homeostasis

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Created by
Amber Lamba

Cards (11)

  • Effects of adrenaline on liver cells
    1. Receptor shape change
    2. G-proteins activated
    3. Adenylyl cyclase activated
    4. Cyclic AMP made
    5. Cyclic AMP is second messenger
    6. Activates/phosphorylates kinase
    7. Enzyme cascade/cascade of reactions
    8. Glycogenolysis/hydrolysis of glycogen stimulated
    9. Gluconeogenesis/glucose transport proteins
    1. proteins
    Subunit released
  • Glycogenolysis
    Break down glycogen
  • Gluconeogenesis
    Glucose from amino acids/lipids
  • Action of ADH on kidney
    1. Hypothalamus detects changes in water potential
    2. Osmoreceptors shrink when less water in blood
    3. ADH produced in hypothalamus
    4. ADH secreted from posterior pituitary
    5. Neurosecretory cells/ADH transported from hypothalamus to posterior pituitary
    6. Aquaporins
    7. ADH increases permeability of distal convoluted tubule/collecting duct
    8. ADH causes more water reabsorption/smaller volume of urine/more concentrated urine
  • Adaptation of PCT cells for selective reabsorption
    • Microvilli
    • Many mitochondria
    • Tight junctions
    • Folded basal membrane
    • Many transport proteins/cotransporters/pumps
    • Aquaporins
    • More ER for increased protein synthesis
  • Negative Feedback mechanism

    1. Change in factor away from the norm/set-point
    2. Detected/sensed by receptor
    3. Hormone released or (nerve) impulse sent
    4. (Hormone/impulse) reaches target organ/effector
    5. (Effector) performs corrective action
    6. (Factor) returns to norm/set-point
  • Reabsorption of glucose

    1. Active transport/pumping of Na+ out of cells into blood/tissue fluid
    2. Sodium (potassium) pumps in basal membrane
    3. Na concentration decreases inside cells/Na* concentration gradient set up
    4. Na+ enters epithelial/tubule cells from lumen/filtrate by facilitated diffusion
    5. Na+ co-transports glucose into cell
    6. This is secondary/indirect active transport
    7. Facilitated diffusion of glucose out of cells into blood
    8. GLUT proteins
  • Roles of ABA in stomata closure
    1. ABA binds to receptors on cell surface membrane (of guard cell)
    2. Proton pumps are inhibited
    3. Stimulates Ca2+ uptake/opens Ca2+ channels
    4. Ca2+ acts as second messenger
    5. K+ diffuses out of the (guard) cell
    6. Water potential of (guard) cell increases
    7. Water leaves (guard) cell by osmosis/down water potential gradient
    8. (Guard) cell becomes flaccid/cell volume decreases (so stoma closes)
  • Mechanism by which guard cells open stomata
    1. H carrier/pump (protein) in cell surface membrane (of guard cell)
    2. Hydrogen ions/protons/H ions/H* leave/exit cell
    3. Using energy/ATP
    4. Low H* (in cell)/more negative charge (than outside)
    5. K* channel (proteins) open
    6. K* move into/enter cell (by facilitated diffusion)
    7. Cl-ions move into/enter (cell)
    8. Water/solute potential of cell decreases
    9. Water moves in (to cell) by osmosis
    10. Cell/vacuole volume increases
    11. Cells are/become turgid
    12. Thick inner cell wall (of guard cell)
  • Ultrafiltration
    • Afferent arteriole (lumen) wider/has larger diameter than efferent
    • Causes high blood/hydrostatic pressure in glomerulus/capillaries
    • Pores/gaps/fenestrations in capillary endothelium
    • Basement membrane acts as a filter
    • Detail of podocytes
    • Passage of substances (e.g. basement membrane stops blood cells/large proteins/molecules above RMM 68 000-70 000 or allows urea/glucose/amino acids/ions/water)
    • Network of capillaries