Question 1

Milk ejection is a neural reflex arc involving afferent input to the hypothalamus from receptors in the nipples and a neural efferent output to the myoepithelial cells in the ducts of the mammary glands.

Accepted Answer

The answer of Milk ejection is a neural reflex arc...

Question 2

Amniocentesis would be an appropriate mechanism to test for Down Syndrome (trisomy 21).

Accepted Answer

Amniocentesis is a prenatal test that can detect chromosomal abnormalities such as Down Syndrome (trisomy 21) by analyzing fetal cells in the amniotic fluid. Therefore, it is an appropriate mechanism for testing for Down Syndrome.

Question 3

Postmenopausal women are at increased risk,compared to premenopausal women,for osteoporosis and atherosclerosis.

Accepted Answer

During menopause, there is a decrease in levels of estrogen which can lead to bone loss and increased risk of osteoporosis. Additionally, estrogen plays a role in protecting against atherosclerosis, so postmenopausal women are at increased risk for this as well.

Question 4

The presence of sex chromatin in a smear of epithelial cells indicates that the donor of the cells is a genetic female.

Accepted Answer

Sex chromatin, also known as Barr bodies, is a structure found in the nuclei of female mammals. It is a condensed X chromosome that is inactive due to X chromosome inactivation. Therefore, the presence of sex chromatin in a smear of epithelial cells indicates that the donor of the cells is a genetic female.

Question 5

Blood in the umbilical arteries is well oxygenated,whereas that in the umbilical vein is poorly oxygenated.

Accepted Answer

Blood in the umbilical vein is well oxygenated as it carries oxygenated blood from the placenta to the fetus, whereas the umbilical arteries carry poorly oxygenated blood from the fetus back to the placenta.

Question 6

Symptoms of preeclampsia generally include glucose in the urine,abnormal fluid retention,and hypertension.

Accepted Answer

Symptoms of preeclampsia generally include high blood pressure, protein in the urine, and often swelling in the feet, legs, and hands, but not glucose in the urine. Glucose in the urine is more commonly associated with diabetes.

Question 7

Amniocentesis is the removal of a sample of amniotic fluid for diagnosis of genetic or chromosomal disorders of the fetus.

Accepted Answer

Amniocentesis is a diagnostic test that involves the removal of a small amount of amniotic fluid from the sac surrounding the fetus to check for genetic or chromosomal abnormalities.

Question 8

A drug company would like to market a new form of birth control.A drug that interferes with endometrial proliferation and inducing changes in the composition of the cervical mucus,even if it doesn't inhibit ovulation,could still be effective.

Accepted Answer

A drug that interferes with endometrial proliferation and induces changes in cervical mucus could still prevent pregnancy even if it doesn't inhibit ovulation. This is because cervical mucus plays a crucial role in sperm transport and fertilization, and changes in its composition can make it difficult for sperm to reach and fertilize egg cells. Moreover, by preventing endometrial proliferation, the drug can make it less likely for a fertilized egg to implant and grow in the uterus, thus preventing pregnancy.

Question 9

A drug company would like to market a new form of birth control.One effective option would be an antagonist to the progesterone receptor.

Accepted Answer

An antagonist to the progesterone receptor can prevent the effects of progesterone, which helps to prevent pregnancy by preventing ovulation. As such, it can be an effective option for birth control.

Question 10

The gene on the Y chromosome that determines whether gonads will be testes or ovaries codes for a protein called Müllerian-inhibiting substance.

Accepted Answer

The gene on the Y chromosome that determines whether gonads will be testes or ovaries codes for a protein called the Testis-determining factor (TDF), also known as SRY (Sex-determining Region Y) protein. Müllerian-inhibiting substance (MIS), also known as Anti-Müllerian Hormone (AMH), is produced by the testes after they have begun to differentiate and leads to the regression of the Müllerian ducts in the male embryo.

Question 11

Oxytocin stimulates myometrial contractions most strongly when plasma progesterone levels are low relative to estrogen.

Accepted Answer

Oxytocin is most effective in stimulating the contraction of the uterus when the levels of progesterone, which inhibits oxytocin's effects, are low relative to the levels of estrogen. This is because estrogen stimulates the production of oxytocin receptors on the myometrial cells, making them more responsive to oxytocin stimulation. When progesterone levels drop, the inhibitory effect is removed, allowing oxytocin to stimulate strong contractions.

Question 12

While passing down the oviduct,the zygote undergoes several rounds of cell division.

Accepted Answer

This statement is true. The zygote undergoes several rounds of cell division while passing down the oviduct, which eventually leads to the formation of a blastocyst.

Question 13

The major constituents of human breast milk are water,protein,fat,and glucose.

Accepted Answer

The major constituents of human breast milk are water, protein, fat, and lactose, not glucose. Lactose is the primary carbohydrate found in human breast milk, not glucose.

Question 14

The onset of puberty may be delayed in girls who have very low amounts of adipose tissue.

Accepted Answer

Adipose tissue, or body fat, plays a role in the production of hormones involved in the onset of puberty. Girls who have very low amounts of body fat may experience delayed puberty.

Question 15

Within the ovary,there are always a large number of ovarian follicles poised to release an ovum at ovulation.

Accepted Answer

The answer of Within the ovary,there are always a large...

Question 16

For a woman who does not want to become pregnant,it is sufficient to forego birth control during lactation because the hormones that control lactation will prevent ovulation.

Accepted Answer

While lactation can suppress ovulation and reduce the likelihood of pregnancy, it is not a foolproof method of birth control. The effectiveness of lactation as birth control depends on factors such as the frequency and intensity of breastfeeding, the age of the baby, and the mother's individual hormonal profile. Additionally, a woman may ovulate before menstruation returns, making it possible to become pregnant even if she has not had a period yet. Therefore, it is not sufficient to rely solely on lactation for birth control unless the mother is prepared for the possibility of pregnancy. It is important to consult with a healthcare provider and use additional forms of contraception if preventing pregnancy is a priority.

Question 17

An individual with androgen insensitivity syndrome is a genetic male with ovaries.

Accepted Answer

An individual with androgen insensitivity syndrome is genetically male (with XY chromosomes) but has testes, not ovaries; their bodies are unable to respond to androgens properly, leading to female or ambiguous physical traits.

Question 18

Steroid hormones generally bind with receptors inside target cells and control the rate of formation of mRNAs that lead to the synthesis of proteins.

Accepted Answer

This statement is true. Steroid hormones are able to penetrate the plasma membrane of target cells and bind to intracellular receptors. The hormone-receptor complex then binds to DNA and controls the transcription of specific genes, leading to the formation of mRNA and ultimately protein synthesis.

Question 19

Many (10-25)antral follicles begin the process of development each menstrual cycle,but only one will usually progress to the point of ovulation.

Accepted Answer

This statement is true. Many antral follicles begin to grow each menstrual cycle, but usually only one will become dominant and mature enough to release an egg during ovulation. The remaining follicles will either stop growing or undergo atresia (degeneration).

Question 20

During meiosis,crossing-over results in the exchange of homologous genes from one of a pair of chromatids to the other with no net change in possibilities for genetic expression.

Accepted Answer

Crossing-over during meiosis results in the exchange of genetic material between homologous chromosomes, leading to new combinations of genes and increasing the genetic diversity among offspring.

Quiz 17: Reproduction