What does bipotentiality of sex differentiation mean?
Outcomes of earlier stages do not necessarily determine the direction of development at subsequent stages
Raw materials to develop in either direction are available at each stage
How many chromosomes go humans have? How many of those are sex chromosomes?
46, 2
What determines chromosomal sex?
Whether the sperm fertilizing the ovum has an X or Y chromosome
What is the sex chromosome complement of an individual with Turner syndrome?
XO
Do individuals with Turner syndrome have functional gonads?
No, they are infertile
When do gonads begin to sex differentiate?
6 weeks after conception
What are the two structures that make up the undifferentiated gonad?
The medulla and the cortex
Where are primordial germ cells produced and where do they typically migrate to?
PGCs are produced in the yolk sac and they migrate to the undifferentiated gonad
What must occur for the undifferentiated gonads to develop into testes?
Must have a functional Y chromosome with an SRY gene which stimulates an autosome to produce H-Y antigen (which stimulates the medulla to develop into testes and the cortex to fade away)
What must occur for the undifferentiated gonads to develop into ovaries?
Must have migration of the primordial germ cells to the undifferentiated gonad and
the absence of a functional Y chromosome and
the presence of at least 2 functional X chromosomes- (the medulla fades away and the cortex develops into ovaries)
What happens if the primordial germ cells do not migrate?
In the XX individual, the gonads will remain in the undifferentiated state, or become gonadal streaks.
In the XY individual, testes will develop (assuming the other conditions are all met).
What three things must be present for male internal genitalia to develop?
Androgens, Mullerian Inhibiting Factor and Inductor Substance
Wolffian ducts develop into the epididymus, vas deferens, and seminal vesicle, and the Mullerian ducts recede
What must be present for the female internal genitalia to develop?
Absence of androgens,
Absence of Mullerian Inhibiting Factor and
Absence of Inductor Substance
Mullerian ducts develop into oviducts, uterus, and vagina, and Wolffian ducts recede
What structures make up the internal genitalia (internal reproductive plumbing) of males?
Epididymis, vas deferens, seminal vesicles, ejaculatory ducts and tubes
What structures make up the internal genitalia (internal reproductive plumbing) of females?
Uterus,
oviducts, and
vagina
What factor(s) must be met for male external genitalia to develop?
Presence of androgens and the ability to respond to androgens
What factor(s) must be met for female external genitalia to develop?
Provides nutrients for ovum from ovulation until the ovum is inside the oviduct
What is the name of the phenomenon in which organs of the peritoneal cavity are irritated by blood released at ovulation which may result in intense pain?
Mittelschmerz
What are the three names for the second half of the menstrual cycle?
Secretory phase,
postovulatory phase,
luteal phase
Is the length of the postovulatory phase variable or fixed? How long is it?
Fixed, 14 +/-2 days
After ovulation, what develops from the remains of the Graafian follicle? This is the hormone producing site of the postovulatory phase
The corpus luteum
What hormones does the corpus luteum produce?
Progesterone,
estrogen,
androgens and
inhibin
What color is the corpus luteum?
Yellow
What occurs in the proliferative phase in terms of the uterus?
Cells of the endometrium increase in size and number after menses to ovulation
What occurs during menses in terms of the uterus?
Endometrium sloughs off and is eliminated in menstruation
Does menstrual bleeding occur in the follicular of the luteal phase?
The follicular phase
What does menstrual fluid consist of?
Approximately 2-4 tablespoons of blood,
cell fragments from the cells of the endometrium,
glandular secretions from endometrial cells and
the unfertilized ovum
What occurs in the secretory phase in terms of the uterus?
Endometrial cells fill with fats and glycogens
What are prostaglandins and what effect do they have on the uterus?
these are paracrines, meaning they act on tissues very close to their site of production. Women with dysmenorrhea (cramps) have very high levels of prostaglandin in their uteri. The prostaglandins are actually stimulating small contractions in their uterine muscles.
Can any drugs inhibit prostaglandins? If so, which ones? When should they be taken?
Over the counter drugs like ibuprofen, aspirin and acetaminophen can be taken to inhibit prostaglandin production by the endometrium but must be taken 2-3 days before cramps start in order to stop the release of the hormones.
What role do prostaglandins play in labor?
Prostaglandin levels are high during labor and can be used to stimulate labor along with oxytocin
When does a female have the most ova in her ovary
Before she is born, 20 weeks after conception (about 7 million)
Around the time of ovulation, the cells lining the cervix produce what kind of mucus?
Clear, slippery like raw egg whites and relatively easy for sperm to penetrate
What is the major hormone produced by the ovarian follicle and by the corpus luteum, respectively?
Ovarian follicle= estrogen,
corpus luteum= progesterone
What are the hair-like cells on the fimbria that help transport the ovum into the lumen of the fallopian tube?
Cilia
Which has the narrower lumen, the ampulla or the isthmus of the oviduct?
The isthmus
Where does fertilization usually occur?
The ampulla-isthmus junction of the oviduct
How long does it take for the ovum to move from the wall of the ovary to the ampulla-isthmus junction of the oviduct?
Just minutes
How long does the ovum stay at the ampulla-isthmus junction?
2-2.5 days
How long is the ovum most capable of being fertilized?
Relatively no, that is why surgery on the vagina usually does not require anesthesia
What is the Grafenburg spot?
Otherwise known as the G spot, this is a small highly sensitive region of the vaginal wall of some women. It has a spongy and striated texture. Stimulation can result in ejaculation of fluids through the urethral opening
Where does vagina lubrication during sexual excitement come from?
Comes from interstitial fluid forced from between cells of the vaginal lining when blood vessels in the region enlarge by engorging with blood during sexual excitement
What is the mons pubis?
A mound of fat and connective tissue on the pubic bone, covered with hair after puberty. Marks the front of the vulva
What are the Bulbs of the Vestibule?
Specialized erectile tissue located in the labia majora that engorge with blood in sexual excitement
Can the thickness and vascularization of the hymen vary from woman to woman?
Yes
What is totally sealed hymen without an opening called?
An imperforate hymen
What do the Glands of Bartholin do?
Thought to play some role in vaginal lubrication
What are differences in breast size between women usually due to?
Amount of adipose tissue or connective fat
What are the structures within the breast in which milk is stored momentarily before letdown?
The sinuses
What are the Montgomery glands and what do they do?
The Montgomery glands are glands on the areola of the breast that secrete antibacterial substances during breast feeding that both lubricate the nipple and reduce the risk of breast infections.
What happens to the color of the areola during and after pregnancy?
The areola darkens with pregnancy and stays dark afterwards
What do endocrine glands produce?
Hormones
What are the reproductive actions of estrogen?
Proliferation of the endometrium during the follicular phase of the monthly cycle
How are hormones transported to the posterior pituitary?
Axons carry hormones produced by cell bodies located in the paraventricular and supraoptic nuclei of the hypothalamus to the posterior pituitary
What is the major difference between an endocrine gland and an exocrine gland?
While an exocrine gland is ducted, an endocrine gland is a ductless gland that discharges hormones directly into the bloodstream and the released hormones are transported long distances through the blood to their target tissue where they act.
What are the two simultaneously present endocrine glands of the pituitary gland?
The posterior pituitary
The anterior pituitary
Do the anterior and posterior pituitary glands directly communicate with each other?
No
What is the structure that connects the hypothalamus to the pituitary?
The infindibulum
Does the posterior pituitary produce hormones?
No! It only RELEASES hormones that are produced in the hypothalamus
What are the two hypothalamic nuclei that produce hormones released by the posterior pituitary?
Paraventricular nucleus
Supraoptic nucleus
What hormone does the paraventricular nucleus produce?
Oxytocin
What hormone does the supraoptic nucleus produce?
Antidiuretic Hormone (ADH) or Vasopressin
What are the two things that oxytocin does?
Stimulates milk letdown during breast feeding
Stimulates contractions of the uterus
What is the primary stimulus for oxytocin release?
High, but we do not know if a high level of oxytocin causes labor or is a result of labor
What is a synthetic oxytocin that can be used to stimulate labor?
Pitocin
What does ADH/Vasopressin do?
Promotes the retention of water by blocking water loss in urine
Increases blood pressure, vasoconstrictor
What are some inhibitors of ADH/Vasopressin?
Caffeine and alcohol
Explain how hormones are produced in the hypothalamus and released in the posterior pituitary
Cell bodies in the hypothalamus (specifically the paraventricular nucleus and the supraoptic nucleus) produce the hormone (oxytocin and ADH/ Vasopressin), they leave the cell bodies, travel down the cell axons through the infindibulum and then terminate in the posterior pituitary where those hormones are released into the pituitary and then into the blood stream where they act on their target tissue