Hormone Actions
Which of the following Given below is PRIMARILY sleep promoting NEUROTRANSMITTER? A .Serotonin B. Melatonin C. Acetyl Choline D. Growth Hormone E.GABA
GABA
GABA is the primary inhibitory neurotransmitter in the central nervous system and plays a crucial role in promoting sleep by reducing neuronal excitability. It helps facilitate the onset and maintenance of sleep.
Which of the following endocrine glands is derived from the neuroectoderm?
A) Adrenal cortex
B) Thyroid gland
C) Adrenal medulla
D) Pancreas
Adrenal medulla
Explanation: The adrenal medulla originates from neural crest cells (neuroectoderm-derived).
Which of the following hormones plays a key role in long-term adaptation to starvation?
A) Insulin
B) Glucagon
C) Cortisol
D) Epinephrine
Cortisol
Explanation: Cortisol promotes gluconeogenesis and protein catabolism during prolonged fasting.
The most common cause of Cushing’s syndrome is:
A) Ectopic ACTH production
B) Adrenal tumor
C) Exogenous corticosteroid use
D) Pituitary adenoma
Exogenous corticosteroid use
Explanation: Exogenous steroids cause adrenal suppression, leading to Cushing’s syndrome.
A patient with primary hyperparathyroidism would have which lab finding?
A . high calcium, low PTH
B. Low calcium, high PTH
C. High calcium, high PTH.
D. Low calcium, Low PTH
High calcium high PTH
Which Hormone increase blood glucose level?
A. Insulin
B. Glucagon
C. Prolactin
D. Oxytocin
Glucagon
7. Which of the following pairs of endocrine glands is correctly matched with their embryological origin?
A) Thyroid - Mesoderm
B) Adrenal cortex - Ectoderm
C) Posterior pituitary - Neuroectoderm
D) Anterior pituitary - Neural crest
Posterior pituitary - Neuroectoderm
Explanation: The posterior pituitary originates from the neuroectoderm, while the anterior pituitary is from surface ectoderm.
What is the primary function of aldosterone in homeostasis?
A) Increase sodium excretion
B) Increase potassium reabsorption
C) Increase sodium retention and potassium excretion
D) Decrease water retention
Increase sodium retention and potassium excretion
Explanation: Aldosterone increases Na+ reabsorption and K+ excretion, maintaining blood pressure and volume.
A patient with Addison’s disease is most likely to have:
A) Hypokalemia
B) Hypertension
C) Hyperpigmentation
D) Metabolic alkalosis
Hyperpigmentation
Explanation: Addison’s disease leads to ACTH overproduction, increasing melanocyte-stimulating hormone (MSH).
Which of the following is the most specific test for diagnosing acromegaly?
A) Random growth hormone (GH) level
B) IGF-1 level
C) Oral glucose tolerance test (OGTT) with GH measurement
D) Pituitary MRI
ral glucose tolerance test (OGTT) with GH measurement
Explanation: In acromegaly, GH fails to suppress after oral glucose administration. IGF-1 is a good screening test, but OGTT is the gold standard for diagnosis.
Which hormone is responsible for regulating water balance in the body?
A. Oxytocin
B. Vasopressin
D. Prolactin
Vasopressin
Which gland secretes a hormone that is necessary for normal calcium homeostasis but does not respond to hypothalamic regulation?
A) Thyroid
B) Parathyroid
C) Pituitary
D) Adrenal cortex
Parathyroid
Explanation: PTH secretion is controlled by calcium levels, not the hypothalamic-pituitary axis.
How does the hypothalamus regulate body temperature homeostasis?
A) Via the anterior pituitary
B) By controlling sweat glands
C) By adjusting metabolic rate
D) Through sympathetic output
Through sympathetic output
Explanation: The hypothalamus modulates sympathetic activity to regulate thermogenesis and vasodilation.
A thyroid nodule with increased radioiodine uptake suggests:
A) Papillary carcinoma
B) Follicular carcinoma
C) Benign hyperfunctioning adenoma
D) Medullary carcinoma
Benign hyperfunctioning adenoma
Which test is most useful in differentiating between central and nephrogenic diabetes insipidus.
A. Serum osmolality
B. Urinary sodium concentration
C. Water deprivation test with desmopressin administration
D. Random urine osmolality
Water deprivation test with desmopressin administration
A hormone that binds to nuclear receptors increases metabolic rate and oxygen consumption in most tissues. Which of the following mechanisms best explains this hormone’s effect?
A) Activation of phospholipase C
B) Increased sodium-potassium ATPase expression
C) Inhibition of cAMP production
D) Activation of tyrosine kinase receptors
Increased sodium potassium atp ase expression
Thyroid hormone (T3) binds to nuclear receptors and upregulates Na⁺/K⁺ ATPase expression, increasing ATP consumption and heat production.
This explains its role in increasing basal metabolic rate.
Which of the following glands undergoes involution with age?
A) Pancreas
B) Thyroid
C) Thymus
D) Adrenal gland
Thymus
Explanation: The thymus shrinks after puberty and is replaced by fat.
Which hormone primarily prevents hypoglycemia during fasting?
A) Insulin
B) Epinephrine
C) Cortisol
D) Glucagon
Glucagon
Explanation: Glucagon stimulates glycogenolysis and gluconeogenesis, raising blood glucose.
A 46-year-old woman presents with progressive fatigue, weight gain, and swelling of her face and hands. She also complains of cold intolerance and constipation. Physical exam reveals dry skin, bradycardia, and a delayed relaxation of deep tendon reflexes. What is the most likely diagnosis?
A) Addison’s disease
B) Cushing’s syndrome
C) Hypothyroidism
D) Hyperparathyroidism
Hypothyroidism
Explanation:
Symptoms of cold intolerance, weight gain, fatigue, and constipation suggest hypothyroidism.
Bradycardia and delayed reflexes are classic signs of severe hypothyroidism (myxedema).
Most common cause: Hashimoto’s thyroiditis (autoimmune destruction of the thyroid).
A patient presents with symptoms of hypoglycemia. which test is most useful to diagnose insulinoma?
A. Random blood glucose.
B. C peptide level during fasting hypoglycemia
C. Serum insulin level alone.
D. HbA1 c level
C peptide level during fasting hypoglycemia
A researcher studying insulin signaling inhibits phosphoinositide 3-kinase (PI3K) activity in a cultured cell. Which of the following processes will most likely be impaired.
A) Activation of cAMP
B) Increased calcium release from the endoplasmic reticulum
C) Translocation of GLUT4 to the plasma membrane
D) Inhibition of glycogen synthesis
Translocation of GLUT4 to the plasma membrane
Explanation:
Insulin signaling occurs via the Receptor Tyrosine Kinase (RTK) pathway, activating PI3K.
PI3K activation leads to Akt (PKB) phosphorylation, which promotes GLUT4 translocation for glucose uptake.
Blocking PI3K disrupts this process, reducing glucose uptake in muscle and adipose tissue.
A tumor in which endocrine gland is most likely to cause a patient to develop pheochromocytoma?
A) Adrenal cortex
B) Adrenal medulla
C) Pituitary gland
D) Thyroid gland
Adrenal medulla
Explanation: Pheochromocytomas arise from chromaffin cells in the adrenal medulla.
Which of the following best describes a negative feedback loop?
A) A process where the output enhances the original stimulus
B) A process where the output reduces the original stimulus
C) A system where the stimulus keeps increasing without control
D) A mechanism that always leads to disease
A process where the output reduces the original stimulus
A 52-year-old man presents with uncontrolled hypertension, episodes of sweating, and palpitations. His blood pressure readings are variable, with sudden spikes. Laboratory tests show elevated plasma metanephrines. What is the most likely diagnosis?
A) Cushing’s syndrome
B) Pheochromocytoma
C) Primary hyperaldosteronism
D) Acromegaly
Pheochromocytoma
Explanation:
Classic triad: Episodic headaches, sweating, palpitations (due to excess catecholamines).
Paroxysmal hypertension with BP spikes suggests pheochromocytoma (adrenal medullary tumor).
Confirmatory test: 24-hour urinary metanephrines or plasma metanephrines.
Which imaging modality is most sensitive for detecting adrenal tumors causing hyperaldosteronism?
A. Ultrasound
B. Non contrast CT scan
C . MRI
D. PET Scan
Non contrast CT scan