the external environment
What is negative feedback
A way of regulation of homeostasis
A set point and when external environment changes it make signals to go back to the set point
Change is detected by receptor (sensor cells) then sends the info of the change to the integrator through a sensory pathway (afferent)
The integrator determines if action is needed. The info is sent to the effectors (efferent pathway)
Then effectors bring back conditions to regular level
What are the factors of the internal environment of animals that are homeostaticslly regulated
Temp
Concentration of water and nacl in cells (cell volume)
Volume and pressure of blood vessels
Concentration of waste and chemicals
Concentration of O2 and CO2
pH
Nutrient concentration for energy production by the cells
What is osmoregulation
Regulation of the internal osmotic (water/salt/waste) environment in cells
What is bulk flow
Movement of fluid though out the body
If you have higher solute concentration on the inside which way does the water move
What happens after this?
To higher solute concentration side
So the side that water moves to has higher pressure and lower water potential (energy needed to move water across)
What plays a role in water portential
Osmosis, hydrostatic, gravity, humidity.
The side with more solute (that water moves into,has higher pressure) is
The side with less solute (that water moves out of, lower pressure) is
Is same amount on either side (same pressure and solute)
Hyperosmotic
Hypoosmotic
Isoosmotic
If cells are not kept isoosmotic they
Shrink or swell
Is water enters into plant cells what happens
They get turgor pressure from the influx of water which limits the further influx of water
Animal cells don’t do this
What is an osmoconformer homeostasis strategy
What is it found in
Adjusts the osmotic strength of cells to match strength of extracellular fluid and also match the environment
Y=x=z
Marine inverts, hagfish,elasmobranchs
What is an osmoregulatir homeostasis strategy
What is it found in
Change the osmotic strength of extracellular fluid to match the cells and protect from the changed external environment
In freshwater invertebrates , most vertebrates
External does not equal internal
Y=x not equal z
Can organism be isoosmotic in freshwater
No
What type of transport is water doing
What types of transport is ion and other solutes doing
Passive
Active
What are the challenges of terrestrial animal water loss and gain
Water loss for terrestrial animals, dessication
Because they have higher water and salt concentration internal than the external environment.
What are the challenges of marine (salt water) animal water loss and gain
Water loss
They have more salt concentration (solute) outside their body than inside (the water is salty) so the external environment is hyperosmotic
This means water from body travels out to the higher salt (solute area)
And salt tries to travel in
What are the challenges of freshwater (non salt) animal water loss and gain
Water gains
More solute (salt) on inside of body than outside. water travels in and salt tries to leave. so environment is hypoosmotic
If fish in hyperosmotic (saltwater) environment what does it do
Hyper so more solutes on outside (more osmolarity) than inside
Water leaves so water loss is and issue
To compensate for water loss it drinks more water. It produces less urine to conserve water
Gain salt by diffusion through gills into tissues, but then they pump the ions out
If teleost (fish) in hypoosmotic environment what does it do
Compensating for water gains so they make a large volume of dilute urine
Gain salt through food or salt is actively pumped in through the gills
Since they’re gaining water and losing salt to the environment
What do birds do to excrete salt
They have salt glands that lead to the nostrils and the beak
The glands concentrate salt from the food they eat and push it out through the nose
Terrestrial environments are
Dry
So they lose water to the environment
To combat this they limit salt intake and consume water
How does excretion help in osmoregulation
Eliminate waste/toxins which helps in controlling/mainting the content of extracellular fluid (salt, water, ph)
