Endocrinology

Question 1

What is the neuro control center for reproductive hormones? What are the components of this center?

Answer 1

Hypothalamus

Consists of ..
Proventricular nucleus PVN
Surge center
Tonic center

Question 2

T/F: the surge center of the hypothalamus is only present in females, not males

Answer 2

True

Both males and females have a tonic center

Question 3

Hypothalamic nuclei front he surge and tonic center terminate in the _______________

Answer 3

Hypothalamic-hypophyseal portal system (H-HPS)

Question 4

Characteristics of reproductive hormones?

Answer 4

Act in small quantities
Short half life
Bind specific receptors

Cause release of other hormones 
Can stimulate the gonads 
Can cause sexual promotion 
Can help maintain pregnancy 
Leuteolysis

Question 5

Where is GnRH released from?

Answer 5

Hypothalamic nuclei

Question 6

What hormones are released from the anterior pituitary?

Answer 6

FSH
LH
prolactin

Question 7

What hormones are released from the posterior pituitary?

Answer 7

Oxytocin

Question 8

T/F: FSH and LH are decapeptide hormones

Answer 8

False

GnRH is a decapeptide
FSH, LH, and inhibin are glycoproteins (large molecule requiring a receptor)

Question 9

Progesterone, testosterone and estradiol are all produced from what common molecule ?

Answer 9

Cholesterol

Question 10

(Steroid/protein) hormones travel freely through plasma membrane into cytoplasm and bind directly to specific nuclear receptors

Answer 10

Steroid

Results in new protein synthesis

Question 11

What is the target tissue of LH in the female vs the male?

Answer 11

Female — ovary theca interval and luteal cells

Male —testis leydig cells

Question 12

What is the target tissue of FSH in the female vs the male?

Answer 12

Female — ovary (granulosa cells)

Male — Sertoli cells

Question 13

What factors determine the strength of hormones?

Answer 13

Pattern and duration of secretion

Half life

Receptor density

Receptor-hormone affinity

Question 14

Episodic hormone secretion is associated with hormones under ________ control

Answer 14

Nervous

Question 15

In what type of hormone secretion pattern does the hormone stay low, but may fluctuate at very low levels

Answer 15

Basal

Question 16

Where are steroid hormones metabolized and excreted?

Answer 16

Met in liver and excreted in urine and feces

Question 17

Where are protein hormones metabolized and excreted?

Answer 17

Met — Liver and kidney

Ex in urine

Question 18

What is estrus vs anestrus?

Answer 18

Estrus — period of sexual receptivity

Anestrus — not cyclone

Question 19

What type of estrous cycle do cattle, swine, and rodents have?

Answer 19

Polyestrus

Question 20

What type of estrous cycle do sheep, goats and deer have?

Answer 20

Seasonally polyestrus, short day breeders

Question 21

What type of estrous cycle do mares have?

Answer 21

Seasonally polyestrus, long day breeder

Question 22

What type of estrous cycle does the bitch have?

Answer 22

Monestrus

Zonary attachments leave placental scars which require healing time

Question 23

What is the dominant hormone during the follicular phase?

Answer 23

Estrogen

Question 24

What is the dominant ovarian structure and hormone in the luteal phase

Answer 24

Corpora lutea

Progesterone

Question 25

What are the 4 stages of the estrous cycle?

Answer 25

Proestrus Estrus Metestrus Diestrus

Question 26

What occurs in proestrus and how long does it last?

Answer 26

P4 drops due to luteolysis FSH and LH are being secreted—> estrogen secretion from follicles

Question 27

What occurs in estrus?

Answer 27

Period of sexual receptivity Peak E2 secretion Duration varies between species

Question 28

What occurs during metestrus?

Answer 28

CL formation —> begins secreting progesterone | Estrogen levels begin to drop

Question 29

What occurs during diestrus?

Answer 29

Sustained secretion of high levels of P4 from corpus luteum Ends with luteolysis

Question 30

What are signs of estrus in the cow?

Answer 30

Increased locomotion Increased vocalization twitching Elevation of the tail Standing to be mounted Mounting other females

Question 31

What are signs of estrus in the mare?

Answer 31

Increased locomotion Tail flagging Urination stance Clitoral exposure by labial eversion

Question 32

Signs of estrus in the bitch?

Answer 32

Roaming Immobile stance Tail deflected to one side Urinating in presence of male

Question 33

How long is anestrus in the bitch?

Answer 33

5 months

Question 34

How long does proestrus last in the bitch?

Answer 34

9 days

Question 35

How long does estrus last in the bitch?

Answer 35

9days

Question 36

How long does diestrus last in the bitch?

Answer 36

60 days

Question 37

In a Queen that is not mated what additional phase do they have in their estrous cycle?

Answer 37

Postestrus (7-10days)

Question 38

Females that do not exhibit regular estrous cycles are in _____________

Answer 38

Anestrus ``` Can be caused by.. Pregnancy Lactation Season (photoperiod) Stress Pathology ```

Question 39

What is true vs apparent anestrus ?

Answer 39

True anestrus — insufficient hormonal stimulus —factors: nutrition, eliminate stresses, detect and treat pathology Apparent anestrus —failure to detect estrus —failure to know that she is pregnant

Question 40

What is the purpose of seasonal anestrus?

Answer 40

Carry developing fetus during a favorable time Give birth during an advantageous time for new born (eg lambs born in early spring)

Question 41

What two speices are induced ovulatory?

Answer 41

Queen and llama

Question 42

What is roughly the length of diestrus in mares, cows, does, and sows?

Answer 42

15-17days

Question 43

What is the length of estrus in the mare?

Answer 43

4-7days

Question 44

How long does estrus occur in cows, ewes, does, and sows?

Answer 44

1-2 days As short as 6 hours in the cow Up to 3 days in sow