BIOL 3324 Lecture Notes - Lecture 20: Detrusor Urinae Muscle, Ascending Limb Of Loop Of Henle, Urination
17 Nov 2016
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Plasma clearance= plasma volume cleared of substance/minute. Subs is filtered but not reabsorbed or secreted: plasma clearance rate= gfr. Subs filtered and reabsorbed, not secreted: plasma clearance < gfr. Subs filtered and secreted but not reabsorbed: plasma clearance > gfr. Urinary bladder= stores urine before excretion: mucosa= epithelial lining. Vesicles that can add plasma membrane to increase surface area: muscularis 3 muscles= detrusor. Allows bladder to fill without causing tension. Parasympathetic expulsion of urine through contraction: always has like a funnel shape, fills bottom upward, sphincters regulate urine flow. Constantly send signal to keep it contract. To release urine you need to relax the muscle. Urethra: female= only for urine expulsion, male= for urine and semen. Storage reflex: during bladder filling, sympathetic activity relax detrusor muscles. Contraction of internal sphincter: somatic stimulation. Micturition reflex= release of urine: when urine reaches 200-300 ml, baroreceptor send signal to micturition center in pons.
