L2 and 3- Homeostasis and Regulation Flashcards
4 cellular functions
- Self-organization
-obtaining nrg and raw materials, eliminating waste,
making proteins, etc. - Self-regulation
-maintaining self-integrity in the face of disturbances - Support and movement
-cell contains structures that give it form, cell moves
materials, cell moves through environment. - Self-replication
-Reproducing to repair damage and carry on species
The process of correcting deviation in internal conditions, which threaten other functions is called
homeostasis
Who is the father of modern physiology?
Claude Bernard
Define homeostasis
the dynamic steady state in which the changes that do occur are minimized by compensatory physiological processes.
Animals keep their internal environment around some optimal level within a narrow limit by carefully regulating mechanisms.
How do cels which do not have contact with external environment get what they need?
Via extracellular fluid.
Membrane of cells exchange material between ECF and ICF
ECF is made up of 2 components:
Blood plasma + interstitial fluid
Central theme of homeostasis
Cells make up body systems. Body systems maintain homeostasis. Homeostasis is essential for the survival of cells (it’s a cycle).
Factors of the internal environment that are homeostatically regulated:
- Concentrations of:
a. nrg rich molecules
b. O2 and CO2
c. waste products
d. pH
e. Water, salt, and other electrolytes - Some animals also regulate:
a. volume and pressure
b. temperature
c. Social parameters (ex: termites)
Climate change, predators, acute disease/injury are all examples of….
ways in which homeostasis can be disrupted
What happens to the mean recovery time of fish the longer they are exposed to air?
It increases.
Takes longer for fish to re-achieve homeostasis the longer they’re out of water.
Air exposure disrupts homeostasis, ESPECIALLY AT WARMER TEMPS.
Mortality increases with higher air exposure time.
2 main strategies to maintain homeostasis:
- Regulators
- Conformers
also (but not a main strategy): 3. avoiders
What do regulators do to maintain homeostasis?
Use internal mechanisms to define a constant state (ex: monkeys)
What do conformers do to maintain homeostasis
Internal state varies with that of the environment (ex: snail)
What do avoiders do to maintain homeostasis
minimize internal variation by avoiding environmental disturbances (ex: monarch butterflies)
Define enantiostasis
Organism can maintain its normal function despite outside environment changing, but does it whilst NOT maintaining homeostasis (ex: animals that dwell in tidal zones)
T/F The blue crab maintains internal homeostasis
False. The blue crab maintains ENANTIOSTASIS.
At LOW environmental salt, oxygen binding is inhibited. Therefore the crab increases ammonia concentration, which makes inner fluid LESS ACIDIC and increases oxygen binding.
Thus, crab gets needed O2, but changes internal conditions.
Using a drawing, describe how cells obtain/excrete material
Ex:
Draw lungs, blood plasma, interstitial fluid, and cells
O2 from lungs to blood, to interstitial fluid, to cells, CO2 from cells to interstitial fluid, to blood, to lungs.
Or:
Gastrointestinal tract sends nutrients to blood, to interstitial fluid, to cells. Cells exchange H2O and ions with gastrointestinal tract.
The primary way animals regulate their internal environment is through ______ _______
Negative feedback
Define negative feedback
A change in a controlled variable triggers a response that opposes the change, driving the variable in the opposite direction of the initial change.
What do control systems regulate?
a “controlled variable”