NURS 231/NURS231 Module 5 V2 |
Pathophysiology Q&A with Rationale | Portage
Learning
1. A patient presents with extreme thirst and the excretion of large volumes of very dilute
urine. Laboratory results show a low urine specific gravity. Which condition is most likely?
A. Diabetes Insipidus (DI)
B. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
C. Cushing’s Syndrome
D. Hashimoto’s Thyroiditis
Correct Answer: A
Explanation: Diabetes Insipidus is characterized by a deficiency of ADH or a decreased
renal response to ADH. This leads to the inability to concentrate urine, resulting in polyuria
and polydipsia. The low specific gravity confirms that the urine is highly dilute compared to
plasma.
2. Which hormone is primarily responsible for the ‘fight or flight’ response and is secreted by
the adrenal medulla?
A. Cortisol
B. Aldosterone
C. Thyroxine
,D. Epinephrine
Correct Answer: D
Explanation: Epinephrine and norepinephrine are catecholamines secreted by the adrenal
medulla during stress. They increase heart rate, blood pressure, and blood glucose levels to
prepare the body for action. This mechanism is essential for the sympathetic nervous
system’s rapid response.
3. In the negative feedback loop of the thyroid gland, an increase in serum T3 and T4 levels
will lead to which of the following?
A. Increased secretion of TSH from the anterior pituitary
B. Stimulation of the thyroid gland to produce more hormone
C. Decreased secretion of TRH from the hypothalamus
D. Increased conversion of T4 to T3 in the periphery
Correct Answer: C
Explanation: The hypothalamic-pituitary-thyroid axis operates on a negative feedback
system. When thyroid hormone levels are high, they signal the hypothalamus to reduce
TRH and the pituitary to reduce TSH. This regulation ensures that hormone levels remain
within a narrow physiological range.
4. A patient is diagnosed with Graves’ disease. What is the underlying pathophysiology of this
disorder?
A. Thyroid-stimulating immunoglobulins (TSI) mimicking TSH
, B. Iodine deficiency leading to thyroid enlargement
C. Autoimmune destruction of the thyroid follicles
D. A benign pituitary tumor secreting excess TSH
Correct Answer: A
Explanation: Graves’ disease is an autoimmune condition where the body produces
antibodies known as thyroid-stimulating immunoglobulins. These antibodies bind to and
activate TSH receptors on the thyroid gland, causing hyperthyroidism. This chronic
stimulation also frequently results in a diffuse goiter and exophthalmos.
5. Which clinical manifestation is a hallmark of primary adrenal insufficiency (Addison’s
Disease)?
A. Central obesity and ‘buffalo hump’
B. Hyperpigmentation of the skin
C. Hypertension and hypokalemia
D. Hyperglycemia
Correct Answer: B
Explanation: In primary adrenal insufficiency, the loss of negative feedback leads to high
levels of ACTH. ACTH shares a precursor with melanocyte-stimulating hormone, leading to
characteristic skin darkening. Other symptoms include hypotension and hyponatremia due
to lack of aldosterone.
Pathophysiology Q&A with Rationale | Portage
Learning
1. A patient presents with extreme thirst and the excretion of large volumes of very dilute
urine. Laboratory results show a low urine specific gravity. Which condition is most likely?
A. Diabetes Insipidus (DI)
B. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
C. Cushing’s Syndrome
D. Hashimoto’s Thyroiditis
Correct Answer: A
Explanation: Diabetes Insipidus is characterized by a deficiency of ADH or a decreased
renal response to ADH. This leads to the inability to concentrate urine, resulting in polyuria
and polydipsia. The low specific gravity confirms that the urine is highly dilute compared to
plasma.
2. Which hormone is primarily responsible for the ‘fight or flight’ response and is secreted by
the adrenal medulla?
A. Cortisol
B. Aldosterone
C. Thyroxine
,D. Epinephrine
Correct Answer: D
Explanation: Epinephrine and norepinephrine are catecholamines secreted by the adrenal
medulla during stress. They increase heart rate, blood pressure, and blood glucose levels to
prepare the body for action. This mechanism is essential for the sympathetic nervous
system’s rapid response.
3. In the negative feedback loop of the thyroid gland, an increase in serum T3 and T4 levels
will lead to which of the following?
A. Increased secretion of TSH from the anterior pituitary
B. Stimulation of the thyroid gland to produce more hormone
C. Decreased secretion of TRH from the hypothalamus
D. Increased conversion of T4 to T3 in the periphery
Correct Answer: C
Explanation: The hypothalamic-pituitary-thyroid axis operates on a negative feedback
system. When thyroid hormone levels are high, they signal the hypothalamus to reduce
TRH and the pituitary to reduce TSH. This regulation ensures that hormone levels remain
within a narrow physiological range.
4. A patient is diagnosed with Graves’ disease. What is the underlying pathophysiology of this
disorder?
A. Thyroid-stimulating immunoglobulins (TSI) mimicking TSH
, B. Iodine deficiency leading to thyroid enlargement
C. Autoimmune destruction of the thyroid follicles
D. A benign pituitary tumor secreting excess TSH
Correct Answer: A
Explanation: Graves’ disease is an autoimmune condition where the body produces
antibodies known as thyroid-stimulating immunoglobulins. These antibodies bind to and
activate TSH receptors on the thyroid gland, causing hyperthyroidism. This chronic
stimulation also frequently results in a diffuse goiter and exophthalmos.
5. Which clinical manifestation is a hallmark of primary adrenal insufficiency (Addison’s
Disease)?
A. Central obesity and ‘buffalo hump’
B. Hyperpigmentation of the skin
C. Hypertension and hypokalemia
D. Hyperglycemia
Correct Answer: B
Explanation: In primary adrenal insufficiency, the loss of negative feedback leads to high
levels of ACTH. ACTH shares a precursor with melanocyte-stimulating hormone, leading to
characteristic skin darkening. Other symptoms include hypotension and hyponatremia due
to lack of aldosterone.
