Exam 5: Intro to Repro Endocrinology

Question 1

What does a 3% increase in reproductive rates equate to?

Answer 1

1 million more beef calves per year

3. 2 million pigs per year
4. 7 million gallons of milk per year

Question 2

What does the endocrine system use hormones to do?

Answer 2

Bathe cells in body tissues

Question 3

What allows for the precise control over reproductive function in both the male and female?

Answer 3

The interaction of anatomical structures, hormones, and target tissues

Question 4

What is secretion, transport, and clearance controlled by?

Answer 4

Feedback mechanisms

Question 5

What does transport depend on?

Answer 5

Water solubility or whether the hormone is protein bound

Question 6

What does clearance occur via?

Answer 6

Metabolic destruction
Binding with tissues
Hepatic excretion
Renal excretion

Question 7

Where do reproductive hormones come from?

Answer 7

Hypothalamus
Pituitary gland
Gonads

Question 8

Describe the hypothalamus

Answer 8

The master organ

Combination of neuro and endocrine center

Question 9

What does the hypothalamus regulate?

Answer 9

Endocrine system
Body temperature
Appetite
Sexual behavior
Fear/rage centers

Question 10

What does the hypothalamus control?

Answer 10

Action of the pituitary through the median eminence

Question 11

What does the median eminence do?

Answer 11

Connects the hypothalamus with the pituitary

Question 12

What does the hypothalamus secrete?

Answer 12

Gonadotropin Releasing Hormone (GnRH)

Question 13

What specifically secretes GnRH?

Answer 13

The axon of neurons

Question 14

How does GnRH get to the pituitary?

Answer 14

Enters into the portal system and is carried locally to the pituitary

Question 15

Describe the anterior pituitary

Answer 15

Located just below the hypothalamus

Receives GnRH from hypothalamus via portal system

Question 16

What does the anterior pituitary release?

Answer 16

Lutenizing hormone (LH)
Follicle stimulating hormone (FSH)

Question 17

Can you get LH as a pharmaceutical?

Answer 17

No, but you can get products that act like LH

Question 18

What does LH drive?

Answer 18

Ovulation

Question 19

What can FSH do?

Answer 19

Increase the amount of follicular waves

It is used to superovulate cows

Question 20

Describe the surge center

Answer 20

Releases large volumes of GnRH

This surge of GnRH will then have a LH surge

Question 21

Describe the tonic center

Answer 21

Slow, consistent release of GnRH

Question 22

What is the posterior pituitary the site of?

Answer 22

Oxytocin release

Question 23

Describe oxytocin

Answer 23

Formed in the parventricular nuclei of hypothalamus and travels down nerve ending to the posterior pituitary where it is eventually released by exocytosis

Question 24

What kind of hormone is oxytocin?

Answer 24

Neuroendocrine

Question 25

What do the gonads receive?

Answer 25

Hormonal stimulation from the gonadotropins released from the AP (FSH and LH)

Question 26

What do the testicles secrete?

Answer 26

Testosterone | Estrogen

Question 27

What does LH act on in the testicles?

Answer 27

The Leydig cells to secrete testosterone

Question 28

What does FSH stimulate in the testicles?

Answer 28

The Sertoli cells to produce estrogen from testosterone

Question 29

What are the sertoli cells responsible for?

Answer 29

Spermatogenesis

Question 30

What is testosterone responsible for?

Answer 30

Distinguishing characteristics of males Maleness Penis/scrotum formation

Question 31

What is the SRY gene?

Answer 31

The sex determining region of the Y chromosome that causes genital ridge to produce testosterone and become testes Testicular descent Muscle formation

Question 32

What do the ovaries secrete?

Answer 32

Estrogen | Progesterone

Question 33

What does FSH act on the ovary (follicle) to do?

Answer 33

Produce estrogen and stimulate follicular development

Question 34

What does LH act on the ovary to do?

Answer 34

Stimulate ovulation and corpus luteum funciton

Question 35

Describe the process to start ovulation

Answer 35

Hypothalamus produces GnRH acting on the AP to produce of FSH and LH FSH and LH act on ovary to stimulate follicular development The follicle produces estrogen, which has a positive feedback early on Estrogen drives the cycle faster Ultimately, enough feedback causes a surge of GnRH, which causes a surge in LH which causes ovulation

Question 36

What does inhibin do?

Answer 36

It has a negative feedback on FSH and suppresses additional FSH release

Question 37

Why is suppressing additional FSH release important?

Answer 37

It stops the process and keeps cows from being a litter bearing species

Question 38

What occurs once the animal ovulates?

Answer 38

There is a CL that produces progesterone, which has a negative feedback on the hypothalamus and pituitary

Question 39

What can progesterone do to the stallion? Why?

Answer 39

Dampen the activity/attitude | It has a negative feedback on the hypothalamus and suppresses LH thus dampening testosterone production

Question 40

Describe the male system of hormone release

Answer 40

Hypothalamus releases GnRH, which has a positive feedback on the AP AP releases LH and FSH LH has a positive feedback on Leydig cells causing the release of testosterone FSH has a positive feedback on Sertoli cells which causes spermatogenesis and the release of inhibin

Question 41

What are the actions of testosterone?

Answer 41

Positive feedback on virilizing effects Negative feedback on hypothalamus and AP Positive feedback on Sertoli cells

Question 42

What are the actions of inhibin?

Answer 42

Negative feedback on hypothalamus and AP