Physiology - Renal Topic #7 and #8

  1. Micturition
    • from ureters, pulsatile contractions push urine into bladder
    • filling pressure helps close entrance to bladder
    • bladder made of thin layer of smooth muscle and epithelium
  2. urine exit from bladder prevented by:
    • internal urethral sphincter
    • smooth muscle (opens under passive pressure)
    • external urethral sphincter
    • skeletal muscle under voluntary control
    • tonic neural activity stimulates contration
    • don know what to do with below??
    • histology
    • effect of tonic neural activity from CNS on external sphincter
    • effect of sympathetics
  3. Micturition Reflex
    • stretch receptors in bladder synapse in spinal cord
    • excite:
    • inhibit:
    • RESULT:
  4. Incontinence
    • inability to prevent urine discharge
    • result of
    • motor neuron pathway to external sphincter can be disrupted
    • voluntary pathways are under developed in infants
  5. The Kidney and Potassium
    • most K+is reabsorbed in proximal tubule
    • K+can be either secreted or reabsorbed by distal tubule and collecting duct
    • H+/K+ATPase in distal nephron
    • effect: acidosis is often accompanied by hyper kalemia
  6. Control of Potassium Excretion
    • high K+stimulates aldosterone secretion
    • increases Na+/K+ATPase pumping
    • more K+exits into filtrate
    • potential problems:
    • if ECF volume is low:
    • if plasma K+is high:
  7. ECF Potassium Balance (non-renal influences)
    • acid/base balance
    • Insulin
Card Set
Physiology - Renal Topic #7 and #8
Topic #7 - Micturition (Urination)----Topic #8 - Potassium Balance