GnRH, a hypothalamic hormone, needed in reproduction, acts on [2017]
anterior pituitary gland and stimulates secretion of LH and FSH
posterior pituitary gland and stimulates secretion of oxytocin and FSH
posterior pituitary gland and stimulates secretion of LH and relaxin
anterior pituitary gland and stimulates secretion of LH and oxytocin.
(1)
Gonadotropin releasing hormone (GnRH) is secreted by the hypothalamus which stimulates the anterior lobe of pituitary gland to secrete luteinising hormone (LH) and Follicle Stimulating Hormone (FSH).
Hypersecretion of growth hormone in adults does not cause further increase in height, because [2017]
epiphyseal plates close after adolescence
bones loose their sensitivity to growth hormone in adults
muscle fibres do not grow in size after birth
growth hormone becomes inactive in adults.
(1)
Epiphyseal plate is a hyaline cartilage plate in the metaphysis at each end of long bone. It is part of long bone where new bone growth takes place. In adults, elevated levels of GH results in acromegaly where no increase in height occurs because of ossified epiphyseal plate.
A temporary endocrine gland in the human body is [2017]
corpus cardiacum
corpus luteum
corpus allatum
pineal gland
(2)
Corpus luteum is a temporary endocrine gland in human females. It secretes progesterone which stimulates the uterine glands to produce increased amount of watery mucus and is also essential for maintenance of endothelium. In absence of fertilisation, corpus luteum disintegrate leading to menstruation.
Graves’ disease is caused due to [2016]
hyposecretion of thyroid gland
hypersecretion of thyroid gland
hyposecretion of adrenal gland
hypersecretion of adrenal gland
(2)
Exophthalmic goitre or Graves' disease is a thyroid enlargement (goitre) in which the thyroid secretes excessive amount of thyroid hormone. It is characterised by exophthalmia (protrusion of eye balls because of fluid accumulation behind them), loss of weight, slightly rise in the body temperature, excitability, rapid heart beat, nervousness and restlessness.
Name a peptide hormone which acts mainly on hepatocytes, adipocytes and enhances cellular glucose uptake and utilisation. [2016]
Insulin
Glucagon
Secretin
Gastrin
(1)
Insulin is a peptide hormone, secreted by the cells of the islets of Langerhans in the pancreas, that promotes the uptake of glucose by body cells, particularly in the liver (hepatocytes) and muscles (adipocytes) and thereby controls its concentration in the blood.
The posterior pituitary gland is not a ‘true’ endocrine gland because [2016]
it is provided with a duct
it only stores and releases hormones
it is under the regulation of hypothalamus
it secretes enzymes
(2)
Posterior lobe of pituitary gland does not secrete any hormone. Its hormones are synthesised by the hypothalamus. It only stores and releases these hormones. Hence, it cannot be considered as true gland.
Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other? [2016]
Aldosterone – Atrial Natriuretic Factor
Relaxin – Inhibin
Parathormone – Calcitonin
Insulin – Glucagon
(2)
Relaxin hormone is secreted by ovary and placenta during pregnancy, which relaxes ligaments in pelvis and softens and widens cervix during childbirth. Inhibin secreted by granulosa cells in the ovaries inhibits secretion of FSH by anterior pituitary. Thus, relaxin and inhibin have different functions and are not antagonistic.
Which one of the following hormones is not involved in sugar metabolism? [2015]
Insulin
Glucagon
Cortisone
Aldosterone
(4)
Aldosterone (salt-retaining hormone) is the principal mineralocorticoid in humans, secreted by adrenal cortex. Its main function is to regulate sodium content of the body.
Which one of the following hormones though synthesised elsewhere, is stored and released by the master gland? [2015]
Prolactin
Melanocyte stimulating hormone
Antidiuretic hormone
Luteinising hormone
(3)
Two hormones viz oxytocin (OT) and antidiuretic hormone (ADH) are synthesised in the hypothalamus, but stored and released by the posterior lobe of pituitary gland.
Fight-or-flight reactions cause activation of [2014]
the parathyroid glands, leading to increased metabolic rate
the kidney, leading to suppression of renin-angiotensin-aldosterone pathway
the adrenal medulla, leading to increased secretion of epinephrine and norepinephrine
the pancreas leading to a reduction in the blood sugar levels
(3)
Hormones epinephrine and norepinephrine are secreted from adrenal medulla. They are emergency hormones released in condition of stress, emergency, etc. Epinephrine and norepinephrine are also released by adrenergic nerve fibres of sympathetic nervous system where they act as neurotransmitters.
