This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Hormone Release Regulation”.
1. Which gland is the coordination center of the endocrine system in the human body?
a) Hypothalamus
b) Penial gland
c) Thalamus
d) Thymus
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Explanation: Hypothalamus accepts signals from the central nervous system and combines them. This gland releases regulatory hormones (releasing factors) in response to these signals that travel directly to the nearby pituitary gland, via special blood vessels and nerves that connect the two glands.
2. Which are the hormones that are produced from the posterior part of the pituitary gland?
a) Oxytocin and calcitonin
b) Oxytocin and vasopressin
c) Calcitonin and vasopressin
d) Thyroxine and calcitonin
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Explanation: The posterior pituitary comprises the axonal endings of several hypothalamus-originating nerves. These neurons develop the short peptide hormones oxytocin and vasopressin, which pass down the axon to the pituitary nerve endings, where they are retained in secretory granules awaiting the release signal.
3. Which are the hormones that are produced from the anterior part of the pituitary gland?
a) Melatonin
b) Steroid hormones
c) Tropic hormones
d) Serotonin
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Explanation: The anterior pituitary responds to hypothalamic hormones, producing tropical hormones or “tropins” held throughout the blood. The next section of endocrine glands, which comprise the adrenal cortex, thyroid gland, ovaries and testes, is stimulated by these comparatively long polypeptides.
4. Which hypothalamic hormone stimulates the anterior pituitary gland resulting in the release of ACTH?
a) Melatonin
b) Glucagon
c) Calcitonin
d) Corticotropin releasing hormone
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Explanation: The hypothalamus-releasing hormone corticotropin activates the anterior pituitary to release ACTH, which passes to the adrenal cortex region fasciculata and induces the release of cortisol. In several forms of target cells, cortisol which is the ultimate hormone in this cascade, serves to modify their metabolism through its receptor.
5. Which hormone acts on the muscles of uterus and mammary glands?
a) Oxytocin
b) Vasopressin
c) Estrogen
d) Progesterone
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Explanation: Oxytocin works on the uterine and mammary smooth muscles, inducing uterine contractions during labor and facilitating the secretion of milk during lactation. It also facilitates myoepithelial cell contraction, allowing milk to be ejected into the ducts and cisterns.
6. Which hormone increases the water reabsorption in the kidney and regulates the processes thereby?
a) Melatonin
b) Vasopressin
c) Oxytocin
d) Insulin
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Explanation: The tonicity of body fluids is controlled by Vasopressin. In addition to hypertonicity, it is expelled from the posterior pituitary and allows the kidneys to reabsorb solute-free water and return it to the circulation of the nephron tubules, thereby restoring the tonicity of the fluids in the body to normal.
7. Which class of nervous system contains hypothalamus, the major regulator of hormone action?
a) Peripheral nervous system
b) Semi-autonomous nervous system
c) Central nervous system
d) Somatic nervous system
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Explanation: The hypothalamus is involved, in major functions of the central nervous system, since it gathers input from almost all areas of the nervous system. As such it is regarded as the relation between the nervous system and the endocrine system.
8. Which cell secretes the growth inhibiting hormone somatostatin?
a) Nerve cells
b) Germ cells
c) Alpha cells
d) Islet cells of pancreas
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Explanation: Islet cell clusters which are also known as islets of Langerhans, secrete the hormones somatostatin, and other pancreatic polypeptides. Among the alpha, beta and delta cells of the islets of Langerhans, somatostatin is specifically secreted by the delta cells.
9. Which are the three mechanisms by which the endocrine glands are induced to produce and release hormones?
a) Hormonal stimuli, neural stimuli and humoral stimuli
b) Chemical stimuli, temperature stimuli and pressure stimuli
c) Hormonal stimuli, neural stimuli and cell mediated stimuli
d) Chemical stimuli, humoral stimuli and hormonal stimuli
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Explanation: There are three pathways by which hormones are activated by endocrine glands for their synthesize and release. They are humoral stimuli, hormonal stimuli, and neural stimuli. Humoral stimuli lead to the regulation of hormone production, in response to changes in extracellular fluids such as blood or blood ion concentrations. Hormonal stimuli refer to the activation of a hormone, in reaction to other hormones. Neural stimuli are referred to as the direct stimulation of endocrine glands by the nervous system to release hormones.
10. The synthesis and release of hormones are primarily regulated by negative feedback mechanism.
a) True
b) False
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Explanation: Negative feedback mechanism is the major mechanism for the regulation of almost all endocrine hormones. Excessive production of certain hormones like gonadotropic hormones can inhibit their secretory center (hypothalamus) and in turn inhibit the production of the same. In this way, the hormone concentration in the blood is kept within the required range.
Sanfoundry Global Education & Learning Series – Molecular Endocrinology.
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