Physio E4 Reproductive

How do gametes form?

How do gametes form?

meiosis

What is TDF?

testes determining factor

What chromosomes do females have?

XX

What chromosomes do males have?

XY

What determines the sex of a child?

determined by the contributing sperm

What determines whether embryonic gonads become testes or ovaries?

TDF

What does the Mullerian duct turn into?

uterus and uterine tubes

What factor determines if the Mullerian duct develops or degenerates?

Mullerian inhibition factor (MIF)

What happens if MIF is present? Absent?

Present: mullerian ducts degenerates

Absent: mullerian ducts develop into uterine tubes

What hormone leads to the development of the prostate, penis and scrotum?

Testosterone

The vagina, labia, and clitoris will develop in the absence of what?

Testosterone

What hormone determines whether the Mesoneprhic (Wolffian) duct will develop or degenerate?

Testosterone

What happens to the Wolffian (mesonephric) duct if there is no testosterone present?

degenerates

What does the Mesonephric duct turn into?

epididymides, ductus deferential, ejaculatory ducts

Where is testosterone secreted from?

testes

97% of testosterone is bound to what?

albumin and sex hormone binding globulin

5-alpha reductase converts testosterone to what?

DHT (more potent androgen)

How is testosterone eliminated?

metabolized and eliminated in the liver via bile or urine

Androgens work at nuclear receptors to affect what?

DNA-RNA transcription

Secondary sex characteristics of males

later growth spurt: body, muscle, penis and testis growth

Body hair is stimulated by __ at puberty for both males and females

androgens via the adrenal gland cortex

Other androgen effects

male pattern baldness, increased skin thickness, acne, bone deposition, protein and muscle development, increased RBC formation, increased prostate size

LH goes to ____ causing them to secrete gonadal hormones ____

Leydig cells; testosterone

Testosterone is provides negative feedback to what androgen?

LH>FSH

FSH goes to the ____ to secrete ___

seminiferous tubules (Sertoli cells); inhibin

Inhibin provides negative feedback for what androgen? (male and female)

FSH only!!!

What is the role of Leydig cells? Sertoli cells?

Leydig: secrete testosterone → androgenic effects, spermatogenesis

Sertoli cells: secrete inhibin, spermatogenesis

What 2 hormones influence spermatogenesis?

FSH and testosterone

Where are FSH receptors found? Male

Sertoli cells

Where are LH receptors found? Male

Leydig cells

What are the two compartments of the testis?

Seminiferous tubules and Interstitial tissue

What is acrosome?

cap of digestive enzymes on the sperm

What is the end result of the maturation stage of spermatogenesis?

4 sperm

Pathway of sperm maturation

seminiferous tubules → rete testis → efferent ductules → epididymis

What is the role of the epididymis?

site of sperm maturation and storage

Pathway of sperm ejaculation

epididymis → vas deferens → ejaculatory duct → urethra

What is the role of the seminal vesicle?

adds lube (seminal fluid)

What does seminal fluid consist of?

fructose (energy), fibrinogen, prostaglandins

What does prostate fluid consist of?

citric acid, calcium, zinc, coagulation proteins, proibrinolysin

What does bulbourethral gland fluid consist of?

galactose and mucus (increase motility)

What are the components needed for an erection?

vascular, nerve (SNS and PNS), psychological, hormonal (testosterone)

An erection results form blood flow into the __

corpus cavernosa

How does the PNS lead to an erection?

PNS nerve → NO induced vasodilation of the arterioles leading to the corpus cavernosa

Inhibiting what hormone prolongs vasodilation?

PDE5

What is under SNS control?

emission and ejaculation via the pudendal nerve

Point and Shoot:

PNS stimulation is needed for erection

SNS stimulation is needed for ejaculation

What is the site of fertilization?

ampulla

What is the endometrium?

inner layer of uterus, where embryo implants and develops

What is the myometrium?

middle muscle layer, contracts during birthing

What are the 2 primary female sex hormones?

estrogen and progesterone

Estrogen is secreted from….

the ovaries (primarily in non-pregnant females) and small amount from the adrenal cortex

Progesterone is secreted from….

corpus luteum in latter half of ovarian cycle

Where are estrogen and progesterone metabolized?

liver

When is secretion of FSH and LH elevated?

birth - first 6 months post natal

During puberty onset and during reproductive years which hormone is higher?

LH

If FSH > LH =

no cycle (menopause- no negative feedback)

Secondary sex characteristics of women

growth spurt, breast development, menarche

Hormone flow of female reproductive system

Hypothalamus: GnRH → ant. pituitary: FSH & LH → gonads: estrogen, progesterone, and inhibin

Ovarian follicles secrete (follicular phase)

estradiol

Corpus luteum secretes (luteal phase)

progesterone (important in pregnancy)

Granulosa cells of ovarian follicles secrete

inhibin

What is the avg. Ovarian cycle length?

28 days

What causes the LH surge during ovulation?

due to estrogen hitting threshold

primary follicles grow layers of granulosa cells in response to

FSH

After ovulation, the remaining follicle becomes

corpus luteum

Corpus luteum secretes

estradiol and progesterone (play a roll in uterine cycle)

Phases of the ovarian cycle

follicular phase, ovulation, luteal phase

Follicular phase

day 1-13; initiated by FSH; increasing level of estradiol from granulosa cells

At the end of the follicular phase, FSH and estradiol are high causing

stimulation of LH from follicles and Hypothalamus/ant. pit. —> LH surge

Ovulation phase

LH surge initiates → cause follicle to rupture → oocyte is released

Luteal phase

rupture follicle becomes corpus luteum: secretes estradiol and progesterone (peaks 1 week post ovulation) and inhibin → high levels feedback on pituitary gland and inhibit FSH and LH secretion

Changes in the endometrium follow changes in the

follicles of the ovaries

phases of the uterine (menstrual) cycle

menstrual, proliferative, secretory

What defines the first day of the menstrual cycle?

first day of menses

The development o the endometrium is regulated by secretion of

estradiol and progesterone in the ovaries

Proliferative phase occurs while the ovary is in

follicular phase

Proliferative phase

increasing levels of estradiol stimulate the growth of the endometrium →becomes more vascular and develops progesterone receptors

Secretory phase occurs

post ovulation, when the ovaries are in the luteal phase

Secretory phase

secretion of progesterone stimulates the endometrium to become even thicker more vascular → prepared to nourish a growing embryo

Menstral phase occurs

because of the fall in estradiol and progesterone when corpus luteum degenerates

Menstral phase

arteries in the endometrium constrict and this region is sloughed

The association between the acrosome cap and zona pellucida cells stimulates the entry of __

Ca2+ → release of acrosomal enzymes (allow sperm to digest zona pellucida on way to oocyte)

__ days post fertilization the blastocyte implants into the endometrium. by the __ day its completely buried

6; 7-10

When implantation occurs, the blastocyte releases what?

hCG —> keeps the corpus luteum alive

What is the point of keeping the corpus luteum alive?

continues to release estradiol and progesterone → prevents menstruation

When secretion of hCG declines what takes over hormone production?

the placenta

Do maternal and fetal blood mix?

no; they are separated only by two cell layers

What diffuses from the maternal blood to the fetal blood?

oxygen and nutrients; Alcohol can also

What diffuses from the fetal blood to the maternal blood?

CO2 and waste

How much weight do women gain in pregnancy?

25-35 lbs

How much weight is in extra blood and ECF?

5 lbs

Does women’s metabolism increase during pregnancy?

yes; leads to overheating sensation

Nutritional maternal changes

increased need for iron, Vit D, Ca, Vit K

Changes in maternal blood flow

CO increases 30-40% by 27th week → increased aldosterone and fluid retention

Respiration maternal changes

20% increase in O2 consumption, increased ventilation, increased sensitivity to CO2

What increases to protect mother from hemorrhage during childbirth?

blood coagulability

GFR increases ___ by mid-pregnancy

40-50%

What pulls water of the GI system during pregnancy?

progesterone

What hormone weakens joints widening the pelvis?

progesterone

Average gestation period

40 weeks; measured from first day of LKMP