Question

Norepinephrine
(i) Is released by sympathetic fibers
(ii) Is released by parasympathetic fibers
(iii) Increase the heart rate
(iv) Decreases the blood pressure
A) (ii) and (iii)
B) (i) and (iii)
C) (i) and (iv)
D) (ii) and (iv)

Answer 1

Hint: Norepinephrine is the hormone produced by the adrenal glands and it is also called the noradrenalin. It is also produced by the neurotransmitter. It acts as the chemical messenger used to transmit the signals in the nerve system in the whole body. This hormone is produced by the inner part of the adrenal gland; it is also called the adrenal medulla. It joins with the adrenaline and increases the heart beat rate and blood bumping of the heart.

Complete answer:
Option A: The nerve fibers of the parasympathetic fibers nervous system are cranial nerves, vagus nerve and lumber of spinal nerve. During this nerve stimulation it increases the digestive secretion and also reduces the heartbeat. Norepinephrine hormone will increase the heart beat. So, ii is not correct and iii is correct.
So, it is not the correct answer.
Option B: Sympathetic fibers are also called the small fiber nerves. It is developed by the collections of nerve clusters called ganglia. It is available on the outside of the spinal cord. It will increase the rate of heart beat, muscle contraction and rate of conduction. So, i is correct. And i and iii are also correct.
So, option B is the correct answer.
Option C: Sympathetic fibers release the norepinephrine. Blood pressure is increased during the large amount of norepinephrine hormone excretion. So, i is correct but iv is not the correct answer.
Hence option C is not the correct answer.
Option D: Parasympathetic fibers do not produce the norepinephrine hormone. Decreasing blood pressure is not possible during the excretion of hormones.
So, both i and iv are not correct. Hence option D is not correct.

Hence, Option B is the correct answer.

Note:
Norepinephrine is produced by some neurons of the sympathetic nervous system and also produced by adrenal medulla. It also increases the heart rate. This will release during the physiological changes which are activated by the stressful event. Locus coeruleus is the brain part which is called the activation area of this hormone. It is the origin of norepinephrine hormone pathways in the brain. It will reduce the fat of the human body by releasing the fatty acids.