Parenchymal tissue of the testes is

Correct Answer: B

Rationale: The correct answer is B: Seminiferous tubules. These are the structures within the testes where sperm production occurs. This is the main function of testicular parenchymal tissue. Interstitial cells of Leydig (A) produce testosterone, spermatozoon (C) is a mature sperm cell, and semen (D) is a fluid that contains sperm and other substances. These choices are incorrect as they do not specifically represent the parenchymal tissue of the testes where sperm production takes place.

Correct Answer: C

Rationale: The correct answer is C: Ulna. The ulna is the medial lower arm bone located on the pinky side. It articulates with the humerus at the elbow joint and with the radius at the wrist joint. The humerus (A) is the upper arm bone, not located in the lower arm. The radius (B) is the lateral lower arm bone, not the medial one. Carpals (D) refer to the wrist bones, not the lower arm bones. Therefore, the ulna is the correct answer as it is the specific bone that fits the description of being the medial lower arm bone.

Correct Answer: A

Rationale: The correct answer is A: Cortical bone. Haversian canals are found in cortical bone, which is the dense outer layer of bone tissue. These canals contain blood vessels, nerves, and lymphatics, allowing for the exchange of nutrients and waste products. Cancellous bone (B) is spongy bone with a network of trabeculae and does not contain Haversian canals. Spongy bone (C) is a type of bone tissue with a porous structure but lacks the organized Haversian system seen in cortical bone. "N/A" (D) is not a valid option as it does not provide any relevant information.

Correct Answer: C

Rationale: Rationale for Correct Answer (C): 1. Electromyography (EMG) specifically measures muscle contraction strength. 2. It involves placing electrodes on the skin to record electrical activity produced by muscles. 3. EMG is commonly used in clinical and research settings to assess muscle function and diagnose neuromuscular disorders. Summary of Incorrect Choices: A. Electromyograph: Incorrect term, should be "Electromyography". B. Electroencephalography: Measures brain activity, not muscle contraction. D. Electroencephalography: Same as choice B, measures brain activity, not muscle contraction.

Correct Answer: A

Rationale: Rationale: 1. Human chorionic gonadotropin (hCG) acts like TSH, stimulating T4 secretion by the maternal thyroid. 2. hCG is produced by the placenta and has a similar structure and function to TSH. 3. hCG binds to the TSH receptor on the thyroid gland, triggering T4 release. 4. Other options do not specifically target the thyroid gland for T4 secretion. Summary: A: hCG mimics TSH and directly stimulates T4 release. B: hCS, hPL - involved in placental growth and lactation, not thyroid stimulation. C: IGF I and II - growth factors, not directly related to thyroid function. D: EGF - promotes cell growth and differentiation, not linked to thyroid hormone secretion.