Anatomy of the bladder, urethra and internal gonads_ part 1.pdf

05/01/24 Anatomy of the bladder, urethra and internal gonads: part 1 Learning objective: describe the anatomy of the bladder and process of micturition. Learning objective: describe the anatomy of the female urethra, and its anatomical relations. Learning objective: describe the anatomy of the prost...

05/01/24 Anatomy of the bladder, urethra and internal gonads: part 1 Learning objective: describe the anatomy of the bladder and process of micturition. Learning objective: describe the anatomy of the female urethra, and its anatomical relations. Learning objective: describe the anatomy of the prostate and the male urethra. Learning objective: describe the anatomy of the ovaries, uterus, cervix and vagina – including some basic embryology. The urinary bladder: Found in the anterior pelvic cavity. Surfaces: Superior surface ( covered in peritoneum ). Posterior surface ( base ). 2x inferolateral surfaces. Apex ( connected to umbilicus ). Internal anatomy: Majority of the internal bladder is lined with detrusor muscle. This is involuntary smooth muscle with interlaced bres. The movement of these is controlled by the parasympathetic ner vous system. Except for the trigone, this is the space bet ween three openings. It doesn’t expand/shrink when the bladder lls/empties. Urethra sphincters: Internal sphincter is made of smooth muscle which is involuntary. Controlled by the ANS- sympathetic stimulation by the hypogastric ner ves keep it closed. External sphincter is made of skeletal muscle and is voluntary. Somatic control by the pudendal nerve. Micturition: 1. Bladder feels slowly with urine. No change in pressure because of elastic walls and inhibition of parasympathetic activity until threshold. This inhibition means the walls won’t contract. 2. Urethral sphincters relax. Internal does so via the parasympathetic activity and the external is doing so via somatic activity. 3. Detrusor muscle will contract via parasympathetic bres which originate from pelvic splanchnic ner ves ( S2-S4 ). 4. Bladder is emptied into urethra. Bladder fills urethral with urine Sphincters Dettusor relax muscles contract Bladder empties into urethra Micturition is controlled by higher brain centres through a spinal re ex: Parasympathetic ner ves originate from S2-S4. Travel to bladder in pelvic splanchnic nerves. The ganglia are closer to the target muscle ( parasympathetic neurones have a short post-ganglionic neurone ). Sympathetic ner ves originate from L1-L2. Travel via hypogastric plexuses. Somatic nerves originate from S2-S4. Travel via the pudendal nerve.