Nokea
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.
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Hyoscine produces all of the following actions EXCEPT:
- A. Sedation
- B. Antiemetic action
- C. Stimulation of the respiratory center
- D. Increase of salivary secretion
Correct Answer: D
Rationale: Hyoscine, also known as scopolamine, is an anticholinergic drug that acts by blocking muscarinic receptors. It produces sedation by crossing the blood-brain barrier and affecting the central nervous system. Its antiemetic action is due to its ability to inhibit the vomiting center in the brain. Stimulation of the respiratory center is not a typical action of hyoscine. Lastly, hyoscine decreases salivary secretion due to its anticholinergic effects. Therefore, the correct answer is D (Increase of salivary secretion) as it is inconsistent with the pharmacological actions of hyoscine.
Which hormone is produced by the pancreas and acts on the liver to increase blood glucose levels?
- A. glucagon; liver
- B. melatonin; liver
- C. glucagon; kidney
- D. calcitonin; thyroid
Correct Answer: A
Rationale: The correct answer is A: glucagon is produced by the pancreas and acts on the liver to increase blood glucose levels. Glucagon triggers the liver to break down glycogen into glucose, releasing it into the bloodstream. Melatonin is a hormone produced by the pineal gland and is not involved in glucose regulation. Glucagon does not act on the kidney but specifically targets the liver. Calcitonin is produced by the thyroid gland and plays a role in calcium regulation, not glucose metabolism.
Identify a characteristic of type I diabetes (IDDM).
- A. Development has a correlation with obesity.
- B. Most common form of diabetes.
- C. Body cells do not respond to insulin.
- D. Treatment usually involves insulin injections.
Correct Answer: D
Rationale: Sure! The correct answer is D because type I diabetes (IDDM) is characterized by the body's inability to produce insulin, leading to high blood sugar levels. Insulin injections are necessary to replace the missing insulin.
A is incorrect because type I diabetes is not associated with obesity. B is incorrect because type II diabetes is actually the most common form. C is incorrect because in type I diabetes, the body's cells do not produce insulin, rather than not responding to it.
Cellular responses to hormones that initiate second-messenger systems include ________.
- A. possible activation of several different second-messenger systems
- B. cyclic AMP phosphodiesterase formation of an active second messenger
- C. formation of a specific protein kinase that acts on a series of extracellular intermediates
- D. hormone binding to intracellular receptors
Correct Answer: A
Rationale: The correct answer is A because cellular responses to hormones initiating second-messenger systems can activate various pathways. Different hormones can utilize different second messengers such as cAMP, cGMP, IP3, and DAG. This diversity allows for a wide range of responses in target cells.
Choice B is incorrect because cyclic AMP phosphodiesterase degrades cAMP, not forms an active second messenger.
Choice C is incorrect as it describes the mechanism of a specific protein kinase, which is not a characteristic of second-messenger systems.
Choice D is incorrect since hormone binding to intracellular receptors typically leads to gene transcription regulation, not direct activation of second-messenger systems.
The liberation of proteins to free amino acids (final digestive step) occur in all of the following EXCEPT:
- A. enterocyte cytoplasm
- B. brush border
- C. small intestine lumen
- D. stomach
Correct Answer: D
Rationale: The liberation of proteins to free amino acids occurs primarily in the small intestine lumen. In the stomach, proteins are broken down into smaller peptides but not fully liberated to amino acids. The enterocyte cytoplasm is where amino acids are absorbed. The brush border aids in absorption but doesn't release proteins to amino acids. Therefore, the correct answer is D (stomach) as it is not the site for the final step of protein digestion.