FORMATIVE Flashcards
A 55-year-old woman stopped menstruating approximately 3 months ago. Worried that she may be pregnant, she decided to have a pregnancy test. The test came back negative. Which of the following series of tests results would confirm that the woman is postmenopausal?
Increased LH, increased FSH, decreased estrogen
Menopausal changes in women result from a decrease in ovarian function, decreased estrogen, and removal of negative feedback resulting in increased luteinizing hormone (LH) and follicle-stimulating hormone (FSH) production and release.
Two days before the onset of menstruation, secretions of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) reach their lowest levels. What is the cause of the is low level of secretion?
Secretion of estrogen, progesterone, and inhibin by the corpus luteum suppresses hypothalamic secretion of GnRH and pituitary secretion of FSH
Estrogen and, to a lesser extent, progesterone secreted by the corpus luteum during the luteal phase have strong feedback effects on the anterior pituitary gland to maintain low secretory rates of both FSH and LH. In addition, the corpus luteum secretes inhibin, which inhibits the secretion of FSH
A 20-year-old male patient presents to the doctor’s office complaining about continuous growth, lack of facial hair development, and smaller penis and testicles than his college friends. Laboratory values include total testosterone 1 ng/mL and LH 1.5 mU/mL. Thyroid-stimulating hormone and prolactin levels are normal. He has no history of medications, drug use, or disease. GnRH stimulation test over a 7-day period produces elevations in circulating levels of LH. Continued growth in this case is caused by:
Decreased testosterone production
The presentation of this young male patients with decreased testosterone explains why he has not developed secondary sexual characteristics normal for his age. Increased estradiol production would have led to epiphyseal closure
In the patient described above, it was observed that in addition to being much taller than young adults his age, his arms were very long. The excessive height and arm length resulting from delayed epiphyseal growth plate closure is caused by:
Decreased estradiol production
The excessive height and arm length resulting from delayed epiphyseal growth plate closure is caused by decreased estradiol production in bone.
If a woman hears her baby cry, she may experience milk ejection from the nipples even before the baby is placed to the breast. What is the explanation for this?
The sound of the hungry baby’s cry elicits secretion of oxytocin from the posterior pituitary, which reaches the breast and causes contraction of the myoepithelial cells
Neural projections from higher centers of the brain to the hypothalamus can elicit the secretion of oxytocin into the blood from the posterior pituitary gland. Upon reaching the breast, oxytocin stimulates contraction of the myoepithelial cells, forcing milk from the alveoli and ducts to the nipple.
Which of the following is produced by the trophoblast cells during the first 3 weeks of pregnancy
hCG
Human chorionic gonadotropin is secreted from the trophoblast cells beginning shortly after the blastocyst implants in the endometrium.
Before implantation, the blastocyst obtains its nutrition from the uterine endometrial secretions. How does the blastocyst obtain nutrition during the first week after implantation?
The trophoblast cells digest the nutrient-rich endometrial cells and then absorb their contents for use by the blastocyst
As the blastocyst implants, the trophoblast cells invade the decidua, digesting and imbibing it. The stored nutrients in the decidual cells are used by the embryo for growth and development. During the 1st week after implantation, this is the only means by which the embryo can obtain nutrients. The embryo continues to obtain at least some of its nutrition in this way for up to 8 weeks, although the placenta begins to provide nutrition after about the 16th day beyond fertilization (a little more than I week after implantation).
The first important cardiovascular change in neonatal circulation after the baby takes the first breath is
Decrease in pulmonary vascular resistance
During fetal circulation, foramen ovale permits the blood flow
from the right atrium to the left atrium
The fetal lungs are collapsed and have a high vascular resistance. Oxygen-rich blood from the inferior vena cava bypasses the lungs through the open foramen ovale in the atrial septum to the left atrium.
Short and long protocols involving GnRH analogs are used in in vitro fertilization (IVF). The long protocol involves:
use of a GnRH agonist which initially enhances and subsequently reduces secretion of FSH and LH
The goal is to suppress/down-regulate the HPO axis, which ultimately leads to reduced FSH & LH synthesis/secretion. In the short protocol, GnRH antagonists rapidly reduce secretion of FSH & LH. In the long protocol, a GnRH agonist is given chronically (not in a pulsatile manner). This results in an initial “flare” or enhanced production of FSH & LH, followed by GnRH receptor down-regulation/desensitization, resulting in reduced FSH & LH production.
The hormonal imbalance observed in women with polycystic ovary syndrome is associated with all of the following EXCEPT:
development of male secondary sex characteristics due to excessive androgen production by the granulosa cells
Women with polycystic ovary syndrome develop male secondary sex characteristics due to excessive androgen production by the thecal cells, not the granulosa cells. All other statements are correct.
A substance is freely filtered and has a certain concentration in peripheral plasma. You would expect the substance to have virtually the same concentration in
A. the glomerular filtrate. B. the afferent arteriole. C. the efferent arteriole. D. all of these places. All of the above
In the face of a 20% decrease in arterial pressure, GFR decreases by only 2%. What could account for this finding?
Efferent arteriolar resistance increases.
The lowering of pressure upstream from the glomerulus is offset by contraction of the efferent arteriole, an action that by itself raises glomerular capillary pressure. The net effect leaves glomerular capillary pressure almost unchanged.
The hydrostatic pressure within the glomerular capillaries
is much higher than in most peripheral capillaries
Glomerular capillary pressure starts at about 60 mm Hg and falls very little along the length of the capillaries. This value is far higher than in most peripheral capillaries
We can calculate the renal clearance of any substance if we know which pair of values?
Plasma concentration and urinary excretion rate
The excretion rate of a substance divided by its plasma concentration yields the clearance.
