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Vision is the most important of the body’s five senses. it provides a means of understanding the world around, as well as facilitating communication. the visual sense are the organs are the eyes: they detect light, and send nerve impulses to the brain that interpreted as “seen” images.

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Endocrine glands are also known as ductless glands. They secrete hormones directly into the bloodstream. The endocrine glands I in both males and females are the same except for the testis (male) and the ovary (female). The majority of endocrine glands are controlled by the pituitary gland but some are stimulated by the nervous system or by chemical substances.

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The brain is made up of very soft and delicate tissues. It is protected from injury by the cranium and layers of membranes called meninges. The brain consists of two layers. The outer layer is called the grey matter and the inner layer is called the white matter. The grey matter is made up of cell bodies of neurons while the white matter consists of nerve fibers..

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The nervous system is extremely complex. It operates off two main types of cells and a combination of chemical and electrical signals. This article will introduce you to the basics.