Theme 4 - Dr. Robinson Flashcards
What is homeostasis and what is it’s significance?
The same, standing or stopping. The significance is to maintain a steady internal environment.
Biochemical reactions are sensitive to changes in temp, pH, [solute], water, and pressure.
(Internal/external) cells are protected by fluids in homeostasis
Internal cells
What does extracellular fluid do?
Connects all cells to the external environment
What are the 7 factors of the internal environment that are homeostatically regulated.
- Temperature
- [water and NaCl] (cell volume)
- Vol and pressure of blood vessels
- [ ] of waste chemicals
- [O2 and CO2]
- pH
- Nutrient [ ] for NRG production by cells
What are the 4 homeostasis topics and their definitions
- Osmoregulation (regulation of internal osmotic (water/salt/waste) environment
- Circulation (bulk flow of fluid within the body (water, solutes, nutrients, gases)
- Gas Exchange (exchange w/ environment)
- pH regulation (controlling the [proton H+] of body fluids
What does bulk transport use in osmoregulation?
Hydrostatic pressure
In osmoregulation, how is diffusion specified?
Fick’s Law
Diffusion Rate = D A dC / dX
Why is osmosis important to animal cells?
Cells will shrink or swell if not maintained isosmotic
Why is osmosis important to plant cells?
Cells will develop turgor pressure as water enters, which limits further influx of water
What are osmoconformer strategies?
Adjust osmotic strength of cells [Y] and extracellular fluid [X] to match environment [Z]
Marine inverts, hagfish, elasmosbranchs
What are osmoregulator strategies?
Adjust osmotic strength of extracellular fluid [x] to match cells [Y] and protect the internal environment from the external [Z]
Freshwater inverts and most vertebrates
What is hyper osmotic? What type of environment is hyper osmotic?
- Lose water to and gain self from the environment
- Eliminate salt and consume, produce, conserve water
- Limit salt intake
(Marine environments)
What is hyposomotic? What type of environment is hyposmotic?
- Gain water from and lose salt to the environment
- Eliminate water and consume/conserve salt
- Limit water intake
(Freshwater environments)
What is excretion?
Elimination of waste/toxins, aids in controlling content of extracellular fluid (salt/water/pH)
What are the 3 steps of excretion as a mechanism for osmoregulation?
- Filtration (non-selective)
- Secretion (selective)
- Reabsorption (selective)
How do aquatic organisms excrete ammonia? (NH3)
- Diffusion into the environment (across body/gills)
- Excretion in filtrate/urine
- Ammonium (NH4) / sodium exchangers
How do Terrestrial organisms excrete ammonia (NH3)?
- Cannot use diffusion or ion exchange
- Only excretion in filtrate
- Produce urea
- Produce uric acid (animals that develop in eggs)
What are osmoregulatory challenge adaptations for migratory salmon?
Fresh water -> Marine -> Fresh water
- Ion exchangers on gills
-Kidneys
What are osmoregulatory challenge adaptations for Marine Mammals?
No access to fresh water
- No gills
- lose little water by evaporation
- Gain by eating food and metabolic water
Why circulate fluids?
Processing of pH, osmolarity, waste, nutrients, and gas exchange.
Transportation of hormones, heat, gases, nutrients, immune components, solute
Why do smaller organisms not need circulatory systems?
Diffusion is adequate for small organisms. Larger animals need circulation.
What is an open circulatory system?
Open system has no distinction between hemolymph and interstitial fluid
What is a closed circulatory system?
Closed system has blood separated from interstitial fluid.
What are the 5 points of circulation in animals?
- Heterotrophs with digestive system
- High metabolic rates demand rapid circulation
- Flexible tubes
- Cardiovascular system is a muscular pump and vessels
- Can be open or closed
