How your body is organized Lesson 6 February 7th, 2011

How your body is organized All living things are made up of cells, but the organization of those cells is what makes multicellular organisms possible. Cells that join and work together are called tissues Example – the muscles that move your eyes are tissues Tissues that join together and work together are called organs Example – the heart is a major organ in the body Organs work together in systems The circulatory system includes organs such as the heart, blood, arteries and veins.

How your body is organized Cells, tissues, organs and systems work together to keep you alive. Each cell, tissue, and system is shaped and organized in a special way to help carry out its job. Example The digestive system has all the organs it needs to change food into energy your body can use.

Animal Tissue Types: (4 major types) Epithelial tissues Connective tissues Muscle tissues Nerve tissues Ended here

Epithelial Tissues The main purpose of epithelial tissues is to protect the organism from dehydration while also providing a resistance to friction. These thin sheets of tightly packed cells cover surfaces such as skin as well as the lining of internal organs.

Connective Tissue The main purpose of connective tissues is to provide support and insulation. These cells and fibers are held together by a liquid, a solid or a gel, known as a matrix.

Connective tissues are cells in a matrix Connective tissues are cells in a matrix. Blood cells course through the body in a fluid matrix. In fibrous connective tissue cells are scattered among the collagen fibers they secreted. In bone and cartilage, cells are scattered throughout the hard or pliable matrix.

Muscle Tissue The main purpose of muscles tissues is for the body to move. They are made of long, thin fibers that contain specialized proteins capable of shortening or contracting. Muscle tissues are of three types.

Striated Striated muscle cells are large, multinucleate, and column shaped cells; they are chiefly attached to the skeleton.

Smooth Smooth muscle cells are small and mononucleate; they are found in the walls of tubes such as blood vessels, glandular ducts, and the digestive system.

Cardiac Cardiac muscle cells of the heart are small, striated, and branched.

Nervous Tissue The main purpose of nervous tissues is to provide sensory sensations which allow for communication with the brain which allow for the coordination of body functions (including reactions). These thin cells with fine branches at the ends are capable of conducting electrical impulses. Nervous tissues consist of the neurons themselves that transmit impulses and the cells that act as supporting connective tissue in the brain and spinal cord.

Nervous Tissue

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