Nokea
All are characteristics of smooth muscle, except?
- A. Usually forms 2 layers at right angles to each other
- B. Utilizes troponin to help initiate muscle contraction
- C. Contains no striations
- D. Action potentials travel between muscle fibers quickly via tight junctions
Correct Answer: b
Rationale: The correct answer is B because smooth muscle does not utilize troponin to help initiate muscle contraction. Instead, smooth muscle contraction is regulated by calcium-calmodulin complex.
A: True - Smooth muscle usually forms 2 layers at right angles to each other.
C: True - Smooth muscle contains no striations.
D: False - Action potentials in smooth muscle travel slowly via gap junctions, not tight junctions.
You may also like to solve these questions
What is observed when aqueous silver nitrate is added to this mixture?
- A. white precipitate
- B. white solution
- C. yellow precipitate
- D. yellow solution
Correct Answer: C
Rationale: When aqueous silver nitrate is added to a mixture, a yellow precipitate forms if there are chloride ions present. This is due to the formation of silver chloride, which is insoluble in water. The reaction is AgNO3 + Cl- → AgCl↓ + NO3-. Therefore, choice C is correct.
Choice A (white precipitate) is incorrect because silver chloride is yellow, not white. Choice B (white solution) is incorrect as a precipitate forms, not a solution. Choice D (yellow solution) is incorrect because the product is a solid precipitate, not a solution.
Twenty-eight-year-old Alicia has recently been diagnosed with hyperthyroidism. Signs and symptoms of hyperthyroidism include:
- A. Tachycardia, sweating, and tremors.
- B. Fatigue, lethargy, and weight gain.
- C. Muscle twitching, tetany, and galactorrhea.
- D. Scotoma, alopecia, and hirsutism.
Correct Answer: A
Rationale: Symptoms of hyperthyroidism include increased heart rate (tachycardia), excessive sweating, and tremors due to the overactive thyroid gland.
Which artery generally gives rise to inferior thyroid artery?
- A. Arch of aorta
- B. Brachiocephalic artery
- C. External carotid artery
- D. Thyrocervical trunk
Correct Answer: D
Rationale: The correct answer is D, the thyrocervical trunk. This artery generally gives rise to the inferior thyroid artery. The thyrocervical trunk is a branch of the subclavian artery, supplying blood to the thyroid gland. The other choices are incorrect because the arch of aorta does not give rise to the inferior thyroid artery, the brachiocephalic artery does not directly supply the thyroid gland, and the external carotid artery does not typically provide blood to the thyroid gland. Therefore, the thyrocervical trunk is the most likely source for the inferior thyroid artery.
Which of the following is not part of the alimentary canal?
- A. Mouth
- B. Pharynx
- C. Larynx
- D. Oesophagus
Correct Answer: C
Rationale: The correct answer is C: Larynx. The alimentary canal is the digestive tract where food passes through. The larynx is not part of this pathway; it is part of the respiratory system, specifically involved in phonation and protecting the trachea during swallowing. The mouth, pharynx, and esophagus are all part of the alimentary canal, where food is ingested, swallowed, and transported to the stomach for digestion. Therefore, the larynx is the correct answer as it is not part of the digestive process.
Identify the endocrine gland within the abdominal cavity, near the small intestine.
- A. Adrenal gland
- B. Hypothalamus
- C. Pancreas
- D. Thyroid gland
Correct Answer: C
Rationale: The correct answer is C: Pancreas. The pancreas is an endocrine gland located in the abdominal cavity near the small intestine. It secretes hormones like insulin and glucagon that regulate blood sugar levels. The adrenal gland (A) is located on top of the kidneys, the hypothalamus (B) is in the brain, and the thyroid gland (D) is located in the neck. These glands are not near the small intestine, making them incorrect choices.