Module 4 PDF (Lecture 5 - sex hormones and menstrual cycle) copy.pdf

Module 4 PDF (Lecture 5 - sex hormones and menstrual cycle) copy.pdf

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Sex Hormones and the Menstrual Cycle
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Endocrine system The endocrine system is the name given to the body’s system of glands that controls hormone output into the bloodstream There are many, many hormones we will focus on ones involved in sex differentiation and reproduction (sex hormones)
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The main sex hormones Androgens Testosterone Produced in the gonads (gonads = testicles or ovaries) and adrenal cortex (sits on top of kidneys) Goes throughout the body and brain Masculinizes fetus in utero and at puberty, increases muscle mass, maintains libido 5-alpha-dihydro-testosterone (DHT) Produced in the external genitalia, prostate, skin Goes to external genitals, prostate gland, skin Develops and maintains male external genitalia and prostate, works on hair distributions
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Sex Hormones Estrogens Estrodiol Produced in gonads and adrenal glands Goes throughout the brain and body Feminizes body at puberty, works on menstrual cycle, increases bone density Progestins Progesterone Produced in ovaries, placenta, and adrenal glands Goes to the uterus Helps with menstrual cycle and pregnancy
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Sex Hormones - Proteins Releasing hormone Gonadotropin-releasing hormone (GnRH) Produced in brain (hypothalamus) Goes to the pituitary gland Causes release of gonadotropins
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Sex Hormones - Proteins Gonadotropins Follicle-stimulating hormone (FSH) Made in pituitary, goes to gonads Spermatogenesis or ovarian follicle maturation Luteinizing hormone (LH) Made in pituitary, goes to gonads Stimulates sex hormones secretion and ovulation Human chorionic gonadotropin (hCG) Made in the conceptus (an embryo) and goes to ovary Maintains the corpus luteum (part of ovarian follicle)
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Sex Hormones - Proteins Others Prolactin Made in pituitary, goes to breasts Prepares breast for lactation (men have prolactin too, hypo- or hyper- levels associated with sex functioning problems) Growth hormone Made in pituitary, goes throughout body Growth spurt at puberty Abnormal functioning causes problems (hypo —shorter, rounder faces, retention of “baby fat,” reduced bone strength
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  • Spring '14