Reproductive Physiology 2010

Front 1

What gene is for the TDF? (testis-determining factor)

Back 1

SRY

Front 2

What happens in the absence of SRY?

Back 2

The ovary will develop

Front 3

What do Mullerian (paramesonephric ducrs develop into?

Back 3

-upper vagina, uterus and uterine tubes
-occurs with absence of AMH

Front 4

What female genitalia develop in the absence of testosterone --> DHT?

Back 4

External genitalia:
-Lower vagina
-Labia minora
-clitoris
-Labia majora

Front 5

development of the gonad into testis requires what? What else does this gene do?

Back 5

-SRY
-promotes differntiation of testicular cells (spermatogonia, sertoli cells and leydig cells)

Front 6

What does T stimulate the wolffian ducts to develop into?

Back 6

-epididymis, vas defererns and seminal vesicles

Front 7

What does DHT stimulate the development of?

Back 7

-prostate, penis, glans penis and scrotum

Front 8

hCG

Back 8

-stimulates the leydig cells of the early developing testes to hypertrophy and produce testosterone

Front 9

What produces anti-mullerian hormone?

Back 9

sertoli cells

Front 10

What enzyme converts testosterone into DHT?

Back 10

-5 alpha-reductase

Front 11

What converts testosterone into estradiol?

Back 11

aromatase

Front 12

Kallmann syndrome

Back 12

-anosmia due to agenesis of the olfactory lobes and hypogonadism secondary to deficiency of GnRH
-failure of fetal GnRH to migrate from olfactory placode to hypothalamus
-inheritance is X-linked
-other manifestations include microphallus and cryptochidism, associated midline defects, and unilateral kidney agenesis

Front 13

Describe the type of secretion of GnRH by the fetus detected by 20-23 weeks?

Back 13

-pulsatile secretion

Front 14

What does LH stimulate in males? What does FSH stimulate?

Back 14

LH--> leydig cells --> testosterone

FSH--> Sertoli cells --> Spermatogenesis

Front 15

What inhibits GnRH release?

Back 15

-androgens (T, DHT, high DHEA/androstenedione, anabolic steroids)
-estrogens
-prgesterone and synthetic progestins
-LH and FSH
-high levels of stress and exercise

Front 16

How does GnRH work?

Back 16

-acts through G-protein associated receptors to increase gonadotropin hormone synthesis and release (increase adenylate cyclase, cAMP and Ca++)
-receptors with down regulate and uncouple if GnRH is continuously present

Front 17

Describe the composition of LH?

Back 17

-alpha + beta subunit
-alpha subunit (same alpha subunit used for FSH, TSH LH and hCG)
-beta subunit from a different gene and is responsible for the unique activity of LH

Front 18

What inhibits the release of LH?

Back 18

-sex steroids

Front 19

Describe the composition of FSH?

Back 19

-alpha and beta subunit
-apha (same as FSH TSH LH and hCG)
-beta is from a different gene and is unique for the activity of FSH

Front 20

What inhibits synthesis of FSH and what activates it?

Back 20

-inhibin and sex steroids inhibits
-activin activates

Front 21

Where is activin released from?

Back 21

sertoli cells

Front 22

FSH function in males?

Back 22

-stimulates spermatogenesis in testes
-stimulates sertoli cells (increase inhibin B secretion, increase androgen binding glycoprotein and increase LH/hCG receptors)

Front 23

First physcial sign of male puberty? When does sperm production begin?

Back 23

-First physical sign is enlargement of testis which is preceded by increases in FSH and LH levels
-Sperm production begins at about 13 years

Front 24

SHBG

Back 24

-Sex-hormone binding globulin
-affects the bioavailability of sex hormones since only unbound or "free" hormone is biologically active and able to enter a cell and activate the hormone receptor

Front 25

androgen actions on metabilism, muscle, RBC, fat and liver?

Back 25

-Anabolic (stimulates tissue growth and metablism )
-muscle (increases protein synthesis, muscle mass and metabolism)
-increase red blood cell production
-redistribution of body fat
-liver (increase VLDL, LDL and decrease HDL)

Front 26

androgen actions on CT and Glands?

Back 26

CT:
-increase bone mass
-cartliage growth (growth of laynx = deepening of voice, epiphysis)
-hair growth (pubic and axillary hair; beard, pattern baldness)

Glands:
-Sebaceous glands --> leads to acne
-prostate, seminal vesicles, Cowpers

Front 27

androgen actions on CNS and male sex development?

Back 27

CNS
-sexual behavior and libido
-feeling of energy and wellbeing
-competitive behavior
-aggression

Front 28

What age does male puberty begin? When does it end?

Back 28

Begins at age 10. Ends at 15-17

Front 29

What produces Inhibin?

Back 29

-ovarian granulosa cells
-testicular Sertoli cells
-pituitary
-placenta

Front 30

What are the forms of Inhibin?

Back 30

-Form A and B
-A is produced by females only
-B is produced by both sexes
-Both forms supress FSH release
-Inhibin B increases androgen production by theca cells and leydig cells (paracrine effect)

Front 31

Where is activin produced?

Back 31

ovarian granulosa cells, testicular sertoli cells, placenta and pituitary cells

Front 32

Actions of activin?

Back 32

-increases FSH synthesis and release
-decreases T secretion from leydig cells
-probably acts mostly as a paracrine factor since follistatin prevents blood borne actions

Front 33

Follistatin

Back 33

-prevents activin in the blood from stimulating pituitary FSH release
-binds activin thus decreasing free activin plasma levels

Front 34

describe the steps of spermatogenesis

Back 34

1)Spermatogonia
2) Mitosis
3)Pimary spermatocytes
4)Meiosis I
5)Secondary spermatocytes
6)Meiosis II
7)Spermatids
8)spermigenesis and maturation
9)Spermatozoa

Front 35

How long does spermatogenesis take?

Back 35

64 days

Front 36

What autonomic neurotransmitters stimulate penile vasodilation to produce an erection?

Back 36

-Ach, NO, VIP, PGE1 and PGI1

Front 37

What autonomic neurotransmitters stimulate ejactulation?

Back 37

NE and endothelin

Front 38

What do phosphdiesterase-5 inhibitors do?

Back 38

-inhibit breakdown of cGMP and potentiates the vasodilation produced by nitric oxide (NO)
-(viagra)

Front 39

What does continuous GnRH do?

Back 39

-inhibits LH and FSH

Front 40

What does FSH in females do?

Back 40

-stimulates the development of follicles within the ovary
-stimulates follicle cells (granulosa cells) to secret estrogen

Front 41

What does LH do in female?

Back 41

-causes mitosis for theca cells
-Stimulates secretion of androgens by the theca cells (androgens converted to estrogens by granulosa cells)
-stimulates ovulation (LH surge)
-promotes formation of the corpus luteum
-Stimulates secretion of progesterone by the corpus luteum

Front 42

Gonadarche

Back 42

stimulation of gonad development by GnRH/FSH and LH and the poduction of androgens and estrogens

Front 43

Adrenarche

Back 43

increased androgen secretion by the adrenal cortex.
-usually before gonadarche in boys
- around year 8. often after gonadarche in girls-terminal hair and axillary and pubic regions (9-14), development of sdoriferous sweat glands

Front 44

first physical signs of female puberty?

Back 44

-enlargement of breats (thelarche and increased body growth, which is preceded by increases in FSH and LH levels

Front 45

Menarche

Back 45

-onset of menstrual cycles, begins about 11 - 14 years
-Incomplete maturation of the hypothalamic positive feedback response to estrogens (LH surge) produces some anovulatory cycles
-90% of girls have regular ovulatory cycles within 5 years of the onset of menarche
-Epiphyseal plates close at a median age of about 17 years in females

Front 46

When are primary oocytes formed?

Back 46

-all primary oocytes are formed before 6 months of age

Front 47

Steps of oogenesis

Back 47

1)oogonia
2)mitosis
3)oogonia
4)meiosis I
5)primary oocyte
6) polar body, follicle maturation meiosis I completed just before ovulation
7)Secondary oocyte
8)polar body, ovulation and derilization. Meiosis II
9) Zygote

Front 48

When does the oogonium develop?

Back 48

-Oogonium develop before birth.
-Oogonium multiply by mitosis in the fetal ovary, primary oocytes stay in meiosis I prophase for many years

Front 49

Primordial follicle

Back 49

-Oocyte – primary oocyte arrested in meiosis I prophase

Granulosa cells (single layer of spindle shaped to cuboidal cells surrounding oocyte)
-Spindle cells form contacts with oocyte
-Basal lamina separates follicle from stroma

Front 50

Primary Follicle

Back 50

-Zona pelucida - mucopolysaccaride layer that protects the egg
-Granulosa cells (Grow and divide to form several layers of cells, all connected by gap junctions
Maintain contact with oocyte
Secrete Zona pelucida)
-Basal lamina

Front 51

Secondary Follicle

Back 51

-Zona pelucida
-Granulosa cells (Secrete fluid that will form and fill the antrum.
Some cells form the cumulus oophorus)
-Basal lamina
Theca cells - form two layers around the basal lamina
-Theca interna - steroid production
-Theca externa - surround blood vessels

Front 52

What happens to the follicles at each cycle?

Back 52

-After puberty - 10-20 follicles begin to mature each cycle (~3 mo to mature)

FSH & LH stimulate cells surrounding oocyte to proliferate and produce steroids

Most follicles undergo atresia
apoptosis = programmed cell death
Graafian follicle
Dominant follicles survive
granulosa cells up regulate FSH receptors

Front 53

Graafian follicle

Back 53

each cycle usually only one follicle has the right combination of antrium steroids, FSH & LH receptors … to survive & ovulate

Front 54

Main function of Granulosa cells?

Back 54

-Produce estrogens, inhibin & activin
-Stimulated by FSH, also have LH receptors

Front 55

Main functions of Theca cells?

Back 55

-Produce androgens (estrogen precursor steroids)
-Stimulated by LH

Front 56

Main function of estrogens in female genitalia?

Back 56

-Stimulates proliferation of the endometrium of the uterus

-Stimulates vaginal mucosa and secretory glands, prepares for fertilization

Front 57

General functions of estrogens

Back 57

-bone density prevent osteoporosis

-protein production by liver
(Increases blood levels of sex steroid binding globulins, high density lipoproteins (HDL), clotting factors, thyroid binding globulin, and other proteins)

-Lowers circulating cholesterol
(anti-atherosclerotic effect (↑ HDL, ↓ LDL))

-Central nervous system
(Influences reproductive behavior & general mood, may increase anxiety
May be neuroprotective & slow dementia)

Front 58

Functions of progesterone?

Back 58

-Maintains secretory endometrium
-Causes thick, rubbery cervical secretions
-Helps maintain pregnancy, inhibits uterine contraction, helps prepare breast for lactation
-Anti-depressant, calms anxiety & promotes normal sleep patterns
-Normalizes blood clotting
-Improves vascular tone
-Precursor of corticosteroid and sex steroid biosynthesis
Effects on fluid retention?

Front 59

Follicular phase

Back 59

-FSH and LH stimulate ovarian follicle growth, maturation and estrogen production

-Estrogens stimulate growth of the uterine lining

Front 60

What stimulates ovulation?

Back 60

LH surge

Front 61

Luteal phase

Back 61

LH stimulates lutinization and production of progesterone
Progesterone prepares the uterine lining for pregnancy

Front 62

Follicular phase

Back 62

-FSH Levels rise and stimulate granulosa cells
increase growth, estrogen production (increase aromatase activity), increase FSH receptors
-Estrogens ( Estradiol & Estrone)
(produced from androgen precursors
stimulate endometrium of the uterus)
-Hormones & growth factors produced by the granulosa cells stimulate the maturation of the dominate follicle
LH stimulates Thecal cell production of androgens
Testosterone & Androstenedione

Front 63

Ovulatory phase

Back 63

-Increasing estrogen levels produced by mature follicle over several days stimulates LH release (temporary positive feedback)

-Mature Graafian follicle ruptures (ovulation) releasing oocyte and surrounding granulosa cells (corona radiata) into the abdominal cavity

Front 64

Signs of Ovulation

Back 64

-Increase in basal body temperature
-Changes in cervical mucus
-Cervix softens
-Mittelschmerz---pain

Front 65

Luteal phase

Back 65

-LH surge also triggers remaining follicle cells (corpus luteum) to produce primarily progesterone

Progesterone:
-slight rise in body temp
-stimulates endometrial gland secretions and prepares the endometrium for implantation
-causes changes in cervical secretions creating conditions unfavorable for the passage of sperm or microorganisms

Front 66

What does Activin do specific to females?

Back 66

-Stimulates development of embryonic tissues

-Decreases T secretion from thecal cells [& Leydig cells] (offset by increase in FSH)

Front 67

Menses

Back 67

-Corpus luteum is desensitized to LH & steroid production stops unless stimulated hCG
-Estrogen & progesterone levels drop
-Vasoconstriction of the endometrial spiral arteries deprives decidual layer of blood and menses begins
-Low Estrogen levels stimulate FSH release and a new cycle begins

Front 68

Main components of the ectoderm?

Back 68

-external (surface) ectoderm
-neural tube
-neural crest

Front 69

external (surface) ectoderm

Back 69

-Epidermis; Epithelium and glands of the mouth and nasal cavity; and anterior pituitary gland; sensory receptors; cornea & lens

Front 70

neural tube

Back 70

Brain (pineal, posterior pituitary gland) & spinal cord

Front 71

neural crest

Back 71

ANS neurons and glia; some skeletal elements; melanocytes; adrenal chromaffin cells, C cells & other hormone producing cells

Front 72

Mesoderm

Back 72

connective tissues & mesenchyme
bones & muscles
circulatory system
urinary system
reproductive system
peritoneum
mesothelium
Adrenal cortex

Front 73

endoderm

Back 73

The endoderm forms the epithelial lining of :
-most of the digestive tube
-liver and pancreas
-the auditory tube and tympanic cavity
-the trachea, bronchi, and lungs
-the urinary bladder and part of the urethra
-the follicles of the thyroid gland and thymus

Front 74

hCG produced by the placenta?

Back 74

stimulates continued steroid production by the corpus luteum which is important for maintaining pregnancy during the first trimester and by the placenta during the rest of the pregnancy
(hCG also important for stimulating the developing testes of the male)

Front 75

____ is a minor hormone in the non-pregnant female but is a major hormone of pregnancy

Back 75

Estriol

Front 76

Estrogens (estrone, estradiol, estriol) & progesterone produced by the placenta are important for what?

Back 76

maintaining pregnancy during the last two trimesters
-Fetal adrenal & liver produce DHES-S required for estriol synthesis

Maintains the endometrium

Help prepare the mother for lactation - Estrogen stimulates gland development and duct growth

Front 77

How is progesterone important in pregnancy?

Back 77

is produced in the placenta from cholesterol provided by the maternal blood (LDL)

inhibits uterine smooth m. activity
-Levels decline just prior to parturition

Helps along with other hormones to prepare the mother for lactation (stimulates duct development) but inhibits milk secretion

Front 78

How is Corticotrophin-releasing hormone CRH important in pregnancy?

Back 78

Stimulates the secretion of cortisol and other adrenal steroids by the fetal adrenal
-Cortisol required for the maturation of many tissues
-DHEA-S needed for estriol production by the placenta

Role in timing delivery? (of sheep)

Front 79

Placental-variant GH and Human Chorionic Somatomammotropins (hCS1 & 2) (also called Human Placental Lactogens)

Back 79

Metabolic effects similar to GH help maintain blood glucose to supply the developing fetus
-Insulin resistance and lipolysis

Help prepare the mother for lactation

Stimulate protein synthesis

Front 80

Cardiovascular changes to meet needs of fetus During Pregnancy

Back 80

-20-30% rise in cardiac output due to placenta
-15% increase in heart rate
-30-50% increase in blood volume
-Blood flow of the uterine artery increases from approximately 20 mL/min in the first trimester to approximately 500-800 mL/min in the third trimester
-Progenterone & Estrogens inhibit vasoconstrictive actions in peripheral vessels (decrease TPR)

Front 81

Respiratory changes During Pregnancy

Back 81

-30% increase in tidal volume
-Decrease in airway resistance
-Minute respiratory volume increases as O2 needs increase
-Decrease in expiratory reserve volume

Front 82

Urinary system changes During Pregnancy

Back 82

Urinary system changes
Increase in glomer

Front 83

Reproductive system changes
During Pregnancy

Back 83

Uterus increases in size from 80 g to 1200g

hyperplasia and hypertrophy

Front 84

Pregnancy-induced Hypertension

Back 84

-Elevated blood pressure

-Preeclampsia (~5% of pregnancies)

-Autoimmune or allergic reaction to presence of fetus

-Eclampsia

Front 85

Preeclampsia

Back 85

Sudden hypertension

Large amounts of protein in the urine
Generalized edema, blurred vision & headaches

Front 86

Eclampsia

Back 86

convulsions & coma in mother (50K-75K maternal deaths worldwide annually)

Front 87

what is Maternal insulin resistance caused by?

Back 87

placental growth hormones (pvGH, hCS1 & hCS2), cortisol and prolactin

normally accompanied by an increase in maternal beta cell mass and insulin output

Front 88

When does labor begin?

Back 88

when inhibition is overcome by an increase in the actions of estrogen
-progesterone inhibits uterine contraction
-placenta stimulates fetal anterior pituitary to secrete ACTH which stimulates the fetal adrenal gland to secrete DHEA
-placenta converts DHEA to estrogen
estrogen stimulates prostaglandin production
increased Oxytosin and increased Progesterone receptors

Front 89

Oxytocin's role in labor?

Back 89

Oxytocin receptors in the uterus are up regulated at parturition

Oxytocin stimulates the contraction of the uterine smooth muscle (myometrium)

Front 90

What is produced by the uterus to increase contractions?

Back 90

prostaglandins

Front 91

Prolactin

Back 91

-single chain polypeptide
-Secreted by mammotropes (lactotropes) of the anterior pituitary
-Increased by estrogens, TRH, VIP,
-Release stimulated by sensory stimulation (suckling, sexual stimulation, ?)
-No prolactin feedback inhibition
-Release inhibited by dopamine (Prolactin Release-Inhibiting Hormone)

Front 92

What is the main hormone that stimulates milk production?

Back 92

Prolactin is the main hormone that stimulates milk production (High prolacin inhibits LH release)

Front 93

What is contained in human milk?

Back 93

Human Milk
500 - 2000 ml/day
1% protein - casein, lactalbumin, lactoglobin, others {lactoferrin, B12 binding protein, Ig A, hormones, growth factors}
7% lactose
3.5% fat
Cells (mostly macrophages {lysozyme