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Physiology 210 > Reproductive Physiology > Flashcards

Reproductive Physiology Flashcards

1
Q

Function of the reproductive system

A
  • provides gametes for procreation of species
  • mating
  • fertilization
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2
Q

Organs of the reproductive system

A
  • called gonads
  • pathway for gamete transport
  • accessory organs and glands
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3
Q

Functions of gonads

A
  • organs which produce gametes
  • source of sex steroid hormones
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4
Q

Gonads of the male reproductive system

A

testis

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5
Q

Scrotal sac

A
  • outside the body
  • testes, blood vessels, nerves
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6
Q

Function of blood vessels in scrotal sac

A
  • countercurrent blood flow to regulate temperature
  • 2C below core body temperature for spermatogenesis
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7
Q

Function of spermatic cord in scrotal sac

A
  • passes through slit in abdomen (inguinal canal)
  • combination of vas deferens, blood vessels and nerves
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8
Q

Descent of testes

A

8 weeks - testes high in abdomen near kidneys
8-12 weeks - testes move down towards inguinal canal
7-9 months - testes pass through inguinal canal and rest in scrotum
birth - testes have have descended into scrotal space

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9
Q

Testes

A
  • found inside scrotal sac
  • male gonads
  • divided into many compartments - highly twisted tubules called seminiferous tubules
  • lead into rete testis network
  • lead into efferent ductules
  • lead into epididymis
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10
Q

Seminiferous tubules

A
  • site of sperm production
  • sit on basement membrane and contain a lumen
  • cells are called spermatogenic cells
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11
Q

Mumps virus

A
  • causes seminiferous tubules to become smaller
  • lumen becomes bigger and spermatogenic cells look small
  • effects spermatogenesis process
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12
Q

Leydig cells

A
  • found in connective tissues surrounding seminiferous tubules
  • also called interstitial cells
  • produce hormone testosterone
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13
Q

Sertoli cells

A
  • epithelial cells lining seminiferous tubule
  • help the process of sperm development
  • laid out side by side and sit on basement membrane
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14
Q

Smooth muscle cells

A
  • just outside basement membrane
  • muscle-like
  • have contractile properties - help with peristalsis of sperm
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15
Q

Tight junctions

A
  • join epithelial cells
  • do not allow infections that harm sperm through
  • create invisible ring-like structure
  • form blood-testis barrier: form basal compartment and luminal compartment
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16
Q

7 Functions of Sertoli Cells

A
  • support sperm development - trophic
  • secrete luminal fluid for sperm housing
  • secrete androgen-binding protein under influence of FSH: androgen buffer, maintains high luminal conc. of testosterone
  • act as target cells for testosterone and FSH
  • secrete inhibin
  • phagocytosis of old/damaged sperm
  • site of immunosuppression (blood testis barrier)
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17
Q

Testosterone - corticosteroid synthesis

A
  • steroid hormone
  • synthesized from cholesterol
  • produced by adrenal cortex, gonads, and testes
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18
Q

In adrenal gland - corticosteroid synthesis

A
  • intermediary hormone called progesterone is synthesized
  • depends on enzymes present, progesterone is converted to mineralocorticoids, glucocorticoids, or androgens
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19
Q

In male gonads - corticosteroid synthesis

A
  • formation of mineralocorticoids and glucocorticoids is bypassed in male gonads and more testosterone is produced
  • testosterone receptors is located in intracellular locations - lipophilic nature to diffuse across membranes and influence gene transcription
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20
Q

In Leydig cells

A

cholesterol –> pregnenolone –> progesterone
- both progesterone and pregnenolone product androgens (testosterone)

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21
Q

4 ways testosterone is used/converted into

A
  • as testosterone
  • converted to dihydrotestosterone (DHT) by 5-alpha reductase in prostate gland
  • concerted to estrogen by aromatase in liver, adipose tissue, brain and testes
  • broken down into inactive molecules
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22
Q

Puberty (10-14 years)

A
  • sexual maturation
  • reproductive organs mature
  • secondary sexual characteristics develop
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23
Q

Plasma testosterone levels during lifespan

A
  • before birth: high peak of testosterone then decreases until birth
  • neonatal: high peak of testosterone then decreases until childhood
  • puberty until adulthood: high at puberty then slowly declines around age 40 - andropause
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24
Q

Sperm production during lifespan

A
  • begins at onset of puberty with sharp rise until adulthood
  • sperm production is maintained until age 40-45 then starts to decline
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25
Q

Hypothalamic-pituitary-leydig cell axis

A

higher centers –> cues/signals –> hypothalamus –> GnRH –> anterior pituitary –>
- LH –> Leydig cells –> testosterone
- FSH –> Sertoli cells

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26
Q

GnRH (gonadotropin releasing hormone)

A
  • pulsatile secretion every 90 minutes
  • called pulse generator
  • pulsatile to activate receptors (would no activate if constant release of GnRH)
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27
Q

High frequency pulses of GnRH

A
  • predominant secretion is luteinizing hormone (LH)
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28
Q

Low frequency pulses of GnRH

A
  • predominant secretion is follicle stimulation hormone (FSH)
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29
Q

Testosterone in negative feedback regulator

A
  • hypothalamus - dampens amplitude of pulsatile secretion
  • anterior pituitary - causes decreased responsiveness due to down regulation of GnRH receptors
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30
Q

6 Effects of androgens

A
  • stimulate spermatogenesis
  • promote development of secondary sex characteristics during puberty and maintenance in adult life
  • increase sex drive
  • promote protein synthesis in skeletal muscle
  • stimulate growth hormone secretion for bone growth
  • promote development of male reproductive structures during embryonic life
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31
Q

Spermatogenesis

A

formation of the male gamete or sperm

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32
Q

Mitosis

A
  • enlarge and split a cell into 2 identical daughter cells that are genetically identical to original cell
  • one remains a spermatogonium to ensure numbers are not depleted
  • the other is a committed cell called a primary spermatocyte with a 2n
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33
Q

Meiosis

A
  • each daughter cell receives half the chromosomes
  • reduced from 46 chromosomes, diploid to a 23 chromosome haploid
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34
Q

What comes after the secondary spermatocyte

A

each one gives two spermatids - 4 spermatids produced

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35
Q

Duration of primary spermatocyte to spermatozoa

A

64 days

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36
Q

Where does spermatogenesis occur

A
  • seminiferous tubule in the space between two adjacent Sertoli cells
  • tight junction divides basal and luminal compartment and allows primary spermatocyte to move through
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37
Q

What is spermiogenesis

A
  • last stage of spermatogenesis
  • spermatids mature into motile spermatozoa
  • nucleus, acrosomal vesicle, flagella, remodeled cytoplasm
  • 24 days
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38
Q

Head of a sperm

A

nucleus - contains haploid number of chromosomes
acrosome - vesicle at the tip containing enzymes necessary for fertilization

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39
Q

Midpiece of a sperm

A

many mitochondria which generate ATP needed for movement of tail

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40
Q

Tail of a sperm

A

whip-like movements propel sperm

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41
Q

Sperm maturation

A
  • spermatozoa released into lumen in immature form
  • fluid pressure generated by Sertoli cells pushes the sperm forward towards the epididymis
  • reside in epididymis for 6-12 days
  • fluid is reabsorbed and sperm is concentrated
  • move to vas deferens by peristalsis
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42
Q

Inhibin

A
  • peptide hormone
  • regulate axis at level of anterior pituitary to decrease secretion of FSH
  • does not act at hypothalamic level
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43
Q

Seminal fluid comes from 3 glands

A
  • seminal vesicle
  • prostate gland
  • bulbourethral gland
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44
Q

Functions of seminal fluid

A
  • dilution of sperm
  • provides energy as fructose
  • formation of semen clot (fibrin-like protein that forms plug)
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45
Q

Seminal vesicles

A
  • secrete alkaline (balance acidic environment of female tract) fluid with fructose, enzymes (produce semen clot), and prostaglandins (cause contraction of female tract for sperm to move forward)
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46
Q

Prostate gland

A
  • secrete citrate (energy for sperm) and enzymes (PSA breaks down seminal clot making semen for fluid and is biomarker for cancer)
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47
Q

Bulbourethral gland

A
  • secrete viscous fluid with mucus
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48
Q

3 phases of neural control for male reproduction

A
  • erection phase
  • emission phase
  • ejaculation phase
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49
Q

Erection phase

A
  • parasympathetic nervous system
  • relaxation of blood vessels and increased blood flow into tissue
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50
Q

Emission phase

A
  • sympathetic nervous system - thoracolumbar division
  • acts of muscle tissue of prostate gland, vas deferens and seminal vesicle
  • causes smooth muscle contraction leading to movement of sperm from vas deferens with mixing of seminal fluid into urogenital tract
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51
Q

Ejaculation phase

A
  • rapid contraction of skeletal muscle for semen expulsion outside of body
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52
Q

Parasympathetic control of erection

A
  • causes release of nitric oxide
  • NO stimulates cGMP
  • cGMP acts on smooth muscle of blood vessel to vasodilation
  • cGMP is broken down by enzyme phosphodiesterase
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53
Q

Erectile dysfunction

A
  • treated with Viagra (Sildenafil)
  • acts as a inhibitor of enzyme phosphodiesterase
  • actions of cGMP are prolonged maintaining vasodilation and erection
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54
Q

2 final sperm maturation processes

A
  • capacitation
  • acrosome reaction
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55
Q

Capacitation

A
  • occurs as sperm moves through female reproductive tract
  • receptors are made available through the removal of the glycoprotein layer
  • area of acrosomal cap is altered
  • tail movements change from wave-like to whiplash
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56
Q

Acrosomal reaction

A
  • binding of sperm with zona pellucida (egg outer layer)
  • creating pores which acrosomal enzymes can be released by exocytosis
  • enzymes allow sperm to digest a path through zona pellucida to oocyte
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57
Q

3 characteristics of female repro system

A
  • cyclic changes in activity - menstrual cycle
  • restricted periods of fertility - ovulation
  • limited production of gametes
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58
Q

Menarche

A
  • onset of puberty
  • first menstrual cycle
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59
Q

Menopause

A
  • lost ability to reproduce around 45-50
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60
Q

Female gonads

A

ovaries

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61
Q

Female reproductive tract

A

uterus, Fallopian tubules, vaginal canal

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62
Q

Ovaries

A

site of ova maturation
- specifically opening of fallopian tubes

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63
Q

Uterine tubes

A
  • fallopian tubes or oviducts
  • transport ova from ovaries to uterus
  • fimbria stick out and sit close to ovary
  • fimbria have ciliated cells which capture and move egg
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64
Q

Site of fertilization

A

uterine tube

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65
Q

Movement of ovum through uterine tube

A
  • initially - peristaltic contractions
  • mostly - ciliary actions
  • duration - 4 days to uterus
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66
Q

Ectopic pregnancy

A
  • cilia does not move egg properly and will plant in fallopian tubes
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67
Q

3 layers of uterus

A

outer
- perimetrium - protective covering
- myometrium - smooth muscle
- endometrium - epithelial cells and connective tissue and glands to produce glycogen
inner

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68
Q

Ovary

A
  • covered by capsular structure
  • contains follicles suspended in connective tissue
  • contains blood vessels
  • contains follicles in different stages of growth
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69
Q

Names of follicle development

A
  • primordial follicles
  • primary follicles
  • mature follicles
  • corpus luteum
  • corpus albicans
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70
Q

Corpus luteum

A
  • mature follicle that released its egg
  • remains and acts as endocrine gland
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71
Q

3 cycles in female body

A
  • hormonal cycle
  • ovarian cycle
  • uterine cycle
  • average 28 days
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72
Q

Ovarian cycle

A

2 phases
- follicular phase (first 14 days): development of follicles when eggs are growing
- ovulation: 14th day
- luteal phase (last 14 days): egg is released and related to secretory gland

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73
Q

Uterine cycle

A

3 phases
- menstrual phase (day 1-5): first day of bleeding and shedding of endometrial layer
- proliferative phase: development of growth, layers become wider and blood vessels grow
- secretory phase: further vascularization and development of uterine gland
- menstrual phase and proliferative coincide with follicular phase
- secretory phase coincide with luteal phase

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74
Q

Oogenesis

A

development of female gamete/oocyte

75
Q

Folliculogenesis

A

maturation of ovarian follicle
- contributes and takes part in hormonal cycle

76
Q

Primary oocyte stage

A
  • each follicle contains 1 oocyte
  • begins with primordial follicle stage: single oocyte surrounded by single layer of granulosa
  • granulosa will begin mitosis
  • granulosa secrete proteins and glycoproteins which form thick layer called zona pellucida
77
Q

Preantral follicle stage

A
  • many layers of granulosa cells
  • connective tissues differentiate and become theca layer (internal and external)
  • no antrum
78
Q

Early antral follicle stage

A
  • development of fluid-filled space known as antrum begins to form
79
Q

Mature follicle stage

A
  • major growth of antral space
  • granulosa layers outside oocyte suspended in bridge-like fashion called cumulus oophorus
80
Q

Corpus albicans stage

A
  • empty follicle/endocrine structure will die off
  • forms scar tissue and will dissipate
81
Q

Random selection of pre-antral follicles

A
  • 10-25 follicles are selected
  • the follicle that secretes the highest amount of estrogen will be the dominant follicle
  • remainder of follicles die off known as atresia or programmed cell death
82
Q

Hormonal cycle

A
  • estrogenic phase - first 14 days
  • progestational phase - after ovulation
83
Q

Early-mid-follicular phase

A
  • day 1-7
  • 10-25 have selected and grow rapidly
  • estrogen is predominant hormone
  • 2 cell compartment: granulosa and theca cells
  • FSH causes granulosa cells to increase by mitosis
84
Q

Theca cells

A
  • has receptors for LH
  • convert cholesterol –> progesterone –> androgens
  • permeate granulosa cells which convert androgens to estrogen
  • some estrogen moves into blood stream and some stay in antrum
85
Q

FSH upregulates

A
  • enzyme aromatase that converts androgens to estrogen in granulosa cells
86
Q

Late follicular/corpus luteum phase

A
  • day 7-14
  • rise of estrogen causes granulosa cells to start developing LH receptors
  • granulosa cells convert cholesterol to progesterone
  • small rise in progesterone occurs towards late follicular phase
  • increasing estrogen concentration
87
Q

7 functions of granulosa cells

A
  • secrete antral fluid
  • provide nutrients for developing oocyte
  • secrete paracrine factors that support follicular development
  • secrete inhibin
  • secrete estrogens
  • have aromatase enzyme which converts androgens to estrogen
  • secrete substance that forms zona pellucida
88
Q

Hypothalamic-pituitary-ovarian axis in women

A
  • GnRH released in pulsatile manner
  • pulses change every 24 hours (males do every 90 minutes)
  • anterior pituitary secretes 2 hormones: LH and FSH
    acts on ovary and estrogen and progesterone
89
Q

Estrogen has a negative feedback

A
  • effects level of anterior pituitary and hypothalamus
  • estrogen can either dampen the amplitude or reduce the responsiveness of the pituitary
90
Q

Estrogen has a positive feedback

A
  • increase amplitude or responsiveness of pituitary to GnRH
91
Q

Progesterone has a ____ feedback

A

negative depending on phase of cycle

92
Q

Oogenesis

A

beginning with oogonium to ovum

93
Q

DNA replication

A
  • early fetal development
  • primary oocyte
  • do not complete division in fetus
  • meiotic arrest
  • at birth all contain 46 chromosomes each with two sister chromatids (2n x 2)
94
Q

Meiosis I

A
  • monthly from puberty to menopause oocyte released from arrest to complete meiosis I
  • 2 daughter cells called secondary oocyte and first polar body
  • secondary oocyte has n x 2
  • happens at time of ovulation from dominant follicle
95
Q

Meiosis II

A
  • occurs after fertilization only if secondary oocyte is fertilized by male gamete
  • 2 daughter cells called ovum and second polar body produced
  • ovum has n
96
Q

Net result of oogenesis

A
  • 1 egg with n number of chromosomes
97
Q

Net result of spermatogenesis

A
  • 4 spermatozoa with n numbers of chromosomes
98
Q

estrogen and progesterone are not required for sexual ____ but for sexual ____

A
  • differentiation
  • maturation
99
Q

Menstrual phase - menstrual cycle

A
  • day 1-5
  • shedding of uterine lining
  • tissues die and slough into vagina causing menstrual flow
  • triggered by decreased estrogen and progesterone
100
Q

Proliferative phase - menstrual cycle

A
  • day 5-14
  • endometrial lining develops, layer grows, and glands enlarge
  • smooth muscle layer thickens
  • cervical glands secrete thin mucus
  • estrogen stimulate uterine lining development
101
Q

Secretory phase - menstrual cycle

A
  • endometrium prepared for implantation
  • blood supply increased
  • glands enlarge and secrete glycogen-rich fluids
  • cervical secretions more sticky forming plug
  • progesterone mainly and estrogen
102
Q

Estrogen has an inhibitory effect on

A
  • gonadotropin secretion when estrogen levels are low during early-mid-follicular phase
103
Q

Increase in FSH secretion at the end of the cycle:

A
  • stimulates preantral and early antral follicles to grow
  • increase in FSH due to decrease in progesterone, estrogen and inhibin
104
Q

Rapidly increasing estrogen causes a sharp rise in

A
  • LH surge
  • positive feedback on gonadotropins
  • upregulation on LH receptors
105
Q

LH surge causes

A
  • ovulation
  • 18 hours before time
  • remains for about 12 hours after following be LH and FSH decline
106
Q

As LH and FSH level decrease, estrogen levels will

A
  • decrease
  • dominant follicle has ruptured and released oocyte
107
Q

During luteal phase, estrogen levels

A
  • peak again
  • comes from corpus luteum as a temporary endocrine gland
108
Q

Progesterone during follicular phase

A
  • low
  • near the end will rise a bit due to granulosa cells beginning to release progesterone
  • after corpus luteum formed, there is large increase
109
Q

Why do the gonadotropins, LH and FSH remain low throughout luteal phase

A
  • estrogen and progesterone has negative feedback and suppresses LH and FSH
  • gonadotropins levels must be kept low so another LH surge/ovulation does not occur in luteal phase
110
Q

Low levels of estrogen have a ___ effect on ____ and levels will _____

A
  • negative feedback
  • FSH
  • decrease
111
Q

High levels of estrogen had a ____ effect on ____ and levels will ____

A
  • positive feedback
  • LH
  • increase
112
Q

Inhibin role

A
  • decline in FSH levels during follicular phase
  • causes atresia of the non dominant selected follicles
113
Q

In the dominant follicle

A
  • stimulation of meiosis I in the oocyte
  • estrogen secretion starts decreasing after ovulation
  • progesterone secretion increases
  • ovulation
  • transformation of follicle into corpus luteum
114
Q

Fertilization

A

process by which male and female gametes fuse together to form zygote

115
Q

Gestation

A
  • length of time on intrauterine fetal development
  • 9 months or 40 weeks
116
Q

Embryo

A

first 2 months of life

117
Q

Fetus

A

developing human from 2 months to birth

118
Q

Parturtition

A

childbirth

119
Q

Site of fertilization

A

Fallopian tube

120
Q

Sperm is viable for

A

5 days

121
Q

Oocyte is viable for

A

12-24 hours

122
Q

Why do only several hundred sperm make it to uterine tubes?

A
  • damage due to acidic environment in female tract
  • loss of sperm from female reproductive tract due to leakage from cervix
  • loss of energy
123
Q

Capacitation

A
  • previously regular wavelike action of sperm’s tail is replaced by whiplike action that propels sperm forward
  • sperm’s plasma membrane becomes altered so it is capable of fusing with surface membrane
  • occurs in female repro tract
124
Q

Polyspermy

A
  • egg that has been fertilized by more than one sperm
  • not favored and prevented to maintain 2n chromosome
125
Q

Steps of fertilization

A

many sperm bind to glycoprotein receptors on zona pellucida –> binding triggers acrosomal reaction –> plasma membrane of sperm head is altered so enzymes exposed to outside –> enzymes digest zona pellucida –> first sperm to penetrate zona pellucida fuses with membrane –> egg secretory vesicles are released into space between zona pellucida and egg plasma membrane –> hardens layer

126
Q

Blocks to polyspermy

A
  • change in membrane potential
  • release of contents from cortical granules
  • enzymes enter and harden zona pellucida
  • enzymes inactive sperm binding receptor
127
Q

What happens to the oocyte during fertilization

A
  • sperm fusion stimulated 2nd meiotic division of oocyte
  • oocyte converted to fertilized ovum
  • sperm plasma membrane disintegrates
  • chromosome from sperm and ovum migrate to center
  • DNA replicated to a zygote (2n)
128
Q

Morula

A
  • less than 16 cells
  • zona pellucida intact
  • cell cleavage: number of cells increase but no overall growth of size
  • cells are totipotent
129
Q

Identical twins

A
  • division of totipotent morula cells
130
Q

Fraternal twins

A
  • fertilization of two oocytes
131
Q

Blastocyst

A
  • 4-5 days after fertilization
  • lose totipotentiality and differentiate
  • no zona pellucida
132
Q

Outer cell of blastocyst

A
  • trophoblast
  • will become fetal placenta
133
Q

Inner cell of blastocyst

A
  • will become embryo
  • when inner cell mass if pushed to one side of blastocyst, fluid filled cavity called blastocoel is formed
134
Q

Implantation

A
  • 6-7 days after fertilization
  • sticky trophoblast cells anchor to endometrial lining
  • proliferation into syncytiotrophoblast (fused) and cytotrophoblast (hormones)
135
Q

Decidual response

A
  • when fused syncytiotrophoblast layer penetrates endometrial layer, all blood vessels start branching closer to blastocyst
  • gland-like structures provide glycogen from embryo
136
Q

Placenta has 2 compartments

A
  • fetal placenta - blastocyst
  • maternal placenta - uterine tissue
137
Q

Amnion

A
  • innermost membrane that encloses the embryo fused with the chorion which is the outer layer
138
Q

Chorion

A
  • embryonic derived portion of placenta
  • made of trophoblasts
  • invades the maternal endometrium and develops finger-like projections called chorionic villi
139
Q

Umbilical cord

A
  • contains two umbilical arteries and an umbilical vein
  • arteries carry deoxygenated nutrient depleted blood from fetus to placenta
  • vein carries oxygenated nutrient rich blood from placenta to fetus
140
Q

Functions of placenta

A
  • temporary endocrine gland
  • exchange tissue
  • filter/immunological barrier
141
Q

hCG

A
  • very sharp peak at 2 months which then decreases and stays at low constant level
  • released from chorionic layer of placenta
  • helps maintain corpus luteum in early parts until placenta is formed and takes over
142
Q

Progesterone and estrogen levels during pregnancy

A
  • high increasing levels
  • estrogen higher than progesterone
143
Q

After delivery, progesterone and estrogen levels

A

drop

144
Q

hPL

A
  • growth hormone-like and anti-insulin like actions in mother
  • keeps glucose and nutrient levels high in mother’s plasma providing more nutrition for fetus through placenta
  • helps fetus take up more glucose into its own body
145
Q

Progesterone functions during pregnancy

A
  • decreases uterine contractions
  • inhibits secretion of LH and FSH from anterior pituitary
  • stimulates growth of alveolar ducts or glands
  • causes cervical glands to secrete a sperm-unfriendly mucus
146
Q

Estrogen functions during pregnancy

A
  • causes growth of myometrium
  • causes growth of mammary ducts
  • inhibits LH and FSH from anterior pituitary
147
Q

Hormone pathway during pregnancy

A
  • cholesterol –> progesterone –> androgens –> estrogen
  • SEE TABLE
148
Q

Control of parturition

A
  • weak uterine contractions develop and push fetus forwards to cervix
  • pressure of fetus against cervix sends positive message to posterior pituitary to release oxytocin
  • oxytocin acts on uterine myometrial layer binding to tissue and causing more contractions
149
Q

Hormones involved in parturition

A

myometrial contractions increased by estrogen, prostaglandins, oxytocin and stretch from fetus’s head

150
Q

Cervical ripening

A
  • prepares the tissues to make cervix softer and easier for expansion
  • due to prostaglandins and relaxin (progesterone inhibits this)
151
Q

Mammary gland

A
  • contain mammary glands that are the site of milk production and storage
  • alveoli clustered into lobules and clustered into lobe
152
Q

Birth to puberty - mammary glands

A
  • breast tissue has rudimentary ducts
153
Q

Puberty - mammary glands

A
  • estrogen causes ducts to start growing and branch out
  • progesterone causes growth of alveolar tissues
  • fat is deposited around alveolar space
154
Q

Pregnancy and lactation - mammary glands

A
  • estrogen, progesterone, prolactin, hPL
  • prolactin is released from anterior pituitary and promotes lactation and milk production
  • oxytocin required for milk ejection/let-down
155
Q

Galactopoiesis

A
  • maintenance of lactation while mother is breast feeding
  • requires prolactin
156
Q

2 cells required for milk ejection

A
  • alveolar epithelial cells - synthesize milk
  • myoepithelial cells - contractile properties to expel milk, has receptors for oxytocin to cause contraction
157
Q

Suckling

A
  • activates tactile mechanoreceptors in mother’s breast tissue
  • activates hypothalamus and stimulates oxytocin secretion
  • causes contraction of myoepithelial cells and milk is ejected
158
Q

Dopamine in mammary glands

A
  • inhibits prolactin secretion for anterior pituitary cells
  • suckling decreases dopamine secretion
159
Q

Male chromosomes

A

XY
- presence of Y leads to development of male gonads - testes

160
Q

Female chromosomes

A

XX
- absence of Y leads to development of female gonads- ovaries

161
Q

Chromosomal sex is determined at

A

exact moment of fertilization

162
Q

Gonadal sex is determed by

A

chromosomal sex

163
Q

Site at where male or female gonads develop

A

urogenital ridge or gonadal ridge

164
Q

Presence of Y chromosome of what gene

A

SRY gene

165
Q

Female differentiation occurs by

A

default

166
Q

Klinefelter’s syndrome

A
  • Male XXY
  • infertile - spermatogenesis does not occur
167
Q

Turner’s syndrome

A
  • Female XO
  • streaked ovaries - do not look round but are flattened structures
168
Q

Phenotypic sex

A
  • dictated by factors produced by gonads
  • determined by internal and external genitalia
169
Q

Undifferentiated reproductive tract includes a

A

double genital duct system

170
Q

Ducts in male differentiation

A

Wolffian ducts persist and Mullerian ducts regress

171
Q

Ducts in female differentiation

A

Mullerian ducts persist and Wolffian ducts regress

172
Q

Male differentiation

A
  • testes produced by presence of Y
  • testes secrete MIH from Sertoli cells
  • Leydig cells secrete testosterone to develop male internal genitalia
  • testosterone is converted to DHT by 5-alpha reductase which causes masculinization of male external genitalia
173
Q

Male internal genitalia

A
  • epididymis, vas deferens, seminal vesicles, ejaculatory ducts, testes
174
Q

Male external genitalia

A
  • penile structure and prostate gland
175
Q

Female differentiation

A
  • do not have MIH so Mullerian ducts persist and Wolffian duct regress due to lack of testosterone
  • Mullerian duct will grow into female internal genitalia
  • since no DHT, male external tissue does not develop
  • some modulation due to estrogen
176
Q

Female internal genitalia

A
  • uterine structures, Fallopian tubes, cervix, vaginal space
177
Q

Congenital adrenal hyperplasia - sexual disorders

A
  • female genotype, male phenotype
  • too much androgen production in fetal stage causes male external appearance
  • decreased cortisol –> increase ACTH –> adrenal androgens –> mascularization
  • infertile
178
Q

Androgen insensitivity syndrome - sexual disorders

A
  • male genotype, female phenotype
  • tissues in body were unresponsive to testosterone during development
  • testes developed corrected
  • mutation in receptors of Wolffian ducts cannot bind testosterone
  • male genitalia do not develop
  • androgens converted to estrogen in target tissues to product female genitalia
  • infertile
179
Q

What triggers the onset of puberty

A
  • increased secretion of GnRH, increased secretion of LH and FSH, increased secretion of sex steroids
  • genetic influences and environmental influences alter GnRH levels
180
Q

Prepubertal child

A
  • hypothalamic-pituitary-gonadal axis is dormant because hypothalamus is suppressed
  • low levels of GnRH, LH, FSH
  • low levels of sex steroids provide strong negative feedback to higher centers
181
Q

Time of puberty in the axis

A
  • Kisspeptin - neuropeptide releases GnRH in hypothalamus
  • Adipose tissue - source of hormone leptin which acts on hypothalamus to release kisspeptin to regulate pulse generator
182
Q

Andropause

A
  • in males
  • start anywhere from age 40 onwards
  • lowering of male hormones
183
Q

Menopause

A
  • in females
  • reproductive status comes to a halt
  • follicular depletion throughout life by apoptosis - atresia
  • decreased responsiveness to gonadotrophs, decreased estrogen and inhibin
  • ovulation and menstrual cycles become irregular and stop
  • decreased E, I, P remove negative feedback
  • FSH (especially) and LH increase
  • cardiovascular effects and osteoporosis because of decreased estrogen

Physiology 210 (12 decks)

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