ANS 2: Week 2 Notes
ANS 2: Week 2 Notes ANS 002
Popular in Introductory Animal Science
Popular in Animal Science and Zoology
This 7 page Class Notes was uploaded by Mackenzie Hayes on Sunday April 10, 2016. The Class Notes belongs to ANS 002 at University of California - Davis taught by Dr. James Murray in Spring 2016. Since its upload, it has received 186 views. For similar materials see Introductory Animal Science in Animal Science and Zoology at University of California - Davis.
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Date Created: 04/10/16
Animal Science 2: Week 2 Notes 4/4: ● California livestockbased annual income: ($) ○ Milk + Cream ~ 9 billion ○ Cattle + Calves ~ 4 billion ○ Chicken + Eggs ~ 1.5 billion ○ Turkey ~ 230 million ○ Hogs + Pigs ~ 40 million ○ Aquaculture ~ 13 million ● ^ equals about $1.5 billion (8% total US GDP; 30% CA GDP) ● Immediate ancestors to domestic species arebiologically the same animals ○ Yet considered to be a ifferent species ○ i.e.: domestic dog = most morphologically diverse species on earth ○ Controlling traits of a species starts with understanding anatomy, hormones, and reproduction ● Reproductive Biology: ● Main Points to Know: ○ Male + Female anatomy ○ Spermatogenesis + oogenesis ○ Function of cells in testes + ovary ○ Hormones involved in reproduction ● Generalized Male Reproductive Anatomy: ○ Ductus deferens = vas deferens (transfers sperm to glands) ○ Bladder is the “landmark” but not part of reproductive system ○ Testis (produce sperm + testosterone) ■ Problematic to health if not descended ■ Housed inside the scrotum ○ Epididymis (site of male meiosis + where sperm mature) ■ Takes 6 weeks for sperm to fully develop ○ Glands: ampullary, vesicular, prostate, bulbourethral ■ Add components to seminal fluid ■ No ampullary gland in bulls ○ *be able to label diagrams of reproductive system* ● Castration: purposes ○ Sometimes for management (improve aggression) ○ Convenience (can’t impregnate females) ○ Production (will put on more fat / marbling) ● Testicular Anatomy: *needs rich blood supply* ○ Pampiniform plexus (cools + heats the blood entering and leaving) ○ Consists of billions of seminiferous tubules ■ Drain into larger ducts = epididymis to proceed to ejaculation 4/6: ● Testis: ○ Composed of seminiferous tubules + space ○ Bloodtestis barrier much like bloodbrain barrier ○ Sertoli Cel: nurses sperm cells through meiosis ○ Spermatogonial Cells go through meiosis ○ Spermatids: haploid cells produced from spermatogonial dividing ○ Leydig/Interstitial Ce: receives hormone from pituitary + produces testosterone ● Hormones of Male Reproduction: ○ *be able to replicate chart* ○ Negative feedback inhibits further production ○ Positive feedbac promotes more production (uncommon) ■ The product also acts as the “trigger” ● Spermatogenesis: *continuous while oogenesis is not* ○ Replicates DNA (2N, 2C → 4N, 4C) ○ Cell can then become 4 haploid sperm or duplicate itself ○ Crossing over occurs randomly in both sexes 4/8: ● Female Reproduction: ● The egg = the largest cell in the body / sperm = the smallest ○ Smooth outer egg membrane ○ Comes from ovary (site of oogenesis) ○ Moves to infundibulum (essentially covers the ovary + shuttles egg to oviduct) ○ Fertilization takes place in oviduct ● Most mammals have similar configuration ○ Shape of uterine horn + cervix will differ ● Reproductive Organs of Hens: ○ *NOT controlled by hormones* systematic, make an egg each day ○ Oviduct has many functional regions ■ Magnum puts albumen around yolk ■ Isthmus puts down shell membrane ■ Uterus “shell gland”, lays on calcified hard shell ○ Like other females, hens are still born with all the egg cells for their lifetime ■ Takes about 24 hours to produce an egg ○ Sperm is held in the infundibulum for later fertilization ● Oogenesis: ○ Estrous cycle lengths: ■ Cattle 21 days ■ Horse 2123 days ■ Pig 21 days ■ Goat 21 days ■ Sheep 1617 days ■ Mouse 45 days ○ Estrous types: ■ Monoestrous (dog) ■ Polyestrous (cattle) ■ Seasonally polyestrous (goat) ■ Reflex ovulator (cat) ■ Anestrous ● Hormones: ○ GnRH : released by hypothalamus to stimulate release of LH and FSH ○ FSH : female growth in ovary; male stimulates cells in testes ○ LH : female stimulates estrogen production + ovulation, male stimulates testosterone production in Leydig cells ● Cells of the Follicle: ○ Theca Cells: respond to LH to make androgens ○ Granulosa Cells: respond to FSH to produce estradiol ■ Essentially convert androgens into estrogen (estradiol) ○ Corpus Luteus: produce progesterone