Pregnant Uterus

Question 1

What is the role of reproductive system is to?

Answer 1

Produce a gamete called oocyte and prepare for implantation

Question 2

What is the hormone that controls the reproductive cycle

Answer 2

Gonadotrophic hormone: it is released from hypothalamus then to anterior pituitary gland then releases luthenizing hormone (LH) and (FSH)

Question 3

How is GnRH released

Answer 3

Through pulse frequency of ovarian cycle

Question 4

What increases the pulse frequencies of ovarian cycle

Answer 4

Oestrogen

Question 5

What decreases pulse frequencies

Answer 5

Progesterone

Question 6

What does the increased frequencies allow

Answer 6

For the production of (fsh) and (lh)

Question 7

After How many days does a switch over from inhibitions to secretion of (LH) by oestrogen occur

Answer 7

After day 10 after 36 hours of High levels of oestrogen

Question 8

What happens on day 14 of her ovarian cycle

Answer 8

Surge of (LH) breaks follicular wall and allow corpus luteum to be released for ovulation

Question 9

Name the two phases in ovarian cycle

Answer 9

lateal and follicular phase

Question 10

What is the most abundant oestrogen produced in ovarian

Answer 10

Estradiol (most dominant on tissues prior to pregnancy)

Question 11

How is estradiol produced

Answer 11

It is produced by cholesterol converted to androstenedione which then makes testosterone, testosterone then through aromatase becomes estradiol. Other oestrogens are produced directly from androstenedione through aromatase

Question 12

What are the functions of oestrogen

Answer 12

• It has effect on CNS (sexual drive)
• stimulation of bone and muscle growth
• establishment and maintenance of female secondary sex characteristics
• maintenance of accessory reproductive glands and organs
• NB stimulation of endometrial growth and secretion

Question 13

What happens on day 14

Answer 13

• LH allows for release of follicle for ovulation
• increase levels of progesterone * which produces corpus luteum
  (LH maintains corpus luteum maturation), (prosesterone level decrease after day 21 if no pregnancy decreasing progesterone levels releases carpus albicans )

Question 14

During which uterine phase is there destruction of functional zone

Answer 14

Menstrual phase for up to 7 days

Question 15

What happens in the uterine e cycle during proliterative phase

Answer 15

After day 7 due to the rising oestrogen levels there is repair and regeneration of functional zone

Question 16

What happens during secretary phase

Answer 16

Rising progesterone levels from day 14 allow uterine glands to secrete proteins, lipids and glycogen. The glands also become increasingly elongated and sacculated.

Question 17

When does fertilisation take place

Answer 17

1 day after ovulation

Question 18

Where does fertilization occur

Answer 18

In uterine tubes

Question 19

Name the first and second layer of oocyte

Answer 19

1. Zone pellucida

2. Corona radiata

Question 20

fertilization can be divided into which steps

Answer 20

Acrosome reaction
Oocyte activation
Cortical reaction

Question 21

What happens in acrosome reaction

Answer 21

The head piece of the sperm when reaches oocyte releases digestive hormones such as hyaluronidase and acrosine (protein digesting enzyme) digest the corona radiata of the ovum creating gaps allowing the sperm to pass towards the zone pellucida

Question 22

What happens after a single cell enters an oocyte

Answer 22

There is membrane fusion which results in activation of oocyte and completion of meiosis by oocyte

Question 23

What is involved in oocyte activation

Answer 23

The entrance of sodium ions into the oocyte which results in the depolarization of the membrane
Calcium entrance released from SER resulting in exocytosis of vesicles that are adjacent to occyte membrane this then leads to the completion of meiosis 2 and formation of second polar body

Question 24

What happens during cortical reaction

Answer 24

The is a release of enzyme by oocyte that will inactivate the sperm receptors on the surface of the oocyte, there will also be hardening of the Zola pellucida

Question 25

What is the main reason for cortical reaction

Answer 25

To prevent Poly sperming

Question 26

After the three phases of fertilization what occurs inside the oocyte

Answer 26

The female pronucleas and nucleus of fertilizing sperm migrate towards each other

Question 27

What occurs as the female and male pro-nucleui approach each other

Answer 27

Spindle fibres begin to appear for the first cell division and cromatin condenses into chromosomes

Question 28

What is meant by amphimix

Answer 28

This is the moment of conception and completion of fertilization as it involves the couple fusion of maternal and paternal chromosomes leading to gamete with 46 chromosomes.

Question 29

What happens after fertilization is completed

Answer 29

The first cleavage occurs which is el division of the gamete into two daughter cells called blastomeres (occuring 30 hours after fertilization)