The heart pumps the blood to the lungs so it can pick up oxygen and then pumps oxygen-rich blood to the body The eye Structure and Function of the Eyes The structures and functions of the eyes are complex. Each eye constantly adjusts the amount of light it lets in, focuses on objects near and far, and produces continuous images that are instantly Even an organ as apparently simple as the gallbladder Gallbladder and Biliary Tract The gallbladder is a small, pear-shaped, muscular storage sac that holds bile and is interconnected to the liver by ducts known as the biliary tract.
See also Overview of the Liver and Gallbladder Merck and Co. From developing new therapies that treat and prevent disease to helping people in need, we are committed to improving health and well-being around the world. The Manual was first published in as a service to the community.
Learn more about our commitment to Global Medical Knowledge. This site complies with the HONcode standard for trustworthy health information: verify here. Here to help you with the most basic of all anatomical terms are the foundational building materials of the body: cells , tissues , and organs. These are the basis for the entire body. Once you have these down, we can move on to organ systems or get more specific, like the nervous system.
Cells are the smallest unit of life. To understand what a cell looks like, picture a chicken egg. It has an outer membrane in the case of an egg, it's a hard shell, but most cells aren't like that ; it's filled with nutrient-rich fluid whites of the egg versus cytoplasm in a cell and has a nucleus egg yolk.
Not all cells look alike. Nerve cells are long, thin and covered in myelin, natural insulation. Nerve cells conduct impulses, which are used to communicate. They're basically the telephone wires of the body, and they look the part. Muscle cells are thick and elongated, like live rubber bands.
Red blood cells are flat and discoid-shaped. The shapes of the cells help them with their individual functions. Each cell serves a specialized purpose in the body.
Muscle cells contract and nerve cells transmit impulses. Red blood cells bind to oxygen, while white blood cells fight infection. When cells of a certain type are grouped together, the resulting structure is called tissue. There is muscle tissue, which is made of strands of muscle cells. Adipose tissue is one layer of skin made of fat cells. Connective tissue is a term used for various types of tough, fibrous matter like tendons or ligaments.
Most of the time in first aid, we refer to tissues more than cells. Cells are typically microscopic, while tissues can be seen and manipulated.
When you look at a laceration to determine if it needs stitches , you are looking for adipose tissue in the wound.
Indeed, stitches hold together the tissue, not the individual cells. When different types of tissues are organized together to perform a complex function, it's called an organ.
The heart is an organ. It has muscle tissue, connective tissue, and nerve tissue all working together to pump blood. Most organs contain more than one tissue type. For example, the stomach consists of smooth muscle tissue for churning movement while it is innervated, but it is also supplied by blood, which is a connective tissue. The next level is the organ system level. Many organs working together to accomplish a common purpose create an organ system. For example, the heart and the blood vessels of the cardiovascular system circulate blood and transport oxygen and nutrients to all the body cells.
Levels of Organization : Molecules form cells. Cells form tissues, and tissues form organs. Organs that fulfill related functions are called organ systems. An organism is made up of interconnected organ systems. Privacy Policy.
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