Ch 44 %28doc%29 - Slide: 1 Chapter 44 - Osmoregulation...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Slide: 1 Slide: 2 Excretory system The organs and processes which regulate water level and ion concentrations (osmoregulation) and remove nitrogenous waste (excretion). Slide: 3 Balance of uptake and loss of water and solutes to regulate body fluid composition Uptake Ingestion of food Ingestion of water Cellular respiration (metabolism) Osmosis (freshwater animals) Loss Elimination Excretion Osmosis (saltwater animals) Evaporation across skin (terrestrial animals) Evaporation due to Respiration (terrestrial animals) Osmoregulation Slide: 4 Osmosis Differences in solute concentrations on 2 sides of a selectively permeable membrane result in movement of water from areas of lower concentration to higher concentration Selectively permeable membrane (SPM) prevents the movement of solutes via diffusion, so H 2 O must move instead Net water flow Hypoosmotic (hypotonic)to Hyperosmotic (hypertonic) Isoosmotic (isotonic) = No net water flow Hyperosmotic, hypoosmotic and isoosmotic are all comparisons of the 2 sides of the selectively permeable membrane i.e. The left side is hyperosmotic AS COMPARED TO the right side so H 2 O moves from right to left i.e. The left side has a > solute concentration AS COMPARED TO the right side so H 2 O moves from right to left i.e. The left side is isoosmotic AS COMPARED TO the right side so equal amounts of water move in both directions Figure 44.2 and 7.12 (Campbell 8th ed.) http://www.one-school.net/Malaysia/UniversityandCollege/SPM/revisioncard/biology/movementacrossmembrane/images/isotonicbloodcell.png Slide: 5 Osmoregulation Due to osmosis, water enters (freshwater) or leaves (saltwater) a fish. To compensate for H 2 O gains or losses it it regulates (+/-) Saltwater fish hypo tonic (compared to the H 2 O it’s swimming in) so loses H 2 O H 2 O loss due to osmosis (across gills and skin) Must gain H 2 O. Gets some from food but not enough so actively drinks But saltwater contains many ions (salt etc) so must excrete excess Excretes most in highly concentrated urine (i.e. solutes >> H 2 O) and rest actively (uses energy) pumped out across gill membranes. Freshwater fish hyper tonic (compared to the H 2 O it’s swimming in) so gains H 2 O H 2 O gain due to osmosis (across gills and skin)and some more in food Must lose H 2 O, so does NOT drink!, but instead excretes a lot of H 2 O in highly dilute (H 2 O >> solutes) urine. Also, loss of ions due to diffusion across gills Uptakes some ions in food and actively uptakes rest across gill membranes Figure 44.4 (Campbell 8th ed.)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Slide: 6 Osmoregulation in Fish Anadromous and catadromous fish must be able to adjust their physiology to deal with being hypo- and hypertonic at different times in their life. Anadromous
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Ch 44 %28doc%29 - Slide: 1 Chapter 44 - Osmoregulation...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online