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brs (phase 1a) > (endo) male & female reproductive systems > Flashcards

(endo) male & female reproductive systems Flashcards

1
Q

what is the function of the testes?

A

site of spermatogenesis

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2
Q

where are the testes suspended and why?

A

suspended in scrotum to keep temperature 2-3 degrees lower than in body
= as if temperature increases, spermatogenesis ceases

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3
Q

what is the function of the epididymis?

A

stores and matures the sperm

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4
Q

what happens to sperm that is not ejaculated?

A

if not ejaculated -> broken down

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5
Q

what is the function of the ductus deferens?

A

transports sperm to penis

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6
Q

what is the function of the prostate and seminal vesicles?

A

secrete seminal fluid to support ejaculated sperm

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7
Q

what is the function of the penis?

A

deposits sperm in vagina

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8
Q

what are the components of seminal fluid?

A

fructose

citric acid

bicarbonate (neutralise vaginal acidity)

fibrinogen

fibrinolytic enzymes

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9
Q

what muscles make up the penis?

A

x2 corpora cavernosa

x1 corpora spongiosum

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10
Q

explain the nervous control of an erection

A

erection is due to arterial relaxation due parasympathetic stimulation, which results in increasing arterial pressure which obstructs venous drainage

(‘point & shoot’)

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11
Q

explain the nervous control of ejaculation

A

ejaculation is due to sympathetic stimulation

‘point & shoot’

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12
Q

what is the function of the bulbo-urethral glands?

A

secrete sugar-rich mucus into urethra for lubrication and contribute to pre-ejaculatory emissions from penis

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13
Q

describe the route of the spermatic cord

A

suspends the tests, is formed at deep inguinal ring and passes along inguinal canal and then down to scrotum

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14
Q

name some structures of the spermatic cord

A

vas deferens

testicular artery

pampiniform plexus of veins

autonomic nerves

lymph vessels

artery of vas

cremasteric artery

genital branch of genitofemoral nerve

remnants of processus vaginalis

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15
Q

what are the tissue layers surrounding the testes?

A

tunica vasculosa
tunica albuginea
tunica vaginalis

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16
Q

what is the function of the tunica vasculosa of the testes?

A

contains the blood vessels

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17
Q

what is the function of the tunica albuginea of the testes?

A

thick layer that forms the septa dividing the testis into lobules

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18
Q

what is the function of the tunica vaginalis of the testes?

A

covering testis AND epidydimis

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19
Q

explain the structure of the testes

A

approx 300 lobules in each testis separated by septa

= each lobule contains 1-4 coiled seminiferous tubules which have closed loops

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20
Q

explain the path of sperm from the serminiferous tubules to the vas deferens

A

seminiferous tubules
= rete testis
= epidydimis
= vas deferens

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21
Q

what is the arterial blood supply of the testes?

A

testicular arteries from the aorta via the spermatic cord

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22
Q

what is the lymphaic drainage of the testes?

A

para-aortic lymph nodes

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23
Q

what term is used to describe male sterilisation?

A

vasectomy

= cutting of the vas deferens

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24
Q

where does the vas deferens empty?

A

into the junction w the duct of the seminal vesicle

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25
Q

describe the structure of the fallopian tubes

A

extend from the fimbrae connected to the ovary all the way to the uterus

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26
Q

where does fertilisation occur?

A

in the ampulla of the fallopian tubes (widest part)

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27
Q

explain how the fallopian tubes are adapted to their function

A

1) contain cilia = that waft to direct the zygote towards the uterus
2) made up of spiral muscle = that is sensitive to oestrogen levels +

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28
Q

how does an oocyte move down the fallopian tube?

A

via peristalsis of the spiral muscle and wafting of the cilia

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29
Q

what happens if motility is reduced in the fallopian tube?

A

increased risk of ectopic pregnancy

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30
Q

how is the uterus supported in place? (2)

A

1) tone of the pelvic floor muscles (levator ani, coccygeus muscles)
2) ligaments (broad, round, uterosacral)

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31
Q

why is it important that the uterus is supported in place?

A

to prevent uterine prolapse

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32
Q

what is the top of the uterus called?

A

uterine fundus

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33
Q

what are the layers of the uterus called?

A

serosa/perimetrium
myometrium
endometrium

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34
Q

which uterine layer is sensitive to hormonal action?

A

myometrium

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35
Q

explain how menstruation occurs

A

endometrial layer = spiral arterioles

= progesterone levels fall at the end of the menstrual cycle
= intermittent vasoconstriction
= ischaemia/necrosis
= shedding of the endometrial lining
= haemorrhage that is menstruation
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36
Q

why is the intermittent vasoconstriction of the spiral arterioles of the endometrial layer important?

A

intermittent vasoconstriction leads to ischaemia/necrosis of the of the endometrial lining
= shedding/haemorrhage

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37
Q

which structure is lateral to the cervix and why is this important?

A

approx 1cm lateral to the cervix is the ureter

= important when considering cervical cancer

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38
Q

how is sterility maintained in the female reproductive tract?

A

all areas superior to the cervix are sterile

1) frequent shedding of the endometrium
2) thick cervical mucus
3) narrow external ox
4) acidity as ph < 4.5

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39
Q

explain how the acidic vaginal pH is achieved

A

oestrogen stimulates the vaginal epithelium to secrete glycogen

lactobacilli digest the glycogen releasing lactic acid

= lowers the pH of the vagina below 4.5 so preventing infection by other organisms

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40
Q

why is it important that the pH of the vagina is acidic?

A

preventing infection by other organisms

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41
Q

why can overuse of antibiotics be harmful for the vaginal environment?

A

natural flora of the vaginal environment
= disrupted by antibiotic use
= can cause overgrowth + infections (e.g. candiadiasis)

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42
Q

what is the arterial supply to the ovaries?

A

ovarian arteries (from aorta)

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43
Q

what is the arterial supply to the uterus/vagina?

A

uterine arteries (from the internal iliac artery)

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44
Q

what is the lymphatic drainage of the ovaries?

A

para-aortic lymph nodes

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45
Q

what is the uterus/vagina drainage of the ovaries?

A

Iliac, sacral, aortic and inguinal lymph nodes

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46
Q

which cells are examined in a smear test?

A

cells around the external os

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47
Q

oestrogen stimulates the production of which type of cervical mucus?

A

thin, watery mucus

= allows sperm to

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48
Q

progesterone stimulates the production of which type of cervical mucus?

A

thick, viscous mucus

i.e. mechanism of action of the progesterone-only pill

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49
Q

secretions from where lubricate the vagina during sexual arousal?

A

greater vestibular glands (i.e. Bartholin’s glands near the external vaginal orifice)

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50
Q

name the male gonads

A

testes

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51
Q

name the female gonads

A

ovaries

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52
Q

what is gametogenesis?

A

production of gametes for reproduction

males = spermatogenesis
females = oogenesis
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53
Q

when does gametogenesis begin in males?

A

at puberty

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54
Q

explain what happens in spermatogenesis

A

spermatogonia undergo differentiate and self-renewal from puberty onwards

pool of spermatogonia available for subsequent spermatogenic cycles all throughout life

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55
Q

‘males have continuous fertility’ - what does this mean?

A

pool of spermatogonia available for subsequent spermatogenic cycles all throughout life

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56
Q

explain what happens in oogensis

A

BEFORE BIRTH

1) multiplication of oogonia to 6 million/ovary
2) oogonia to primary oocytes within ovarian follicles (primordial follicles)
3) primary oocytes undergo meiosis + HALT in prophase
4) some primoridal follicles undergo atresia and degenerate

PUBERTY
= due to further atresia <0.5 million/ovary

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57
Q

explain what happens in oogensis

A

BEFORE BIRTH

1) multiplication of oogonia to 6 million/ovary
2) oogonia to primary oocytes within ovarian follicles (primordial follicles)
3) primary oocytes undergo meiosis + HALT in prophase
4) some primoridal follicles undergo atresia and degenerate = so at birth 2 million/ovary

PUBERTY
= due to further atresia <0.5 million/ovary

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58
Q

what occur within primordial follicles?

A

oogonia converted into primary oocytes in ovarian follicles

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59
Q

how do primary oocytes develop before birth?

A

primary oocytes undergo meiosis and halt in prophase

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60
Q

how many oogonia are found per ovary before birth?

A

2 million/ovary

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61
Q

how many oogonia are found per ovary by puberty?

A

0.5 million/ovary

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62
Q

how does the number of oogonia change from before birth to puberty?

A

before birth = 6 million/ovary

at birth = 2 million/ovary

puberty = 0.5 million/ovary

due to further atresia

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63
Q

describe the process of stermatogenesis

A

spermatogonia
(mitosis)
primary spermatocytes

(first meiotic division)
secondary spermatocytes
(second meiotic division)
spermatids
(differentiation)
spermatozoa
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64
Q

where does spermatogenesis take place?

A

intratubular compartment of the seminiferous tubules

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65
Q

how many days does spermatogenesis take?

A

approx 64 days until spermatozoa are ready for release

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66
Q

what surrounds the seminiferous tubules?

A

tunica propria

= made of flattened cells forming a basement membrane

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67
Q

explain the arrangement of cells in the seminiferous tubules

A

most of the cells that lie against the basement membrane and have round nuclei are spermatogonia

mature as they move inwards forming primary and secondary spermatocytes (rarely seen)

ultimately spermatids are released into duct

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68
Q

explain how the structure of the seminiferous tubules helps achieve continuous fertility

A

from the outer basement layer to the inner duct, spermatogonia are at different progressive stages of spermatogenesis

= spermatids continuous released into the inner duct to provide a continuous pool

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69
Q

which cells support spermatogenesis?

A

1) Sertoli cells

2) Leydig cells

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70
Q

where are Sertoli cells found?

A

within the seminiferous tubules

71
Q

where are Leydig cells found?

A

outside/in-between the seminiferous tubules

72
Q

what main reproductive hormones are produced in males?

A

1) androgens
2) inhibin + activin
3) oestogens

73
Q

which androgens are produced by males?

A

1) testosterone
2) dihydrotestosterone
3) androstenedione

74
Q

how can oestrogens be produced in males?

A

androgen aromatisation

75
Q

what is inhibin and what is its function?

A

a protein produced by Sertoli cells that circulates in the ‘inhibin B’ form

= exerts negative feedback on pituitary release of FSH

as inhibin B expression + secretion

1) negatively correlated with FSH
2) positively correlated with Sertoli cell function + spermatogenic status

76
Q

how does inhibin affect FSH release?

A

inhibin B expression + secretion is negatively correlated with pituitary FSH

77
Q

how does inhibin affected by Sertoli function?

A

Inhibin B expression + secretion is POSITIVELY correlated with Sertoli function and spermatogenic status

78
Q

which receptors are found on Sertoli cells?

A

FSH receptors

Sertoli cells are found within the seminiferous tubules

79
Q

which receptors are found on Leydig cells?

A

LH receptors

Leydig cells are found between the seminiferous tubules

80
Q

what are the two main functions of Sertoli cells?

A

1) support developing germ cells

2) hormone synthesis

81
Q

how do Sertoli cells support developing germ cells?

A

1) assist movement of germ cells to tubular lumen
2) transfer nutrients from capillaries to developing germ cells
3) phagocytosis of damaged germ cells

82
Q

how do Sertoli cells support hormone synthesis?

A

1) inhibin and activin (effects on FSH secretion)
2) anti-Mullerian hormone (AMH)
3) androgen-binding protein (ABP)

83
Q

what are the functions of inhibin and activin?

A

inhibin - inhibits FSH release from the pituitary gland via negative feedback

activin - stimulate FSH release from the pituitary gland via positive feedbackwhat

84
Q

what is the function of AMH?

A

anti-Mullerian hormone produced by immature Sertoli cells
= aids in the regression of the Mullerian ducts in male sexual development which would otherwise go on to form the fallopian tubes/uterus/cervix

85
Q

which cells release AMH?

A

immature Sertoli cells

86
Q

how is Mullerian duct development prevented in men?

A

AMH (anti-Mullerian hormone) aids in the regression of the Mullerian ducts

= would otherwise go on and form fallopian tubes/uterus/cervix

87
Q

what is the function of ABP?

A

androgen-binding protein

= directs testosterone from Leydig cells to germ cells

88
Q

what stimulates ABP release?

A

FSH

as ABP is released from Sertoli cells, whose function depends on FSH receptor activation

89
Q

why do Leydig cells have a pale cytoplasm?

A

contain lots of cholesterol to make testosterone

90
Q

which receptors are found on Leydig cells?

A

LH receptors

91
Q

what is the function of Leydig cells?

A

hormone synthesis

92
Q

which hormones are synthesised by Leydig cells?

A

on LH stimulation:

  • testosterone
  • androstenedione
  • dihydroepiandrostenedione (DHEA)

= can be aromatised to oestrogens

93
Q

which stimulates and inhibits AMH transcription?

A

stimulates = FSH

inhibits = testosterone

94
Q

what is the term used to describe female gametogenesis?

A

oogenesis

95
Q

describe the process of oogenesis

A

oogonia
(mitosis)
primary oocytes

(first meiotic division)
secondary oocytes
(second meiotic division)
ootids
(differentiation)
ova
96
Q

what happens in terms of oogonia during the second trimester of pregnancy?

A

all oogonia in foetus develop into primary oocytes

forming primordial follicles

97
Q

why are primary oocytes associated with primordial follicles?

A

primary oocytes arrest in the first meiotic division stage until menarche
= granulosa cells surround these primary oocytes and form primordial follicles

98
Q

what happens to primordial follicles at menarche?

A

recommence growth, partly dependent on FSH

99
Q

what is produced alongside secondary oocytes?

A

(secondary oocytes, capable of fertilisation, produced following menarche)

first polar body = small haploid cell w no cytoplasm

100
Q

what stimulates the second meiotic division in oogenesis?

A

fusion of the secondary oocyte + sperm

= causes calcium influx that stimulates the 2nd meiotic division forming the ova

101
Q

describe the stages of folliculogenesis

A

1) primodrial follicle (primary oocytes)
2) pre-antral follicle (primary)
3) antral follicle (secondary)
4) mature/Graafian follicle
5) ruptures surface of ovary
6) corpus luteum

102
Q

what is a primary/pre-antral follicle?

A

one in which the primary oocytes are surrounded by layers of granulosa and theca cells

103
Q

what is a secondary/antral follicle?

A
  • antrum develops

- contain FSH and LH receptors

104
Q

what is the mature/Graafian follicle?

A
  • forms due to the LH surge

- secondary ooycte forms

105
Q

what is the function of the corpus luteum?

A

oestrogen & progesterone production (stimulated by LH/HCG)

106
Q

what happens to corpus luteum function in pregnancy?

A

normally CL = progesterone + oestrogen production BUT in pregnancy, placenta takes over this role

107
Q

how is the mature/Graafian follicle selected?

A

loads of follicles develop initially
BUT the one that produces most oestrogen
= dominant follicle
= takes over
= inhibits FSH stimulation of other follicles

108
Q

at which stage in life are primary follicles most numerous?

A

before menarche as primary follicles form at birth and remain arrested until menarche

109
Q

describe the cells found in a mature/Graafian/preovulatory follicle

A

1) inner granulosa cells bind FSH = to aromatise androgens into oestrogens
2) outer theca cells bins LH = to produce androgens

110
Q

which reproductive hormones are produced by females?

A

1) oestrogens
2) progestogens
3) androgens
4) relaxin & inhibin

111
Q

in females, where are oestrogens produced and which ones?

A

inner granulosa cells

= oestradiol, oestrone, oestriol

112
Q

in females, where are progestogens produced and which ones?

A

outer theca cells

= progesterone

113
Q

in females, where are androgens produced and which ones?

A

outer theca cells

= testosterone, androstenedione, DHEA

114
Q

in females, where is relaxin produced and what is its function?

A

ovaries and placenta (esp corpus luteum)

= relaxes pelvic ligaments ans softens cervix for childbirth

115
Q

in females, where is inhibin produced?

A

ovaries and placenta

116
Q

where are theca cells found?

A

associated with the OUTER part of the ovarian follicles

117
Q

where are granulosa cells found?

A

associated with the INNER part of the ovarian follicles

118
Q

what are the two main functions of theca cells?

A

1) support folliculogenesis

2) hormone synthesis

119
Q

how are theca cells involved in folliculogenesis?

A

structural and nutritional support of growing follicle

120
Q

how are theca cells involved in hormone synthesis?

A

LH stimulates androgen synthesis

so overactivity - high androgen levels (common cause of infertility)

121
Q

why is overactivity and underactivity of theca cells harmful?

A

overactivity = leads to hyperandrogenism (common cause of infertility)

underactivity = infertility due to subsequent lack of oestrogen

122
Q

what are the two main functions of granulosa cells?

A

1) hormone synthesis

2) turn into granulosa lutein cells after ovulation

123
Q

how are granulosa cells involved in hormone synthesis?

A

1) FSH stimulates granulosa cells to convert androgens to oestrogens (by aromatase)
2) secrete inhibin and activin (act on pituitary FSH secretion)

124
Q

where does androgen aromatisation occur in females?

A

granulosa cells

on FSH stimulation, androgens are aromatised to oestrogens

125
Q

from where are inhibin and activin secreted in females and males?

A

females = inner granulosa cells

males = inner Sertoli cells

(both controlled by FSH stimulation)

126
Q

what happens to granulosa cells after ovulation?

A

after ovulation, turns into granulosa lutein cells that produce

1) progesterone
2) relaxin

127
Q

what is the function of progesterone in females?

A

under negative feedback

= promotes pregnancy by maintaining the endometrium

128
Q

what is the function of relaxin in females?

A

helps the endometrium prepare for pregnancy by relaxing the pelvic ligaments & softening the cervix

129
Q

besides, granulosa cells in females, where else is inhibin released from?

A

also synthesised in the placenta

130
Q

what is the function of inhibin and activin?

A

inhibin = inhibits pituitary FSH secretion

activin = stimulates pituitary FSH secretion

131
Q

which structure is mainly responsible for progesterone secretion?

A

corpus luteum

132
Q

what does progesterone negatively feed back to?

A

anterior pituitary and hypothalamus

133
Q

which structure release relaxin into circulation in females?

A

granulosa cells

= specifically the corpus luteum and placenta

134
Q

where does androgen aromatisation occur in males and in females?

A

males = outer Leydig cells (androgens also produces here)

females = inner granulosa cells (from androgens produced in outer theca cells)

135
Q

describe the hypothalamic-pituitary axis for LH/FSH

A

kisspeptin

GnRH

LH/FSH

gonads

oestrogen, testosterone production

= reproduction

136
Q

describe the hypothalamic-pituitary axis for TSH

A

TRH

TSH

thyroid gland

T3/T4

= metabolism

137
Q

describe the hypothalamic-pituitary axis for prolactin

A

dopamine

prolactin

breast

= lactation

138
Q

describe the hypothalamic-pituitary axis for ACTH

A

CRH

ACTH

adrenal gland

cortisol & androgen production

= stress response

139
Q

describe the hypothalamic-pituitary axis for GH

A

GHRH

GH

liver

IGF-1

= growth

140
Q

describe the hypothalamic-pituitary axis for ADH

A

ADH act on the kidneys

= water reabsorption

141
Q

describe the hypothalamic-pituitary axis for oxytocin

A

oxytocin acts on the uterus/breast

= parturition/lactation

142
Q

in what manner are GnRH and LH released?

A

pulsatile

143
Q

in what manner are the sex steroids released?

A

diurnal

144
Q

explain the effect of hyperprolactinaemia on the HPG axis

A

excess prolactin
= binds to receptors on kisspeptin neurones
= INHIBITS kisspeptin release
= decreases downstream GnRH/LH/FSH/testosterone/oestrogen release

= oligomenorrhoea, amenorrhoea, erectile dysfunction, infertility, osteoporosis, low libido

145
Q

in hyperprolactinaemia, what does prolactin bind to?

A

prolactin receptors on KISSPEPTIN neurones

= to inhibit kisspeptin release into the hypothalamus

146
Q

what are the four main hormones involved in the menstrual cycle?

A

LH
FSH
oestrogen
progesterone

147
Q

which two cycles make up the menstrual cycle?

A

1) ovarian cycle - associated w folliculogenesis and corpus luteum formation
2) uterine cycle - associated w state of the endometrial lining

= both cycles driven by hormonal level changes

148
Q

what are the different stages of the ovarian cycle?

A
  • follicular phase
  • ovulation
  • luteal phase
149
Q

what are the different stages of the uterine/endometrial cycle?

A
  • menstrual phase
  • proliferative phase
  • secretory phase
150
Q

what are the first 14 days of the menstrual cycle called?

A

follicular phase

151
Q

what are the last 14 days of the menstrual cycle called?

A

luteal phase

152
Q

why is day 14 of the menstrual cycle important?

A

ovulation

153
Q

what is the average length of a normal menstrual cycle?

A

approx 28 days

can range from 21-35

154
Q

what occurs on the first day of the menstrual cycle?

A

first day of bleeding

blood + cellular debris from necrotic endometrial lining

155
Q

what is the term used to describe a menstrual cycle that lasts greater than 35 days?

A

oligomenorrhoea

156
Q

which feedback loops drive the menstrual cycle?

A
  • hypothalamic kisspeptin + GnRH
  • pituitary LH and FSH
  • ovarian oestrogen, progesterone, activin, inhibin
157
Q

which stage of the menstrual cycle is variable?

A

follicular phase

usually this is prolonged in women w a longer than usual menstrual cycle

158
Q

what happens in the follicular phase, in terms of hormones?

A

1) LH & FSH rise
2) this rise stimulates follicular development and subsequent oestrogen secretion from the maturing follicles
3) oestrogen levels subsequently rise
4) FSH falls a little due to negative feedback
5) a high enough oestrogen level causes a switch to positive feedback at the APG, resulting in an LH surge (and to a lesser extent FSH)

159
Q

where is oestrogen primarily secreted from in the menstrual cycle?

A

developing, maturing follicles during folliculogenesis (stimulated by FSH)

(most oestrogen is secreted from the dominant/Graafian follicle)

160
Q

in the follicular phase, what does oestrogen stimulate in granulosa cells?

A

(oestrogen, produced by the developing follicles, acts on granulosa cells)

= to stimulate the development of LH receptors and accelerate growth

(? to increase the responsiveness of granulosa cells to the LH surge)

161
Q

in the follicular phase, what impact does the rising oestrogen level have?

A

as oestrogen levels rise there is a switch to positive feedback at the pituitary, resulting in an LH surge and lesser extent FSH

162
Q

why is the LH surge required?

A

results in the final maturation and subsequent release of the dominant follicle

(other follicle regress)

163
Q

what happens to the other follicles after ovulation?

A

undergo follicular atresia (regress)

164
Q

in terms of the uterine/endometrial cycle, what happens in the menstrual phase?

A

degenerating spiral arteries

= blood + ischaemia/necrotic functional layer of the endometrium is shed

165
Q

what happens in the proliferative phase of the uterine cycle and which hormone stimulates this?

A

stimulated by OESTROGEN

= endometrium proliferates to form a new functional layer + cervical mucus thins to allow sperm passage

166
Q

what is the function of the corpus luteum and when does it form?

A

secretes progesterone + oestrogen

= forms after ovulation, in the luteal phase

167
Q

what happens, in terms of hormones, in the luteal phase?

A

1) corpus luteum secretes loads of progesterone
2) progesterone inhibits LH/FSH secretion and slowly the CL involutes (unless rescued by hCG produced by the implanting conceptus)
3) involution of the CL causes progesterone and oestrogen levels to fall
4) FSH/LH can then rise for the next cycle

168
Q

what is the main source of oestrogen in the luteal phase?

A

corpus luteum

169
Q

what are the two ways in which the corpus luteum is maintained?

A

1) if egg not fertilised = LH

2) if fertilisation has occurred = hCG produced by the implanting conceptus

170
Q

why does the corpus luteum involute if fertilisation does not occur?

A

CL releases progesterone + oestrogen

= negative feedback inhibits LH/FSH secretion
= with no hCG either, from the implanting conceptus, CL cannot be maintained

171
Q

what happens in the secretory phase of the uterine cycle?

A

1) endometrium differentiates and secretes a glycogen-rich fluid in preparation for a potential embryo
2) spiral arteries constrict causing ischaemia + necrosis due to falling progesterone levels

172
Q

in which scenario does the endometrial layer not shed in the menstrual cycle and why?

A

when there is a successful pregnancy

hCG secreted by the conceptus –> maintains CL –> continuous secretion of progesterone (and oestrogen) –> maintains endometrial lining

173
Q

what happens to basal body temperature after ovulation and why?

A

increase by approx 0.5 degrees Celsius

= due to progesterone secretion (from the newly formed CL)

brs (phase 1a) (7 decks)

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