Hormones within the Female and The Oestrous cycle

Question 1

What is the function of Oestrogen ?

Answer 1

Rebuilds the uterine lining (endometrium) after menstruation. Stimulates the release of LH in the pituitary gland

Question 2

What is the function of Progesterone ?

Answer 2

Maintains the lining of the uterus ready for the fertilized egg. Inhibits the production of FSH. Mostly produced in the corpus luteum but in smaller amounts by ovaries.

Question 3

What is the function of Prostaglandins ?

Answer 3

Help uterine contractions; produced by most cells.

Question 4

What is the function of Oxytocin ?

Answer 4

Produced by the hypothalamus and released by the pituitary gland. Helps stimulate contractions and lactation.

Question 5

What is the function of Cortisol ?

Answer 5

Considered the stress hormone. Linked to start of parturition and increased maternal interest in the offspring.

Question 6

What is the function of Gonadotropin releasing hormone (GnRH) ?

Answer 6

Light stimulates pineal gland - reduces melatonin secretion. Allowing GnRH to be secreted and stimulates LH and FSH.
Secreted by hypothalamus (the anterior pituitary), controls other reproductive hormones.

Question 7

What is the function of Luteinising hormone (LH) ?

Answer 7

A surge of LH is released prior to ovulation and causes the release of the ovum from the follicle. Once the follicle has ruptured it becomes the corpus luteum, LH maintains the corpus luteum. The corpus luteum produces progesterone.
Produced by the pituitary gland.

Question 8

What is the function of Follicle stimulating hormone (FSH) ?

Answer 8

Stimulates the ovary to develop follicles, witch release oestrogen.
Produced by the pituitary gland.

Question 9

What is the oestrus cycle ?

Answer 9

the reproductive cycle found in most mammalian placental females, whereby there are recurring periods when the female is fertile and sexually receptive (oestrus) interrupted by periods in which the female is not fertile and sexually receptive.

Question 10

What is a Polyoestrous animal ?

Answer 10

becomes fertile more than once a year.

Question 11

What is a Seasonally polyestrous animal ?

Answer 11

becomes fertile more then once a year, but only during certain periods of the year.

Question 12

What is a Monoestrous animal ?

Answer 12

have one oestrous cycle every year.

Question 13

What are the stages of the oestrus cycle ?

Answer 13

Pro-oestrus
Oestrus
Metoestrus 
Dioestrus
Anoestrus

Question 14

What happens in the Proestrus stage ?

Answer 14

Follicular phase

Follicle enlarges, decrease in progesterone levels leads to an increase in oestrogen levels. GnRH is released.

Question 15

What happens in the Oestrus stage ?

Answer 15

Follicular phase

Female in heat. Oestrogen increases along with LH and FSH leading to ovulation.

Question 16

What happens in the metoestrus stage ?

Answer 16

The corpus luteum starts to decay which increases progesterone levels. This inhibits oestrogen levels and the level drops.

Question 17

What happens in the Anoestrus stage ?

Answer 17

Stage of sexual inactivity

Question 18

What happens in the Dioestrus stage ?

Answer 18

Levels of progesterone peak

Question 19

What happens to the females hormones during parturition ?

Answer 19

Progesterone levels drop allowing other hormones (e.g oxytocin) to effect uterine muscles. The drop in progesterone can depend on placenta or the corpus luteum, depending on species.

Oestrogen and oxytocin levels rise, leading to uterine contractions and cervical softening. Parturition begins

Relaxin secreted by the ovaries, relaxes the pelvic ligaments and opens the birth canal

Oestrogen and progesterone levels drop allowing prolactin to be secreted, triggering lactation.

Question 20

What happens to the females hormones during lactation ?

Answer 20

Nerve impulse by suckeling, milk machine, call of young

Prolactin starts the lactation, triggering milk production in the mammary gland

Oxytocin release

Mammary glands release the milk due to oxytocin. Stimulated by young suckeling.