|Structural organisation of life|
The main aim of the Physiology is to explain the origin, development and progress of the life. Even if it is a virus, or complicated human beings or even a tree, They have their own mechanism of maintaining their daily activities. So we can divide the Physiology into different divisions like Viral Physiology, Plant Physiology, Animal Physiology, Human physiology etc.
Here we are mainly concentrating on Human Physiology. As I mentioned above, to study Human Physiology is a bit difficult as all the systems are too complex. The modern world has different varieties of advanced machines and lab set ups. Still answer to some of the questions on different systems are unknown. Before going to the each system we should study what is the smallest but the most important factor or part in a human being. Do not wait to give an answer. It is none other than the "Cell". In literary words, "it is the building block of the organism or the life". You may surprise if I say at present most of the electrophysiological works are on these small cells. Like studies about the calcium, sodium channels with Patch Clamp technique. We can discuss all these in the coming days.
Cells as the living Units of the body
As I mentioned above the cells are the building blocks of our life. Each parts of our body is having different cells with different functions. For example, the muscle cells maintain the boy movements and postures, nerve cells (neurons) control all our conscious and unconscious activities etc. So the cells they combined to form a tissue, a number of tissues combined to form an organ. Different organs combined to form an organ system. At last different organ system combined to form an organism.
For example, a group of cells combine to form cardiac muscle tissues, blood vessel tissues, blood cells, and all these form heart, blood vessels, blood respectively. And all these together form the Cardiovascular system. Like that some cells may form Nervous system, muscular system, digestive system, reproductive system, excretory system and endocrine system. All these systems together make us a human being!!
About 25 trillion blood cells are in our body, which carry oxygen, carbon-di-oxide, nutrients to the cells and vice verse. Other than this, about 75 trillion cells are there in our body. So a total of 100 trillion cells make a human being alive..!!
Like an organism, cells respire, take food, digest it, excrete the waste, and even reproduce. So there is no wonder how a small cell became the building block of our life. Mostly cells uses ATP as the energy form for their metabolic activities. A slight change in your body can stimulate each and every cells. It can pass informations each other. It can repair the damaged cells, if not able to repair it can degrade it. That is the way you are surviving.
When ever the environment heats, your body temperature decreases, when ever it is cold, the body temperature increases. If your body is suffering from Hypoxia (lack of oxygen) or Hypercapnia (increase in the level of Carbon di oxide) there will be an increase in the respiration, RBC(red blood cells) synthesis, blood flow, heart rate, and even cardiac output. So at any condition our body is having some techniques to balance our self to the environment. That process is termed as "Homeostasis" and we will discuss it in the next class. Till then have a nice day.