What is a Cell?

Trees in a forest, fish in a river, horseflies on a farm, lemurs in the jungle, reeds in a pond, worms in the soil — all these plants and animals are made of the building blocks we call cells. Like these examples, many living things consist of vast numbers of cells working in concert with one another. Other forms of life, however, are made of only a single cell, such as the many species of bacteria and protozoa. Cells, whether living on their own or as part of a multicellular organism, are usually too small to be seen without a light microscope. 

Cells share many common features, yet they can look wildly different. In fact, cells have adapted over billions of years to a wide array of environments and functional roles. Nerve cells, for example, have long, thin extensions that can reach for meters and serve to transmit signals rapidly. Closely fitting, brick-shaped plant cells have a rigid outer layer that helps provide the structural support that trees and other plants require. Long, tapered muscle cells have an intrinsic stretchiness that allows them to change length within contracting and relaxing biceps. 

Still, as different as these cells are, they all rely on the same basic strategies to keep the outside out, allow necessary substances in and permit others to leave, maintain their health, and replicate themselves. In fact, these traits are precisely what make a cell a cell.[cit. Nature.com]

How does our Brain work?

The brain performs an incredible number of tasks including the following:

• It controls body temperature, blood pressure, heart rate and breathing.
• It accepts a flood of information about the world around you from your various senses.
• It handles your physical movement when walking, talking, standing or sitting.
• It lets you think, dream, reason and experience emotions.

All of these tasks are coordinated, controlled and regulated by an organ that is about the size of a small head of cauliflower.
Your brain, spinal cord and peripheral nerves make up a complex, integrated information-processing and control system known as your central nervous system. In tandem, they regulate all the conscious and unconscious facets of your life. The scientific study of the brain and nervous system is called neuroscience or neurobiology. Because the field of neuroscience is so vast -- and the brain and nervous system are so complex -- this article will start with the basics and give you an overview of this complicated organ.
We'll examine the structures of the brain and how each section controls our daily functions, including motor control, visual processing, auditory processing, sensation, learning, memory and emotions. [Source: Craig Freudenrich, Ph.D. and Robynne Boyd]