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Sunday, October 9, 2011

Reproductive Systems! ...from 10/5

I'm skipping over the sheep breeds lecture notes...

Male Reproductive System
GnRH Gonadotropin-releasing hormone (GnRH), also known as Luteinizing-hormone-releasing hormone (LHRH) and luliberin, is a tropic peptide hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is synthesized and released from neurons within the hypothalamus. The peptide belongs to gonadotropin-releasing hormone family.


starts in the hypothalamus, goes to pituitary gland and releases FSH and LH.


Luteinizing hormone (LH, also known as lutropin[1]) is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation[2] and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone (ICSH),[3] it stimulates Leydig cell production of testosterone.[4] It acts synergistically with FSH.


Follicle-stimulating hormone (FSH) is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH andLuteinizing hormone (LH) act synergistically in reproduction.



Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles,[1]birds,[2] and other vertebrates. In mammals, testosterone is primarily secreted in the testes ofmales and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid.
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In men, testosterone plays a key role in the development of male reproductive tissues such as thetestis and prostate as well as promoting secondary sexual characteristics such as increasedmusclebone mass and the growth of body-hair.[3] In addition, testosterone is essential for health and well-being[4] as well as the prevention of osteoporosis.[5]
Testosterone is observed in most vertebrates. Fish make a slightly different form called 11-ketotestosterone.[7] Its counterpart in insects is ecdysone.[8] These ubiquitous steroids suggest that sex hormones have an ancient evolutionary history.[9]
Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone (LH). Leydig cells are polyhedral in shape, display a large prominent nucleus, an eosinophiliccytoplasm and numerous lipid-filled vesicles. They are responsible for sperm production, semifonius tubules, spermatogenia .

Testosterone Aids in muscle building and LIBIDO (sex drive)



Oxytocin is best known for its roles in female reproduction. It is released in large amounts 1) after distension of the cervix and uterus during labor, and 2) after stimulation of the nipples, facilitating birth and breastfeeding. Recent studies have begun to investigate oxytocin's role in various behaviors, including orgasm, social recognition, pair bondinganxiety, and maternal behaviors.[2] For this reason, it is sometimes referred to as the "love hormone".[3]


oxytocin causes contractions in smooth muscle in the scrotum, causing ejaculation.


Epidymis - where the sperm matures, takes 45-50 days, 7 days in the epidymis


Vas deferens - transports sperm from testes during ejaculation, connects to urethra


ACCESSORY SEX ORGANS
Seminal Vesical
prostate gland
bulbourethral (Cowpers) gland


functions of ASO
Add fluid volume, nutrients, and alkaline buffers to semen
sperm plus ASO fluid = SEMEN


Carrier proteins - Albumin - protects the sperm


Anti-biotics are put into semen extenders to protect the sperm, cows, and offspring from common breeding diseases like Leptospirosis 


PENIS
the bulls penis is fibroelastic, and is a sigmoid flexure type (S shaped) it extends upon erection , allowing forextension. found in boars, bulls, and rams.
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ejaculation
Bulls - 5ml - 1.1billion per ml. - low volume, high concentration

the head of the sperm carries genetic info
Aerosome, contacts egg and releases chemicals to dissolve the jelly coat around egg.
The tail pushes the sperm into the egg. it does NOT "swim all the way there"

Bulls reach sexual maturity at 12 months or a 26cm Scrotal Circumference



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