The Human Body

 The Human Body

The human body is an intricate machine with unique systems that keep the body alive and well. Eleven organ systems within the human body work together to help digest food, control hormones, pump blood, remove waste from your cells, and other vital functions.

1) Digestive System

It comprises the alimentary canal and accessory organs. The alimentary canal begins at the mouth and ends at the anus, where solid waste is stored until it leaves your body. Along this digestive tract are three pairs of salivary glands that produce saliva to break down carbohydrates before they pass into the stomach, which stores and churns the food. The next stop is the small intestine, where much of your food’s nutrient absorption occurs. At the end of the small intestine, a valve-like structure called the ileocecal sphincter controls when waste and undigested fiber moves from the small intestine into the large intestine. When you eat a meal, your stomach churns it while secreting digestive juices and hormones to help break the food down. Once this work is done, undigested waste moves into the large intestine before it’s stored in your rectum until you go to the bathroom.

2) Excretory System

It comprises the organs that remove waste from the human body. This is your bladder and kidneys, which remove unwanted water from your blood, converting it to urine. The kidneys filter about a quarter of a liter of blood every minute, removing harmful wastes from your body. These wastes are then transported as urine from the kidneys through two tubes called ureters into your bladder until you go to the bathroom.

3) Respiratory System

It is the second of the two main defense mechanisms against disease-causing agents. It includes your lungs, trachea, bronchi, and alveoli, all of which work together to exchange carbon dioxide in the blood with oxygen in the air that you breathe. The main purpose of breathing is to bring oxygen into your body and release carbon dioxide, a waste product of cellular metabolism.

4) Circulatory System

It is responsible for transporting nutrients and oxygen to cells and removing wastes from the body tissues back to the kidneys. A network of blood vessels called arteries delivers freshly-oxygenated blood from the heart to all of your tissues and organs. This network is called a circulatory system because arteries carry blood away from your heart, and veins carry it back. Within this network are two systems that complete the circulatory system: the lymphatic system, which collects cellular waste for reuse or disposal, and the cardiovascular system, which includes the heart, arteries, veins, and blood.

5) Nervous System

It is responsible for relaying messages within the support network of your body. It includes your brain, spinal cord, nerves and ganglia, all of which work together to control every function in the human body, including movement, mental activity and hormone levels. This system is the control system of your body; without it, you wouldn’t be able to move a muscle or think a thought.

6) Immune System

It is responsible for protecting the human body from microbes and other harmful organisms. It includes lymph nodes, spleen, tonsils, adenoids, thymus, blood, bone marrow, lymphatic fluid and white blood cells. The immune system’s main function is to identify foreign invaders, like bacteria and viruses; neutralize them through antibodies, and dispose of dead cells.

7) Endocrine System

It is responsible for controlling vital bodily functions using hormones secreted by different glands in the body. It includes your pituitary gland, thyroid, parathyroid glands, pineal gland, hypothalamus, adrenal cortex and medulla gland. Each of these glands is responsible for secreting hormones throughout the human body, which directly impacts bodily functions, including metabolism, growth, sexual function, and mood.

8) Digestive System

It is the second of the two main defense mechanisms against disease-causing agents. It includes your mouth, esophagus, stomach, liver, gallbladder, pancreas, small intestine and large intestine. This system is responsible for breaking down all of the food you eat into tiny molecules that the rest of your body can absorb. The digestive system also absorbs necessary vitamins and minerals that can be used by the rest of your body while removing toxins and other waste products not needed by the human body.

9) Reproductive System

The reproductive system in both men and women is responsible for producing new offspring to continue the growth of our species. It includes the penis and testicles in men and the ovaries, fallopian tubes and uterus in women. These organs work together to produce sperm and egg cells and secrete sex hormones that direct sexual activities within the human body.

10) Skeletal System

The skeletal system gives your body its shape and supports all body parts. It includes your skull, jaw, teeth, ribs and sternum, and bones such as the femur, humerus, and spine, which are connected by joints that allow motion throughout the human body.

11) Urinary System

Finally, the urinary system is responsible for removing wastes from your blood and expelling them through urine. It includes your bladder, ureters, kidneys and urethra, all of which work together to remove toxins from the human body daily.