What is adrenaline? Adrenaline: Definition, Role, Effects and Functions

What is adrenaline? It is the main hormone of the brain substance that is produced by the adrenal glands. Adrenaline also acts as a neurotransmitter. However, according to the chemical structure, this substance is still referred to as catecholamines. Adrenaline can be easily found in the organs and tissues of our body. At the moment there is not only a natural hormone, but also a synthetic drug that is often used in medicine.

What is adrenaline?

This substance is important for humans, especially in stressful situations. After all, this hormone allows for a few seconds to decide: to run or to fight back. The adrenaline begins to work when a person experiences anxiety, fear or danger. In large quantities, the hormone can be produced by obtaining various injuries and burns. If a person is in a state of shock, then it is adrenaline that helps him to cope with emotions.

How it works

To understand what adrenaline is, you need to understand how the substance affects the body. The effect of this hormone is similar to the processes that result in the activation of nerve sympathetic fibers. In this case, there is an effect on a- and b-adrenergic receptors.

As a result of the development of adrenaline in the human body, there is a narrowing of the vessels located in the skin, in the abdominal cavity and in the mucous membranes. But that's not all. The vessels located in the brain, in contrast, expand. After that, there is an increase in blood pressure. The heart starts to beat faster. In some cases, there is a threat of arrhythmia, and because of the inhibitory effect of the vagus nerve, there is a risk of developing a reflex bradycardia.

The phases of the influence of adrenaline on blood pressure

There are 4 main phases of the influence of the hormone on blood pressure. Among them are:

1. Heartfelt. In this case there is excitation of b- ₁ adrenergic receptors. As a result, there is an increase in cardiac output, as well as an increase in systolic blood pressure.
2. Vagal. This phase is based on the activation of the basis of the vagus nerve. It is characterized, as a rule, by high blood pressure.
3. Vascular pressornoy. This phase is associated with the excitation of a _1- and a _2- adrenergic receptors. Here, suppression of the vagal phase by peripheral vasopressor processes is noted. At the same time, the arterial pressure rises again.
4. Depressor-vascular. At this stage, the activity of b2-adrenoreceptors is increased. Because of this, there is a decrease in blood pressure.

Adrenaline: a description of the hormone

Adrenaline is different from a synthetic drug. However, their effect on the body is the same. Differently, smooth muscles respond to adrenaline. After all, they have completely different adrenergic receptors. For example, relaxation of smooth muscles of the bronchi and intestines occurs with the stimulation of b ₂ -adrenoreceptors, and the dilatation of the pupil - with stimulation of a _1- adrenoreceptors.

The effects of adrenaline, which are on the human body, also depend on many factors. Do not forget that this is a catabolic hormone. Adrenaline is able to affect all types of material exchange. This hormone increases the blood glucose level. In addition, the substance is able to enhance tissue metabolism.

So what is adrenaline? Experts also refer to it as contrinulsular. Adrenaline is able to enhance gluconeogenesis and glycogenolysis. As a result, all processes of glycogen production in both the liver and skeletal muscles are slowing down. At the same time, the seizure, as well as the destruction of glucose, is enhanced. Because of this, glycolytic enzymes are activated.

It is worth noting that the hormone adrenaline, whose role and functions have long been studied, reduces the synthesis of fats and contributes to their decay. If the concentration of this substance is very high, then in the human body, the catabolism of proteins is also enhanced.

Harmful effects

The hormone has a positive effect on the performance of skeletal muscles. This property of the substance is actual in case of fatigue. However, when the effect of epinephrine on the tissue for a long time, some changes are noted. In the first place, skeletal muscles and myocardium increase . This is a kind of adaptation to constant stress and high physical stress.

In addition, protein catabolism is increased, muscle mass and strength are reduced. As a result of prolonged exposure, a person can dramatically lose weight. A similar phenomenon occurs in the case of distress. The substance affects the central nervous system. As a result, there is an opportunity to increase the time of wakefulness, psychological energy and activity. All this is done by mobilizing all the forces of the body.

Positive sides

Scientists have proved that the hormone is useful. After all, in medical practice, adrenaline is often used. What does it mean to be useful? The hormone has anti-allergic and anti-inflammatory properties. This substance is a barrier to the release of prostaglandins, leukotrienes, kinin, histamine, serotonin and other pathogens. In addition, adrenaline is able to improve blood clotting, increase the number and functionality of platelets.

Do not forget that in the human body this hormone is constantly present. However, under stresses, its quantity rises sharply, and all metabolic processes are restructured. In this case, a person is able to feel a strong emotional surge. Some try to feel it again and again. It is for this reason that people begin to engage in extreme sports. These are peculiar hostages of adrenaline.

Application in medicine

The adrenaline hormone, as defined above, is often used in medicine. Here it is used as a hyperglycemic, antiallergic, bronchodilator, vasoconstrictive, hypertensive agent. In addition, the substance is used for asystole, bleeding from the superficial vessels of the skin and mucous membranes, open-angle glaucoma. Adrenaline is able to alleviate the condition of the patient.

It is worth noting that the therapeutic effect of the hormone appears almost immediately after its introduction intravenously. In other cases, you need to wait a little. If the drug is administered subcutaneously, the effect will occur after 10 minutes, if intramuscularly - after 20 minutes.

Adrenaline is also used in anesthesia. In this case, the hormone narrows the vessels of the mucous membranes and skin, slows down the blood flow. This is necessary in order to reduce the rate of absorption of anesthetics. And this, as a rule, allows to increase the duration of their impact.