Our bodies are made up of 11 basic organ systems that work together to manage all the functions that keep us healthy and alive. These systems, while interdependent, can become out of tune and when one is not functioning properly, the others will attempt to correct the problem and all the systems will work together to try to create what is known as homeostasis, a state of balance within the body. While none of the systems can work independently, they all carry out distinctive duties that manage specific areas of our bodily functions.
The 11 systems are made up of the integumentary system, skeletal system, muscular system, lymphatic system, respiratory system, digestive system, nervous system, endocrine system, cardiovascular system, urinary system, and reproductive systems.
Below is a description of the basic functions of each system as well as some of the diseases and disorders associated with each system. These lists are not complete and do not take the place of medical advice.
This system makes up the largest organ of the body equaling 15-20% of our total body mass. It acts as a barrier to physical, chemical, and biological agents. The skin prevents water loss and regulates body temperature, it transmits the senses of touch, pain, and pleasure, it maintains body temperature by secreting sweat and converts precursor molecules to vitamin D. The hair lubricates the scalp which secretes pheromones and cools or warms our heads. The nails protect our fingers, which are a major tool used for protecting ourselves and providing ourselves with food, shelter, and sensations. The skin leaves us most vulnerable when it is compromised by open wounds, allowing infectious agents into the body. Diseases and disorders associated with the integumentary system include acne, dermatitis, psoriasis, cellulitis, leukoderma, fungi, melanoma, scabies, chicken pox, male pattern baldness, and burns.
The skeletal system supports and protects the body’s internal organs. The ribs protect our abdominal organs, some of the most vulnerable to injury and most dangerous to our well being when injured. The skull protects our brain which controls all functions of our bodies and minds. The skeleton provides the framework and shape to our bodies. It also connects to our major muscles to allow movement. Bones store minerals such as calcium and create blood cells in the soft bone tissue called marrow. Bones can break easily when not provided with enough calcium and are subject to such diseases as arthritis, cancers, scoliosis, gout, bursitis, fractures and breaks.
- Cardiac muscles are found in the heart and power the actions that maintain blood flow through our body;
- Smooth, or involuntary muscles are found in the heart and organs, they surround the internal organs and are responsible for their movement such as moving food through the digestive tract; and
- Skeletal, or voluntary muscles, are responsible for carrying out the actions and movements caused by messages sent from our brains through our nervous system. Skeletal muscles are also responsible for maintaining posture and producing heat. When muscles lack appropriate levels of oxygen they can cramp and tear, creating pain. When not used they can atrophy and become useless. Diseases and disorders of the muscular system include botulism, muscular dystrophy, fibromyalgia, tendinitis, multiple sclerosis, and muscle strain or sprains.
This system transports clean fluids in our body back to the blood and drains excess fluids and debris from the tissues and cells of the body. It also houses the white blood cells (lymphocytes) involved in protecting our bodies from infection. Diseases and disorders specific to the lymphatic system include cancers, anaphylactic shock, mononucleosis, tonsillitis, lupus, Hodgkin’s disease, HIV/AIDs, allergies, and other autoimmune diseases.
This system maintains our breathing. It supplies the body with oxygen for cellular respiration by collecting oxygen in the lungs and disposes of carbon dioxide by breathing out the waste product. It also provides our functions of speech and smell. Diseases and disorders of the respiratory system include asthma, lung cancer, emphysema, COPD, pneumonia, laryngitis, TB, pulmonary and cystic fibrosis, bronchitis, influenza, and asbestosis.
Beginning with our mouths, teeth, and salivary secretions, it is responsible for the breaking down and absorption of nutrients and the elimination of the waste not utilized by the body. It is responsible for identifying which minerals, vitamins, and other essentials from the foods we eat can be absorbed and utilized or stored by the body and which are to be disposed of and carrying out those functions. Diseases and disorders of the digestive system include constipation, diarrhea, obesity, lactose intolerance, inflamed salivary glands, celiac disease, Crohn’s disease, ulcers, cirrhosis, colon cancer, hepatitis, and appendicitis.
This system is actually made up of two distinct parts; the central nervous system (CNS) and the peripheral nervous system. The central nervous system is made up of the brain and spinal cord and the peripheral nervous system is made up of all the nerves that lead into and out of the CNS to other parts of the body. The entire nervous system controls all of the other systems of the body such as digestion and cardiac rhythm and responds to internal and external changes such as activating muscles and breathing and transmits information to the brain such as pain and external sensations. Diseases and disorders of the nervous system include multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, Traumatic Brain Injury (TBI), PTSD and other mental health disorders, cerebal palsy, meningitis, epilepsy, Huntington’s disease, shingles, conjunctivitis, and glaucoma.
The glands of the endocrine system secrete chemicals called hormones that regulate most of the processes in our bodies such as growth, reproduction, metabolism, and even the control of the amount of glucose in our blood. Diseases and disorders of the endocrine system include Type 1 & Type 2 diabetes, hypoglycemia, Grave’s disease, goiter, hyper/hypothyroidism, thyroid cancer, Addison’s disease, growth disorders such as dwarfism, low testosterone, post partum depression.
The heart, made of cardiac muscle, pumps blood and blood vessels such as arteries and veins, transport the blood to every part of our body providing organs and muscles with nourishment. The blood carries oxygen, carbon dioxide, nutrients, waste and more throughout the body. Diseases and disorders associated with the cardiovascular system include myocardial infarction, angina, aneurysm, cardiovascular disease, ischemic heart disease, endocarditis, high blood pressure, mitro valve prolapse, sepsis and septic shock, hemorrhagic fevers, malaria, congenital heart disease, coronary artery disease, Rheumatic fever, stroke, gangrene, and plague.
This system is responsible for eliminating waste products of metabolism and other materials from the body that are of no use. The system is also responsible for maintaining the balanced fluid volume in our bodies by regulating the amount of water that is excreted, maintaining the concentrations of electrolytes, and normal pH levels of the blood. Diseases and disorders of the urinary system include nephrosis, bladder cancer, urethritis, bedwetting (enuresis), urinary and kidney stones and infections, renal failure, incontinence, blood in the urine, and interstitial cystitis.
MALE (prostate gland, penis, testis, scrotum, ductus deferens)
FEMALE (Mammary glands, ovary, uterus, vagina, fallopian tube)
The reproductive system is mainly to create human life. Semen and sperm are produced by the male testes. Male ducts and glands help deliver the sperm. Ovaries produce female sex hormones and eggs. Eggs are fertilized in the fallopian tube by sperm then travel to the uterus, which provides the site for growth. The mammary glands produce milk for the newborn. Diseases and disorders associated with the reproductive systems include prostate, ovarian, breast, testicular and cervical cancers, endometriosis, infections of the reproductive tract, impotence, hypogonadism, ectopic pregnancy, sexual disorders, and dysmenorrhea.
No one system can work without the others in order to maintain balance. When one system fails, the others attempt to regain balance by compensating for the failure, for example, if the cardiac system is failing because the heart is not pumping enough blood, which carries oxygen to the body, the other systems will kick in to compensate. The nervous system alerts the muscular system to cause the diaphragm to contract the lungs, causing the respiratory system to breathe more air, increasing the body’s intake of oxygen, in an attempt to get more oxygen to the blood. When the pancreas fails to regulate blood sugar, the nervous system makes the digestive system thirsty and increases the body’s fluid intake; the urinary system, in turn, increases the body’s fluid output in an effort to flush out the glucose. By working together, the systems are always attempting to maintain the body’s perfect balance.