chapter 1 document 5

Question 1

what is oogenesis?

Answer 1

is the process of formation of female gametes. It starts before birth (in embryonic life) in ovaries and continues in oviduct after puberty. It is periodically repeated and interrupted by 2 blockages. It remains till menopause and is incomplete if fertilization didn’t occur.

Question 2

Multiplication/ mitosis

Answer 2

oogonia produce more oogonia, each oogonium is diploid 2n, made of 1 chromatid surrounded by a discontinuous layer of follicular cells forming a primordial follicle

Question 3

Growth/ interphase

Answer 3

oogonia produce primary oocyte having 2n chromosomes , 2 sister chromatid each chromosome

Question 4

Maturation/ meiosis:

Answer 4

Meiosis I/ reductional: primary oocyte produce, Secondary oocyte + 1stpolar body, each is n chromosome of 2 sister chromatids

Question 5

meiosis II/ equational

Answer 5

secondary Oocyte results in ootid + second polar body, each is n chromosome, 1 sister chromatid

Question 6

Differentiation

Answer 6

ootid changes to an ovum

Question 7

when are the follicules blocked

Answer 7

Each primary oocyte (blocked at pro I) is surrounded by
follicular epithelial cells to form the primordial follicle that remain as such from
birth till puberty.

Question 8

During Maturation phase:

Answer 8

Few hours before ovulation (at day 14 during the female sexual cycle) oocyte I resumes its first meiotic division to give 2 different cells oocyte II and first polar body.

Question 9

Folliculogenesis

Answer 9

Development of follicular cells which starts during fetal life and
resumes its activity at puberty

Question 10

Ovulation

Answer 10

Graffian follicle ruptures & oocyte II will be released in the oviduct. Oocyte II blocked at metaphase II, can survive 24 hrs without fertilization.

Question 11

Yellow body (corpus luteum) = rupture follicle

Answer 11

is the reminder of the Graafian follicle after the release of oocyte II at ovulation.

Question 12

what happens when fertilization doesn’t occur

Answer 12

If fertilization didn’t occur, it changes to White body (corpus albicans) within 14 days after ovulation, during a phase known as luteal phase /postovulation phase. and the oocyte 2 degenerate 24 hours after ovulation

Question 13

what happens if fertilization occurs?

Answer 13

ellow body will persist till the third/fourth month of pregnancy before it changes to a yellow body and degenerates. Oocyte continue meiosis 2 becomes an ootid differentiate into an ovum and become a zygote.