Biosci Midterm Review

Biosci Midterm Review - Midterm Review Chapter 1: Intro. to...

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Midterm Review Chapter 1: Intro. to Sexual Reproduction - Parthenogenesis: eggs of certain species can be fertilized without the presence of sperm - Sperm remain viable for 2 days; eggs for 1-3 days Chapter 2: Male Reproductive System - Testes produce sperm and androgens (testosterone) - Testes descend from body cavity through the inguinal canal - Scrotum moves testes closer and father away from the body to regulate temperature - Testes -> compartments -> seminiferous tubules -> spermatagonia o Spermatagonia (sperm cells) o Sertoli (nurse cells) o Interstitial cells reside outside of tubules and produce testosterone - Sperm: tubules -> epididymis -> vas deferens -> ejaculatory duct -> urethra - Accessory glands add fluids to semen: o Seminal vesicle (adds mobility) o Prostate gland (nutrients/makes sperm less acidic) o Cowper’s gland (expels old sperm before ejaculation [“love drops”]/ makes sperm less acidic) - Semen contains 2-7 hundred million sperm - Tumescence (erection): o Arteries dilate -> blood fills spongy erectile bodies -> dilated arteries block veins so that blood can’t escape - Sperm: o Head- genetic info. o Tail- mobility (via flagellum) o Middle- energy to move (via mitochondria) o Acrosome- “penetrator” Chapter 3: Hormonal Control of the Male Reproductive System - Hormones: o Males- FSH (sperm production), ICSH (testosterone production) o Females- FSH (egg production), LH (estrogen production), Prolactin (increases milk production/prevents ovulation) - Activation (@ puberty): o Gonadotrophin Releasing Factor (GnRF) released from hypothalamus to pituitary gland o Causes pituitary to release FSH and ICSH o FSH targets seminiferous tubules; ICSH targets interstitial cells o Production of testosterone stimulates further production of GnRF Also induces accessory glands to produce fluids - Feedback: o Overproduction of testosterone sends a signal to stop production of ICSH
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o When testosterone breaks down and is expelled from the body, another signal re-starts production of ICSH o Because estrogen is similar in structure to testosterone, it may trigger feedback in too much is injected, resulting in an underproduction of testosterone, and causing female secondary sex characteristics to appear The same holds true for steroids, which inject a “fake” form of testosterone Chapter 4: The Female Reproductive System - The ovary stores/releases eggs and produces androgens (estrogen) - Pre-egg cell= oocyte o Follicle cells provide an outer shell for the oocyte Oocyte is fed nutrients by nurse cells within the follicle Oocyte is surrounded by a clear envelope that holds it together as it divides o At 2 weeks the follicle ruptures and releases oocyte along with one polar body o The follicle becomes the corpus luteum, and eventually degenerates into the corpus albicons - Oviduct is lined with cilia to help transport the oocyte
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This note was uploaded on 05/01/2008 for the course BIO SCI 75 taught by Professor Sander during the Winter '07 term at UC Irvine.

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Biosci Midterm Review - Midterm Review Chapter 1: Intro. to...

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