Physiology - Renal Topic #7 and #8

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
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
Micturition Reflex
- stretch receptors in bladder synapse in spinal cord
- excite:
- inhibit:
- RESULT:
Incontinence
- inability to prevent urine discharge
- result of
- motor neuron pathway to external sphincter can be disrupted
- voluntary pathways are under developed in infants
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
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:
ECF Potassium Balance (non-renal influences)
- acid/base balance
- Insulin

Author

9spr

70622

Card Set

Physiology - Renal Topic #7 and #8

Description

Topic #7 - Micturition (Urination)----Topic #8 - Potassium Balance

Updated

2011-03-05T06:00:53Z

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