The Roles of Adrenalin, Noradrenaline and Cortisol

The endocrine system is made up of various glands that secrete hormones into the bloodstream. These hormones regulate metabolism, growth and development, tissue function, and play a part also in mood. Hormones are chemical messengers secreted directly into the blood to be sent to targeted organs and tissues of the body to perform their specific functions (Waugh & Grant, 2014). Hormones are made in one part of the body and sent to the targeted part of the body to initiate an exact activity and give function to another organ. They coordinate complex processes such as metabolism, growth and development, maintenance of body temperature and thirst, cognitive function and mood. Endocrine glands include organs such as the adrenal, pancreas, thyroid, pineal gland and pituitary glands. Very small amount secreted can cause a major change in the body. There are different types of hormones which perform different functions.

The focus of this essay will be on the three stress response hormones produced in the adrenal gland. The adrenal gland sits above the kidney in humans so there are two adrenal glands in the body since there are two kidneys. A cross-sectional view of each adrenal gland will review two distinctive regions; the inner region called the adrenal medulla and the outer section called the adrenal cortex. Each one of these regions secrete their own set of hormones with specific function. The hormones produced in this gland play a vital role in control and co-ordination of the body stress-response. In stressful situations, impulses are sent from the hypothalamus region of the brain to stimulate sympathetic nervous system. This ultimately stimulate the chromaffin cells which then secrete adrenaline and noradrenalin into the blood.

Adrenal medulla is responsible for the secretion of those hormones that assist with responding to physically and emotionally stressful and challenging situations. Cells of the medulla region are linked to sympathetic division of the autonomic nervous system because these hormones are also used by the nervous system as neurotransmitters. The adrenal medulla releases two water-soluble tyrosine-derivative hormones namely Adrenaline, which is also known as Epinephrine, and Noradrenaline, also known as Norepinephrine. These two hormones are produced from tyrosine amino acids.

Get Help With Your Essay

If you need assistance with writing your essay, our professional essay writing service is here to help!
Find out more about our Essay Writing Service

Adrenaline, along with norepinephrine is largely responsible for the immediate reactions we feel when stressed- to ‘fight or flight’ response. Imagine you're trying to change lanes in your car. Suddenly, from your blind spot, comes a car racing at 100 miles per hour. You return to your original lane and your heart is pounding. Your muscles are tense, you're breathing faster, you may start sweating. This is the effect of adrenaline. Adrenalin hormone is responsible for increasing the heart rate and increasing the contractile force of the heart, increases blood flow to our skeletal muscle. Adrenalin also increases the rate at which glycogen is broken down in the liver, dilates blood vessels leading to skeletal muscle but constrict blood vessels leading to internal organs such as the digestive system. It is adrenaline that gives you a surge of energy which you might need to run away from a dangerous situation and focuses your attention.

The primary role of Noradrenaline is arousal (Tortora & Derrickson, 2011). When stressed, you become more aware, awake, and focused. You become generally more responsive. Noradrenaline helps to shift blood flow away from areas where it might not be so crucial, like the skin, and toward more essential areas at the time, like the muscles, so you can flee the stressful scene. The release of Noradrenaline hormone constricts blood vessels leading to a higher blood pressure.  Adrenalin and Noradrenaline are very similar in the type of response that they create inside the cell and the body as a whole. Both Adrenalin and Noradrenaline are also used as neurotransmitter by the Nervous system, but the major difference is the hormones create a much longer lasting effect than the neurotransmitter.

Cortisol is the other important stress response hormone produced in the adrenal cortex. The corticosteroids are all derived from steroids - specifically from cholesterol. These are not water-soluble, so they need protein carriers to transport them inside the blood plasma and they can easily cross the cell membrane of the target cell because the cell membrane is lipid soluble. Cortisol is responsible for increasing the rate of production of glucose through a process known as gluconeogenesis - the production of glucose from non-carbohydrate sources such as lactic acid, amino acids and glycerol. Cortisol aid in the regulation of blood sugar levels, control metabolism and help with memory formation. It also controls the effect of water balance and salt and blood pressure. Cortisol also support foetus development during pregnancy in women. Cortisol and cortisone also increase the rate at which our liver cells break down adipose tissue and release fatty acids and glycerol into the blood stream which our body can use for glucose and hence energy production. Cortisol and cortisones are used to decrease the overall rate of protein synthesis in our body and they also decrease the effectiveness of our immune system. That means they decrease inflammation and swelling response., This is the reason why these hormones are commonly used by athletes to decrease the amount of swelling and inflammation that take place as result of some type of minor injury.

A negative feedback mechanism is an important type of control that is found in homeostasis. A negative feedback control system responds when conditions change from the ideal or set point and returns conditions to this set point. There is a continuous cycle of events in negative feedback. The role of these three stress-response can be summarised briefly in the diagram below;

References

Tortora, G. J. & Derrickson, B., 2011. Principles of Anatomy and Physiology. Oraganisation, Support and Movement, and Control Systems of the Human Body. 13 ed. Hoboken, NJ: John Wiley and Sons Pte Ltd. .

Waugh, A. & Grant, A., 2014. Ross and Wilson Anatomy and Physiology in Health and Illness. 12 ed. Edinburgh: Elsevier Health Sciences.

Bibliography

AK Lectures. (2014). Adrenal Gland. Youtube [Online]. Available from https://www.youtube.com/watch?v=9o2dqeajWsI [Accessed on 01/02/2020].

Mandel, A. 2019. What are Hormones? [Online]. Available from www.news-medical.net/health/what-are-Hormones.aspx [Accessed on 30/01/2020].

Tortora, G. J. & Derrickson, B., 2011. Principles of Anatomy and Physiology. Oraganisation, Support and Movement, and Control Systems of the Human Body. 13 ed. Hoboken, NJ: John Wiley and Sons Pte Ltd. .

Waugh, A. & Grant, A., 2014. Ross and Wilson Anatomy and Physiology in Health and Illness. 12 ed. Edinburgh: Elsevier Health Sciences.