Chapter4 (Gametogenesis)

Question 1

What is gametogenesis?

Answer 1

Gametogenesis is the production of haploid gametes by diploid multicellular
organisms through the process of meiosis.

Question 2

What is Oogenesis ?

Answer 2

Production of female gametes

Question 3

What is spermatogenesis?

Answer 3

Production of male gametes

Question 4

Where does Oogenesis occur?

Answer 4

With in the follicle of the ovary

Question 5

In spermatogenesis primordial germ (germinal epithelial cells) cells divide repeatedly by mitosis to form

Answer 5

diploid spermatogonia

Question 6

spermatogonium increases in size (2x) to form

Answer 6

a primary spermatocyte (sperm mother cell).

Question 7

the 1st meiotic division in spermatogenesis gives rise to

Answer 7

two secondary spermatocyte,

Question 8

the 2nd meiotic division in spermatogenesis gives rise to

Answer 8

a group of four spermatids.

Question 9

spermatid, unspecialised cells,
differentiates Into

Answer 9

a spermatozoon with
characteristic head and tail.

Question 10

Sperms are produced at the rate of

Answer 10

about 120 million per day.

Question 11

Maturity of a given sperm takes

Answer 11

about 70days (2months).

Question 12

Where does spermatogenesis takes place?

Answer 12

The walls of somniferous tubules

Question 13

The primordial germ cells are formed from

Answer 13

the germinal epithelium lining the outside of the tubule.

Question 14

The final transformation of spermatids to spermatozoa takes place in what part of the wall?

Answer 14

The part of the wall immediately adjacent to the lumen.

Question 15

heads of the developing sperms are enveloped by

Answer 15

large sertoli cells,

Question 16

Where does sperm derive their nourishment from?

Answer 16

sertoli cells,

Question 17

The sperm _____ project into the fluid filled lumen of the tubule.

Answer 17

tails

Question 18

What is the length of sperm?

Answer 18

2.5micro meter long.

Question 19

What does the head of a sperm contains and describe the content?

Answer 19

1. the nucleus which contains the haploid number of chromosomes.
2. the acrosome, a large lysosome which contains hydrolytic enzymes which will be involved in the penetration of the layers of cells surrounding the egg immediately before fertilization.

Question 20

The short neck of the sperm contain

Answer 20

a pair of centrioles lying perpendicular to each other.

Question 21

The middle piece is the first part of the tail and is enlarged by

Answer 21

the presence of many mitochondria.

Question 22

The sperm swims at what speed ?

Answer 22

About 1 - 4mm per minute.

Question 23

Spermatogenesis is controlled by

Answer 23

the hypothalamus and the anterior pituitary gland working together.

Question 24

The hypothalamus secretes

Answer 24

gonadotrophins-releasing hormone (GRH)

Question 25

What stimulates the anterior pituitary?

Answer 25

gonadotrophins-releasing hormone (GRH)

Question 26

The two gonadotrophins are

Answer 26

follicle stimulating hormone (FSH) and luteinising hormone (LH).

Question 27

FSH stimulates spermatogenesis by

Answer 27

stimulating sertoli cells to complete the development of spermatozoa from spermatids

Question 28

Function of the luteinising hormone

Answer 28

stimulates the synthesis of the hormone testosterone by the leydig cells (interstitial cells) of the testis.

Question 29

Function of the Testosterone

Answer 29

stimulates growth and development of the germinal epithelial cells (spermatogonia) to form sperms, and also works with follicle stimulating hormone to stimulate the sertoli cells.

Question 30

increase in the level of testosterone cause a backward effect of

Answer 30

decrease in secretion of gonadotrophins-releasing hormone from the hypothalamus.

Question 31

Inhibin negative feedback causes

Answer 31

Inhibition of follicle stimulating hormone

Question 32

Testosterone negative feedback causes

Answer 32

inhibition of LH

Question 33

Primordial germ cells, divide to form

Answer 33

oogonia during development of foetus

Question 34

oogonium becomes enveloped by a layer of

Answer 34

follicle cells (granulosa cells).

Question 35

The structure of the oogonium envelope by a layer of follicle cell (granulosa cells) is called

Answer 35

Primordial follicle

Question 36

At birth there are about _____ of these follicles,between ______primary follicles in each ovary, but only 200 to 400 complete their development.

Answer 36

1. 2 million 2. 200,000 and 400,000

Question 37

Undeveloped primordial follicle degenerate into

Answer 37

atretic follicles

Question 38

primary oocyte, remains at ______ of meiosis I throughout childhood.

Answer 38

prophase

Question 39

cells from the stroma of the ovary form further layers outside the primary oocytes known collectively as

Answer 39

the theca.

Question 40

As the primary follicle develops, a fluid is secreted by the _____ which contain

Answer 40

1. granulosa cells 2. ostrogen

Question 41

What is the anthrum?

Answer 41

A fluid-filled space in the follicle of the ovum

Question 42

Oestrogen stimulates growth of

Answer 42

the follicles, which eventually becomes a mature follicle

Question 43

When does the secondary oocyte undergoes the second meiotic division l

Answer 43

At fertilization

Question 44

The cortical granules of the eggs form

Answer 44

a layer just beneath the surface.

Question 45

The yolk is concentrated towards

Answer 45

the lower end of the egg, away from the nucleus.

Question 46

What is the animal pole of the egg?

Answer 46

The non-yolky end with the nucleus and active cytoplasm

Question 47

The more inert yolky end is the

Answer 47

vegetative pole.

Question 48

What provides a source of nourishment for the embryo?

Answer 48

The yolk

Question 49

For eggs without yolk nourishment is supplied by

Answer 49

separate yolk filled cells or by a nutritive tissue surrounding the embryo.

Question 50

the inner membrane of the egg is the _____

Answer 50

Plasma membrane

Question 51

the outer egg membrane is the

Answer 51

vitelline membrane

Question 52

Feedback effect of oestrogen

Answer 52

1. stimulates, repair and develop the lining of the uterus, the encometrium. 2. inhibits the secretion of follicle stimulating hormone..

Question 53

What is the target of luteinising hormone in females

Answer 53

it causes ovulation.

Question 54

After ovulation, the remaining part of the graafian follicle is stimulated by______ to develop into the _____

Answer 54

1. luteinising hormone 2. corpus luteum (yelfow body).

Question 55

Released of progesterone is associated with

Answer 55

a rise in body temperature. of the female just after ovulation.

Question 56

The corpus luteum secrete

Answer 56

ostrogen, as well as progesterone

Question 57

What happens if fertilization does not occur?

Answer 57

the corpus luteum starts to degenerate about day 28

Question 58

What causes menstruation (the period)?

Answer 58

the breaks down of endometrium

Question 59

What is the primary location for storage and development of sperm cells

Answer 59

Epididymis

Question 60

Ovulation in occur on what day of the menstrual circle ?

Answer 60

14th

Question 61

Sperm is viable from _____ to _____ in the female genital tract

Answer 61

24 to 72hrs

Question 62

Oocytes is viable from ____ to ____hours

Answer 62

12 to 24hrs

Question 63

The first meiotic division in spermatogenesis gives rise to

Answer 63

Secondary spermatocyte

Question 64

The second meiotic division in spermatogenesis gives rise to

Answer 64

Spermatids

Question 65

Lav

Question 66

Lav