Repro Chapter 1 Part 1 Flashcards Preview

Physio II > Repro Chapter 1 Part 1 > Flashcards

Flashcards in Repro Chapter 1 Part 1 Deck (42):
1

What steroid hormones are involved in male and female reproduction?

androgens, estrogens, progesterone

2

The establishment of _______________ coincides with attainment of puberty.

Hypothalamo-Hypophyseal-Gonadal axis

3

What controls attainment of puberty?

gene expression and repression

4

When is an animal said to have reached puberty?

When the animal is able to release gametes and manifest complete reproductive behavior.

5

Imprinting of the brain is associated with what centers of the brain in males and females?

females: tonic center and surge center

males: tonic center

6

At what age does puberty occur in sheep, swine, cattle, and horses?

sheep and swine: 6-7 months

cattle: 11 months

horse: 15-18 months

7

At what age does puberty occur in cats and dogs?

Cats: 8-13 months

Dogs: 9-12 months

8

Removal of gonads results in lost of ______ and _____ function.

exocrine; endocrine

9

What happens to LH / FSH levels when gonads are removed?

LH / FSH levels increase

10

When is castration performed on farm animals and what is the purpose?

During pre-pubertal period

Manage farm animals

11

What are bulls, stallions, rams, and boars called after castration?

steers, geldings, wethers, barrows

12

What hormones are produced by the hypothalamus?

GnRH, PIH, GnIH, oxytocin

13

Oxytocin cannot be stored. True or false?

False. Oxytocin is stored in the posterior pituitary until the stimulus arrives for its secretion

14

How does oxytocin travel to the PP? Where is it traveling from?

neuronal processes from the hypothalamus

15

What are GnRH and GnIH?

Protein / peptide hormones

Gonadotropin Releasing Hormone

Gonadotropin Inhibiting Hormone

16

How is GnRH formed?

It is syntheszied from the cleavage of a 92 AA protein precursor forming GnRH and GAP.

17

GnRH inhibits prolactin secretion. True or false?

False; GAP inhibits prolactin secretion.

18

GnRH is a decapeptide. True or false?

True

19

How many amino acids is GAP? What is the function of GAP?

56 AA; inhibit prolactin secretion

20

Where is GnRH released?

into the hypophyseal portal circulation

21

What degrades GnRH and how long does it take?

Degraded by proteolysis within a few minutes of release.

22

GnRH is highly conserved throughout ________.

evolution

23

Where are GnRH neurons located?

Scattered throughout the anterior and medial part of the hypothalamus and preoptic septal areas

24

In what pattern is GnRH secreted?

In a pulsatile manner.

25

Where is the GnRH pulse generator located?

In the arcuate nucleus of the mediobasal hypothalamus

26

How are frequency and amplitude of the GnRH pulse dictated?

By the spontaneous activity of the pulse generator

27

________ plays an important role in the synchronization of GnRH neurons.

Kisspeptin

28

What factors stimulate GnRH secretion?

low levels of sex steroids (androgens and estrogens)

high levels of estrogens at certain threshold - acts at surge center

catecholamines

29

What factors inhibit GnRH secretion?

high levels of progesterone and androgens (exert negative FB on GnRH)

corticotrophin releasing hormone (CRH) and opioids

autocrine regulation of GnRH production

GnIH

30

How many AAs long is GnIH?

12 AAs - dodecapeptide

31

What is GnIH secreted by?

by neurons in hypothalamus and septal area

32

______ stimulates the synthesis and secretion of GnIH.

estradiol

33

Where are GnIH receptors present?

Different regions of the brain and gonads (regulation at multiple levels)

34

Where is GnIH released?

1. Into the hypothalamus

2. Into median eminence (reaches par distalis)

35

What are the physiological effects of GnRH?

stimulate synthesis and release of LH / FSH

regulated turnover of its own receptors on gondatrophs

involved in mating behavior

36

GnRH can both stimulate and suppress the reproductive functions. True or false?

True; it depends upon time and manner of presentation

37

Hourly injection of GnRH ________ production of gonadotropins which _______ reproductive processes.

stimulates; stimulates

38

Frequent administration of GnRH (long term use) results in _______ of gonadotropin production which _____ reproductive processes.

inhibittion; inhibits

39

Frequent administration of GnRH (long term use) results in _______ of gonadotropin production which _____ reproductive processes.

inhibition; inhibits

40

Clinically, why would you stimulate reproduction function and what would you use?

To synchronize cattle or initiate ovulation; use GnRH

41

Clinically, why would you inhibit reproduction function and what would you use?

For fertility control in pets and wild animals

Treat polycystic ovarian disease

GnRH

42

What is an example of controlling reproduction function in wildlife using GnRH?

GnRH darts are used to control doe population in Colorado