Lecture 11: Gametogenesis and Fertilization Flashcards

1
Q

Primordial germ cells are progenitors

A

gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Primordial germ cells from yolk sac ______ migrate to ____ ___ which will become _____ _____.

A
  • Endoderm
  • Genital ridge
  • Indifferent gonad
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Intermediate mesoderm gives rise to

A
  • Part of urogenital organs

- Leydig cells, sertoli cells, follicular cells, ovary, testis, ducts, uterus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Urogenital sinus endoderm gives rise to

A
  • Terminal internal parts of genital organs

- Vesicular, prostate and bulbourethral glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Mullerian ducts are also called

A

Paramesonephric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mullerian ducts develop into

A

Fallopian tubes, uterus, cervix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Mullerian ducts in male

A

Disappear under the influence of anti-paramesonephric hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Seminiferous cords consist of

A
  • Sertoli cells

- Primordial germ cells - stem cells for spermatogenesis and stay dormant till puberty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Two parts of the prepuberal testis

A
  • Seminiferous cords

- Inactive interstitial cells of leydig

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cryptorchidism

A
  • Testes fail to descend into the scrotum
  • Inherited as a sex-linked autosomal recessive trait
  • Cryptorchid can be unilateral (fertile) or bilateral (sterile)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Scrotal hernia

A
  • Type of inguinal hernia

- Congenital weakness in abdominal wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Primitive sex cells

A
  • Spermatogonia

- Oogonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Primitive sex cells have complete

A

DNA complement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are more oogonia and spermatogonia made

A

Mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Purpose of spermocyte and oocyte meiosis

A

Insure variation and provide 1/2 of the chromosome in both male (1N) and female (1N) sex cells (gametes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Fertilization

A

Joining of sex cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Fertilization creates

A

Zygote, which restores DNA complement (2N) and initiates cleavage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Mitosis results in formation of

A

2 daughter cells, each having diploid set of chromosomes, the same number of chromosomes as in the mother cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Meiosis results in

A

Gametes - daughter cells that are haploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Are gametes haploid or diploid

A

haploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Two goals of meiosis

A
  • Reduction of diploid set chromosomes into haploid in gametes
  • An exchange of genetic material between make and female chromatids in prophase of meiosis I (crossing over) which results in 4 daughter cells with four different genetic makeups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Oogenesis and spermatogenesis both have (4)

A
  • Multiplication of spermatogonia and oogonia
  • Meiosis
  • Extensive morphological differentiation
  • Incapacity of surviving for very long if fertilization doesn’t occur
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Sperm supply is

A

Continuously renewed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

One Io spermatocytes produces

A

4 sperm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

In sperm, initial large cell results in

A

small cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Do sperm move

A

motile cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Chromosome of sperm

A

X or Y sex chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Are oocytes made after birth?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

One Io oocyte produces

A

1 ovum and 2-3 polar bodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

In oocytes, initial small cell

A

grows into a large cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Do oocytes move?

A

Nope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

In mammals, chromosome for oocyte

A

X chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Where does oogenesis occur?

A

Ovary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Oogonia

A

Prenatal mitosis and differentiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Basic plan of oogenesis

A
  1. Oogenia
  2. Folliculogenesis
  3. Meiosis II
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Second step of oogenesis

A

All are primary oocytes (4N) arrested in meiosis I until puberty. At ovulation, meiosis I is completed except in dogs and mares who ovulate primary oocytes

37
Q

Third step of oogenesis

A

In uterine tube, secondary oocyte (2n) awaits fertilization (1st polar body is present). Meiosis II is completed on sperm contact, resulting in ovum (1n) and second polar body (1n)

38
Q

At puberty, hormone influence on folliculogenesis leads to

A

ovulation

39
Q

Primordial follicles

A
  • Resting follicles

- Oocyte I + single layer of squamous follicular cells

40
Q

Primary follicles

A
  • Activated or growing follicles

- Zona pellucida forms

41
Q

Secondary follicles

A
  • Secretory
  • Antral follicles
  • Fluid filled spaces are formed among the granulosa cells
42
Q

Tertiary mature (Graafian) follicle

A
  • One antrum containing liquor folliculi

- Have an eccentric cumulus oophorus which contains a primary oocyte

43
Q

Zona pellucida acts as

A

An immunologic protective barrier for the developing egg and early embryo

44
Q

After ovulation, the follicular space fills with

A

Blood and clots

45
Q

Corpus hemorrhagicum

A
  • Bloody body

- Is replaced by infiltrating luteal cells to become the corpus luteum

46
Q

Corpus luteum produces

A

Progesterone some estrogen

47
Q

How does the corpus luteum produce progesterone and some estrogen

A
  1. Granulosa luteal cells = large luteal cells
  2. Theca luteal cells = small luteal cells

These cells infiltrate the space left by the ruptured follicle

48
Q

Purpose of progesterone

A
  • Maintains pregnancy
  • Stimulates mammary development
  • Locally down regulates the immune system
49
Q

The corpus luteum regresses during

A

diestrus

50
Q

Corpus albicans (white body)

A

Connective tissue scar that remains during the regression of the corpus luteum

51
Q

Atretic follicle

A

If a follicle is not selected to complete maturation, if will undergo a programmed destruction. The fate of many follicles

52
Q

Ovulation

A
  1. The oocyte departs the ovary, leaving behind a structure known as the corpus hemorrhagicum which becomes..
  2. The corpus luteum of theca and granulosa cells
53
Q

5 steps of the basic plan of spermatogenesis

A
  1. Spermatogonium (2n): mitosis, differentiate
  2. Primary spermocyte (4n): meiosis I - crossover
  3. 2 Secondary spermatocytes (2n): meiosis II
  4. 4 Spermatids (1n): do not divide, but undergo spermiogenesis (metamorphosis)
  5. 4 spermatozoa (sperm, sperm cells)
54
Q

Testis secrete _____ under the influence of ___

A

Testosterone

LH

55
Q

Sertoli cells are activated by

A

Follicle-stimulation hormone

56
Q

During fetal cells, sertoli cells secrete

A

Anti-Mullerian hormone to inhibit uterus formation

57
Q

After puberty, sertoli cells secretes

A

Inhibin and activins to regulate FSH secretion from pituitary

58
Q

In males, sertoli cells secrete

A

Androgen binding proteins to bind testosterone, increase concentrations in the seminiferous tubules, and stimulate spermatogenesis

59
Q

What do sertoli cells do for spermatids

A

Provide support, protection, and nutrition until spermatids transform into mature spermatozoa

60
Q

The size and shape of sperm cell heads is

A

Species-specific

61
Q

Sperm cell head is disc-like in

A

ruminants

62
Q

Sperm cell head is pear shaped in

A

man, stallion

63
Q

Sperm cell head is hook-like in

A

rodents

64
Q

Sperm cell head is spoon-like in

A

guinea pids

65
Q

Sperm cell head is filiform in

A

birds

66
Q

Axonema

A

Core of cilia and sperm flagellum

67
Q

Axoneme of cilia/sperm flagella is a derivative of

A

a modified centriole (basal body)

68
Q

Axoneme consists of

A
  • A pair of central microtubules

- Outer ring of 9 doublets with dynein arms

69
Q

How long does it take for sperm to be to be transported through the epididymis?

A

2 weeks

70
Q

In most mammals, spermatogenesis takes place in orderly

A

waves

71
Q

Almost every animal produces approx. ____ sperm per gram of testicular tissue per day

A

25 million

72
Q

Humans produce only about ___ sperm per gram of testicular tissue per day

A

4 million

73
Q

Spermatogenesis is very sensitive to (6)

A
  1. Temperature (cryptorchids)
  2. X ray irradiation
  3. Nutrition (vitamin A)
  4. Infection and non-infectious diseases
  5. Stress
  6. Drugs
74
Q

Sperm defects are often categorized by

A

the infertility rates associated with them

75
Q

5 difference between spermatogenesis and oogenesis

A
  1. Spermatogonia remain dormant until puberty vs oogonia completing proliferation in early embryonic stage
  2. Meiosis is completed within testes vs by birth all oogonia entered meiosis I but their development is arrested in Meiosis I until puberty. Thus, females are born with primary oocytes. Meiosis I is completed in fallopian tube
  3. Each spermatogonium gives rise to multiple (64-256 spermatozoa) vs one oocyte giving rise to only one ovum
  4. Spermatids undergo metamorphosis vs ova do not
  5. Spermatogenesis may continue throughout the whole life of the animal vs oogenesis stops after the ovary is exhausted of germ cells
76
Q

When does oogenesis stop in dogs?

A

10-12 years

77
Q

When does oogenesis stop in cattle?

A

14-16 years

78
Q

When does oogenesis stop in mares?

A

20-22

79
Q

Three parts of fertilization

A
  1. Capacitation
  2. Acrosome reaction
  3. Fusion
80
Q

Capacitation

A
  • Occurs in uterine environment

- Sperm cells gain the ability to fertilize theoocyte

81
Q

Acrosome reaction

A

-Release of acrosmal enzymes (acrosin)to digest way through zona pellucida

82
Q

Fusion

A
  • Sperm contacts oocyte most commonly in fallopian tube

- Sperm plasma membrane and the vitelline membrane of oocyte

83
Q

Cortex of oocyte below oolemma contains

A

cortical granules

84
Q

Another name of ovum

A

Oocyte II

85
Q

Sperm contact with oocyte plasma membrane causes

A

release of proteases from cortical granules whih modify the zona pellicuda, which is then a barrier to other sperm penetration

86
Q

What causes oocyte to complete Meiosis II

A

Ca++ wave

87
Q

Nuclear material of sperm and ootid is called

A

Male/female pronuclei

88
Q

Syngamy

A

Union of male and female pronuclei. They merge restoring diploid set of chromosomes and enter the first mitotic division