Nokea
Which of the following is a characteristic of steroid hormones?
- A. catalyze cyclic AMP
- B. diffuse through the plasma membranes of target cells
- C. enter the nucleus
- D. activate genes to transcribe mRNA for protein synthesis
Correct Answer: B
Rationale: The correct answer is B because steroid hormones are lipid-soluble, allowing them to easily diffuse through the plasma membranes of target cells. Once inside the cell, they bind to intracellular receptors to regulate gene expression. Choice A is incorrect because steroid hormones do not catalyze cyclic AMP; that is a function of peptide hormones. Choice C is incorrect because steroid hormones do not enter the nucleus directly but bind to intracellular receptors in the cytoplasm. Choice D is incorrect because while steroid hormones do activate genes to transcribe mRNA for protein synthesis, the initial step involves binding to receptors in the cytoplasm, not directly activating gene transcription.
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Receptors for steroid hormones are found .
- A. on nutrient molecules, such as glucose
- B. in the interstitial fluid
- C. in the cytoplasm of the cells of target tissues
- D. in the cell membranes of target tissues
Correct Answer: C
Rationale: The correct answer is C because steroid hormones are lipid-soluble and can diffuse through cell membranes. Once inside the cell, they bind to specific receptors in the cytoplasm. This hormone-receptor complex then enters the nucleus to regulate gene expression. Option A is incorrect because steroid hormone receptors are not found on nutrient molecules like glucose. Option B is incorrect as these receptors are not typically located in the interstitial fluid. Option D is also incorrect because steroid hormone receptors are not located on the cell membranes of target tissues.
Which division of the nervous system sends signals to the adrenal glands during moments of danger?
- A. Central nervous system
- B. Sympathetic division
- C. Parasympathetic division
- D. Peripheral nervous system
Correct Answer: B
Rationale: The correct answer is B: Sympathetic division. This division of the autonomic nervous system is responsible for the body's "fight or flight" response during moments of danger. When an individual perceives a threat, the sympathetic division activates to prepare the body for action, including sending signals to the adrenal glands to release adrenaline and cortisol, which help increase heart rate, blood pressure, and energy levels. The other choices are incorrect because:
A: The central nervous system consists of the brain and spinal cord, which are responsible for processing and transmitting information within the body, but it does not directly send signals to the adrenal glands.
C: The parasympathetic division is responsible for the body's "rest and digest" functions and works in opposition to the sympathetic division. It does not send signals to the adrenal glands during moments of danger.
D: The peripheral nervous system consists of nerves outside the brain and spinal cord, including sensory and motor nerves, but it does not specifically send signals
An autoimmune form of hypothyroidism when the body destroys the thyroid cells is called
- A. Hashimoto's disease.
- B. Graves disease.
- C. myxedema.
- D. acromegaly
Correct Answer: A
Rationale: Rationale:
1. Hashimoto's disease is characterized by the immune system attacking the thyroid gland, leading to hypothyroidism.
2. It is an autoimmune condition where the body produces antibodies that target and destroy thyroid cells.
3. This results in a decrease in thyroid hormone production.
4. Graves disease (choice B) is a form of hyperthyroidism caused by an overactive thyroid gland.
5. Myxedema (choice C) refers to severe hypothyroidism but is not autoimmune.
6. Acromegaly (choice D) is a disorder caused by excess growth hormone production, unrelated to thyroid function.
The only endocrine glands that lay dormant during childhood to activate at puberty are the:
- A. pancreas
- B. adrenal glands
- C. thyroid gland
- D. ovaries and testes
Correct Answer: D
Rationale: The correct answer is D because the ovaries and testes are the only endocrine glands that are dormant during childhood and activate at puberty to produce sex hormones. The ovaries produce estrogen and progesterone in females, while the testes produce testosterone in males. This activation is essential for the development of secondary sexual characteristics and reproductive functions.
Pancreas (choice A), adrenal glands (choice B), and thyroid gland (choice C) are all active during childhood and do not specifically activate at puberty. The pancreas regulates blood sugar levels, the adrenal glands produce hormones like cortisol, and the thyroid gland regulates metabolism. Hence, choices A, B, and C are incorrect in the context of endocrine glands that lay dormant during childhood to activate at puberty.
Which statement about the adrenal medulla hormones is accurate?
- A. Overproduction of androgens may cause masculinization in women.
- B. Both the adrenal medulla and the thyroid gland have a negative feedback system to the hypothalamus.
- C. Cortisol levels would be altered in a person who normally works a night shift from 11:00 pm to 7:00 am and sleeps from 8:00 am to 3:00 pm.
- D. Epinephrine and norepinephrine are considered hormones when they are secreted by the adrenal medulla and neurotransmitters when they are secreted by nerve cells
Correct Answer: D
Rationale: Epinephrine and norepinephrine are classified as hormones when secreted by the adrenal medulla and as neurotransmitters when released by nerve cells.