Question

How does our body respond when adrenaline is secreted into the blood 0?

Answer 1

Adrenaline and nor-Adrenaline hormone are secreted by the Adrenal medulla which are originated and developed from the neuroectoderm to the embryo. They are primarily consisted of rounded groups of relatively large and granular cells (in the shape of granules). These cells are modified postganglionic cells of the sympathetic nervous system which have completely lost the normal processes and have acquired some of the glandular functions. These cells have also been named as $\textbf{chromaffin cells}$ or $\textbf{phaeochromocytes}$. These cells are also well connected with the preganglionic motor fibres of the symapathetic nervous system. Obviously, the adrenal medulla is just a simple extensor or extension of the sympathetic nervous system, therefore, they are already discussed together as $\textbf{sympathetico-adrenal system}$.

The adrenaline hormone acts in the blood through the means of medulla of the adrenal glands which secrete two main hormones: Norepinephrine (noradrenaline) and epinephrine (adrenaline) are derived from the same, tyrosine aminoacid.

1) $\textbf{Norepinephrine}$ (also known as $\textbf{noradrenaline}$ hormone): It has a regulatory effect, which, regulates the blood pressure under normal conditions. It causes constriction of essentially all the provided blood vessels of the body. It also has an effect of increasing the activity of heart (beating of the heart is more than the normal rate), inhibition of the gastrointestinal tract, dilation or the pupils present in the eye and so forth.

2) $\textbf{Epinephrine}$ (also known as $\textbf{adrenaline}$ hormone): This hormone is secreted at the time emergency (at times of fight, escaping from a dire situation, facing a hungry animal, near-death escape, etc.), hence, it is also known or called as $\textbf{emergency hormone}$. It causes almost the same given effects as those caused by the counterpart, norepinephrine, but the effects differ in the following respects. First off, epinephrine has a greater tendency to increase the effect on cardiac activity than norepinephrine. And secondly, epinephrine causes only weak constriction of the blood vessels of the muscles in comparison with a much stronger and harder constriction that results from norepinephrine. A final and the third difference between the action of epinephrine and norepinephrine relates to their effects on the metabolism of tissues. Epinephrine probably has several more times a greater metabolic effect than its hormonal partners, norepinephrine.

Both of them have their $\textbf{Target Cells}$ (both adrenaline and noradrenaline hormones); as they act on cells of skeletal, cardiac and smooth muscles and blood vessels and fat cells.

Because of their role as hormones, the adrenal glands have also been known as $\textbf{"Glands of Emergency"}$.

Sympatheticoadrenal system: The Stimulation of sympathetic nerves to the adrenal medulla causes large quantities of epinephrine (adrenaline hormone) and norepinephrine (noradrenaline hormone) to be released into the blood circulation and then these hormones are carried out to all the tissues of the body. Both of the hormones (epinephrine and norepinephrine) and the sympathetic nervous system act on primarily at the sense organs and produce similar effects on them (for an example, it accelerates heart beat when sensing danger, raises blood pressure to a new high, slows the act of peristalsis, etc.). Since the sympathetic nervous system and the adrenal medulla have quite a crucial function as a completely integrated intricate system, it is also known $\textbf{sympatheticoadrenal system}$. This is the main reason why, the adrenaline hormone is reponsible for $\textbf{"fight or flight response"}$.

Answer 2

If more adrenaline is released then the responses would be as follows :

(i) The glucose concentration of the blood would increase as the glycogen will be converted to glucose rapidly.

(ii) The muscles would gain more power due to availability of more glucose.

(iii) The heart beat will increase .

(iv) Thus more blood will be pumped.

(v) Thus the blood supply to muscles would increase .

(vi) The person would have perspiration .

The adrenaline is hence also called the emergency hormone as it helps either to fight danger or to run away from danger.