Lee could call a nail, or structures that support the nail, an organ, and count each tooth as an individual organ. It's loads more than you think. Counting each tooth separately brings the list to organs.
Many other organs are listed only once, even though there are many of them throughout the body. For instance, ligaments and tendons could dramatically increase the total number of organs when counted individually. This game is endless. The list of 78 counts the nerves just once, but there are trillions of them. Lee often tells her medical and graduate school students to be OK with this type of ambiguity.
However you count them, you should take care of the organs you do have, she added. After all, the body only has so many performers at its organ recital.
Dani Leviss is a freelance science writer who covers water, animals, art, chemistry and technology. Born and raised in New Jersey, Dani studied chemistry by day and edited the student newspaper at Drew University by night. She completed her master's degree in science journalism at NYU. When not writing, you'll find Dani walking her dog, painting or gardening.
Live Science. Dani Leviss. A problem with any of these organs can quickly become life threatening. It is not possible to live without these organs. That said, in the case of the paired kidneys and lungs, a person can live without one of the pair. It forms the core of the central nervous system by creating, sending, and processing nerve impulses, thoughts, emotions, physical sensations, and more. Neurologists are doctors who study the nervous system. Over time, they have identified numerous parts of the brain, including systems within the brain that function similarly to independent organs.
The brain is made up of three main subparts: the cerebrum, the cerebellum , and the brainstem. Within these areas, there are several key components of the brain that, together with the spinal cord, comprise the central nervous system.
The major areas of the central nervous system include :. The corpus callosum connects these two hemispheres. The heart is the most important organ of the circulatory system, which helps deliver blood to the body. It works with the lungs to add oxygen to blood and pump this freshly oxygenated blood through the blood vessels and around the body. The heart also has an electrical system within. Electrical impulses within the heart help ensure that it beats with a consistent rhythm and proper rate.
The heart rate increases when the body needs more blood, such as during intense exercise. It decreases during times of rest. The heart has four chambers. The two upper chambers are called atria, and the two lower chambers are called ventricles. Blood flows into the right atrium from the veins of the heart and body except the lungs , then it flows into the right ventricle.
From there, it flows into the pulmonary artery, which has branches that reach the lungs. The lungs then oxygenate the blood. This oxygenated blood travels from the lungs, through pulmonary veins that lead back and join together, to the left atrium, and then through the left ventricle. From there, the heart pumps the blood through an artery that branches to distribute blood to itself and other body parts except the lungs. The heart has four valves that ensure that blood flows in the right direction.
The heart valves are:. The lungs work with the heart to oxygenate blood. They do this by filtering the air a person breathes, then removing excess carbon dioxide in exchange for oxygen. Several parts of the lungs help the body take in air, filter it, and then oxygenate the blood. These are:. With extensive medical care, a person can live without one lung, but they cannot survive with no lungs. The diaphragm, which is a thick band of muscle directly under the lungs, helps the lungs expand and contract when a person breathes.
The liver is the most important organ of the metabolic system. It helps convert nutrients into usable substances, detoxifies certain substances, and filters blood coming from the digestive tract through a vein before it joins venous blood flow from other parts of the body. Oxygenated blood reaches the liver via an artery. The liver plays many roles in digestion and filtering the blood, including :. The liver partners with the gallbladder to deliver bile to the small intestine.
The liver pours bile into the gallbladder, which then stores and later releases the bile when the body needs it to help with digestion. The kidneys are a pair of bean shaped organs, and each is about the size of a fist. They are located on either side of the back, protected inside of the lower part of the rib cage. They help filter blood and remove waste from the body. Blood flows from the renal artery into the kidneys.
Each kidney contains about a million tiny units for filtration known as nephrons. They help filter waste to the urine and then return the filtered blood to the body through the renal vein.
The kidneys also produce urine when they remove waste from the blood. Urine flows out of the kidneys through the ureters, then down to the urinary bladder. A person can live with just one kidney. When a person is experiencing severe kidney failure, dialysis can filter the blood until they get a kidney transplant or their kidney recovers some function.
Some people need to undergo hemodialysis long term. Learn more about the kidneys here. This procedure hysterectomy stops women from having children and also halts the menstrual cycle in pre-menopausal women. Research suggests that women who have their ovaries removed do not have a reduced life expectancy. Interestingly, in some male populations, removal of both testicles may lead to an increase in life expectancy. The colon or large intestine is a tube that is about six-feet in length and has four named parts: ascending, transverse, descending and sigmoid.
The primary functions are to resorb water and prepare faeces by compacting it together. The presence of cancer or other diseases can result in the need to remove some or all of the colon. Most people recover well after this surgery, although they notice a change in bowel habits.
A diet of soft foods is initially recommended to aid the healing process. The gallbladder sits under the liver on the upper-right side of the abdomen, just under the ribs.
It stores something called bile. Bile is constantly produced by the liver to help break down fats, but when not needed in digestion, it is stored in the gallbladder. When the intestines detect fats, a hormone is released causing the gallbladder to contract, forcing bile into the intestines to help digest fat. However, excess cholesterol in bile can form gallstones, which can block the tiny pipes that move bile around. When this happens, people may need their gallbladder removed.
The surgery is known as cholecystectomy. Every year, about 70, people have this procedure in the UK. In , an Indian woman had 12, gallstones removed — a world record. The appendix is a small blind-ended worm-like structure at the junction of the large and the small bowel.
Due to the blind-ended nature of the appendix, when intestinal contents enter it, it can be difficult for them to escape and so it becomes inflamed. This is called appendicitis. In severe cases, the appendix needs to be surgically removed.
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