Read this article to learn about the role of muscles and glands in controlling human behaviour!
Understanding human behaviour is a very complex task because of the different activities of both the body and mind. The bodily factors which have a bearing on our behaviour include sense organs, nervous system, muscles, endocrine glands, etc.
The role of sense organs and nervous system is already dealt. The muscles and glands influence our behaviour in many ways. Let us understand the role of muscles and glands in controlling our behaviour.
The muscles are responsible for many types of movements and behaviours which are internal as well as external. The main characteristic of muscle tissue is its ability to contract and making movements possible.
There are three types of muscles in our body. They are:
i. Skeletal muscles: As the name implies skeletal muscle attaches to the skeleton and enables body movement. It is normally under voluntary (conscious) control.
ii. Cardiac muscle: It is the muscle of heart and is responsible for pumping the blood. It is under involuntary control.
iii. The smooth muscles form the walls of hollow organs (except heart) and also found in the skin and the eyes. These are responsible for a number of functions such as movement of food through the digestive tract and emptying of the urinary bladder. These are controlled involuntarily. The major functions of the muscular system are:
1. Overall movements of the body such as walking, running, and manipulation of objects with hands, maintenance of body posture, respiration, and production of body heat.
2. Muscles also help in communication functions such as speaking, writing, typing, gestures, and facial expressions.
3. They also help in constriction of organs and vessels which help propel and mix food and water in digestive tract, propel secretions from organs and regulate blood flow through vessels.
Another factor related to functioning of muscles is the muscle tone. This refers to the constant tension produced over long periods of time. Muscle tone is necessary for keeping the back and legs straight, the head held in an upright position and the abdomen from bulging. Muscle contraction is very important to enable the individual to perform long term activities like running, marathon, listening to long lecture, shooting and such other activities.
Energy for muscle contraction is supplied to the muscles in the form of adenosine tri-phosphate (ATP). Muscle fatigue results when ATP is used during muscle contraction faster than it can be produced in the muscle fibbers. From the psychological point of view, the most common type of fatigue is ‘psychological fatigue’.
This involves the central nervous system rather than the muscles themselves. The muscles are still capable of contracting, but the individual ‘perceives’ that additional muscle contraction is impossible. For example, a burst of activity in a tired athlete in response to spectator encouragement is an example of how psychological fatigue can be overcome.
It is important for the nurse to know these functions of muscles and help the patients to maintain rest, relaxation, and exercise to keep the health fit.
There are many glands in human beings situated in different parts of the body.
They are of two types: (i) Duct glands and (ii) ductless or endocrine glands.
1. Duct Glands:
The duct glands release their secretions through small ducts or tubes into the body cavities or on to the surface of the body. For example, salivary gland, sweat glands, lacrimal glands which produce tears, glands which secrete digestive juices, etc.
These glands are activated during emotional situations. For example, sweating increases during fear or anger, tears increase during grief, saliva decreases during fear and make our mouth become dry, digestion slows down during emotions, but constant emotion leads to increased secretion of hydrochloric acid leading to peptic or duodenal ulcers.
2. Endocrine Glands (Ductless Glands):
Endocrine glands are more important from the point of view of behaviour. Endocrine glands release their secretions called ‘hormones’ directly into blood stream.
The normal secretions of these hormones promote healthy and normal personality. But over or under secretion of these hormones affect the development of body, general metabolism, mental development and emotional behaviour. Some of the important glands which are directly related to the development of personality and behaviour are:
1. Pituitary gland:
This is also called the master gland, because it controls the functions of many glands. There are two lobes in this gland. The anterior lobe secretes hormones called trophic hormones which influence the secretions of other glands. For example, thyrotrophic hormone, gonadotrophic hormone, etc.
The anterior lobe controls the growth of body, prolactin secretion in women, insulin secretion, metabolic activities, sexual activities, etc. The hyperactivity of this gland leads to gigantism and under activity leads to dwarfism.
2. Thyroid gland:
It secretes thyroxin hormone. The normal secretion of thyroxin hormone regulates oxygen consumption and helps energy output. Hyperthyroidism causes increased nervous tension or excitement, insomnia and over activity.
Hypothyroidism causes sluggishness, forgetfulness, stupidity, dullness, etc. Hypothyroidism in childhood leads to a disease called cretinism and during adulthood it leads to myxoedema.
3. Parathyroid gland:
These glands are four in number. They secrete a hormone called Parathyroxin. Hyposecretion leads to excitability, muscular tremors, spasms and cramps, complete decline in secretion leads to disease called tetany.
Mentally, the individual becomes highly sensitive to criticisms and unable to control emotions. Hyperactivity results in lassitude, lack of interest, physical weakness and softness of bones due to lack of calcium, and lethargy due nervous weakness.
4. Adrenal glands:
These glands have two parts: Medulla and Cortex. The outer part is called cortex. It produces a hormone called cortin. Under secretion of cortin leads to lethargy, fatigue, lack of interest in sexual activities, irritability, depression, poor memory, sleep disturbances, indecisiveness, etc. over secretion results in over excitability, activeness, appearance of premature sexual characteristics, etc. Excess secretion in women leads to appearance of masculine characteristics such as moustache, hard voice, rough skin and growth of hairs on the chest.
Adrenal medulla secretes a hormone called Adrenaline and Noradrenalin (epinephrine and nor-epinephrine). This hormone plays a very important role during emotional experiences. Adrenaline mobilizes the person for emergencies.
It causes rapid heartbeat, high blood pressure, respiration, release of more energy, increasing muscular strength and decreases the function of digestive and excretory organs.
5. Sex glands:
These glands secrete sex hormones. At least a few male and female traits are related to the balance existing between male and female hormones. Sex hormones are necessary for the development of interest in sex and personality traits.
The sex hormones in males are called Androgens and in females they are called Estrogens and Progesterone. Under or over secretion affects the personality development. So also, early and late maturation affects personality and behaviour in various ways.
In addition to these glands there are some other glands such as: the pancreas produces insulin. When the insulin quantity in blood goes very high, the sugar level comes down particularly in brain, resulting in giddiness, sweating, unconscious, lack of energy in limbs, etc.
pineal gland which is very important in causing males and female characteristics. Thymus gland secretes the hormones which have a bearing on sex organs and sexual activities.
In this way various glands in our body have control over our behaviour. The knowledge of these glands and their functions help nurses to understand various signs and symptoms of diseases and also the behavioural deviations associated with the activities of these glands.