PNB 2275 Study Guide - Gynecomastia, Webbed Neck, Hypothyroidism
Document Summary
Humans have 23 pairs of chromosomes: 22 pairs of autosomes, x and y= 1 pair of sex chromosomes, karyotype (46. Turner syndrome (45, xo) sexual infantilism: ovarian failure (infertility, short stature, webbed neck, low posterior hairline, shield like chest, cardiovascular malformations, hypothyroidism. Infertility due to hypogonadism sparse or absent, facial, axillary, pubic, or body hair: decreased muscle mass and strength, feminine distribution of adipose tissue, gynecomastia ( enlargement of male breasts) small testis and penis. In mammals, the development of the medulla into the testis is thought to be directed by a single testis determining factor (tdf) gene present on the y chromosome: sry gene= sex determining region of the y chromosome. Genetic determination of sex in humans: female= xx eggs, male= xy sperm, get one from each parent. At six weeks of development the internal reproductive organs have the potential to develop into male or female structures. Development into male or female internal structures is based on hormonal influences.
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