Question

Explain about brain and its functions?

Answer 1

The nervous system is your body's decision and communication center. The central nervous system (CNS) is made of the brain and the spinal cord and the peripheral nervous system (PNS) is made of nerves. Together they control every part of your daily life, from breathing and blinking to helping you memorize facts for a test. Nerves reach from your brain to your face, ears, eyes, nose, and spinal cord... and from the spinal cord to the rest of your body. Sensory nerves gather information from the environment, send that info to the spinal cord, which then speed the message to the brain. The brain then makes sense of that message and fires off a response. Motor neurons deliver the instructions from the brain to the rest of your body. The spinal cord, made of a bundle of nerves running up and down the spine, is similar to a superhighway, speeding messages to and from the brain at every second.

The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.

The Cerebrum: The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Here is a visual representation of the cortex:

What do each of these lobes do?

Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solvingParietal Lobe- associated with movement, orientation, recognition, perception of stimuliOccipital Lobe- associated with visual processingTemporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech

Note that the cerebral cortex is highly wrinkled. Essentially this makes the brain more efficient, because it can increase the surface area of the brain and the amount of neurons within it. We will discuss the relevance of the degree of cortical folding (or gyrencephalization) later. (Go here for more information about cortical folding)

A deep furrow divides the cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. Thecorpus callosum is a bundle of axons which connects these two hemispheres.

Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body.

The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex which is only found in mammals. It is thought that the neocortex is a recently evolved structure, and is associated with "higher" information processing by more fully evolved animals (such as humans, primates, dolphins, etc). For more information about the neocortex, click here.

The Cerebellum: The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance.

The cerebellum is assumed to be much older than the cerebrum, evolutionarily. What do I mean by this? In other words, animals which scientists assume to have evolved prior to humans, for example reptiles, do have developed cerebellums. However, reptiles do not have neocortex. Go here for more discussion of the neocortex or go to the following web site for a more detailed look at evolution of brain structures and intelligence: "Ask the Experts": Evolution and Intelligence

Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old.

This system contains the thalamus, hypothalamus, amygdala, and hippocampus. Here is a visual representation of this system, from a midsagittal view of the human brain:

Answer 2

Simple definition of brain functioning : The brain controls all the functions of the body's organs, their functioning.

• The brain consists of the cerebrum, brainstem and cerebellum. It controls most of the body's activities, processes, integrates and coordinates information received from the senses, and makes decisions according to instructions sent to the rest of the body.

• The brain is contained and protected in the bones of the skull of the head.

• The human brain is the central organ of the human nervous system, and the spinal cord forms the central nervous system.

• The brain is not fully understood, and research continues.