Understanding Neurons and Nervous Systems

Neurons: The Basic Unit of the Nervous System

A neuron is the basic unit in the nervous system. It is a specialized conductor cell that receives and transmits electrochemical nerve impulses. A typical neuron has a cell body and long arms that conduct impulses from one body part to another.

Three Different Parts of the Neuron:

• The cell body
• Dendrites
• Axon

Types of Neurons

• Multipolar neurons have one axon and several dendrites. These are common in the brain and spinal cord.
• Bipolar neurons have one axon and one dendrite. These are seen in the retina of the eye, the inner ear, and the olfactory (smell) area.
• Unipolar neurons have one process extending from the cell body. The one process divides with one part acting as an axon and the other part functioning as a dendrite. These are seen in the spinal cord.

The Peripheral Nervous System

The Peripheral nervous system is made up of two parts:

• Somatic nervous system
• Autonomic nervous system

The Somatic Nervous System

The somatic nervous system consists of peripheral nerve fibers that pick up sensory information or sensations from the peripheral or distant organs and carry them to the central nervous system. These also consist of motor nerve fibers that come out of the brain and take the messages for movement and necessary action to the skeletal muscles. It receives external stimuli and coordinates body movements.

The Autonomic Nervous System

It is responsible for those functions that are not under conscious control. The autonomic nervous system can be classified into sympathetic, parasympathetic and enteric division.

The Forebrain

It consists of the cerebrum, which is the largest part of the brain and is the center of intelligence, memory, emotion, personality, speech and the ability to feel.

The outer layer of cerebrum is cortex, which receives the information collected by the sensory nerves and sends them to other regions of the brain for further processing. The inner part consists of the thalamus, hypothalamus and pituitary gland.

The thalamus transmits the messages from the sensory organ to the cortex, while the hypothalamus is responsible for regulating pulse, appetite and automatic processes. Pituitary glands secrete hormones that regulate growth, metabolism, sexual maturity and response to stress.

Our Five Senses:

• Sight (ver)
• Hearing (oir)
• Taste (sabor)
• Smell (olor)
• Touch (tocar)