Nokea
Identify the mechanisms that control the production and release of hormones.
- A. hormonal, neural and sensory
- B. hormonal, humoral and neural
- C. hormonal, humoral and sensory
- D. humoral, neural and sensory
Correct Answer: B
Rationale: The correct answer is B: hormonal, humoral, and neural. Hormonal regulation involves feedback loops where hormone levels control their own production. Humoral regulation involves substances in body fluids influencing hormone release. Neural regulation involves the nervous system influencing hormone production. Option A is incorrect because sensory mechanisms do not directly control hormone production. Option C is incorrect because sensory mechanisms are not typically involved in hormone regulation. Option D is incorrect because hormonal control is a key mechanism that was omitted.
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In type 1 diabetes there is an osmotic effect of glucose when insulin deficiency prevents the use of glucose for energy. Which classic symptom is caused by the osmotic effect of glucose?
- A. Fatigue
- B. Polyphagia
- C. Polydipsia
- D. Recurrent infections
Correct Answer: C
Rationale: Polydipsia is caused by the osmotic effect of glucose, leading to excessive urination and increased thirst.
Exemplify hormones secreted by the anterior pituitary.
- A. anti-diuretic hormone and oxytocin
- B. ACTH and insulin
- C. growth hormone and LH
- D. thyroxine and cortisol
Correct Answer: C
Rationale: The correct answer is C: growth hormone and LH. The anterior pituitary gland secretes these hormones. Growth hormone regulates growth, metabolism, and body composition, while LH (luteinizing hormone) plays a role in reproductive function.
A: Anti-diuretic hormone and oxytocin are produced by the posterior pituitary gland.
B: ACTH (adrenocorticotropic hormone) is secreted by the anterior pituitary, but insulin is produced by the pancreas.
D: Thyroxine is released by the thyroid gland, and cortisol is produced by the adrenal glands, not the anterior pituitary.
When an action potential reaches the axon terminal, what happens next?
- A. The muscle fiber contracts
- B. Acetylcholinesterase breaks down acetylcholine in the synaptic cleft
- C. Endosomes containing neurotransmitter fuse to cell membrane, and release neurotransmitter into the synaptic cleft
- D. Sodium channels open at the motor end plate, moving the cell membrane closer to threshold
Correct Answer: c
Rationale: The correct answer is C because when an action potential reaches the axon terminal, endosomes containing neurotransmitters fuse with the cell membrane and release neurotransmitter into the synaptic cleft. This process is known as exocytosis. This neurotransmitter then binds to receptors on the postsynaptic neuron, initiating a new action potential.
Choice A is incorrect because the muscle fiber contraction is initiated by the binding of the neurotransmitter to receptors on the muscle cell, not directly by the action potential reaching the axon terminal.
Choice B is incorrect because acetylcholinesterase breaks down acetylcholine in the synaptic cleft after it has already been released and has completed its role in transmitting the signal.
Choice D is incorrect because sodium channels opening at the motor end plate is part of the process of muscle cell depolarization and contraction, not directly related to the release of neurotransmitter at the axon terminal.
A 34-year-old carpenter presents to the emergency room after an accident in which he inadvertently chopped off the tip of his index finger. He is taken to the operating room for reattachment of the digit, and after sedation, a local anesthetic is administered around the site of the injury. The local anesthetic used in the procedure did not contain any epinephrine, as it usually does for most surgical procedures. The reason for this is
- A. Epinephrine causes increased blood loss during delicate surgery
- B. Epinephrine causes swelling of the tissues, making surgery more challenging
- C. Epinephrine is contraindicated in emergency surgery
- D. Epinephrine causes vasoconstriction, which can lead to vascular ischemia in digits
Correct Answer: D
Rationale: The correct answer is D. Epinephrine causes vasoconstriction, which can lead to vascular ischemia in digits. In delicate surgeries like finger reattachment, maintaining adequate blood flow is crucial for successful outcomes. Using epinephrine can constrict blood vessels excessively, leading to reduced blood supply and potential tissue damage. This can result in vascular ischemia, compromising the viability of the reattached finger.
Explanation for incorrect choices:
A: Epinephrine actually helps in reducing blood loss by constricting blood vessels.
B: Epinephrine reduces tissue swelling, making surgery easier.
C: Epinephrine is not contraindicated in emergency surgery; it is often used to control bleeding and prolong anesthesia.
The body’s major metabolic hormone is released from the:
- A. Pituitary
- B. Thyroid
- C. Thymus
- D. Hypothalamus
Correct Answer: B
Rationale: The correct answer is B: Thyroid. The body's major metabolic hormone, thyroxine (T4) and triiodothyronine (T3), is released from the thyroid gland. The thyroid gland plays a crucial role in regulating metabolism. Pituitary (A) releases various hormones but not the major metabolic hormone. Thymus (C) is responsible for immune function, not metabolism. Hypothalamus (D) regulates the pituitary gland but does not directly release the major metabolic hormone.