Nokea
Endocrine glands differ from exocrine glands in that .
- A. endocrine glands are formed by epithelial tissue, but exocrine glands are primarily connective tissue
- B. endocrine glands release hormones, whereas exocrine glands release waste
- C. endocrine glands are ductless and exocrine glands release secretions at the body's surface or into ducts
- D. endocrine glands are all interconnected, whereas exocrine glands act completely independently
Correct Answer: C
Rationale: Correct Answer: C
Rationale:
1. Endocrine glands are ductless: Endocrine glands release hormones directly into the bloodstream instead of using ducts.
2. Exocrine glands release secretions at the body's surface or into ducts: Exocrine glands release their secretions through ducts to the body's surface or specific locations.
3. Therefore, the key difference is the presence of ducts: Endocrine glands lack ducts, while exocrine glands have ducts for secretion. This distinction makes choice C the correct answer.
Summary:
A: Incorrect. Endocrine glands and exocrine glands can both be formed by epithelial tissue.
B: Incorrect. Exocrine glands release enzymes and other substances, not waste products.
D: Incorrect. There is no interconnection requirement for endocrine glands, and exocrine glands can also be interconnected.
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Which glands are responsible for the regulation of calcium levels in the blood?
- A. Parathyroid and thyroid
- B. Adrenal medulla and pancreas
- C. Testes
- D. Parathyroid and thymus
Correct Answer: A
Rationale: The correct answer is A: Parathyroid and thyroid. The parathyroid glands produce parathyroid hormone (PTH), which regulates calcium levels in the blood by increasing calcium absorption from the intestines and releasing calcium from bones. The thyroid gland produces calcitonin, which helps lower blood calcium levels by promoting calcium deposition in bones. The other choices (B: Adrenal medulla and pancreas, C: Testes, D: Parathyroid and thymus) are incorrect because they do not play a direct role in regulating calcium levels in the blood.
The posterior pituitary gland receives hormone messages from the hypothalamus via ________.
- A. a capillary network
- B. neurons that extend from the hypothalamus to the pituitary
- C. Schwann cells
- D. both a and b
Correct Answer: B
Rationale: The correct answer is B: neurons that extend from the hypothalamus to the pituitary. The hypothalamus produces hormones that are stored and released by the posterior pituitary gland. This communication is facilitated by specialized neurons that extend from the hypothalamus to the pituitary, forming the hypothalamic-pituitary axis. These neurons release hormones into the bloodstream, which then reach the posterior pituitary gland and stimulate the release of its stored hormones. Choice A is incorrect because the posterior pituitary does not directly receive messages through a capillary network. Choice C is incorrect as Schwann cells are responsible for myelinating peripheral nerves, not hormone communication. Choice D is incorrect because while the hypothalamus communicates with the pituitary gland through neurons, it does not involve a capillary network.
In relation to noradrenaline, all of the following are true EXCEPT:
- A. It stimulates α and β receptors
- B. It decreases heart rate
- C. It decreases blood pressure
- D. Causes vasoconstriction
Correct Answer: C
Rationale: Rationale:
- Noradrenaline stimulates both α and β receptors, leading to increased heart rate and vasoconstriction.
- It does not decrease heart rate; it actually increases heart rate due to its actions on β receptors.
- Noradrenaline causes vasoconstriction by activating α receptors, leading to increased blood pressure.
- The incorrect statement is C, as noradrenaline actually increases blood pressure by causing vasoconstriction.
The transcription of new messenger RNA is a function of __________.
- A. pancreatic hormones
- B. steroid hormones
- C. catecholamines
- D. pituitary gland hormones
Correct Answer: B
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Which form of intestinal smooth muscle contraction does NOT occur in normal health?
- A. peristalsis
- B. weak antiperistalsis
- C. peristaltic rushes
- D. tonic contractions
Correct Answer: C
Rationale: The correct answer is C: peristaltic rushes. Peristaltic rushes are abnormal and excessive contractions that can result in diarrhea or bowel urgency. In normal health, peristalsis (A) is the coordinated contraction and relaxation of intestinal smooth muscles that moves contents along the digestive tract. Weak antiperistalsis (B) refers to reverse contractions that are weaker than normal peristalsis. Tonic contractions (D) are sustained contractions that help maintain muscle tone and control flow. Therefore, peristaltic rushes are the only option that does not occur in normal health due to their abnormal and disruptive nature.