Nokea
Dopamine and homovanillic acid are secreted in ______________.
- A. Neuroblastoma
- B. Adenoma
- C. Pheochromocytoma
Correct Answer: A
Rationale: Step-by-step rationale:
1. Dopamine and homovanillic acid are neurotransmitters.
2. Neuroblastoma is a type of cancer that originates in neuroblasts, which are immature nerve cells.
3. Neuroblastoma can produce neurotransmitters like dopamine and homovanillic acid.
4. Therefore, dopamine and homovanillic acid are secreted in neuroblastoma.
Summary:
- Choice A is correct as neuroblastoma can secrete dopamine and homovanillic acid.
- Choices B and C are incorrect as they are unrelated to the secretion of these neurotransmitters.
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Identify the growth factor that is released by cancer cells to create a capillary network that aids the cancer growth.
- A. macrophage colony-stimulating factor
- B. platelet derived growth factor
- C. tumor angiogenesis factor
- D. epidermal growth factor
Correct Answer: C
Rationale: The correct answer is C, tumor angiogenesis factor. Cancer cells release this growth factor to promote the formation of new blood vessels (angiogenesis) around the tumor, providing a supply of nutrients and oxygen to support their growth. This process is essential for cancer progression.
A: Macrophage colony-stimulating factor is involved in the production and differentiation of macrophages, not in angiogenesis.
B: Platelet-derived growth factor promotes cell growth and division, but it is not specifically responsible for angiogenesis in the context of cancer.
D: Epidermal growth factor is a signaling molecule that promotes cell proliferation and differentiation but is not the primary factor released by cancer cells to induce angiogenesis.
Which of the following hormones are responsible for the 'fight-or-flight' response?
- A. Epinephrine and norepinephrine.
- B. Insulin and glucagon.
- C. Esrtogen and progesterone.
- D. Thyroxin and melatonin.
Correct Answer: A
Rationale: The correct answer is A: Epinephrine and norepinephrine. These hormones are released by the adrenal glands during stressful situations to trigger the 'fight-or-flight' response. They increase heart rate, blood pressure, and energy production to prepare the body for action. Insulin and glucagon (B) regulate blood sugar levels. Estrogen and progesterone (C) are female sex hormones. Thyroxin and melatonin (D) are involved in metabolism and sleep regulation, respectively. Therefore, only A directly relates to the physiological response of 'fight-or-flight'.
Which gland is considered the most influential endocrine gland?
- A. Pineal gland
- B. Pituitary gland
- C. Thyroid gland
- D. Adrenal gland
Correct Answer: B
Rationale: The correct answer is B: Pituitary gland. The pituitary gland is considered the most influential endocrine gland because it controls the functions of other endocrine glands by secreting various hormones that regulate growth, reproduction, metabolism, and other bodily functions. It is often referred to as the "master gland" due to its crucial role in maintaining hormonal balance and homeostasis in the body.
Rationale:
A: Pineal gland - The pineal gland primarily regulates the sleep-wake cycle through the secretion of melatonin and is not as influential in overall endocrine function as the pituitary gland.
C: Thyroid gland - The thyroid gland regulates metabolism through the production of thyroid hormones, but it does not have the same level of control over other endocrine glands as the pituitary gland.
D: Adrenal gland - The adrenal gland produces hormones like cortisol and adrenaline, which are important for stress response and metabolism, but it does not have the same regulatory influence over other
The most common second messengers for peptide hormones are ______ and _____.
- A. peptide hormones and calcium.
- B. calcium and glucose.
- C. cAMP and calcium.
- D. cAMP and sodium.
Correct Answer: C
Rationale: The correct answer is C: cAMP and calcium. Peptide hormones bind to their receptors on the cell surface, activating G-proteins which then trigger the production of cAMP as a second messenger. cAMP then further activates protein kinases to initiate various cellular responses. Calcium is also a common second messenger in peptide hormone signaling pathways, regulating processes like muscle contraction and gene expression. Choice A is incorrect because peptide hormones themselves are not second messengers. Choice B is incorrect as glucose is not a common second messenger for peptide hormones. Choice D is incorrect as sodium is not typically involved in peptide hormone signaling pathways.
Where does the middle thyroid vein drain?
- A. Brachiocephalic vein
- B. External jugular vein
- C. Internal jugular vein
- D. Subclavian vein
Correct Answer: C
Rationale: The middle thyroid vein drains into the internal jugular vein due to its anatomical location in the neck. The internal jugular vein receives blood from the brain, face, and neck, making it a suitable drainage site for the thyroid gland. The other options (A, B, D) are incorrect because the brachiocephalic vein drains the upper body, the external jugular vein drains the scalp and face, and the subclavian vein drains the upper extremities, none of which are anatomically linked to the thyroid gland.