Micturition and Reproductive System PDF

### Micturition - **Stimulus for urination:** stretching of detrusor muscle - **Bladder level reaches:** 200-400 ml causing stretching of detrusor muscle - **This generates:** impulse that go to the spinal cord - **Motor impulses:** are returned to the detrusor muscle to contract - **External ureth...

### Micturition - **Stimulus for urination:** stretching of detrusor muscle - **Bladder level reaches:** 200-400 ml causing stretching of detrusor muscle - **This generates:** impulse that go to the spinal cord - **Motor impulses:** are returned to the detrusor muscle to contract - **External urethral sphincter:** to relax - **Urine flows into:** urethra - **Bladder is emptied:** (voluntary control is not possible past a certain point) ### Characteristics of Urine - **Amount:** 1-21/24hours output - **Color:** yellow; concentrated is darker while dilute is lighter - **Specific gravity:** normal 1.010-1.025; measures dissolved materials in urine; indicator for concentrating ability - **pH:** 4.6-8.0; diet is a great influence on level - **Constituents:** made up of 95% water - **Nitrogenous wastes:** urea, creatinine, uric acid ### Reproductive System - **Continues the human species:** (production of gametes (sperm and egg cells) for fertilization during intercourse) ### Meiosis - **Produces:** gamete (sex cells) - **One cell with diploid (46) number of chromosomes divides twice resulting in:** - **4 functional cells (spermatocytes):** with a haploid (23) number of chromosomes for sperm - **1 functional cell:** with a haploid (23) number of chromosomes and 3 polar bodies for egg ### Male: - **Spermatogenesis** - **Sperm production** - **Sperm-3 parts:** - **Head:** contains 23 chromosomes; acrosome (coating of head that contains an enzyme that digests the membrane of the egg) - **Middle piece:** contains the mitochondria that produce ATP - **Flagella:** provides motility (needs ATP) - **Semen-consists of sperm and secretions from seminal vesicles, prostate gland, and bulbourethral glands** - **pH:** 7.4 - **2-4 ml expelled** - **Each ml contains 100 million sperm cells** - **Takes place in the testes** - **Spermatogonia (sperm-generating cells) are found in the seminiferous tubules and become sperm** - **FSH initiates sperm production** - **Testosterone (directed by LH) promotes maturation of sperm** - **Inhibin decreases secretion of FSH** - **Production begins at puberty (10-14 y/o)** - **Millions are formed each day, production decrease but never ceases** ### Testes