Farm Animal Reproduction chapter2

Tunica dartos

Contracts the scrotal skin

When it’s warm out the Tunica Dartos muscle…

relaxes and the scrotal skin becomes smooth (increasing surface area)

When it’s cold out the Tunica dartos muscle…

Contracts and the scrotal skin become wrinkly (decreasing surface area)

Seminiferous Tubules

make spermatozoa

Rete Tubules

Transport sperm from seminiferous Tubules to the efferent ducts

efferent ducts

Sperm flow

Excurrent duct system parts

Efferent ducts>Epididymis>Ductus Deferens

Mediastinum

Middle section of testes

3 parts of epididymis

Head of epi, body of epi, tail of epi- ALL 3 STORES AND CONCENTRATES SPERM

Head of Epididymis

Not fertilized sperm

Body of Epididymis

Not fertilized sperm

Tail of Epididymis

Fertilized, can be ejaculated

The epididymis

Provides environment for storage and maturation of spermatozoa

Epididymal transit time

Time required to get sperm from the head of the epididymis to the tail of the epididymis

Bull transit time

14 days

Stallion transit time

9 days

Human transit time

7 days

Where does sperm go that isn’t ejaculated?

Voided in the urine

Frequent ejaculation can cause sperm to

deplete in the tail of the epididymis

Reproduction is regulated mainly by these 3

Hypothalamus, Pituitary, and Gonadal axis

Hypothalamus’s name, location, and function

Located in the brain, is the neural control center for reproductive hormones and contains different groups of nerve cell bodies that have different functions

Target tissue of LH and FSH

Gonads

4 different cell types in pituitary gland

Gonadotroph, lactotroph, somatroph, corticotroph

Gonadotroph produces

LH and FSH

Lactotroph produces

prolactin

somatroph produces

growth hormones

corticotroph produces

ACTH

Thyrotroph produces

TSH(thyroid gland)

(GnRH) Gonadotroph-releasing hormone’s source

Hypothalamus

GnRH’s target tissue

Anterior Pituitary

GnRH’s function

causes release of LH and FSH from the gonadotroph cells

Lutenizing hormone (LH) ‘s source

Anterior pituitary

LH’s target tissue

Preovulatory follicle

LH’s function

induce ovulation of preovulatory follicle (WOOSH, surge center)

Follicle stimulating hormone (FSH)’s source

Anterior pituitary

FSH’s target tissue

small and medium size antral follicles

FSH’s function

Stimulates growth of antral follicles

Positive feedback

stimulation of GnRH neurons-increases GnRH release, woosh

Negative Feedback

Suppression of GnRH neurons-Decreases GnRH release, drip

There is constant communication between the gonads and hypothalamus, how do they communicate?

Through steroid E2, P4, Testosterone, feedback

E2, in heat/estrus

Positive feedback

P4, not in heat

Negative Feedback

males only have which part of the hypothalamus

tonic center-drip

which center is very sensitive to positive feedback in the female

Surge center

which center is very sensitive to negative feedback in both male and female

tonic center

LH is important in males because it

produces testosterone

FSH is important in males for

spermatogenesis