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. Non-vital organs are those that a person can survive without. However, this does not mean that conditions affecting these organs are never life threatening or dangerous.
Many infections and cancers in non-vital organs are life threatening, especially without prompt treatment. Injuries to non-vital organs may also affect vital organs, such as when a gallstone undermines liver function. Small and pear shaped, the gallbladder sits in the right upper quadrant of the abdomen, just under the liver. It contains cholesterol, bile salts, bile, and bilirubin. In a healthy person, the liver releases bile into the gallbladder, which the gallbladder stores and then releases to travel down the common bile duct into the small intestine to aid digestion.
However, some people develop gallstones that block the gallbladder or biliary tree, causing intense pain and interfering with digestion. Also, this can sometimes interfere with liver or pancreas function. Learn about some potential gallbladder issues here. Located in the upper left portion of the abdomen, the pancreas has two important roles: It functions as both an exocrine gland and an endocrine gland.
As an exocrine gland, the pancreas produces enzymes a person needs to help digest their food and convert it into energy. Those enzymes include amylase, lipase, trypsin, and chymotrypsin. In its role as an endocrine gland, the pancreas also produces and releases insulin, which helps the body remove glucose from the blood and convert it into energy.
Problems with insulin can lead to a dangerously high level of blood glucose and the onset of diabetes. The main pancreatic duct connects to the common bile duct, which flows from the liver and gallbladder. The kidneys are two bean-shaped organs located at the back of the abdominal cavity, one on each side of the spinal column.
The heart is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. The stomach is a muscular, elastic, pear-shaped bag, lying crosswise in the abdominal cavity beneath the diaphragm.
Its main purpose is digestion of food through production of gastric juices which break down, mix and churn the food into a thin liquid. The intestines are located between the stomach and the anus and are divided into two major sections: the small intestine and the large intestine. The function of the small intestine is to absorb most ingested food. The large intestine is responsible for absorption of water and excretion of solid waste material. Explore the relationships between ideas about internal body organs in the Concept Development Maps Cell Functions.
It is useful to explore what internal organs look like and where they are located in order to understand the specific function of each and how each contributes to keeping the body alive and well. Teaching experiences should begin to encourage students to consider how organs work together, i.
This idea leads to the more complex idea that body parts form connected systems that contribute to the functioning of the body as a whole. Encourage students to work in small groups to create a common drawing of what they know about the inside of the human body. Consider providing each group with an outline of a human body or have students trace around a group member lying on a large sheet of paper.
Ensure students consider the location, size and shape of body parts in their drawings. Have students include labels naming each internal part and consider getting the groups to research information about each organ.
Provide each student group with at least three strips of paper. Display the questions and add further questions to the list as they arise from these discussions and observations.
As a class, complete a bundling activity sorting the questions. Although no one knows where the number originates, the general count is 78 organs, she said. This list includes the vital organs: the tongue, stomach , thyroid, urethra , pancreas , plus many other single or pairs of organs.
Bones and teeth are each counted only once. Among anatomists, viewpoints differ on what counts as an organ. A histologist like Lee, who studies tissue at the microscopic level, may have a longer list of organs than a gross anatomist, who studies what's visible to the unaided eye. For example, scientists made headlines in for labeling the mesentery , which attaches the intestines to the abdominal wall, as an organ. Even though the scientists provided new evidence to call it an organ, it was not controversial, as many histologists and anatomists agreed, Lee explained.
But there's no group charged with keeping an official count of the organs or deciding what qualifies as an organ. Thinking microscopically, when multiple types of tissues join together and function together, the unit is an organ, she said.
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.
0コメント