Introduction of human body
The human body is a complex (intricate) collection of different structural cells, which begins from atoms, molecules and compounds; and cells, tissues, organs and complex systems are, all together, form the whole human body.
Chemically, the human body is the organized and functional forms of different types of bio-chemicals. In it, the atoms of different elements are organized in compounds and controls biological functions. The chief elements are oxygen, hydrogen, carbon, nitrogen, phosphorus and sulphur.
When two or more atoms combine with each other, they make a molecule, for example: when two atoms of oxygen combine together, one molecule of oxygen is made, which is written as O2. When a molecule has more than one atom, it is called compound.
Cells are the microscopic body units. The human body is made up of millions of cells. These cells are very tiny, so can be seen only with the help of microscope. The cells are also known as the units of life, because all the basic life processes are being done in them like- growth, metabolism, respiration, digestion, excretion, irritability and reproduction. The cells are in different shapes and sizes.
The group of same type of cells i.e. same properties, shape and functions is called tissues. Tissues have divided into four groups like- Epithelial tissue, Connective tissue, Muscular tissue and Nervous tissue.
Organs are a pair of two or more types of tissues that complete a particular type of work altogether. Stomach is the best example of it. The tissue named epithelium acts as the layer of stomach and protects it from different types of enzymes and hydrochloric acid (HCL) secreted from its wall. The smooth muscle tissues churn food and break in to small pieces. The nervous tissues send nerve impulses that start muscular contractions and co-ordinates them. The connective tissues help in keeping all the remaining tissues together.
The different organs of the body arrange together and perform a particular function. This type of functions, together, is known as system. For example- there are many organs in respiratory system that help in exchanging outside air by mechanical process. The different organs of the digestive system convert the solid foods particles in to soft ones, due to which these particles are absorbed by the body easily. All the body’s systems are important and their works co-ordinate in keeping human body as grow and active. There is no any importance of a system alone. The organs of all the systems remain connected for doing their works.
Different systems arrange together and form human body, it has described below briefly-
This system consists of hair, nail, skin, excretory and oily glands. It covers the internal organs and protects them. It is helpful in regulating body temperature. Sensory receptors are also present in it that receive stimuli and control them.
Skeletal system :
The whole skeletal system of the body is covered with muscles, which are collectively known as muscular system. The entire body gets movement only through muscular system. The skeletal and muscular systems, together, are also known as locomotar system. It generates heat in the body and keeps substances active through body organs. In this system, there are three different types of muscles found like- skeletal muscles, smooth muscles and cardiac muscles. In addition to them, fasciae and tendons are also found in it that connect the muscles with bones.
Nervous system :
The nervous system regularizes and controls most of the body’s functions. It receives impulses from sensory nerves (organs) and moves the muscles after analysis. Central nervous system and peripheral nervous system are the two parts of this system-
- The brain and spinal cord form the central nervous system.
- In the peripheral nervous system, 12 pairs of cranial nerves grown from the brain and 31 pairs of spinal nerves grown from the spinal cord present.
In addition to them, an autonomic nervous system is also found. It is the autonomic part of the nervous system. It controls automatic functions taken place in the body like- heart beating, secretions from the glands of digestive tube, etc. it has two types of nerves- sympathetic and parasympathetic.
It is known as the transport systems of the body and nourishes all the body’s organs. It consists of heart, blood and blood vessels. By pumping of the heart, the blood is reached to the tissues of entire body through the blood vessels. Only the blood carries food particles, oxygen, wastes products and other necessary products from one part of the body to another.
T here are two types of blood vessels-
The arteries carry pure blood (with oxygen) from the heart to tissues.
The veins carry impure blood (without oxygen) from the tissues to heart.
Lymphatic system :
This system consists of lymph, lymph vessels, lymph nodes and other lymph tissues, spleen, tonsils and thymus gland. This system is also like the circulatory system and there is a strong (deep) relation between them. Lymphatic system is a part of immune system.
This system acts as digestion of foods and their absorption and removes out wastes (unnecessary) products from the body. This system consists of mouth, pharynx, oesophagus, stomach, small intestine, large intestine, rectum, anus, and different types of accessory organs like teeth, tongue, 3 pairs of salivary glands, pancreas, liver, gall bladder and bile duct.
The digestive system is a system formed from many organs, in which each of them has its own individual work.
This system maintains the existence of living organisms by giving birth to their own kind. Penis cells grow in it and spermatozoa in male and ova in female are being produced. This system is related to producing young ones. In this system, the external and internal reproductive organs of male and female are included.
When human anatomy and physiology have proper understanding, specific stability remains maintained in the internal organs of the body, which is called homeostasis. Actually, the external environment of the body goes on changing all the time; however the internal environment of it remains stable. In normal conditions, hormones secrete from favorable mechanisms of the body through controlling centers of the brain that are reached in the blood directly through different organs. It maintains homeostasis. Few functions of the body like- blood pressure, body temperature, inhaling and exhaling and heart beat are controlled by homeostasis mechanism.
To keep the body healthy, chemical balance or hormonal balance should be necessary inside and outside of these cells. For this balance, the composition of extra cellular fluid should be stable well. Extra cellular fluid circulates inside the entire body and through this fluid; many substances are carried inside and outside of the cells. In this way, this fluid controls the temperature and pressure of body systems as well as it maintains the balance of acid and alkaline, oxygen and carbon-di-oxide properly and keeps water, nutrients and the concentration of many hormones found in the blood as balanced.
Practically all the processes of the body help in completing homeostasis. For example- the kidneys filter blood and remove out regulated water and wastes products carefully. For providing oxygen and removing out carbon-di-oxide from the body, the lungs work with the co-operation of heart, blood vessels and blood. Nutritive elements are absorbed by small intestine and mixed in the blood and then forwarded to the different parts of the body according to need. Normally, all the body systems work with internal homeostasis resulting human health always remains in sound condition.
The whole regulation process of homeostasis is possible by coordinated feedback process of many organs and tissues in addition to direct or indirect control of the sensible net of the nervous and hormonal systems. If all the systems work properly, one feels better (remain healthy), which shows homeostasis. It concordance between body’s systems are broken, he/she starts feeling unhealthy. If internal homeostasis does not come again on tract by the body itself or through treatment, human is died.
Stress and homeostasis :
For completion of homeostasis, one should need to make (prepare) his/her body and mind as favorable against different types of imbalances occurring inside and outside of the body. The factors responsible for homeostasis imbalances are known as stressors or means of generating pressure and the total disorders that eliminate favorable changes from the body is called stress.
Microbiological (virus, bacteria), physiological (tumors, abnormal functions), growing (old stage, hereditary changes), stressors, physical changes (heat, noise), chemicals (eatables, hormones) or psychology (emotional wave, mental disorders), etc. can disturb homeostasis balances. Little stress is normal and can be beneficial in fabliau. For example- little pressure falls on bones, muscles and joints while walking that is helpful in providing strength to them. By avoiding walking and moving or by extra pressure, the bones and muscles are fallen weak while the bones are broken and muscles are torn by over physical pressure.
The people who do not able to control their nature (habit), susceptibility of diseases are increased in their body. The people who remain busy in their work have the susceptibility of heart disease like smokers and those having increased cholesterol level in their blood. It has observed by studies that the ability of immune system is decreased (affected) due to living as tensed (stressed) for a long time and few medical experts have noticed that only the stress is the reason of many diseases.
Due to over and continual stress, disease, disability even death can be taken place. It has been seen practically that stress is responsible directly or indirectly for cancer, coronary heart diseases, lungs related diseases, accidents, suicide, etc.