Nokea
Trabecular bone is otherwise called as
- A. Compact bone
- B. Cortical bone
- C. Spongy bone
- D. None of the abov
Correct Answer: C
Rationale: Trabecular bone, also known as spongy bone, is characterized by its porous structure with trabeculae. It is found at the ends of long bones and inside flat bones. Spongy bone provides structural support and flexibility. Compact bone (A) is dense and forms the outer layer of bones. Cortical bone (B) is synonymous with compact bone. Choice D is incorrect as trabecular bone is specifically known as spongy bone.
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Before implantation, the blastocyst obtains its nutrition from the uterine endometrial secretions. How does the blastocyst obtain nutrition during the first week after implantation?
- A. It continues to derive nutrition from endometrial secretions
- B. The cells of the blastocyst contain stored nutrients that are metabolized for nutritional support
- C. The placenta provides nutrition derived from maternal blood
- D. The trophoblast cells digest the nutrient-rich endometrial cells and then absorb their contents for use by the blastocyst
Correct Answer: D
Rationale: Step 1: The trophoblast cells of the blastocyst invade the endometrial lining during implantation.
Step 2: The trophoblast cells secrete enzymes to digest the nutrient-rich endometrial cells.
Step 3: The digested nutrients are absorbed by the trophoblast cells.
Step 4: These nutrients are then utilized by the blastocyst for its growth and development.
Step 5: This process ensures that the blastocyst receives the necessary nutrition for the first week after implantation.
Summary:
A: Incorrect. Endometrial secretions are no longer the source of nutrition after implantation.
B: Incorrect. While the blastocyst may contain some stored nutrients, they are not sufficient for the first week post-implantation.
C: Incorrect. The placenta is not fully functional until later in pregnancy, so it does not provide nutrition in the first week.
Choose the correct sequence of human embryonic development.
- A. Fertilization - organogenesis - gastrulation - cleavag
- B. Cleavage - fertilization - gastrulation - organogenesis.
- C. Fertilization - cleavage - organogenesis - gastrulation.
- D. Fertilization - cleavage - gastrulation- organogenesis.
Correct Answer: D
Rationale: The correct sequence of human embryonic development is D: Fertilization - cleavage - gastrulation - organogenesis.
1. Fertilization: The union of egg and sperm forms a zygote.
2. Cleavage: Zygote undergoes rapid cell division without growth.
3. Gastrulation: Formation of three germ layers (ectoderm, mesoderm, endoderm).
4. Organogenesis: Organ formation from germ layers.
This sequence reflects the chronological order of events in early human development.
Choice A is incorrect as organogenesis occurs after gastrulation.
Choice B is incorrect as fertilization should precede cleavage.
Choice C is incorrect as organogenesis occurs after gastrulation.
Which of the following are the advantages of a vaginal hysterectomy over an abdominal hysterectomy?
- A. Fewer complications
- B. Increased recovery time
- C. Radical hysterectomy can even be done laparoscopically
- D. No pain
Correct Answer: A
Rationale: Vaginal hysterectomies generally have fewer complications and quicker recovery times compared to abdominal procedures.
The male sex of the child involves the following during fecundation:
- A. the spermatozoon should contain the X sex chromosome;
- B. the spermatozoon should contain the Y sex chromosome;
- C. the ovule should contain the contain the Y sex chromosome;
- D. the spermatozoon should contain the Y sex chromosome and the ovule should contain the contain the X sex chromosome;
Correct Answer: B
Rationale: Step 1: At fertilization, the sperm contributes either an X or Y sex chromosome.
Step 2: The ovum always contributes an X sex chromosome.
Step 3: If the sperm carries the Y chromosome, the resulting child will be male.
Therefore, the correct choice is B.
Summary:
A: Incorrect. If the sperm contains the X chromosome, the child will be female.
C: Incorrect. Ovule always contains an X chromosome.
D: Incorrect. This choice combines correct and incorrect information, as the sperm must contain the Y chromosome for a male child.
A drug is given that affects the initial phases of spermatogenesis to aid in a patient’s infertility complaints. How much time would it take for the effects of this drug to be seen?
- A. 4.6 days
- B. 16 days
- C. 22 days
- D. 86 days
Correct Answer: D
Rationale: The correct answer is D (86 days) because spermatogenesis is a process that takes around 74 days from the initial division of spermatogonia to the release of mature spermatozoa. The drug affecting the initial phases of spermatogenesis would take at least one full cycle of spermatogenesis to show its effects, which is around 74 days. Therefore, it would take approximately 86 days for the effects of the drug to be seen.
Choice A (4.6 days) is too short for spermatogenesis to complete, so the effects of the drug would not be observable in this time frame. Choice B (16 days) and Choice C (22 days) are also insufficient for a full cycle of spermatogenesis to occur, hence the effects of the drug would not be evident within these durations.