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Bmsc 208 > Repro 2 > Flashcards

Repro 2 Flashcards

1
Q

Bipotential parts of external genitalia

A

Genital tubercle, urethral groove, urethral fold, labioscrotal swelling

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2
Q

If female genital tubercle

A

Forms clitoris

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3
Q

If female urethral folds and grooves

A

Form labia minora, opening of vagina and urethra

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4
Q

If female labioscrotal swellings

A

Form labia Majora

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5
Q

If male genital tubercle

A

Forms glans penis

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6
Q

If male urethral folds and grooves

A

Form shaft of penis

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7
Q

If male labioscrotal swellings

A

Form shaft of penis and scrotum

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8
Q

External genitalia development is driven by

A

Presence or absence of androgens (DHT)

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9
Q

At 10 weeks of female growth (external)

A

In absence of androgens external genitalia is feminized

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10
Q

At 10 weeks of male growth (external)

A

DHT causes development of male external genitalia

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11
Q

At birth males (external)

A

Testosterone causes Testes to descend from abdominal cavity into scrotum

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12
Q

When did importance of DHT come to light

A

Studies of male pseudohermaphrodites

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13
Q

What do pseudohermaphrotdites lack

A

Have defective gene for 5a reductase
Needed for conversion of testosterone to DHT

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14
Q

What does no DHT cause for pseudohermaphrodites

A

Despite having testosterone
- failure of male external genitalia and prostate development
- appear female at birth, male internal
- at puberty testes begin to secrete testosterone causing masculinzatin of external genitalia

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15
Q

Testis and ovaries both produce

A

Hormones and gametes

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16
Q

Ovum

A
  • some of largest cells in body
  • nonmotile, move via smooth muscle contraction or cilia
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17
Q

What are all females born with

A

All oocytes, cyclically released during reproductive years
After ~40 years in ceases

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18
Q

Sperm

A
  • quite small
  • only flagellated cells in body
  • highly motile
  • continuously produces after reaching reproductive maturity
  • sperm and testosterone production dismisses with age but not cease
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19
Q

Gametogenesis

A

Production of gametes

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20
Q

What does gametogenesis begin with

A

Mitosis in utero to increase germ cell numbers

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21
Q

Female germ cells

A

Oogonia

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22
Q

Male germ cells

A

Spermatogonia

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23
Q

How many viable gametes does 1 sperm cell produce

A

4

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24
Q

How many viable gametes does 1 female germ cell produce

A

1

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25
Q

Steps of gametogenesis

A
  1. Germ cells in embryonic gonads undergo mitosis divisions to increase number
  2. Meiosis: Duplication of chromosomes (92 chromatids)
  3. One primary gamete divides into 2 secondary gametes (each with 46 chromosomes)
  4. Secondary gametes divide again to produce haploid gametes (23 chromatids)
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26
Q

Female gametogenesis

A
  • significant mitosis in embryonic and fetal development (lots of oogonia)
  • enter meiosis and create large pool of primary oocytes
  • stay arrested until reproductive age
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27
Q

At birth ~ how many primary oocytes in each ovary

A

5000

28
Q

When does second meiotic division occur for females

A

Ovary releases egg and it does not until Fertilization

29
Q

When does mitosis and first stage of meiosis occur by in females

A

Fifth month of fetal development

30
Q

When does meiosis resume in females

A

Puberty

31
Q

First meiotic division in females

A

Produces large secondary oocyte and tiny first polar body (46 chromosomes)

32
Q

What happens when egg begins second meiotic division

A

Polar bodies break down

33
Q

How many chromosomes does secondary oocyte contain

A

46

34
Q

Once sperm begins to fertilize secondary oocyte what does it undergo

A

Meiotic division shedding a polar body containing 23 chromosomes
Leaves 23 in ovum and 23 new chromosomes enter sperm

35
Q

Why dont polar bodies survive

A

Uneven division
Very small with very little cytoplasm and few organelles

36
Q

In both males and females gametogenesis is under control of

A

Hormones from brain and from endocrine cells in gonads

37
Q

When does significant mitosis happen for males

A

Once reach reproductive age

38
Q

At birth what do testes contain

A

Only immature germ cells and remain quiescent

39
Q

At puberty what happens to germ cells in males

A

Mitosis resumes producing spermatogonia

40
Q

What happens to spermatogonia if they do not continue in mitosis

A

Some enter meiosis producing primary spermatocytes, secondary spermatocytes, spermatid then sperm

41
Q

What directs resproduction

A

Brain

42
Q

For both male and female what doses reproduction begin with

A

Secretion of peptide hormones from hypothalamus and anterior pituitary that control gonadal secretion of sex hormones
- androgens, estrogens, progrestorone

43
Q

What sex hormones do both sexes produce

A

Androgens, estrogens, progesterone

44
Q

Males primarily secrete

A

Androgens
95% testes, 5% adrenal cortex
Most converted in periphery to DHT

45
Q

Females primarily secrete

A

Estrogens and progesterone (ovaries)

46
Q

What is the sex hormone precursor

A

Cholesterol

47
Q

What is the main control pathway for the reproductive system

A

Hypothalamic pituitary gonadal axis

48
Q

Gonatropin releasing hormone (GnRH)

A

Produces in hypothalamic neurons
Controls secretion of 2 anterior pituitary gonadotropins from gonadotropes

49
Q

What are the 2 ant. Pit. Gonadotropins

A

Follicle stimulating hormone (FSH)
Luteinizing hormone (LH)
Act on gonads

50
Q

What regulates GnRH

A

Kisspeptin

51
Q

What does LH act on

A

Endocrine cells
In females gamete production

52
Q

What does FSH act on

A

Gamete production

53
Q

How does GnRH get to anterior pituitary

A

Hypophyseal portal system

54
Q

How does hypophyseal portal system work

A

GnRH secreted enters capillary bed at base of hypothalamus
Travels through portal veins to 2nd capillary bed in ant. Pit.
GnRH stimulates gonadotropes
LH and FSH enter 2nd capillary bed and travail via blood stream to gonads

55
Q

What is short loop negative feedback

A

Involves LH and FSH inhibiting GnRH release from hypothalamus

56
Q

Low estrogen or androgen(testosterone)

A

Absence of negative feedback
Increases in GnRH, LH and FSH

57
Q

Moderate estrogen or androgen

A

Negative feedback
Decreases GnRH

58
Q

High androgen

A

Negative feedback
Decreases

59
Q

Sustained high estrogen

A

Positive feedback
Increases to drive LH

60
Q

Why is estrogen negative feedback to a point

A

Flips to positive driving GnRH and LH even higher
Plays role in female reproductive cycle

61
Q

What does feedback at anterior pituitary affect

A

Gonadotropes

62
Q

What does feedback at hypothalamus act on

A

Directly on GnRH neurons or via kisspeptin

63
Q

How is GnRH released from hypothalamus

A

In pulsatile fashion every 1-3 hours in both sexes

64
Q

Females have a surge of GnRH release

A

Corresponding with ovulation

65
Q

Children with GnRH deficiency

A

Not mature sexually without gonadotropin stimulation
Synthetic GnRH must be delivered in pulsatile manner

66
Q

What does constant delivery of GnRH lead to

A

Down regulation of receptors in pituitary gonadotropes
- receptors internalize
- must be pulsatile

Bmsc 208 (33 decks)

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