Melatonin is a hormone that regulates the 24 hour rhythm of our body such as the sleep-wake cycle etc. Melatonin is produced by pineal gland in the brain, which is responsible for operation and regulation of the biological clock in mammals.

Correct Option: D

Melatonin is a hormone that regulates the 24 hour rhythm of our body such as the sleep-wake cycle etc. Melatonin is produced by pineal gland in the brain, which is responsible for operation and regulation of the biological clock in mammals.

Adrenal gland has two parts-cortex and medulla. The medulla is stimulated by sympathetic nervous tissue to produce adrenaline and non-adrenaline while the cortex is stimulated by pituitary hormone to release cortisol, aldosterone and estrogens. Thus injury to adrenal cortex is not likely to affect the secretion of adrenaline.

Correct Option: C

Adrenal gland has two parts-cortex and medulla. The medulla is stimulated by sympathetic nervous tissue to produce adrenaline and non-adrenaline while the cortex is stimulated by pituitary hormone to release cortisol, aldosterone and estrogens. Thus injury to adrenal cortex is not likely to affect the secretion of adrenaline.

Adrenaline (called Frieght-Flight-Fight hormone) is responsible for the dilation of blood vessels, increased oxygen consumption by tissues & glucogenesis to prepare the body for emergency reactions under the threatening conditions.

Correct Option: B

Adrenaline (called Frieght-Flight-Fight hormone) is responsible for the dilation of blood vessels, increased oxygen consumption by tissues & glucogenesis to prepare the body for emergency reactions under the threatening conditions.

In 1912, Gudernatsch discovered that metamorphosis in frog’s tadpole is controlled by the thyroxine hormone which has the iodine as the main constituent. If thyroxine or iodine is added in water having tadpoles in it, then it increases the rate of metamorphosis in tadpole.

Correct Option: B

In 1912, Gudernatsch discovered that metamorphosis in frog’s tadpole is controlled by the thyroxine hormone which has the iodine as the main constituent. If thyroxine or iodine is added in water having tadpoles in it, then it increases the rate of metamorphosis in tadpole.

Melanocyte-stimulating hormone (MSH) or Melanotropin is secreted by the intermediate lobe of adenohypophysis (pars intermedia) of pituitary gland in mammals (other than man) so named ‘intermedin’. In lower vertebrates, it targets chromatophores & does wider distribution of the melanin grannules in chromatophores, so that the skin colour darkens. In birds & human beings and other mammals its role is uncertain but in man it is probably responsible for bronzing of skin, moles etc.

Correct Option: A

Melanocyte-stimulating hormone (MSH) or Melanotropin is secreted by the intermediate lobe of adenohypophysis (pars intermedia) of pituitary gland in mammals (other than man) so named ‘intermedin’. In lower vertebrates, it targets chromatophores & does wider distribution of the melanin grannules in chromatophores, so that the skin colour darkens. In birds & human beings and other mammals its role is uncertain but in man it is probably responsible for bronzing of skin, moles etc.