Gametogenesis

Question 1

The development of a human from a zygote to birth is divided into two main periods. Which of the following periods are correct?
A. Embryonic and Postnatal
B. Embryonic and Feotal
C. Postnatal and Prenatal
D. Before life and After life

Answer 1

B

Question 2

Zygote undergoes cell division, migration, growth, differentiation, Reproduction and responsiveness.

Is this True or False?

Answer 2

False, because the zygote only undergoes cell division, migration, growth, and differentiation.

Question 3

The difference between Spermatogenesis and Oogenesis

Answer 3

Spermatogenesis – maturation of male gametes.

Oogenesis – maturation of female gametes

Question 4

What regulates the maturation of sperms and at what stage of life does it begin?

Answer 4

The maturation process begins at puberty – regulated by testosterone.

Question 5

List 3 things you know about spermatogonia

Answer 5

1. lie dormant in seminiferous tubules.
2. Increase in number during puberty.
3. Transformed into primary spermatocytes.

Question 6

Spermatogonia undergo mitosis to form primary spermatocytes. Primary spermatocytes undergo meiotic division to form secondary spermatocytes.
These then go through a second meiotic division to form four haploid spermatids. The 2 haploid spermatids undergo spermiogenesis which transforms them into mature sperms.

is this true or false?

Answer 6

Spermatogonia undergo mitosis to form Primary spermatocytes and undergoes meiotic division to form two haploid secondary spermatocytes.
These then go through second meiotic division to form four haploid spermatids. The four haploid spermatids undergo spermiogenesis which transforms them into mature sperms.

Question 7

Mature sperm cells are active and motile consisting of:

A. Head: contains a nucleus, and has an acrosome which assists in penetration of zona pellucida in fertilization. Neck. Tail: provides motility of sperm.

B. Head: contains a nucleus, Neck, Tail.

C. Head: contains a nucleus, and has an acrosome which assists in penetration of Primordial follicle in fertilization. Neck. Tail: provides motility of sperm.

Answer 7

A

Question 8

Characteristics of Oogonia

Answer 8

Oogonia are the primordial germ cells.

Oogonia develop into primary oocytes – no oogonia develop after birth.

Question 9

DESCRIBE PRENATAL OOCYTES FORMATION.

Answer 9

As oocytes form – connective tissue cells surround them forming a layer of follicular cells.
Primary oocyte + Follicular cell layer = Primordial follicle
As primary oocyte enlarges during puberty, primordial follicle becomes primary follicle.
Primary oocyte surrounded by glycoproteinaceous material – zona pellucida
Follicular cells secrete oocyte maturation inhibitor which pauses meiotic process of oocyte

Question 10

Primary oocytes were suspended in which stage of cell division and that stage if prolonged what gonna happen?

Answer 10

prophase – long duration of this phase can lead to meiotic errors

Question 11

What are Polar bodies ?

Answer 11

cells that form based on meiotic divisions, and then degenerate.

Question 12

Are the following statements about the uterus true or false?

1. Thick-walled, pear shaped, skeletal organ.
2. Two major parts: body and cervix.
3. Body of uterus narrows from the fundus to ilium.
4. Cervix is the end of the vaginal end of the uterus.

Answer 12

1. FALSE
2. TRUE
3. FALSE
4. TRUE

Question 13

EXPLAIN WHAT YOU KNOW ABOUT THE Lumen of cervix – cervical canal.

Answer 13

Has an opening at each end.
Internal os – communicates with cavity of uterine body.
External os – communicates with the vagina.

Question 14

Name and explain the three layers of uterus, after that Name and explain the three layers of the thin, internal layer of Uterus.

Answer 14

Body of uterus has three layers:
Perimetrium - Thin external layer, firmly attached to:
Myometrium – Thick, smooth muscle layer.
Endometrium – Thin, internal layer.
Three layer of endometrium:
Compact layer – around neck of uterine glands.
Spongy layer – contains bodies of uterine glands.
Basal layer – blind ends of uterine glands.

Question 15

THE COLLECTIVE NAME FOR SPONGY AND COMPACT LAYERS.

Answer 15

compact and spongy layers collectively known as functional layer

Question 16

Name the layer of endometrium that is not removed during menstruation.

Answer 16

Basal layer

Question 17

Uterine tube is divided into:

Answer 17

Infundibulum
Ampulla
Isthmus
Uterine part

Question 18

Almond-shaped reproductive glands. Located close to lateral pelvic walls on each side of the uterus. Produce oocytes, oestrogen, and progesterone.

Name the reproductive female organ that matches the following characteristics.

Answer 18

Ovary

Question 19

Describe oocyte transport.

Answer 19

Fimbriated end of uterine tube comes in close proximity to the ovary.
Finger-like processes of the tube – fimbriae move over the ovary.
Movements of fimbriae “sweeps” secondary oocyte into infundibulum.
The oocyte then passes into ampulla – as a result of peristalsis – causing the oocyte to pass toward uterus.

Question 20

Describe Sperm Transport.

Answer 20

Sperm rapidly transported from epididymis to urethra by peristaltic contractions of ductus deferens.
Accessory sex glands – seminal glands, prostate and bulbourethral glands produce secretions added to the semen.
Transport occurs in two phases:
Emission: semen passes to prostatic part of urethra through ejaculatory ducts after peristalsis of the ductus deferens.
Ejaculation: semen is expelled from urethra through external urethral orifice.

Question 21

A. Human oocytes are usually fertilized within——— of ovulation.
B. An oocyte cannot be fertilized after——- it begins degeneration.
C. Most human sperm cells do not survive for more than ——– in the female genital tract.

Answer 21

A. 12 hours
B. 24 hours
C. 48 hours

Question 22

Termination of pregnancy – ovarian and menstrual cycle will resume after about 2-3 weeks.

True or False? explain.

Answer 22

False, because resume after 6-10 weeks

Question 23

Hormones that produce changes in the ovaries and corpus luteum formation.

Answer 23

Follicle-stimulating Hormone & Luteinising Hormone

Question 24

1. Primary follicle increases in size – adjacent connective tissue forms a capsule. Name that capsule.
2. Name and explain the 2 layers this above capsule forms.

Answer 24

1. theca folliculi
2. This capsule forms two layers:
   Theca interna – vascular and glandular layer
   Theca externa – capsule like layer

Question 25

Fill in the missing words.

1. Follicular cells divide and stratify.
2. Follicle becomes oval with the ——- in the centre.
3. Fluid-filled spaces form between cells, fuse to form —— containing ———.
4. Once antrum forms it is now termed ———.
5. Primary oocyte pushed to one side of follicle and surrounded by clump of cells called ———-.
6. Follicle continues to grow until it produces a swelling on ovarian surface – growing follicles produce ———.

Answer 25

2. Oocyte
3. Antrum, Follicular fluid
4. Secondary oocyte
5. Cumulus oophorus
6. Oestrogen

Question 26

1. What hormone triggers Ovulation.

2. Expelled secondary oocytes surrounded by what? and together they form what?

Answer 26

1. Triggered by surge in luteinizing hormone (LH).
2. Expelled secondary oocyte surrounded by zona pellucida and layer of follicular cells – together forming corona radiata.

Question 27

Fill in the missing information about Corpus leutum.
After ovulation.
Walls of —A—– and —B—– are thrown into folds.
Under —-C— influence these develop into corpus luteum – glandular structure secreting –D—— and —–E—-.
Prepares endometrium for implantation of —-F—–.

Answer 27

A. Ovarian follicle
B. Theca folliculi
C. LH
D. progesterone
E. Oestrogen
F. Blastocyst

Question 28

What is menstrual phase?

Answer 28

Functional layer of uterine wall passes out with menstrual flow. Usually lasts 4-5 days. Blood discharged from vagina is combined with small pieces of endometrial tissue. After menstruation the eroded endometrium is thin.

Question 29

What is proliferative phase?

Answer 29

Lasts approximately 9 days – controlled by oestrogen.
Increase in thickness of endometrium and water content.
Repair and proliferation occur in this phase. Early in this phase the surface epithelium reforms and covers endometrium. Glands increase in size and spiral arteries elongate.

Question 30

What is Luteal phase

Answer 30

Lasts approximately 13 days – influenced by LH, progesterone and oestrogen.
Progesterone stimulates glandular epithelium to secrete a glycogen-rich material.
Glands become wide, tortuous and saccular – Endometrium thickens.
Spiral arteries grow into superficial layer and become coiled – Lacunae develop.
If fertilization does not occur:
Oestrogen and progesterone levels fall – secretory endometrium enters ischaemic phase.
Menstruation occurs.

Question 31

What is Ischemic phase

Answer 31

Occurs when oocyte not fertilized.
Spiral arteries constrict – endometrium has pale appearance.
Constriction occurs due to decrease in hormone production
Resulting in stoppage of glandular secretion and shrinking of endometrium.
Towards end of this phase the spiral arteries constrict for longer periods – resulting in ischemic necrosis in superficial tissues.
This is followed by rupture of blood vessels – high blood flow also causes pieces of endometrium to detach and this flows into uterine cavity and through vagina