Reproductive system 3

Question 1

What is the Oestrus cycle

Answer 1

Cyclical patterns of ovarian fertility in sexually mature females

Question 2

What are functions of the oestrous cycle

Answer 2

-Produces oocyte for fertilization
-Prepares female repro tract to receive fertilised ova
-Stimulate female to allow male to mate her

Question 3

Induced ovulators

Answer 3

Require a stimulus to ovulate

Question 4

Function of oestrogen

Answer 4

-Optimises chances of fertilisation
-Stimulates follicle growth
-Initiates sexual receptivity

Question 5

Functions of progesterone

Answer 5

-Creates good conditions for foetus growth
-Grows mammary glands
-Prevents oestrous behaviour

Question 6

OESTRUS CYCLE

Answer 6

1. PRO-OESTROUS: Oestrogen is produced and the Oocyte matures within the follicle. It lasts 7-10 days and can be seen through swelling of vulva and blood discharge.
2. OESTROUS: Female allows herself to be mated and ovulation occurs. it lasts 5-10 days
3. METOESTROUS: Period after the heat - Depends on if animal is pregnant. Changes go back to normal if not.
4. ANESTRUS: Resting phases with little/no ovarian activity before next cycle. Can last 3-9 months.

Question 7

Queen oestrous cycle

Answer 7

-Several oestrus periods during mating season
-Induced ovulators
-Oestrus causes lordosis, calling, rubbing

Question 8

Cow oestrous cycle

Answer 8

-Oestrous lasts 12-24 hrs
-Ovulation occurs 10-15hrs after oestrous
-cycle only lasts 21 days

Question 9

Mare oestrous cycle

Answer 9

-cycle activated by day length
-17-21 days
-Several oestrus periods during breeding season

Question 10

Implantation

Answer 10

1. Zygote divides by mitosis and becomes a blastocyst. Cells in the blastocyst become an embryo and trophoblasts become extraembryonic membranes.
2. Blastocyst implants into uterine endometrium, which catches and binds to it.
3. Blastocyst buries into uterine wall
4. Blastocyst starts developing the placenta

Question 11

Ectopic pregnancy

Answer 11

Occurs when the blastocyst implants outside of the uterus and can lead to non viable pregnancy.

Question 12

Function of extraembryonic membranes

Answer 12

Protect the embryo

Question 13

Extraembryonic membrane structures

Answer 13

-Chorion: outer layer
-Amnion: surrounds embryo and protects with fluid
-Allantois: collects foetal urine and forms part of umbilical cord

Question 14

Foetal development

Answer 14

Embryonic stage: head/tail development, spinal cord and organ formation
Foetal stage: organ function, growth.

Question 15

What happens in parturition

Answer 15

Progesterone drops and oxytocin and relaxin released.

Question 16

Function of mammary gland

Answer 16

-Milk synthesis and secretion

Question 17

Location of mammary glands

Answer 17

On either side of the midline on the ventral wall of the abdomen (or near groin as an udder)

Question 18

Development of mammary gland

Answer 18

1. Puberty: Oestrogen causes initial development
2. Pregnancy: Glands are enlarged due to progesterone and milk is produced a few days before birth.
3. Milk: Oxytocin causes contractions around glands and milk is squeezed through teats.

Question 19

How milk is made in mammary gland alveoli

Answer 19

-Alveolus lumen has secretory epithelial cells.
-Milk is synthesised across these cells
-Milk is secreted into the lumen

Question 20

Colostrum

Answer 20

First milk
-Transfers passive immunity to offspring

Question 21

Mastitis, Metritis and Agalactia syndrome in sows

Answer 21

-Milk production is reduced/lost
-Mammary gland gains an infection
-Uterus becomes inflammed