- Which of the following is the primary function of the Sertoli cells in the testes?
a) Production of testosterone
b) Nourishment and support of sperm cells
c) Transportation of sperm
d) Storage of sperm
Answer: b) Nourishment and support of sperm cells
Explanation:
Sertoli cells, also known as nurse cells, provide nourishment, protection, and structural support to developing sperm cells during spermatogenesis. They also help in the formation of the blood-testis barrier and release hormones like inhibin to regulate sperm production.
- Which hormone is responsible for the contraction of the uterus during childbirth?
a) Estrogen
b) Oxytocin
c) Progesterone
d) Relaxin
Answer: b) Oxytocin
Explanation:
Oxytocin is the hormone responsible for stimulating uterine contractions during labor, helping to push the baby through the birth canal. It also aids in milk ejection from the mammary glands during breastfeeding.
- Which of the following structures in males is homologous to the female clitoris?
a) Glans penis
b) Scrotum
c) Urethra
d) Prostate gland
Answer: a) Glans penis
Explanation:
The glans penis in males is homologous to the clitoris in females, meaning both structures develop from the same embryonic tissue and have similar nerve endings, making them highly sensitive to touch.
- The phase of the menstrual cycle during which the endometrium is thickest and most prepared for implantation is called:
a) Menstrual phase
b) Proliferative phase
c) Secretory phase
d) Follicular phase
Answer: c) Secretory phase
Explanation:
The secretory phase occurs after ovulation when progesterone from the corpus luteum causes the endometrium to become highly vascularized and glandular, preparing it for possible implantation of a fertilized egg.
- The fluid-filled cavity in the blastocyst is known as the:
a) Amniotic cavity
b) Chorionic cavity
c) Blastocoel
d) Yolk sac
Answer: c) Blastocoel
Explanation:
The blastocoel is a fluid-filled cavity that forms within the blastocyst during early embryonic development. It helps maintain the structure of the blastocyst and plays a role in the differentiation of cells into the inner cell mass and trophoblast.
- During which stage of pregnancy does the fetus begin to make voluntary movements?
a) First trimester
b) Second trimester
c) Third trimester
d) Just before birth
Answer: b) Second trimester
Explanation:
Voluntary fetal movements, also known as “quickening,” typically begin during the second trimester (around 18–20 weeks). This is when the mother can first feel the fetus moving.
- The hormone detected in pregnancy tests is:
a) Luteinizing hormone (LH)
b) Follicle-stimulating hormone (FSH)
c) Human chorionic gonadotropin (hCG)
d) Progesterone
Answer: c) Human chorionic gonadotropin (hCG)
Explanation:
Pregnancy tests detect the presence of human chorionic gonadotropin (hCG), a hormone produced by the placenta shortly after implantation. The levels of hCG rise significantly in early pregnancy.
- The first meiotic division of the oocyte occurs at which stage of the menstrual cycle?
a) After fertilization
b) Before ovulation
c) At ovulation
d) After implantation
Answer: c) At ovulation
Explanation:
The primary oocyte is arrested in prophase I until ovulation, when it completes the first meiotic division to become a secondary oocyte. The second meiotic division occurs only if fertilization takes place.
- Which of the following structures prevents the entry of more than one sperm during fertilization?
a) Corona radiata
b) Zona pellucida
c) Acrosome
d) Blastocoel
Answer: b) Zona pellucida
Explanation:
The zona pellucida is a glycoprotein layer surrounding the egg that, after the first sperm penetrates, undergoes biochemical changes (cortical reaction) to prevent additional sperm from entering, thus ensuring monospermy.
- Which of the following embryonic layers gives rise to the heart and blood vessels?
a) Ectoderm
b) Mesoderm
c) Endoderm
d) Neural crest
Answer: b) Mesoderm
Explanation:
The mesoderm is the middle germ layer in the embryo that differentiates into various structures, including the cardiovascular system (heart, blood vessels), muscles, bones, and kidneys.
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