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MedSci ๐Ÿ‘ฉ๐Ÿปโ€โš•๏ธ > reproductive system๐Ÿ๐ŸŒธ lecture 1 > Flashcards

reproductive system๐Ÿ๐ŸŒธ lecture 1 Flashcards

1
Q

Reproduction is the processโ€ฆ

A

which new individuals of a species are produced and the genetic material is passed on from generation to generation

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2
Q

Reproductive processes are mediated by

A

a hierarchical arrangement of endocrine glands ultimately under the control of the central nervous system, but with complex regulatory mechanisms operating between the various levels of the hierarchy.

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3
Q

Hypothalamus main function is to

A

act as a homeostatic regulator for reproduction, stress, body temperature, hunger, thirst, and sleep.

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4
Q

The hypothalamus is a

A

neuroendocrine organ, as it processes both neural and hormonal information.

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5
Q

Posterior pituitary

A

hormones are released from the posterior pituitary.

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6
Q

Neurosecretory neurones are aggregatedโ€ฆ

A

into nuclei

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7
Q

Neurosecretory cells possess long axon tracts which pass into the

A

posterior pituitary

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8
Q

The neurosecretory peptide hormones are synthesised where ?

A

in the hypothalamus

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9
Q

travel bound to carrier proteins down to the axon terminals and stored in

A

secretory vesicles

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10
Q

Nerve impulses travel along the axon to trigger exocytosis of the secretory vesicles which releases

A

peptide hormones.

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11
Q

The two neurosecretory peptide hormones are

A

oxytocin and antidiuretic hormone (ADH or vasopressin).

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12
Q

neurosecretory peptide hormones are synthesised in the hypothalamus and transported to..

A

posterior pituitary, where they are stored and released

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13
Q

Oxytocin

A

has major efects on smooth muscle contraction, causing milk ejection and contraction of uterus during childbirth. Secretion is stimulated in response to stimulation of nipples or uterine distension. Oxytocin is used to induce labour.

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14
Q

Anterior pituitary

A

Neurosecretory neurones synthesise releasing and inhibiting hormones in their cell body into vesicles, which travel to the axonal terminus

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15
Q

In response to nerve impulses, these neurosecretory peptide hormones are secreted into

A

linking hypophyseal portal vessels, a vascular arrangement in which blood lows from one capilliary bed to another without going through the heart in its journey.

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16
Q

Gonadotrophs

A

anterior pituitary secretory cells arranged in clumps at the termini of the portal blood vessel.
Inhibiting hormones act on

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17
Q

Gonadotrophs (producing the two gonadotrophins;

A

Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH)).

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18
Q

Gonadotrophin releasing hormone (GnRH)

Site of secretion , Chemical class

A

Hypothalamus
Water Soluble
Peptides and proteins

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19
Q

Follicle-stimulating hormone

Site of secretion , Chemical class

A

Anterior pituitary

Water Soluble
Peptides and proteins

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20
Q

Luteinising hormone

Site of secretion , Chemical class

A

Anterior pituitary

Water Soluble
Peptides and proteins

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21
Q

Oxytocin

Site of secretion , Chemical class

A

Posterior pituitary

Water Soluble
Peptides and proteins

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22
Q

Androgens

Site of secretion , Chemical class

A

Testes

Lipid Soluble Steroid hormones

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23
Q

Oestrogens

Site of secretion , Chemical class

A

Ovary

Lipid Soluble Steroid hormones

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24
Q

Progestagens

Site of secretion , Chemical class

A

Ovary

Lipid Soluble Steroid hormones

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25
Q

Features of hormone regulation

A

Homeostatic mechanisms involving negative and positive feedback loops regulate hormone levels

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26
Q

Negative feedback

A

control is one of the most important mechanisms. This often involves signalling between the hypothalamus, the pituitary and the target organ.

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27
Q

Pulsatile release

A

Hypothalamic secretions are released in discrete bursts, separated by periods of little or no secretion. Seen as a pulsatile release of pituitary hormones. This prevents receptor desensitisation and down-regulation.

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28
Q

Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH)

A

Bind to receptors in the ovary and testis. Promote the synthesis of sex steroid hormones and gametogenesis.

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29
Q

Androgens

A

Testosterone is the main secretory product of the testis, and associated with the development and maintenance of male characteristics and fertility.

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30
Q

Testosterone 5ฮฑ Dihydrotestosterone

Some key properties

A
  • Male sex development
  • Spermatogenesis
  • Sexual behaviour
  • Muscle development
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31
Q

Oestrogens Main role

A

is in development and maintenance of female characteristics and fertility.

The main site of oestrogen production is the granulosa cells of the growing follicle.

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32
Q

Oestradiol
Oestrone
Oestriol

Some key properties

A
  • Female sex development
  • Growth of the endometrium
  • Regulation of the menstrual cycle
  • Bone growth
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33
Q

Progesterone is the major

A

steroidal hormone of the corpus luteum and of the placenta. Associated with the preparations for pregnancy and its maintenance.

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34
Q

Sex determination

A

Commitment of the bipotential gonad to a testis or an ovary.

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35
Q

The Sex-determining Region on the Y chromosome (known as the SRY gene) provides

A

the pathway for testes to develop.
The presence of a testis determines the sexual fate of the embryo, against the basic feminine trend. In the absence of SRY, the embryo develops into a female.

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36
Q

Sex diferentiation

A

The phenotypic development of genital structures due to the action of hormones produced following gonadal development.

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37
Q

Male diferentiation The internal genitalia

Mรผllerian duct regression occurs under the control of

A

Anti-mรผllerian hormone (AMH)

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38
Q

Male diferentiation The internal genitalia

Testosterone secreted by the testis actively maintain

A

Wolffian ducts.

39
Q

Male diferentiation The internal genitalia

The Wolan ducts develop into

A

epididymis, vas deferens and seminal vesicles.

40
Q

The internal genitalia

The testis descends from its internal position to the scrotum, usually after

A

7th month.

41
Q

The internal genitalia Female diferentiation

The Wolan ducts

A

begin to regress slowly from about 10 weeks.

Female diferentiation of the genital tract lags behind male organogenesis

42
Q

Female diferentiation The internal genitalia

The Mรผllerian ducts develop

A

fallopian tubes, uterus, cervix, and upper vagina.

43
Q

The external genitalia

A

The male and female external genitalia develop from a single bipotential precursor.

44
Q

The external genitalia

Male diferentiation
How is the shaft of the penis formed

A

Fusion of the urethral folds enclosing the urethral tub

45
Q

The external genitalia

Male diferentiation
How is the scrotum formed

A

Labioscrotal swellings fuse in the midline

46
Q

The external genitalia

Male diferentiation

Hope is the glans penis formed

A

The genital tubercle (glans area) expands

47
Q

The external genitalia Female diferentiation

How is the labia minora and majora formed

A

The urethral folds and labioscrotal swellings remain separate

48
Q

The genital tubercle (glans area) forms

A

the clitoris

49
Q

Puberty

A

Puberty is the physical, emotional, and sexual transition from childhood to adulthood.

50
Q

reawakeningโ€ of the reproductive endocrine systems, which leads to full

A

secondary sexual maturation with capacity for reproduction

51
Q

gonadotrophins are very low during childhood until

A

initiation of events leading to puberty.

52
Q

Endocrine changes during puberty

irst endocrine sign of puberty

A

An increase in plasma LH levels

and is the result of an increase in GnRH release.

53
Q

Gonadotrophin secretion (both LH and FSH) occurs in early puberty at

A

night during sleep.

54
Q

In late puberty, daytime

A

LH pulses also increase.

55
Q

Sex steroids rise in response to

A

increase in plasma LH.

56
Q

Secondary sexual characteristics

A

Characteristics develop at diferent chronological ages in different individuals the sequence in which the changes occur are quite characteristic for each sex staging criteria (Tanner stage) allows abnormalities to be detected, and comparisons made between individuals.

57
Q

Menopause

A

The menopause is the consequence of the ovaries running out of follicles, and occurs between 50 and 52 years of age.

58
Q

Menopause

Postmenopausal oestrogen production

A

one year after the menopause the ovary has essentially ceased producing hormones (ovarian senescence). Oestrogen production reduces to less than one- tenth of previous.

59
Q

Menopause

Oestrogen (oestrone) arises mainly from

A

production in the stromal cells of adipose tissue. Oestrone is a weak oestrogen.

60
Q

Menopause Symptoms

Vasomotor

A

hot lushes night sweats

61
Q

Menopause Symptoms

Genitourinary symptoms

A

atrophic changes vaginal dryness

62
Q

Menopause Symptoms

Bone metabolism

A

osteoporosis

63
Q

Menopause Symptoms

Behavioural/Psychological changes

A

depression, tension, anxiety, mental confusion loss of libido

64
Q

Most of these symptoms of the menopause may be prevented or arrested by

A 
oestrogen treatment (known as menopausal hormone therapy).
However higher risk of cancers
65
Q

GnRH only has a

A

Positive effect

66
Q

5 alpha dihydeotestostrone

A

More patient has a more direct effect on target tissue

67
Q

Oestradiol is produced

A

From puberty to menopause

By grandulosa cells and granule follicles

68
Q

Oestrone

A

. Main one in men
Produced in fat tissue
Important after menopause

69
Q

Oestriol

A

Weaker

Important during pregnancy

70
Q

Progesterone

A

Only in women for pregnancy regulation/ maintains lining of uterus
. Seen after mensuration

71
Q

How many chromosomes

A

46

72
Q

How many autosomes

A

22 pairs of autosomes

73
Q

Why do males develop earlier

A

Due to driving hormones

74
Q

Mรผllerian duct regression due to

A

Secretions from the sitloe cells

75
Q

Wolffian duct driven by

A

Secretions from the laydig cells e.g testosterone

76
Q

Androgen insensitivity syndrome

A

. Person is Xy
. Has has testes, but the genital ducts and/or external genitals are female.
. This person has a mutation in their androgen receptor gene which prevents androgen function
. In the absence of androgen action, the external genitalia will appear female.

77
Q

Breast development
Time and age
What leads to it

A

.First physical sign of secondary sexual maturation at age ~10-11
.Oestrogen secretion leads to the appearance of a breast bud, followed by formation of a breast mound
.Ovulation, with subsequent progesterone secretion, leads to full breast development

78
Q

Sexual hair development
Age and time
What causes it

A

Usually within 6 months of the appearance of the breast bud at age ~10-12
Due to exposure of hair follicles to androgens
Axillary hair follows ~1 year after pubic hair

79
Q

Growth spurt
Stimulated
Ages f and m

A

Growth is stimulated by steroid hormones (oestrogen and androgen), with epiphyseal closure (bony ends) by oestrogen.
Occurs in girls age ~11-12, and boys age ~13-15

80
Q

Menarche

Age and time

A

Menarche occurs at an average age of 12-13 years.
The first ovulation does not take place until 6-9 months after menarche, because the positive feedback mechanisms of oestrogen have not developed.

81
Q

Regular ovulatory cycles are established โ€ฆ

A

1-2 years after menarche.

82
Q

Testicular and penile enlargement

Are

A

First signs of secondary sexual development is enlargement of the testicles

83
Q

What causes Testicular and penile enlargement

A

Leydig cells enlarge and secrete testosterone, giving rise to increased testicular size.
Elongation and enlargement of the penis begins within year of testicular enlargement.

84
Q

Physical changes in boys
Sexual hair growth
Time

A

Pubic hair appears about 6 months after the beginning of testicular enlargement

85
Q

Physical changes in boys

Sexual hair growth Axillary hair begins

A

18 months later, and facial hair later

86
Q

Physical changes in boys

Spermache

A

Motile sperm is seen in urine at ~13-14 years

First ejaculation occurs soon after

87
Q

Physical changes in males and females

A

Body shape in males and females is determined by the differential affects of androgen and oestrogen

88
Q

The timing of puberty
Girls
And what weight must be attained before the activation of the hypothalamo-pituitary-gonadal axis can occur.

A

The age at which girls first menstruate shows a clear trend towards earlier menarche in girls.
Mean weight of girls at the beginning of menarche is ~47 kg.

89
Q

Precocious puberty

The appearance of the physical & hormonal signs of puberty before: ages m and f

A

7 yrs in girls 9 yrs in boys

90
Q

Precocious puberty

A

Usually a GnRH dependent problem, often extreme cases are due to a hypothalamic tumour

91
Q

Delayed puberty

A

The lack of appearance of the physical and hormonal signs of puberty

92
Q

Delayed puberty

Ages and cause

A

~13 years in girls ~14 years in boys

Occurs when the gonadotrophin signals from the pituitary are inadequate for sex steroid hormone secretion.

93
Q

Menopause
Age and cause
Definition

A

The menopause is the ovaries running out of follicles,
50 and 52 years of age
Last natural menstrual bleeding signifies the end of her reproductive life and is referred to as the menopause

94
Q

Postmenopausal oestrogen production

A

one year after essentially ceased producing hormones

Oestrogen production reduces to less than one-tenth of previous
Oestrogen (oestrone) arises mainly from production in the stromal cells of adipose tissue.

MedSci ๐Ÿ‘ฉ๐Ÿปโ€โš•๏ธ (15 decks)

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