Introduction to Immune System
The immune system is a host protection system encompassing many biological structures and procedures within an organism that defends the body against disease. To function appropriately, an immune system must notice a wide variety of agents, termed as pathogens, from viruses to parasitic worms, and differentiate them from the organism’s own healthy tissue. In most of the species, there are two core subsystems of the immune system namely the innate immune system and the adaptive immune system. Both of these subsystems with the help of humoral immunity and cell-mediated immunity perform their functions. In humans, the blood-brain barrier, blood-cerebrospinal fluid barrier, and similar fluid–brain barriers distinct the peripheral immune system from the neuroimmune system, that safeguards the brain.
Parts of the Immune System
Many cells and organs work in collaboration to safeguard the body. White blood cells, also known as leukocytes, play a significant role in the immune system. Few types of white blood cells that are called phagocytes helps in chewing up invading organisms. While others, known as lymphocytes, assists to help the body remember the invaders and terminate them.
One of the crucial types of phagocyte is known as neutrophil that helps in fighting the bacteria. When an individual gets a bacterial infection, health care professionals can order a blood test to diagnose if it has resulted in lots of neutrophils. Remaining types of phagocytes perform their own tasks to ensure sure that the body responds to invaders.
The two main types of lymphocytes are B lymphocytes and T lymphocytes. Lymphocytes begin in the bone marrow and either stay there and mature into B cells or go to the thymus gland to develop into T cells. B lymphocytes are considered as the body’s military intelligence system. They look for their targets and send defences to lock onto them. T cells are considered as soldiers. They help in destroying the invaders that the intelligence system discovers.
How Does the Immune System Work?
When the body gets aware of any foreign substances (called antigens), the immune system immediately begins to works to recognize those antigens and finish them. B lymphocytes get active to make antibodies, also known as immunoglobulins. These proteins lock onto particular antigens. After they are built, antibodies normally stay inside the bodies, in case the situation to fight the same germ arise again. That’s the reason when someone gets sick with a particular disease like chickenpox, normally never get sick from it again.
The immune system in the human body is essential for survival. In case of absence of an immune system, the bodies would be open to getting harm from bacteria, viruses, parasites and many more. It is because of the immune system that sustains our healthy body as we drift through a sea of pathogens. This wide network of cells and tissues are consistently on the lookout for invaders, and once an enemy is observed, a complicated attack is mounted.
The immune system is spread throughout the entire body and includes many types of cells, organs, proteins, and tissues. Importantly, it can differentiate our tissue from foreign tissue. Dead and damaged cells are also recognized and removed away by the immune system. If the immune system senses a pathogen such as a bacterium, virus, or parasite, it mounts a so-called immune response.
White blood cells
White blood cells are also known as leukocytes. They circulate within the body in blood vessels and the lymphatic vessels that parallel the veins and the arteries. White blood cells are on continuous round searching for pathogens. When they discover the target, they start to reproduce and send signals out to other cell types to perform the same task. Our white blood cells are deposited in various places in the body, which are known as lymphoid organs. These incorporate the following:
Thymus: a gland among the lungs and just underneath the neck.
Spleen — an organ that screens the blood. It is located in the upper left of the abdomen.
Bone marrow — placed in the middle of the bones, it also builds red blood cells.
Lymph nodes —tiny glands situated throughout the body, connected by lymphatic vessel
The immune system and microbial infection
The immune system keeps a record of every microbe it has ever defeated, in types of white blood cells (B- and T-lymphocytes) known as memory cells. This means it can recognize and destroy the microbe quickly if it enters the body again before it can multiply and make you feel sick.
Some infections just like the flu or the common cold have to be fought several times as many different viruses of the same nature can cause these sicknesses. Catching a cold or flu from one virus does not give you immunity against the others.
Parts of the immune system
The main parts of the immune system include white blood cells, antibodies, complement system, lymphatic system, spleen, bone marrow, and thymus.
There are two subsystems within the immune system, namely the innate (non-specific) immune system and the adaptive (specific) immune system. Both of these subsystems are interconnected and work in collaboration whenever a germ or harmful element activates an immune response.
The innate immune system provides a general defence against harmful germs and substances, so it’s also called the non-specific immune system. It mostly fights using immune cells such as natural killer cells and phagocytes (“eating cells”). The main job of the innate immune system is to fight harmful substances and germs that enter the body, for instance through the skin or digestive system.
The adaptive (specific) immune system builds antibodies and utilizes them to particularly fight certain germs that the body has contact with in the past. Because the adaptive immune system is continuously learning and adapting, the body can also kill bacteria or viruses that transforms over time the passage of time.
How an Immune Response Works?
The immune system needs to be able to tell self from non-self. It does this by noticing proteins that are discovered on the surface of the entire cells in the body. It learns to ignore its self-proteins at the very initial stage.