Physiology 1020 Lecture Notes - Lecture 14: Secondary Sex Characteristic, Leydig Cell, Ejaculation

• School: Western University
• Department: Physiology
• Course: Physiology 1020
• Professor: John Bell

Document Summary

Each cell in the body has 23 pairs of chromosomes (46 total a set from. Combine during fertilization to produce diploid zygotes. This includes a pair of sex chromosomes mom and a set from dad: large x and small y. Eggs contain an x, sperm can carry either an x or a y. Sperm with an x that penetrates an egg= female (xx) Sperm with a y that penetrates an egg= male (xy) During the first 6 weeks of development, male and female embryos contain indifferent gonads. Gonads will eventually form testes or ovaries. There are also two sets of primitive reproductive tracts: wolffian duct or. Once the testes or ovaries have developed, the reproductive tracts and external genitalia will follow. In a developing male embryo, the presence of the y (sry/tdf) causes the indifferent gonads to develop into testes at 6-7 weeks. At 7 weeks, testicular cells produce mullerian inhibiting hormone (mih) which shrinks and regresses the mullerian duct.