Nervous system
The hypothalamus, in the brain, is the center of the central nervous system, where stimuli from the different parts of the body are sent. It is the hypothalamus that recognizes these stimuli, and then initiates a respond appropriate for that specific stimulus.
An example is when the body is hypoglycemic, the low concentration of glucose in the body would be the stimulus recognized by the hypothalamus. It would then initiate the pancreas to secrete more glucagon so that blood sugar concentration would increase. The nervous system is composed of the spinal cord and the brain, which is composed of neurons and neuralgia.
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Circulatory system
This is responsible in bringing blood and essential nutrients to the different parts of the body. It is composed of the heart, the veins and the arteries that transport blood for the survival of the human body.
The blood contains cellular elements (red blood cells, white blood cells, platelets) that are crucial for maintaining life. When a person loses large volumes of blood, he can bleed to death. That is how crucial the circulatory system’s function is.
Excretory system
The body has to excrete the toxic waste products of the body to allow proper functioning of the organs. The major organs involved in excretion are the kidneys. The kidneys are also responsible in maintaining the critical 7.35 to 7.45 pH (alkalinity or acidity) of blood.
This slight alkalinity of the body makes it possible for the normal function to occur. When the body’s pH is increased or decreased from the normal, conditions result which could cause coma and eventually death. The kidneys could maintain the normal pH through the retention and excretion of bicarbonate and hydrogen ions, and through the excretion of acidic waste products of metabolism.
Muscular system
This system provides the muscular structure and support for the body. Through the muscular system, man could move and function well. He is able to flex his arms, stand straight and lift weights because of his muscles. There are several types of muscles, such as, skeletal, cardiac, voluntary and involuntary; each with its specific role in the human body.
Digestive system
It includes the mouth, the esophagus, the stomach, the small and large intestines and the rectum. Without this system the food that people eat would not be digested. It also allows the essential nutrients from foods to be absorbed by the intestinal villi in the small intestines.
Skeletal system
This provides the skeleton of the body where the muscles and organs are housed. It also protects major organs, namely, the brain, the heart, lungs, kidneys and the digestive organs. It provides support for the whole body, and also in locomotion.
Integumentary system
The integumentary system is the skin, which is the largest organ of the body. It protects all the internal organs, including the muscles, from invading foreign substances. It also acts as a thermal regulator, preserving the human body’s temperature. Without the skin, the body would be easily invaded by infectious microorganisms and toxic substances, too.
Endocrine system
This involves the ductless glands which secrete hormones directly into the bloodstream. These hormones are responsible for important body functions like the maintenance of blood sugar concentration through insulin and glucagon; the growth and development of the body through growth hormone, thyroxine and triiodothyronine.
Respiratory system
This involves the lungs, which are responsible in respiration. Through the lungs man breathes in oxygen and exhales carbon dioxide. Body cells could obtain oxygen so they could perform their biological functions well.
These are some of the systems involved in the human body and how the body systems work. All of them are interdependent on each other and are expected to perform their functions in conjunction with the function of the other organs.
