El sistema nervioso

 El sistema nervioso

Introducción

El sistema nervioso es una red compleja de nervios y células que transportan mensajes desde y hacia el cerebro y la médula espinal a diversas partes del cuerpo. Es responsable de coordinar todas las funciones corporales y las respuestas a los estímulos internos y externos.

El sistema nervioso se divide en dos partes principales:

1. Sistema Nervioso Central (SNC)

2. Sistema Nervioso Periférico (SNP) 

The Nervous System

Introduction

The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body. It is responsible for coordinating all bodily functions and responses to internal and external stimuli.

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Main Divisions

The nervous system is divided into two main parts:

1. Central Nervous System (CNS)

Components: Brain and spinal cord.

Function: Processes information and coordinates activities throughout the body.

Brain: Controls thoughts, memory, emotion, touch, motor skills, vision, breathing, and other vital functions.

Spinal Cord: Connects the brain to the rest of the body and controls reflexes.

2. Peripheral Nervous System (PNS)

Components: All the nerves that lie outside the CNS.

Function: Connects the CNS to limbs and organs.

Divided into:

Somatic Nervous System: Controls voluntary movements.

Autonomic Nervous System (ANS): Regulates involuntary body functions (e.g., heartbeat, digestion).

Sympathetic Division: Prepares the body for "fight or flight."

Parasympathetic Division: Promotes "rest and digest" responses.

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Neurons: The Functional Units

Structure: Consist of a cell body, dendrites, and an axon.

Function: Transmit electrical impulses.

Types of Neurons:

Sensory Neurons: Carry signals from sensory organs to the CNS.

Motor Neurons: Carry signals from the CNS to muscles and glands.

Interneurons: Connect neurons within the CNS.

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Neurotransmitters

Chemicals that transmit signals across synapses between neurons.

Common examples:

Dopamine: Involved in pleasure, movement, and motivation.

Serotonin: Affects mood, sleep, and appetite.

Acetylcholine: Involved in muscle activation and memory.

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Diseases of the Nervous System

Alzheimer’s Disease: Degeneration of brain cells causing memory loss.

Parkinson’s Disease: Affects movement due to low dopamine levels.

Multiple Sclerosis (MS): Immune system attacks the protective covering of nerves.

Epilepsy: Characterized by recurrent seizures due to abnormal brain activity.