BIO270H1 Lecture Notes - Urination, Natriuresis, Aldosterone
Document Summary
Environment can be external for animal for cell or for enzymes. Interstitial fluid: of ecf bathing a cell body. Osmotic regulation: movement of solutes; driving force for movement of water: hydrostatic forces between plasma and interstitial. Osmoregulators: constant osmolarity regardless of external environment. Perturbing: disrupts function of enzymes; na+, k+,so4+, cl- Polyols (glucose and glycerol) and uncharged amino acides. Osmotic stresses: swelling of structure, metabolite concentration affected, deformation of cytoskeleton. Animals regulate ecf composition to maintain volume. Traps water layer thus reducing cost of osmoregulation. Cornified stratum cornam: keratin modified with kipids. Asymmetrical distribution of membrane transporters: selective and directional. Transporters: na+/k+ atpase, ion channels, electroneutral cotransporters, electroneutral exchanger. Mitochondria rich: chloride cells (mitochondria-rich, pavement cells (a subset of which are mitochondria-rich) Anadromous: saltwater fish migrate to fresh (salmon) Upregulation of transporters : reverse nacl transport, more na+k+atpase. Large amount of salt in a little water: Vasolactive intestinal peptide (vip): chlorine out of apical, (-) gradient, na+ moves.
