1. C’EST QUOI LE SYSTÈME NERVEUX ? Définition : Le système nerveux est le système qui : • reçoit les informations du corps et de l’environnement • analyse ces informations • envoie des réponses rapides Rôle : ✔ détecter un danger ✔ bouger ✔ penser ✔ respirer ✔ sentir douleur / chaleur / lumière ⸻ 2. LES PARTIES DU SYSTÈME NERVEUX A. Système nerveux central (CNS) Contient : • cerveau • moelle épinière 👉 rôle : contrôle et coordination ⸻ B. Système nerveux périphérique (PNS) Contient : • tous les nerfs du corps 👉 rôle : transporter les messages entre corps et cerveau ⸻ 3. LES NEURONES (cellules nerveuses) Définition : Cellule spécialisée qui transporte les influx nerveux (messages électriques) ⸻ Structure du neurone : 1. Dendrites 👉 reçoivent le message 2. Corps cellulaire 👉 contient noyau 3. Axone 👉 transporte message loin du corps cellulaire 4. Gaine de myéline 👉 protège axone et accélère message 5. Nœuds de Ranvier 👉 permettent au message d’aller plus vite 6

What is the nervous system?

The system that receives information from the body and environment, analyzes that information, and sends rapid responses.

Function of the nervous system

Detect danger, move, think, breathe, feel pain/heat/light.

Central Nervous System (CNS)

Contains the brain and spinal cord, responsible for control and coordination.

Peripheral Nervous System (PNS)

Contains all the nerves in the body, responsible for transporting messages between the body and brain.

Neuron

A specialized cell that carries nerve impulses (electrical messages).

Dendrites

Part of a neuron that receives messages.

Axon

Part of a neuron that carries messages away from the cell body.

Myelin sheath

Protects the axon and speeds up the transmission of messages.

Nodes of Ranvier

Spaces along the axon that allow the message to travel faster.

Sensory neuron

Transmits messages from receptors to the brain or spinal cord.

Relay neuron

Transmits messages between neurons in the brain or spinal cord.

Motor neuron

Transmits messages from the brain or spinal cord to muscles or glands.

Receptors

Specialized cells that detect stimuli from the environment.

Stimulus

A change in the environment that can elicit a response.

Reflex

A rapid, automatic, involuntary response to a stimulus.

Reflex arc

The pathway that includes the stimulus, receptor, sensory neuron, relay neuron, motor neuron, effector, and response.

Synapse

The small space between two neurons.

Cerebrum

Part of the brain responsible for thought, memory, intelligence, language, and voluntary movements.

Cerebellum

Part of the brain responsible for balance, posture, and coordination of muscles.

Medulla oblongata

Part of the brain responsible for respiration, heartbeat regulation, and involuntary reflexes.

Hypothalamus

Part of the brain that regulates temperature, hunger, and thirst.

Pituitary gland

The master gland that controls hormones.

Spinal cord

Part of the nervous system that transmits impulses between the brain and body and controls reflexes.

Effector

An organ that carries out a response, such as a muscle or gland.

Response

The action performed by the body as a reaction to a stimulus.