A&P Chapter 28

What is the physiological sygnificance of the epididymis?

Epididymis is where sperm collected from the efferent ductules matures, gaining motility and fertility and also provides storage for sperm.

What would happen to the CL if an individual was pregnant?

After ovulation the remaining follicular cells form the corpus luteum (CL). If a woman becomes pregnant, the CL will secrete progesterone to maintain her pregnancy.

How could you tell if someone had cervical cancer?

Cervical cancer forms epithelial lesions on the cervix. It can be invasive, it grows into sub epithelial tissue, and is more dangerous in that form.

Influence of preventing emission on the chance of becoming a father

Decrease. By preventing emission, you decrease the probability of becoming a father. The reason for this is because by preventing emission, you do not allow the sperm to travel to the egg in the ovaries via cilia in the Fallopian tubes, to fertilize the egg. This decreases the probability of becoming a father.

Influence of removing the fetal gubernaculum on eventual sperm production in the adult.

Decrease. If the gubernaculum was removed from a fetus, there would be no way for the testes to descend into the scrotum in the final months of development. If the testes remain in the abdominal cavity, the temperature will be too warm for spermatogenesis production when this individual reaches puberty.

Influence of a faulty blood-testis barrier on the likelihood of becoming a dad.

Decrease. Sertoli cells are connected together by tight junctions forming a barrier that prevents immune cells from entering germinal epithelium. 1N sperm are foreign to the immune system and would be attacked if there was not a barrier separating sperm; thus decreasing the likelihood of a male producing viable sperm.

Influence of selectively destroying all spermatogonial stem cells in a boy on the ability of that boy to become a father later in life.

Decrease. Spermatogonial stem cell (SSC) are the foundation of spermatogenisis which is the production of sperm. Additionally, SSC form two different daughter cells when divided by mitosis, another SSC and a spermatogonia committed to becoming a sperm. Even though spermatogenisis does not occur until a male is post-pubertal, if the SSC are destroyed, the boys ability to become a father would decrease.

Influence of preventing the production of fibrinolysin in a female on volume of the menstrual discharge?

Decrease. The normal amount of menstrual fluid discharged is 50-150ml. Fibrinolysin degrades fibrin which prevents clots. If clots where allowed then there would be less discharge.

How could you tell if a male was undergoing detrumesence?

Detrumesence occurs during the resolution phase of copulation. This can be physically seen by the disappearance of an erection and the penis returning to its unstimulated state. The testes also descend and the scrotum thins and folds return.

Influence of a woman having only 200,000 oocytes at puberty on the time until menopause.

Every woman is born with about 2 million oocytes which run out as she ages and ovulates. When oocytes run out, no more follicles form and no more estrogen is produced. The lack of estrogen causes the symptoms of menopause. If a woman only had 200,000 oocytes at puberty instead of the normal 400,000, menopause would occur sooner.

What would happen if a pre-pubertal female did not have >17% body fat?

Females must reach 17% body fat for cyclicity, less than 17% leads to amenorrhea or anorexia. Puberty is triggered by hypothalamic "waking" when the female body hits this threshold level. If a pre-pubertal female did not hit thresold level of 17% body fat then hypothalamic waking wouldn't occur and cyclicity would happen.

What would happen if all fetal oogonia were removed from an adult woman?

Fetal oogonia differentiate into primary oocytes in the 8th month of fetal development. These primary oocytes enter meiosis and stop at prophase 1. The primary oocytes that do not die off will remain until they are ovulated or even until menopause. If all the primary oocytes differentiated from fetal oogonia were removed from an adult, she would be infertile and would not experience menses because of the lack of estrogen from granulosa cells that are present in the follicles.

What would happen if an X bearing sperm fertilized an egg?

If an X bearing sperm fertilized an egg (also X), the offspring would be a female carrying two X chromosomes.

How could you tell if an individuals seminal vesicles functioned normally?

If semen contained clotting factors and fructose and prostaglandins, then their seminal vesicles function correctly as it is an accessory gland that empty into the ejaculatory duct. This accessory gland secretes these components.

How could you tell if a cell had undergone meiosis?

In Mitosis, 2 identical diploid cells are produced containing 46 chromosomes. In meiosis, 4 genetically different haploid cells containing 23 chromosomes are produced as germ cells that give rise to gametes.

Influence of suckling on milk ejection.

Increase, suckling and tactile sensation on the nipple stimulates the release of oxytocin from the posterior pituitary which causes contraction of smooth muscle in the breast for ejection of milk.

Influence of performing coitus interruptus instead of abstinence on the chances of getting pregnant.

Increase. Abstinence: no copulation= no sperm= 0% chance of pregnancy. Coitus Interruptus- 26% chance of pregnancy due to factors such as lack of self control, possible presence of sperm in the urethra, or sperm could end up near the vaginal opening and make it's way to an oocyte.

Influence of removing mammary ducts from all women on their average lifespan.

Increase. Breast cancer is a leading cause of female mortality. It begins in the mammary ducts as a palpable lump. If the mammary ducts were removed, the chances of getting breast cancer would be decreased and one of the leading causes of female mortality would be eliminated.

Influence of penile NO injection on erection.

Increase. NO activates guanylate cyclase which creates cGMP which causes relaxation of arteries and the corpora cavernosa fills with blood which then causes the penis to enlarge and become rigid and elevated ready for copulation.

Influence of female orgasm on the chances of getting pregnant.

Increase. Orgasm results in spasmodic contractions of the cervix into the vagina along with peristaltic contractions if the uterus that aide in sperm transport into the uterus and oviducts.

Influence of threshold levels of estrogen on ovulation

Increase. Ovulation is directed by threshold level of estrogen. Estrogen is produced by Granulosa cells of follicle. Estrogen causes surge of GNRH & LH. GNRH promotes release FSH and more LH. LH surge brings about ovulation. Follicular fluid is produced at faster rate causing follicle to swell. Follicle produces an enzyme that weakens wall of antrum. Increase pressure from fluid and weak wall causes rupture of follicle.

Influence of a Y bearing sperm fertilizing an egg on the probability of paramesonephric duct degeneration in the embryo.

Increase. The presents of a Y chromosome would cause the paramesonephric ducts degenerate because the paramesonephric duct turns into the uterine tubes in a the female offspring at the fetal week 6, when the embryonic sex differentiation starts to take place, where as the mesospheric duct turn into the ductus deferens in the male offspring and degenerate in the female.

Influence of cervical pressure on parturition.

Increase. The pressure of the baby's head on the cervix will transmit nerve impulses to the brain which will cause the pituitary gland to secrete oxytocin. Oxytocin stimulates uterine contractions and will push the baby towards the cervix resulting in expulsion of the baby.

Influence of phosphodiesterase inhibitors on time of erection

Increase. phosphodiesterase inhibitor, inhibits the ability to lose an erection and the production of PDE5 which aids in the loss of erection so without the production of PDE5, cGMP would be continuous which creates vasodilation and the erection.

How could you tell if you were observing the placental stage of labor?

It would be the 3rd stage of labor, after the dilation and expulsion stages, where continued uterine contractions expel the placenta from the uterus to prevent continued bleeding.

How could you tell if you were observing a primordial or secondary follicle?

Primordial follicles develop in the embryo and the primary oocyte is surrounded by 1 layer of squamous follicular cells. In secondary follicles the primary oocyte is surrounded by zona pellucida, layers of granulosa cells and two layers of theca cells. Secondary follicles also develop from primary follicles that started "the race" during each cycle.

What is the physiologic significance of prostaglandins in semen?

Prostaglandins and fructose are secreted from seminal vesicle, make up 60% of all semen. Prostaglandins function in semen is to stimulate muscular contractions within the female reproductive tract.

What is the physiologic significance of estrogen for lactation?

There are high levels of estrogen during pregnancy, this stimulates mammary ducts to grow in length and branch. This allows for mature mammary glands and ducts for lactation later in pregnancy.

What is the physiologic significance of testosterone?

Testosterone is the hormone responsible for the development of male secondary sex organs and secondary sex characteristics. During puberty, LH stimulates testosterone secretion, which causes enlargement of secondary sex organs, general body growth, hair and apical gland growth in pubic, axillary, and facial areas, spermatogenesis (along with FSH), stimulation and sustenance of libido, and negative feedback to decrease GNRH and LH secretion. Testosterone is important because it allow males to be able to reproduce and thus continue the human race.

What would happen if a female breast did not have an areola?

The areola is said to act as a target for a baby to know where it needs to suckle for food. The areola also contains sebaceous glands which prevent chafing when a baby is nursing.

What would happen if a boy's hypothalamus never became reproductively functional?

The boy would remain pre-pubertal. The hypothalamus produces GnRH which in turn stimulates the anterior pituitary to release FSH and LH. LH stimulates the production of testosterone which, when coupled with androgen-binding protein, stimulated by FSH, stimulates spermatogenesis.

What is the physiologic significance of the follicular phase of the sexual cycle?

The follicular phase is the first day of the menstruation cycle and lasts the first 14 days. Days 1-5 called the menstrual phase where GNRH from the Hypothalamus stimulates FSH secretion from the anterior pituitary which then stimulates the development of primary follicles that respond into secondary follicles. Days 6- 13 the preovuletory phase FSH stimulates growth of primary -> antral follicles. the one that grows the fastest becomes Dominant graafian follicle which the secretes inhibin and estrogen inhibiting FSH and the other antral follicles die.

What would happen if the corpora cavernosa became fibrotic and could not fill with blood.

The male could not gain an erection. The corpora cavernosa receives blood for the deep arteries which dilate and become more permeable to fill the erectile tissue of the corpora cavernosa with blood for an erection.

What is the physiologic significance of the mons pubis?

The only function to the mons pubis is its an adipose mound that signals reproductive age by allowing the growth of terminal hair.

How could you tell if the anterior pituitary was functioning correctly, by looking at steroid secretion from the ovaries?

The ovaries would be stimulating follicle growth, maintenance of female reproductive structures, feminine secondary sex characteristics which are stimulated by estrogen production promoted by FSH as well as ovulation and preparation of the endometrium for implantation stimulated by progesterone production promoted by LH. Both LH and FSH are released from the anterior pituitary in response to GnRH secretion from the hypothalamus during increased levels of leptin.

What is the physiological significance of the ovary?

The ovary is a receptical for eggs. It has 2 functions, to produce oocytes and estrogen/progesterone.

How could you tell if the pampiniform plexus was functioning normally? Why?

The pampiniform plexus is a vascular network of testicular veins that wraps around the testicular artery. The countercurrent heat exchanger pulls heat from the testicular artery. As blood descends down the testicular artery the atrial blood is cooled by the heat transfer to the pampiniform plexus that carries the venous blood and heat away.

What is the physiologic significance of primary sex organs?

The primary sex organs for males are the testes which produce sperm and the ovaries for women that produce eggs. The physiologic significance of these organs are to produce offspring and to carry on genetics.

What is the physiologic significance of the penis?

The sole function of the penis is to deposit semen into the vagina.

What would happen if uterine spiral arteries did not have spasmodic contractions during the premenstrual phase?

The spasmodic contractions cause ischemia and tissue necrosis. If these contractions were to be inhibited, the lining of the uterus would not shed and ultimately you would not have menses.

How could you tell if a gamete was a sperm or an egg?

The sperm carries the Y chromosome and the egg carries the X chromosome. There are other differences as well. The sperm is smaller and produced by males, while an egg is much larger and produced by females.

What would happen if the spermatozoon did not have an acrosome?

The spermatozoon would not be able to penetrate the egg. The acrosome is a sac that contains an enzyme that helps the sperm get into the egg.

What is the physiologic significance of the stratum basalis?

The stratum basalis is a part of the endometrium of the uterus. The stratum basalis contains stem cells that regenerates the strantum funcationalis which is the superficial half of the endothelium that sheds during each menstational period. The stratum basalis is the site of fetal attachment.

How could you tell the difference between the stratum functionalis and stratum basalis of the uterus?

The stratum functionalis is the more superficial portion of the endometrium adjacent to the lumen of the uterus that thickens as menstrual cycle progresses and then is shed during menses. The stratum basalis is deep to the stratum basalis and contains stem cells that regenerate the stratum functionalis after menses.

How could you tell if an individual had another man's spermatogonial stem cells transplanted into their testes?

This individual would have children with the genotype of the donor instead of his own. Since the spermatogonial stem cells undergo mitosis and meiosis in order to produce sperm, these sperm would have the donor's DNA, not that of the recipient.

How could you tell if a woman had a functional stratum basalis?

You could tell because the uterus would have a thick endometrium as a result of mitosis of stratum basalis, aiding in the steps of the uterine cycle preparing the uterus to for the secretory phase.

Influence of becoming pregnant on the amount of hCG in the blood.

hCG, human chorionic gonadotropin comes from the placenta. It prevents the atrophy of the CL, and maintains progesterone levels to prevent menses from occurring and ending the attachment of the fertilized egg to the uterine wall.