Nokea
The posterior pituitary stores and releases:
- A. Growth hormone and prolactin.
- B. Prolactin and oxytocin.
- C. Oxytocin and antidiuretic hormone (ADH).
- D. ADH and growth hormone.
Correct Answer: C
Rationale: The correct answer is C: Oxytocin and antidiuretic hormone (ADH). The posterior pituitary stores and releases oxytocin and ADH, also known as vasopressin. Oxytocin is involved in uterine contractions and milk ejection, while ADH regulates water reabsorption in the kidneys. Choices A, B, and D are incorrect because the posterior pituitary does not store or release growth hormone or prolactin.
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The parathyroid glands maintain adequate levels of blood calcium. This is accomplished through ________.
- A. blocking the action of growth hormone
- B. targeting the bone and activating osteoclasts so that calcium will be released
- C. antagonizing the synthesis of calcitonin
- D. slowing the activity of tissues that require calcium for activity
Correct Answer: B
Rationale: The correct answer is B because the parathyroid glands target the bone and activate osteoclasts to release calcium into the bloodstream. This process helps maintain adequate blood calcium levels. By activating osteoclasts, calcium is released from the bone into the blood, ensuring a balance of calcium levels.
A: Blocking the action of growth hormone is unrelated to the function of parathyroid glands in maintaining blood calcium levels.
C: Antagonizing the synthesis of calcitonin is not the primary mechanism through which parathyroid glands regulate blood calcium levels.
D: Slowing the activity of tissues that require calcium for activity would not help maintain adequate blood calcium levels as it does not address the direct release of calcium from bone by activating osteoclasts.
Glucagon, growth hormone, cortisol, and epinephrine:
- A. are all secreted by the adrenal gland.
- B. expand blood volume.
- C. raise blood glucose levels.
- D. stimulate osteoclastic activity.
Correct Answer: C
Rationale: The correct answer is C: raise blood glucose levels. Glucagon, growth hormone, cortisol, and epinephrine all work together to increase blood glucose levels through various mechanisms. Glucagon stimulates the breakdown of glycogen into glucose, growth hormone promotes gluconeogenesis, cortisol increases blood sugar through gluconeogenesis and inhibiting glucose uptake, and epinephrine triggers glycogen breakdown and inhibits insulin release. Choices A, B, and D are incorrect because not all of these hormones are secreted by the adrenal gland, they do not directly expand blood volume, and they do not stimulate osteoclastic activity, respectively.
A man has been searching for an aphrodisiac or some other agent to enhance 'sexual performance' discovers yohimbine. He consumes the drug in excess and develops symptoms of toxicity that require your intervention. Which of the following should you expect as a response to this drug?
- A. Bradycardia
- B. Bronchoconstriction
- C. Excessive secretions by exocrine glands (salivary, lacrimal, etc.)
- D. Hypertension
Correct Answer: D
Rationale: The correct answer is D: Hypertension. Yohimbine is a known alpha-2 adrenergic antagonist, leading to increased sympathetic activity and consequently, hypertension. This occurs due to increased norepinephrine release and vasoconstriction. Bradycardia (A) is unlikely as yohimbine usually causes tachycardia. Bronchoconstriction (B) is not a common effect of yohimbine. Excessive secretions by exocrine glands (C) are not associated with yohimbine toxicity.
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.
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.