Reproductive Endocrinology + Female Cyclicity(Chappy)

Question 1

What is the definition of ejaculation vs emmision?

Answer 1

Ejaculation: release of spermatozoa from the tip of the penis

Emmision: release of spermatozoa from the tail of the epididymus

Question 2

__________ is the release of spermatozoa from the tail of the epididymus

Answer 2

Emmision

Question 3

________ (Females/Males/Both) have a tonic center in the brain

Answer 3

Both

Question 4

________ (Females/Males/Both) have a surge center in the brain

Answer 4

Female

Question 5

What neurohormones are released from the anterior pituitary?

Answer 5

• FSH
• LH
• Prolactin (impt for dogs)

Question 6

Where is FSH released from?

Answer 6

Anterior pituitary

Question 7

What neurohormones are released from the posterior pituitary?

Answer 7

Oxytocin, Vasopressin

Question 8

Where is GnRH released from?

Answer 8

Hypothalamus

Question 9

List characteristics of reproductive hormones

Answer 9

• Act in small quantities
• Short half life
• Bind specific receptors
• Stimulates gonads
• Can cause release of other hormones
• Can cause sexual promotion (Ex: steroids)
• Can help maintain pregnancy
• Luteolysis

Question 10

List gonadal hormones (hormones produced by the testis/ovary)

Answer 10

- Testosterone
- Estrogen
- Progesterone
- Inhibin

Question 11

How long is an estrous cycle in the queen

Answer 11

14-18 days (17 days)

Question 12

How long is an estrous cycle in the bitch?

Answer 12

4-8 months

Question 13

How long is an estrous cycle in the ewe?

Answer 13

14-16 days

(most LA are 21 days, ewes are shorter)

Question 14

The estrous cycle is 21 days in which animals?

Answer 14

• Horse
• Cow
• Goat (doe)
• Pig

(ewes are 14-16 days)

Question 15

How long is estrus in a dog?

Answer 15

7-9 days

different from ESTROUS cycle which is 4-8 months

Question 16

How long is estrus in a queen?

Answer 16

7-9 days (same as dog)

Question 17

How long is estrus in a mare?

Answer 17

4-7 days

Question 18

How long is estrus in a cow?

Answer 18

6-30 hours

Question 19

How long is estrus in a sheep/goat?

Answer 19

24-36 hrs

Question 20

How long is estrus in a sow?

Answer 20

24-72 hrs

Question 21

An estrous cycle typically lasts 21 days, what animals are exceptions?

Answer 21

• Dog: 4-8 months
• Cat: 17 days
• Ewe: 14-16 days

Question 22

How long is diestrus in a queen?

Answer 22

• 60 days if pregnant
• 45 days if not pregnant

Question 23

How long is diestrus in a dog?

Answer 23

• 60 days regardless if pregnant or not

Question 24

How long is anestrus in a dog?

Answer 24

5 months

Question 25

What type of estrous cycle do dogs have?

Answer 25

Monoestrus, non seasonal

(1 cycle/yr, @ any time of year)

Question 26

What type of estrous cycle do horses have?

Answer 26

• Seasonal, long day (Spring and Summer), polyestrus breeders

(Increased light and decreased melatonin triggers GnRH release)

Question 27

What type of estrous cycle do cats have?

Answer 27

• Seasonal, long day (Spring and Summer), polyestrus breeders in northern hemispheres
• Induced ovulator

Question 28

List Non seasonal, polyestrus breeders

Answer 28

• Cows
• Pigs
• Rodents

(cycle frequently throughout entire year)

Question 29

What type of estrous cycle do sheep and goats have?

Answer 29

• Seasonal, SHORT day (Fall and Winter), polyestrus breeders

(Low light increases melatonin to increase GnRH)

Question 30

What stage of the estrus cycle does ovulation occur?

Answer 30

• Estrus
• EXCEPTION: Cows ovulate in metestrus