Chapter 4 (Ion and Water Balance) Flashcards
What are conformers and what is the difference between ionoconformers and osmoconformers?
- conformers: internal conditions similar to external; will change internal according to external
- ionoconfomers have same ion concentration in ECF as external environment
- osmoconformers have same osmolarity in ECF as external
What are regulators and what is the difference between ionoregulators and osmoregulators?
- regulators: maintain fairly stable internal conditions no matter the external environment
- ionoregulators: use absorption and excretion methods to control ion levels in ECF
- osmoregulators: maintain internal osmolarity
euryhaline vs stenohaline animals
- euryhaline animals can tolerate a wide range of salt conditions
- stenohaline animals can tolerate only a narrow range of salt conditions
concerns and mail goals of freshwater vs saltwater vs terrestrial animals
- freshwater: animal is hyperosmotic to the environment so they risk losing too many ions and gaining too much water; they want to get rid of water and keep ions
- saltwater: animal is hypoosmotic to the environment so they risk losing too much water and gaining too many ions; they want to keep water and lose ions
- terrestrial: risk extreme dryness, want to conserve water
molarity vs osmolarity
- molarity: concentration of one ion
- osmolarity: collective concentration of all ions
corneocytes
- differentiated from keratinocytes
- form a waterproof layer in the epithelium of terrestrial animals to help conserve water
osmosis
movement of water through a semipermeable membrane
How does temperature affect membrane permeability?
- higher temperature = more fluid membrane = greater permeability
- colder temperature = more rigid = less movement of solutes through membrane = less permeability
epithelial vs. endothelial cells
- epithelial cells separate inside and outside environments
- endothelial cells are specialized epithelial cells that line blood vessels
Describe the membrane transport method of passive diffusion.
- lipid soluble solutes can move freely across membrane
- no carrier required
- along concentration gradient
Describe the membrane transport method of facilitated diffusion.
- protein carriers transport impermeable solutes across membrane
- transporters called channels and permeases (molecule binding causes conformational change that lets solute in)
- involves integral membrane proteins
Describe the membrane transport method of active transport.
- moves molecules against a concentration gradient
- uses energy
- primary active transporters and secondary active transporters
primary active transporters vs. secondary active transporters
- primary active transporters involve ATP hydrolysis as source of energy
- secondary active transporters use the energy associated with the electrochemical gradient of one molecule to drive the transport of another molecule
Describe the two types of ion pumping cells of freshwater gills. (PNA- and PNA+)
- PNA- (acid secreting cells) import Na+ from water against the gradiant; acidic environment is created by cell membrane for Na+/H+ exchanger to work; H+ comes from CO2
- PNA+ (base secreting cells) import Ca2+ and Cl- via a Cl-/HCO3- exchanger that also depends on amount of CO2 available
Describe the ion pumping cells of marine/saltwater fish gills.
- produce a net export of Na+/Cl-
- Cl- and some Na+ enters gill cell from blood via Na+/K+ pump and Na+/K+/2Cl- co transporter
- Cl- allow exit of Cl- into water
- negative outside charge may drive Na+ to escape to water through paracellular channels
