Question

One of the functions of adrenaline hormone is:
a. Adrenaline increases blood volume and supply of blood to various organs.
b. Adrenaline increases heart rate and supply of carbon dioxide to the various organs.
c. Adrenaline increases heart rate and supply of blood to various organs.
d. Adrenaline decreases heart rate and supply of blood to various organs.

Answer 1

Hint: The adrenaline hormone is secreted by one of the endocrine glands called adrenal gland which is present on kidneys as a cap like structure. It also produces major steroid hormones such as mineralocorticoids, glucocorticoids and androgens by its outer cortex.

Complete answer:
Adrenaline is also called as epinephrine which is produced by medulla of adrenal glands and serves the role of chemical mediator. It comes into play during the time of acute stress. It is released in noticeable amounts during the time of stress, excitement, dangerous or threatening situation. It makes the body react quickly to the environment by making the heart beat fast, blood flow to brain and muscles and production of glucose etc.

It plays a main role in fight-or-flight response in which it readily increases the cardiac output of the heart by initiating strong contractions and raising blood pressure which increases the heart rate and blood supply to various organs. It also alters the body’s metabolism by increasing the blood glucose level in the body. Adrenaline stimulates the breakdown of glycogen into glucose through glycolysis in the liver. It also increases the supply of fatty acids so that glucose as well as fatty acids can be used as fuel for the body in adverse conditions to make the body alert for stress or danger. Adrenaline causes mydriasis i.e. the contraction of muscles of iris resulting in dilation of pupils to improve vision.

Hence, The correct answer is option (C).

Note: During release of adrenaline, an adrenaline rush begins in the brain. During stressful conditions, the brain sends a signal to the hypothalamus region of the brain which is a command center of the brain. The hypothalamus signals the sympathetic nervous system to transmit signals to the adrenal gland for production of adrenaline.