Nokea
________ vertebrae are the strongest and largest of the vertebral column.
- A. Lumbar
- B. Sacrum
- C. Thoracic
- D. Cervical
Correct Answer: A
Rationale: The correct answer is A: Lumbar vertebrae. The lumbar vertebrae are the largest and strongest of the vertebral column due to their weight-bearing function in supporting the upper body. They have a larger body and thicker structures compared to other vertebrae, providing stability and support. The sacrum, thoracic, and cervical vertebrae are not as large or strong as the lumbar vertebrae, as they have different functions and shapes tailored to their specific roles in the spine.
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The inner mucosal layer of the uterus that is sloughed off approximately every 28 days is called the ________.
- A. endometrium
- B. myometrium
- C. perimetrium
- D. epimetrium
Correct Answer: A
Rationale: The correct answer is A: endometrium. The endometrium is the inner mucosal layer of the uterus that sheds during menstruation. It is where implantation of a fertilized egg occurs. Myometrium (B) is the middle muscular layer, responsible for uterine contractions. Perimetrium (C) is the outer layer of the uterus. Epimetrium (D) is not a recognized term in anatomy.
Which of these is not a function of testosterone?
- A. loss of body hair
- B. thickening of the larynx
- C. anabolism of skeletal muscle
- D. thickening of bones
Correct Answer: A
Rationale: The correct answer is A, loss of body hair. Testosterone is responsible for thickening of the larynx, anabolism of skeletal muscle, and thickening of bones. It promotes growth and development of male secondary sexual characteristics, such as increased body hair. Therefore, loss of body hair is not a function of testosterone. Choice B, thickening of the larynx, is correct because testosterone contributes to the deepening of the voice by thickening the vocal cords. Choice C, anabolism of skeletal muscle, is correct as testosterone enhances protein synthesis in muscles, leading to muscle growth. Choice D, thickening of bones, is correct because testosterone promotes bone growth and mineralization.
Ectoderm, mesoderm, and endoderm are three tissue layers that are formed during _____________ stage.
- A. morula
- B. blastula
- C. gastrula
- D. neurula
Correct Answer: C
Rationale: The correct answer is C: gastrula. During the gastrula stage of embryonic development, the blastula undergoes a process called gastrulation, where the three primary germ layers - ectoderm, mesoderm, and endoderm - are formed. The ectoderm gives rise to the nervous system and skin, the mesoderm forms muscles and organs, and the endoderm develops into the lining of the digestive tract and respiratory system. Morula (A) is an earlier stage where the zygote divides into multiple cells. Blastula (B) is the stage before gastrula where a hollow ball of cells is formed. Neurula (D) is a stage specific to vertebrate embryos where the neural tube begins to form.
The fecundated spermatozoon contains:
- A. 11 pairs of somatic chromosomes;
- B. 22 somatic chromosomes ;
- C. only the X sex chromosome;
- D. the X or Y sex chromosome
Correct Answer: D
Rationale: The correct answer is D because the fecundated spermatozoon can contain either the X or Y sex chromosome, determining the genetic sex of the offspring. Spermatozoa are haploid cells, meaning they contain only one set of chromosomes. During fertilization, the spermatozoon fuses with the ovum, which also contains a single set of chromosomes, resulting in a diploid zygote with a complete set of chromosomes. Choices A and B are incorrect as somatic chromosomes refer to the non-reproductive cells in the body, not the chromosomes found in gametes. Choice C is incorrect because the spermatozoon can carry either the X or Y sex chromosome, not exclusively the X chromosome.
Hair like process on the sperm cell that makes it motile or moveable is
- A. Cilia
- B. Flagella
- C. Pseudopodia
- D. Dendritic processes
Correct Answer: B
Rationale: The correct answer is B: Flagella. Flagella are whip-like structures that provide motility to sperm cells. They enable the sperm cell to move towards the egg for fertilization. Cilia (choice A) are shorter hair-like structures involved in movement but are not found on sperm cells. Pseudopodia (choice C) are temporary projections used for cell movement in some organisms, not sperm cells. Dendritic processes (choice D) refer to branching extensions of nerve cells, not involved in sperm motility. Therefore, flagella is the most appropriate choice for the hair-like process on the sperm cell that makes it motile.