Fertilization

Question 1

Requirements for in vivo fertilization

Answer 1

Coitus
Healthy spermatozoon capacitsted and having undergone acrosomal reaction
Healthy oocyte able to cross talk with sperm

Question 2

What happens in coitus that causes ejaculation

Answer 2

Friction between glans penis mucosa of vagina reinforced by nervous impulses and psychological factors

Question 3

In right quantitumy, number of sperm per ejaculate?

Answer 3

15 million

Question 4

Rogjt ejaculate volume?

Answer 4

1.8 to 5.5

Question 5

Ejaculsye typically contains…

Answer 5

100m sperm per ml

Question 6

What are the sperm factors

Answer 6

Competence -normal morphology + progressive movement in one direction
40 percent of sperms must be mobile
Capable of undergoing capacitation
With stand avidity of vaginal fluid
Navigate through cervical mucus and maintain viability and motility
Survive 30m to 12 hour swim and wait for 72 hours

Question 7

Trisomies … … and … cause spontaneous abortion

Answer 7

16, 22, 15

Question 8

Transport towards ovary is achieved by

Answer 8

Forward propulsion of flagellation
Ciliary escalator creates current in oviductak fluid
Prostaglandins which make cervical mucus more receptive to sperm
Acidity of vaginal fluid neutralized by alkaline sperm

Question 9

What is capacitation

Answer 9

Physiological changes sperm must undergo tr able to penetrate and fertilize secondary oocyte

Question 10

What occurs during capacitation

Answer 10

Changes via cell membrane where receptors are made available through removal of glycoprotein layer

Question 11

Signalling molecules excreted by corina radiate imckude

Answer 11

Progesterone 
Lysophosphatidyl acid
Lysophosohatidyl choline
Monoacylglycerol
Phytosphingosine

Question 12

Acrosomal reaction succeeds capacitation.

What happens then

Answer 12

Release of hyalurinudase from acrosime to digest cumulus cells surrounding oocyte
Exposes acrosin bound to inner acrosomal membrane
Also involved release of neuraminidase

Question 13

Slow block to polyspermy triggered by

Answer 13

Release of cortical granules from oocyte

Question 14

What are the immediate events after fertilization

Answer 14

Completion of second meiotic division
Formation of female pronucleus and expulsion of secondary polar body
Formation of zygote by fusion of Male and female pronuclei
Determination of genetic sex.
Restoration of solid chromosomes
Introduction of genetic variation
Initiation of cleavage

Question 15

What is zonal reaction

Answer 15

Alteration of the properrties of the zona pellucida making it impermeable to any other sperm

Question 16

Molar pregnancy?

Answer 16

Caused by an abnormally fertilized egg. Inbalance in genetic material

Question 17

Mitotix division or cleavage.occurs where?

Answer 17

Within the oviduct

Question 18

Blastocyst forms by day … and arrives in uterine cavity by day …

Answer 18

5 and 7 to 9

Question 19

Hydratiform molar pregnancy

Answer 19

Expulsion of female pro nucleus