Which one of the following does not act as a neurotransmitter?
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Solution
Epinephrine or adrenaline, norepinephrine or noradrenaline and acetylchloline are the neuro-transmitters. These are released by the nerve fibres to transmit the impulse to the next neurone. Cortisone is not the neurotransmitter.
Which one of the following is not a second messenger in hormone action ?
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Solution
cGMP (Cyclic Guanosine Monophosphate) which acts as secondary messenger works on the action of acetylcholine, increase in flow of Ca2+ into muscle fibres & hence causes muscle relaxation. There is no role of sodium in hormonal action.
A steroid hormone which regulates glucose metabolism is
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Solution
Cortisole is the steroid hormone secreted by adrenal cortex and plays an important role in carbohydrate metabolism. It retards the glucose consumption & hence level of glucose in blood increases & blood pressure increases.
Sertoli cells are regulated by the pituitary hormone known as
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Solution
During spermatogenetic developments spermatids get nourished by nurse or sertoli cells. The function of sertoli cells and hence the spermatogenesis is under the direct influence of follicle-stimulating hormone (FSH) secreted by adenohypophyses of pituitary gland.
Parkinson’s disease (characterized by tremors and progressive rigidity of limbs) is caused by degeneration of brain neurons that are involved in movement control and make use of neurotransmitter
Which one of the following hormones is a modified amino acid?
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Solution
Epinephrine is synthesized from amino acid tyrosine. While estrogen and progesterone are modified steroids and prostaglandins are basically fat.
Which of the following hormones is not a secretion product of human placenta ?
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Solution
Human chorionic gonadotropin is released by Anophoblast cells of the placenta. Estrogen and progesterone are also released by placental cells to maintain pregnancy. Prolactin is secreted from anterior lobe of pituitary. Placenta secretes Human Placental Lactogenic Factor which prepare mammary glands to secrete milk.
Which one of the following pairs correctly matches a hormone with a disease resulting from its deficiency?
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Solution
Luteinizing hormone (LH) stimulates ovulation. Deficiency of insulin causes diabetes mellitus. Deficiency of ADH or vasopressin causes diabetes insipidus. Deficiency of parathormone causes tetany. Deficiency of thyroxine causes cretinism in infants and myxoedema in adults.
Chemically hormones are
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Solution
Hormones are chemical messengers formed by endocrine cells. Chemically hormones are of the following types:
Amines – composed of amino group e.g., Melatonin.
Amino acids – eg. thyroxine
Peptides – eg. insulin
Steroids – eg. aldosterone
Which one of the following pairs correctly matches a hormone with a disease resulting from its deficiency ?
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Solution
Deficiency of parathyroid hormone causes tetany. The disease causes sustained contraction of muscles of larynx,face, hands and feet.