BIOM 3200 Lecture 2: BIOM*3200 Part 2

• School: University of Guelph
• Department: Biomedical Sciences
• Course: BIOM 3200
• Professor: Alastair Summerlee

Document Summary

Spermatogenesis interstitial cells- hormone testosterone seminiferous tubule- sperm production stem cells- spermatogonia located outer region sitting in the basement of the membrane mature move toward lumen: spermatogonia (diploid) divide. Species differences ejaculate- volume, density accessory sex glands- number, size erection- 2 types of penis length of intromission. Fertilization series of events beginning with the spermatozoa penetrating the corona radiata (outside layer of egg) and ending with the intermingling of maternal and paternal chromosomes after the spermatozoon enters the egg. Arterioles vasodilate- nitric oxide- increases blood flow in. Vein contracts- reduces blood flow out increases pressure in corpora cavernosa (500mmhg) Nervous control (parasympathetic: no acts on vsmc activates gtp (guanylate cyclase), producing cgmp, cgmp causes ca2+ channels in vsmc to close- cytoplasmic [ca2+] decreases, vsmc relaxes, causing vasodilation of penis and engorgement of the erectile tissue (promotes erection) Viagra inhibits phosphodiesterase that catalyzes breakdown of cgmp increases availability of cgmp promotes erection.