Male Reproductive System Flashcards
_________ is the process of acquiring reproductive competence
Puberty
How does feminization/defemnization occur at the brain?
In females, @FP binds E2 and prevents it from entering brain (no exposure to estradiol —> feminization)
In males, testosterone is able to enter brains and is converted to estradiol —> masculinization
What is the physiologic definition of puberty?
When specific nuclear are capable of releasing adequate quantities of GnRH to :
Cause gonadotropin release
Ultimately cause ovulation and spermatogenesis
Development of hypothalmic nuclei are dependent on what factors?
Threshold bodyweight **
Nutritional factors Environmental factors Social cues Photoperiod Genetics
What is the average age of puberty in bovine?
11months
Average age of puberty in equine
Male 14months
Female 1months
Average age of puberty in canine
6-12months
Breed and size effects
What is the average age of puberty in felines?
5-9months
Breed a photoperiod effects
What muscle is involved in raising and lower the testicles
Cremaster muscle
What type of penis does the stallion have?
Musculocavernosus
Mushroom shaped with slight protrusion of urethral process
No sigmoid flexure
What accessory glands are present in the stallion?
Vesicular glands
Ampullae
Prostate
Bulbourethral gland
What type of penis is in the bull?
Fibroelastic with sigmoid flexure
What accessory glands does the bull have?
Vesicular glands
Ampullae
Prostate
Bulbourethral gland
What type of penis does the boar have?
Fibroelastic with sigmoid flexure, corkscrew with a left hand thread
What accessory glands does the boar have?
Vesicular glands
Bulbourethral glands
Prostate
What type of penis does the male dog have?
Musculovascular
With os penis
Substantial glans penis which is divided into the bulbus glandis (proximally) and the pars longa glandis (distally)
What accessory glands does the male dog have?
Prostate
Where do the 3 fractions of ejaculate come from the in the dog?
Prostate
Tail of epididymis
Prostate
What type of penis does the tom have?
Musculovascular
With penile spines (keratinzied papillae)
What accessory glands does the tomcat have?
Prostate
Bulbourethral
How are the testicles kept at optimal temperature?
Plexus pampiniformis
Counter current heat exchange
Cremaster muscle works to elevate and lower testicles based on temperature
Where does sperm gain its motility?
Tail of the epididymis
What hormones contribute to development of sperm?
Basal levels of GnRH (frequent, intermittent bursts) —> LH and FSH
Leydig cells contain receptors for LH and produce testosterone
Steroli cells contain receptors for FSH and covert testosterone to estradiol
High levels of DHT, T and E2 negatively feedback to tonic center
What effect does testosterone have in the Sertoli cells
Bound by androgen binding protein and transported to lumen of seminiferous tubules for transport to epididymis
Converted to estradiol
Where does spermatogenesis occur?
Seminiferous tubules
What are the steps of spermatogenesis?
Proliferation phase - mitotic division (2n)
Meiotic phase
Primary oocyte (2N -> 4n -> 2N -> N)
—> allows for genetic diversity by replication and cross over
Differentiation phase
No further cell divisions
Spermatid transforms into spermatozoa (from spherical to head+midpiece+flagellum)
How long does it take for spermatogenesis in the bull?
61days
Duration of spermatogenesis in the stallion?
55days
Duration of spermatogenesis in the boar?
39days
