Inside the Human Body
A human body has 10 major systems that work together to maintain homeostasis. These systems include the cardiovascular system, respiratory system, lymphatic system, muscular system, skeletal system, digestive system, nervous system, endocrine system, urinary system and reproductive system. Each has its own purpose in supporting a human being in its day-to-day activities, but some systems work so closely together they are often considered part of the same system. Let's briefly review these systems to better understand how they interact.
-
The Cardiovascular System, the Respiratory System and the Lymphatic System
-
The heart is the pump that circulates blood throughout the body. But the heart is nothing without the system of arteries, veins and capillaries in which the blood moves. The human body is a closed system, meaning that the blood that is in the body is continually circulating throughout the body. This continuous, controlled circulation is vital to homeostasis. The lymphatic system works in tandem with the cardiovascular system to prevent swelling in the body, to remove invading, life-threatening organisms from the blood and to transport fats and fat-soluble vitamins to the circulatory system. Where blood vessels exist, lymphatic vessels are always close by.
The respiratory system provides the breathing mechanism the circulatory system works with to maintain the supply of oxygen in the body. Oxygen is necessary for homeostasis. The respiratory system also removes waste created by our metabolic processes and regulates the blood's PH. The process of respiration is broken down into internal, external and cellular respiration.
The Muscular System and the Skeletal System
-
The internal frame of the body is the skeletal system. Made up of a series of bones referred to as a skeleton, the skeletal system's rigid structure is the framework upon which the other systems are attached. The skeletal system offers a level of protection for the softer parts of the body. It also gives the body a form. Attached to the skeleton and internal organs, the muscles have the responsibility of assisting the movement of the human body. Muscles contract, causing both obvious movement, like walking, and much more subtle movement, like smiling and breathing. Muscles work continually to maintain body posture and other stationary postures or positions.
-
The Digestive System
-
The digestive system includes digestion, absorption and elimination. The system breaks down food in order for it to be absorbed and used for fuel by the cells inside the body. The digestive system begins in the mouth. Included in the digestive system are the liver, the gallbladder and the pancreas. Enzymes play a large role in the breakdown of carbohydrates, proteins and fats.
The Nervous System
-
The nervous system is the controlling and regulating system within the body. It provides communication that maintains continual equilibrium (homeostasis) in the body. Central to its responsibilities is mental activity, including learning and memory. The spinal cord, the brain and all nerves are part of the nervous system's intricate ability to keep track of external and internal environments.
The Endocrine System
-
Regulating bodily activities through hormones, the endocrine system keeps track of growth, development and the metabolism inside the body. Endocrine glands secret a variety of hormones, each having a particular responsibility. Hormones flow directly into the bloodstream and influence cells that are designed to receive that particular type of hormone.
The Urinary System
-
Body fluids must be maintained by volume and composition. The urinary system rids the body of excess fluids in order to regulate the normal fluid limits. The urinary system also regulates electrolytes in fluids and assists in maintaining the pH of the blood and blood pressure. Secreting a hormone called erythropoietin, the urinary system maintains red blood cell output.
The Reproductive System
-
All other systems exist to maintain the individual human body. The reproductive system exists for several reasons--to maintain the survival of the species and to provide the hormones for the overall development of the individual from infant to adult. The reproductive system provides the egg and sperm cells necessary for reproduction, the ability to transport and sustain the egg and sperm, the environment for developing the offspring and the hormones for the growth of the embryo.
-
