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Flashcards in Reproduction 1 Deck (88):
1

The 2 primitive duct systems?

  1. The wolffian
  2. The mullerian 

All early embryos have both

2

What happens in males?

The wolffian ducts progress

Mullerian ducts degenerate

3

What are the importance of the foetal testes?

Secrete both testosteron and mullerian inhibiting factors

Development into male or females depends upon these hormones

4

Testerone

Stimulates by human chorionic gonadotrophin from placenta

5

Mullerian inhibiting factors?

MIF

Induces regression of mullerian ducts

6

Detailed diagram on the pathway to be female or male?

See sheet

7

Development of the gonads?

See sheet

8

Route of sperm

Testes

Epididymis

Vas deferens

Ejaculatory duct

Urethra

9

What does the testes do?

Produce sperm

10

What does the scrotum do?

Sac of skin in which testes are suspended in

11

Accessory glands?

Secrete semen to suspend and sustain sperm

12

Penis?

Transfer sperm to female

13

Testes?

Dual function

Producing sperm

Secreting testosterone

14

What percentage of testicular mass consists of highly coiled seminiferous tubules?

80%

15

Where does the testes develop?

In adominal cavity of foetus

16

When do the testes drop into scrotal sac ?

Just before birth

Sometimes more slowly-before puberty

17

Cryptorchidism?

Individual has reached adulthood and testes have not descended

18

Why do the testes have to descend?

Lower body temp outside the body

Faciliates spermatogenesis

19

Testosterone?

Produced in Leydig cells

Steroid hormone.

 

20

5 types of effects of testerone

 

  1. Before birth
  2. On sex-specific tissues- puberty
  3. On other reproductive events-sex drive
  4. On secondary sexual characteristics
  5. Nonreproductive events-anabolic hormone

21

Effects of testosterone on events before birth (testosterone)?

Masculinises the reproductive tract and external genitalia.

Promotes descent of the testes into the scrotum

22

Effects on sex-specific tissues (testosterone)?

puberty

Leydig cells secrete testerone again at puberty.

Promotes growth and maturation of the reproductive system.

Causes testes to enlarge- capable of spermatogenesis

23

Other reproductive effects of testosterone?

sex drive

Develops libido at puberty 

Can maintain it for life.

Controls GnH secretion

24

Effects on secondary sexual characteristics (testosterone)?

Induces male pattern of hair growth.

Enlarges larynx & thickens vocal cords.

Thickens skin

Causes male body shape

25

Non reproductive events (testosterone)?

Anabolic- promotes protein and bone growth/development.

Thats why males are more muscular than females

Induces oil secretion

26

Spermatogenesis?

Sperm produced in seminiferous tubules in testes

27

2 types of cells used in spermatogenesis?

Germ cells

Sertoli cells- support spermatogenesis

28

Diagram of spermatogenesis?

ADD ADDITIONAL SHEET

29

Name the 3 stages of spermatogenesis?

  1. Mitotic proliferation
  2. Meiotic division
  3. Spermiogenesis

30

Miotic proliferation

Spermatogonia divide.

Divides 3 times before forming primary spermatocytes (46 chromosomes)

31

Meiotic division

1st meiotic divison: each primary spermatocyte divides into 2 haploids (secondary spermatocytes)

2nd meiotic divison: secondary spermatocytes divide to form 2 single-strande spermatids.

32

When is testosterone required for spermatogenesis

During mitosis and meiosis stages

33

Spermiogenesis?

Packaging.

Spermatides converted to spermatozoa.

FSH is required for this process

34

Structure of the sperm?

Acrosome contains enzymes for penetration of ovum.

Nucleus: contains genetic material

Tail: for motility

35

How many days does spermogenesis take?

64 days

36

Name the 6 roles of the sertoli cells?

  1. Form a blood-testes barrier (tight junctions to protect the pserm from antibody attack)
  2. Provide nutrients for the developing cell
  3. Phagocytosis (removes unneeded compounds)
  4. Secrete seminiferous tubule fluid (used to carry cell along pressure gradients)
  5. Secrete androgen binding protein (binds testosterone for sperm production)
  6. Secrete inhibitin (regulates FSH)

37

What do the sertoli cells secrete?

Mullerian inhibiting factor (MIF)

38

Name the 2 gonadotropic hormones that control the testes?

Both produced by the anterior pituitary

LH (acts on leydig cells- regulates testosterone secretion)

FSH (acts on sertoli cells to enhance spermatogenesis)

Both are stimulated for secretion by GnRH

39

What does the testis do?

Produce sperm and secrete testosterone.

Located in the scrotum

40

Epididymis and ductus deferens?

Serve as the sperms exit route from the testis.

The site for maturation of the sperm for motility and fertility.

Concentrate and store the sperm before release

41

Seminal vesicle?

Supply fructose to nourish the ejaculated sperm.

Serete prostaglandins that stimulate motility to help transport the sperm within the male and female.

Provide the bulk of the semen.

Provide precursors for the clotting of semen

42

What does the prostate gland do?

Secretes an alkaline fluid that neurtralises the acidic vaginal secretions.

Triggers clotting of the semen to keep the sperm in the vagina.

43

What does the bulbourethral gland do?

Secrete mucus for lubrication

44

What happens in the hormonal sense during puberty?

Androgen secretion from the adrenal cortex. This stimulates testicular enlargement and public hair growth.

 

Tests mature and produce androgen and sperm triggered by FSH and LH. What triggers GnRH production is not clear

45

2nd sexual characterisitics that occur during puberty?

Appear due to the testosterone and metabolites.

Growth of larynx- deepening of voice

Increased bone mass- increasing mass and strenth

Thickened skin- increased and thickened hair.

46

How long does it take for somatic growth to finish (puberty)?

What hormones induce this growth?

Induced by gonadal sex steroids, growth hormone and insulin-like growth factor.

Pubery last many year: not fully mature until 20-25 yo.

47

Name the 6 essential role female reproductive system function?

  1. Production of ova
  2. Reception of sperm
  3. transport of sperm and ova to site of fertilisation
  4. Gestation
  5. Partuirtion
  6. Nourishment of the infant by lactation

 

48

What do the ovaries do?

Maturation and release of ova

49

What does the oviducts (fallopian tubes) do?

Site of fertilisation

50

What does the uterus do?

Maintains foetus during gestation

Expels foetus at end of gestation

51

What does the cervix do?

Has a small opening to allow sperm through to uterus

Expands greatly during birth

52

What does the vagina do?

Receptacle for sperm.

Birth canal

53

What does the vaginal opening do?

Allow penis in

Allow baby out

54

What does female external genitalia do?

No physiological involvement in reproduction

Involved in stimulation

55

Oogenesis?

Identical meiotic and mitotic division to male sperm production

oogenesis tkes many years 

Begins in utero

 Suspended for many years

Begins again at puberty

Complete meiosis 2 at fertilisation

56

What happens during menopause?

Because all the ovums are produced before birth and none are made during your life there is only a limited number of eggs.

Menopause is when there is no eggs left and oogenesis ceases.

57

Stages of oogonesis?

See additional sheet

58

Before birth: 

Stages of oogenesis?

Mitoitic stage.

One oogonium goes through mitosis to produce lots of primary follicles with 46 chromosomes.

Starts mieosis but is suspended in the prophase stage until puberty

59

After puberty:

What happens in oogenesis?

The primary oocyte enlarges and finishes the first meiosis phase making the first polar body and secondary oocyte.

The secondary oocyte undergoes meiosis 2 but is suspended in the metaphase stage until fertilisation.  This produces the mature ovum and a secondary polar body.

60

What does the polar body contain?

How many are produced?

4 in total are produced.

Contains have the chromosomes but very little cytoplasm.

 

61

Ovarian cycle lasts?

28 days averagely

 

62

What are the 2 phases of ovarian cycle?

Follicular phase 

Luteal phase

 

63

Follicular phase?

1st half of cycle.

Maturation of egg, ready for ovulation at midcycle

64

Luteal phase

2nd half of cycle

After ovulation

Development of corpus luteum

Induces preparation of reproductive tract for pregnancy

65

What day averagely does ovulation take place?

Day 14

66

What does the corpus luteum do?

keep the levels of progesterone high before the placenta can take over

67

Primary follicle characteristics?

Before birth, the primary oocyte is surrounded by a single layer of granulosa cells. This strucutre is called a primary follicle

2 million at birth (decrease after each cycle)

Until puberty: all 1st generation follicle degenerates to scar tissue and after puberty 2nd generation follicles develop cyclically.

68

Secondary follicle?

Oocyte grows and follicle expands.

Becomes differentiated under hormonal influence.

After puberty, about 0.02% will be ovulated the rest will undergo atresia

69

What is atresia?

Degeneration of some follicles into scar tissue

70

The luteal phase?

Follicular cells left behind after ovulation undergo luternisation.

71

Luteinisation meaning?

Transformation to the corpus luteum

72

Corpus luteum?

Secretes progesterone and oestrogen

Oestrogen secreted in follicular phase and progesterone secreted in luteral phase. Essentail for preparation of uterine lining for implantation.

After ovulation, corpus luteum grows for 8-9 days.

No fertilisation: will not survive longer than 14 days.

Degeneration of corpus luteum signals start of a new follicular pahse.

73

What happens to the corpus luteum if fertilisation occurs?

Corpus luteum persists

Produces increasing quantities of progesterone and oestrogen

74

Hormone control over ovarian cycle?

See additional sheet

75

What hormones cause the oocyte to mature and eventually the maturation of corpus luteum?

LH and FSH

76

What causes the maturation of the endometrium?

Estrogen and progesterone.

See additional sheet

77

What does menstruation mark?

The beginning of both uterine and ovarian cycle

78

During the first 12 days of the ovarian cycle estrogen does?

It exerts negative feedback on gonadtropin release

Decrease levels of FSH and LH

79

What does estrogen do during day 12-14 ?

Exerts its positive feedback on the pituitary

Increase levels of FSH and LH

80

What triggers ovulation

Surge in LH

81

What are estrogen and progesterone important for?

The maintenance of the uterine lining

Send negative feedback to the anterior pituitary.

82

What would happen if no progesterone was produced?

The uterine lining sloughs off 

menstruation occurs

83

what happens when there is a decrease in estrogen and progesteron?

Relieves its neative feedback on the anterior pituitary

GnRH , FSH and LH increase.

New ovarian cycle

84

Adrenarche?

Age 6-8 yo.

Adrenal gland secretes androgens.

Eventually cause growth spurt ad public hair stars

85

Thelarce?

Breast development starts

86

Menarche?

onset of menstrual cycle

10-16 yo.

Increase FSH and LH from pituitary 

Ovaries producing steroids.

87

What happens to the epiphseal plates during puberty?

Closure.

Stop growing.

Because of estrogen in females and testosterone in males.

88

Menopause?

FSH levels rise.

Ovarian oestrogen, progesteron and inhibin fall.

Cessation of ovulation and menstruation Hot flushes.