Control of ovarian cyclicity

Question 1

How does the uterine involute post partum?

Answer 1

• Myometrium continues to contract
• Smooth muscle cells decrease in size
• Glands in the myometrium are degraded
• Granulocytes invade the lumen and decompose remnants and kill microorganisms

Question 2

How does the uterine involution process differ between species?

Answer 2

• Occurs rapidly in animals with a diffuse placenta

Question 3

Which process aids uterine involution?

Answer 3

Sucking

Question 4

What is lactational anoestrus?

Answer 4

Where sucking aids uterine involution but inhibits oestrus cycling

Question 5

How can lactational anoestrus be used in pregnancy management?

Answer 5

E.g. Sows come into oestrus shortly after piglets are weaned, so oestrus can be synchronised in a batch of animals by the timing of weaning

Question 6

Which 3 hormones drive the oestrus cycle?

Answer 6

GnRH from the hypothalamus

FSH and LH from the anterior pituitary

Question 7

Give 3 physiological reasons for a decrease in GnRH pulse frequency and reproductive function?

Answer 7

• Lactation
• Pregnancy
• Day length (photoperiod)

Question 8

Give 3 pathological reasons for a decrease in GnRH pulse frequency and reproductive function

Answer 8

Starvation
Stress
Disease

Question 9

Which structure develops into the CL in the ovary?

Answer 9

Mature Graafian follicle

Question 10

Which 2 hormones are produced by the CL?

Answer 10

Oestrogen and progesterone

Question 11

What is the function of the hormones produced by the CL?

Answer 11

Responsible for thickening the endometrium and its development and maintenance

Question 12

How do hormones cause ovulation?

Answer 12

• High levels of oestrogen from the almost mature follicle stimulate the release of GnRH and LH
• GnRH promotes release of FSH and more LH
• LH surge brings about ovulation

Question 13

Which species oestrus cycle is being described?

• 17 day cycle
• Oestrus lasts 30 hours
• seasonal polyoestrous

Answer 13

Sheep