Chapter 20 - Female reproductive system Flashcards Preview

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Flashcards in Chapter 20 - Female reproductive system Deck (96):
0

What does the internal reproductive organs of the female reproductive system consist of?

- Paired ovaries
- Oviducts
- The uterus
- The vagina

1

What does the external reproductive organs of the female reproductive system consist of? (external genitalia)

- The clitoris
- The labia majora
- The labia minora

2

Are mammary glands considered to be a part of the female reproductive system?

Nope

3

Until when are the reproductive organs incompletely developed?

The reproductive organs are incompletely developed and remain in a state of rest until gonadotropic hormones secreted by the pituitary gland signal the initiation of puberty

4

Menarche

The first menstrual flow

5

Ovaries

- Paired
- Covered by germinal epithelium
- Divided into a cortex and medulla

6

Mesovarium

A special fold of the peritoneum that conveys blood vessles to the ovaries

7

Germinal epithelium

- The surface epithelium covering the ovaries
- Is a modified peritoneum

8

Germinal epithelium derive from..

The mesothelial epithelium -> covering the developing ovaries

9

Tunica albuginea

- Located beneath the germinal epithelium
- Poorly vascularized, dense, irregular collagenous connective tissue capsule whose collagen fibers are oriented more or less parallel to the ovary surface

10

Cortex and medulla

- Subdivision of the ovaries
- Consists mostly of a richly vascularized losse connective tissue

11

Where does the blood vessles of the medulla derive from?

They derive from the ovarian arteries

12

Ovarian cortex

- Composed of:
> Connective tissue stroma(=interstitial compartment) that houses fibroblast-like stromal cells(=interstitial cells)
> Ovarian follicles in various stages of development

13

Oogonia

- Primordial germ cells
- Develop in the yolk sac endodermal shortly after the first month of gestation
- Undergo mitotic divisions

14

What happens with the premordial germ cells (oogonia) during the 6th week after fertilization?

- They migrate to the germinal ridges to populate the cortex of the developing ovaries.
- Here they continue to undergo mitotic divisions until near the end of the 5th fetal month

15

How many oogonia does each ovary contain after the end of the 5th fetal month?

- 5 million to 7 million oogonia
- About 1 million oogonia become surrounded by follicular cells and survive to the time of birth.
- The remaining oogonia undergo atresia, which means that they degenerate and die

16

Primary oocyte

- Are oogonia that survived.
- They enter meiosis I and are called primary oocyte

17

Lutenizing (LH) and meiosis inducing factors

Trigger the primary oocyte after being arrested by meiosis-preventing substance. After that we get secondary oocyte and the first polar body

18

Lack of testosteron=

Does not permit the formation of wolffian ducts, the precusor of male genitalia tract

19

Lack of antimullerian hormone=

Permits the development of mullerian ducts, the precusor of female genitalia

20

Primordial follicle

Before puberty all of the follicles are in primordial follicle stage

21

Lutenizing hormone-releasing hormone (LHRH)

- Decapeptide
- Also known as Gonadrotropin-releasing hormone (GnRH)
- Produced by neurosecretory neurons of the arcuate nucleus and preotpic area of the hypothalamus
- Plays a big role in initiating puberty

22

Pulsatile release of FSH and LH

- From the basophils of the anterior pituitary

23

Ovarian follicles evolve through 4 developmental stages:

1. Primordial
2. Primary
3. Secondary
4. Graafian

24

Ovarian follicles

- Surrounded by stromal tissue
- Consists of a primary oocyte and its associated folliclar cells (granulosa cells)

25

Follicular cells are derived from

- Mesothelial epithelium
- Possibly also from the primitive sex cords of the mesonephros

26

Mesonephros

- The structure that develops into the definitive kidney
- A precusor of the metanephros

27

Primordial

Nongrowing follicles

28

Growing follicles

- Primary
- Secondary
- Graafian

29

Primary

- Unilaminar and multilaminar follicles
- Dependent of FSH

30

Secondary

- Secondary (antral) follicles
- Under the influence of FSH

31

Graafian

- Graafian (mature) follicles
- Under the influence of FSH

32

Which follicles are the most primitive follicles?

Primordial follicles

33

Primordial follicles are composed of:

- Primary oocyte surrounded by a single layer of flattened follicular cells

34

Primary oocyte (arrested in the prophase stage of meiosis I)

- Acentric nucleus
- Single nucelolus
- Uncoiled chromosomes

35

Squamous follicular cells (in the primordial follicles)

- Completely surround the primary oocyte
- Are attached to each other by desmosomes
- Separated from the connective tissue stroma by a basal lamina

36

Primordial follicle develop into

Primary follicles

37

Germinal vesicle

Enlarged primary oocyte nucleus

38

Primary follicular cells

- Cuboidal in shape

39

Unilaminar primary follicle

A single layer of follicular cells encricles the oocyte

40

Multilaminar primary follicle

- When follicular cells proliferate and stratify, forming several layers of cells around the primary oocyte.
- The follicular cells are refered to granulosa cells

41

Activin

- Produced by primary oocyte
- The reason for the proliferative activity of the granulosa cells
- Produced by granulosa cells
- Stimulates the release of FSH form the pituitary gland

42

Zona pellucida

- Separates the oocyte from the surrounding follicular cells
- Composed of 3 different glycoproteins secreted by the oocyte
> ZP1
> ZP2
> ZP3

43

Gap junction

- Primary follicular cells and the oocyte
- Necessary for the oocyte to be able to progress through meiosis

44

Inner theca interna

- Formed by stromal cells that are organized around the multilaminar primary follicle
- Composed mostly of a richly ascularized cellular layer

45

Outer theca externa

- Formed by stromal cells that are organized around the multilaminar primary follicle
- Composed mostly of fibrous connective tissue

46

Cells composing theca interna

- Possess LH receptors on their plasmalemma
- Accumulate lipid droplets in their cytoplasm
- produce the male sex hormone adrostenedione

47

Androstenedione

Enters the grnaulosa cells where it is converted by the enzyme aromatase into the estrogen estradiol

48

What separates the granulosa cell from the theca interna?

Thickened basal lamina

49

Secondary (antral) follicles

- Are similar to primary follicles exept for the presence of accumulations of liquor folliculi among the granulosa cells
- NB: Once the multilaminar primary follicle displays the presence of liquor folliculi, it is known as secondary follicle.

50

Liquor folliculi

- Fluid located in the intercellular spaces within the mass of granulosa cells
- Contains:
> Glycosaminoglycans, proteoglycans, and steroid-binding proteins produced by granulosa cells
> Progesteron, estradiol, inhibin, folliostatin (folliculostatin), and activin, which regulate the release of LH and FSH

51

What is released from the basophils in the anterior pituitary gland?

FSH

52

The granulosa cells of the secondary follicle

- Influenced by FSH
> The number of granulosa cells increase
> The number of liquor folliculi increases

53

Corona radiata

Surrounds the primary oocyte

54

When does the stromal cells enlarge and the theca interna is invaded by capillaries that nourish them as well as the avascular granulosa cells?

At the end of secondary (antral) follicles

55

What happens with most of the follicles that reaches the end of secondary (antral) follicles?

They undergo atresia, but some of the granulosa cells associated with the atretic follicles do not degenerat;
instead, they form interstitial glands, which secret small amounts of androgens until menopause is concluded

56

Does every secondary follicle continue to develop into mature follicles?

No, a few secondary follicle continue to develop into mature follicles

57

Graafian (mature) follicles

- May be as large as the entire ovary
- These follicles undergo ovulation
- Looks like a transparent bulge on the surface of the ovary

58

Membrana granulosa

the follicular cells of the wall of the follicle compose the membrana granulosa

59

What is the results of the continued formation of the liquor folliculi in the graafian (mature) follicles?

Cause the cumulus oophorus composed of the primary oocyte, the corona radiata, and associated follicular cells to become detached from its base to float freely within the liquor folliculi.

60

Ovulation

The process of releasing the secondary oocyte from the graafian follicle

61

Meiosis-inducing substance

Under the influence of meiosis-inducing substance the primary oocyte of the gaafian follicle resumes and completes its first eiotic division, resulting in the formation of two daughter cells
> The secondary oocyte
> The first polar body

62

The first polar body

Is composed of a nucleus surrounded by only a narrow rim of cytoplasm

63

What happens with the secondary oocyte after its formation?

It enters the 2nd meiotic division and is arrested in metaphase

64

Stigma

Avascular region

65

What causes ovluation

The connective tissue at the stigma degenerates, as does the wall of graafian follicle in contact with the stigma, forming an opening between the perioteneal cavity and the antrum of the graafian follicle. Through this opening, the secondary oocyte and its attendant follicular cells and some of the liquor folliculi are gently released from the ovary, resulting in ovulation

66

When is ovulation?

14 days before the beginning of menstruation

67

Where is the oocyte fertelized?

In tha ampulla

68

What happens with the oocyte if it is not fertelized?

It degenerates and is phagocytosed

69

Corpus luteum

- Highly vascularized structure
- Composed of:
> Granulose-lutein cells (modified granulosa cells)
> Theca-lutein cells (modified theca interna cells)

70

Granulose-lutein cells (modified granulosa cells)

- Long microvilli
- Develop all organelles necessary for steroid production, inlcuding some lipid droplets
- Produce progesterone
- Convert androgen produces by the theca-lutein cells into estrogens

71

Theca-lutein cells (modified theca interna cells)

- Derived from cell of theca interna
- Secret: progesteron, androgens, and estrogens

72

What does the absens of LH do to the corpus luteum?

It leads to the degeneration of the corpus luteum.

73

Progesteron and estrogen is secreted by?

Granulosalutein and theca-lutein cells

74

What inhibits the secretion of LH?

Progesteron

75

What inhibits the secretion of FSH?

Estrogen

76

Absens of FSH

Prevents the development of new follicles = preventing ovulation

77

If pregnency does not occure the absens of LH leads to..

degeneration of corpus luteum, forming the corpus luteum menstration

78

Human chorionic gonadotropin (hCG)

- Secreted by the placenta
- Maintain the corpys luteum for 3 months -> corpus luteum of pregnancy
- Both placenta and corpus luteum secret hormons necessary for the maintanance of pregnancy

79

Atretic follicles

Follicles that undergo degeneration

80

Medulla

- Central region of the ovary
- Composed of fibroblasts loosely embedded in a collagenn meshwork containing elastic fibers
- Conatins:
> Large blood vessles
> Lymph vessles
> Nerve fibers

81

Cluster of epitheloid interstitial cells

- Located in the medulla of the premenstrual human ovary
- Secret estrogen

82

Interstitial glands

Collection of many clusters of intestitial cells

83

Hilus cells

- Constitutes another group of epitheloid cells in the ovarian medulla
- Contains the same substances in their cytoplasm as the Leydig cells of the testes
- Secret androgens

84

What regulates the maturation of ovarian follicles ond ovulation?

FSH and LH

85

Aromatase

Enzyme of the granulosa cells that converts adrogen into estrogens

86

Granulosa cells of secondary follicles also produce other hormones like that help to regulate the release of FSH:

- Inhibin
- Folliostatin
- Activin

87

Which cells have LH receptors?

Granulosa cells and theca interna cells of the remaining ovulated follicle

88

Which cells are activated by LH to form the copus luteum?

Granulosa cells and theca interna cells

89

What does these lutein cells produce after converting?
Granulosa cells -> Granulosa-lutein cells
Theca interna cells -> Theca-lutein cells

Progesteron

90

Corpus albicans

Corpus albicans, a fibrous connective tissue that continues to be resorbed until it becomes just a scar on the surface of the ovary.

91

How do the cells in corpus luteum die?

Macrophages release tumor necrosis factor- a, which drives cells of the corpus luteum into apoptosis.

92

What is the free, periotoneal, end of the oviduct?

The infundibulum is the free end of the oviduct, and its fimbriae press against the ovary during ovulation to trap the secondary oocyte, its attendant follicular cells, and the first polar body.

93

The ampulla

The ampulla is the enlarged continuation of the infundibulum—normally the site of fertilization

94

The intramural region

The intramural region of the oviduct pierces the
wall and opens into the lumen of the uterus.

95

The isthmus

The isthmus is the narrow region between the
intramural region and the ampulla.