The Nervous SystemThe Nervous SystemFunctions of the Nervous

SystemCentral Nervous System

(NEURONS)Anatomy of a Neuron

Communication Between Neuron

Central Nervous System (BRAIN)

CEREBRUM

CEREBELLUM

Brain Stem

Central Nervous System

Peripheral Nervous System

Functions of the Nervous SystemFunctions of the Nervous System

1.1. Control center for all body activitiesControl center for all body activities2.2. Responds and adapts to changes that Responds and adapts to changes that

occur both inside and outside the bodyoccur both inside and outside the body (Ex: pain, temperature, pregnancy)(Ex: pain, temperature, pregnancy)

Central Nervous SystemCentral Nervous System

NeuronsNeurons : microscopic : microscopic nerve cells that make nerve cells that make up the brain, spinal up the brain, spinal cord, and nervescord, and nerves

- 30,000 neurons can fit - 30,000 neurons can fit on a pinheadon a pinhead

Anatomy of a NeuronAnatomy of a NeuronEach neuron contains:Each neuron contains: - - Cell bodyCell body with nucleus with nucleus - - DendritesDendrites : fibers that receive : fibers that receive

messages from other neuronsmessages from other neurons - - AxonsAxons : fibers that send messages : fibers that send messages

to other neuronsto other neurons

• Neurons do NOT touch; there is a Neurons do NOT touch; there is a gap between them called a gap between them called a synapsesynapse

• Messages are sent across the Messages are sent across the synapses by special chemicals synapses by special chemicals called called neurotransmittersneurotransmitters

• A

Communication Between Communication Between NeuronsNeurons

- The use of The use of neurotransmitters neurotransmitters causes an electrical causes an electrical currentcurrent

There is enough There is enough electrical current in electrical current in the brain to power a the brain to power a flashlightflashlight

Central Nervous SystemCentral Nervous SystemBrainBrain : a mass of 100 : a mass of 100

billion neurons located billion neurons located inside the skullinside the skull

-Learning occurs as more -Learning occurs as more and stronger and stronger connections are made connections are made between neuronsbetween neurons

CEREBRUMCEREBRUM

CerebrumCerebrum : largest part of : largest part of human brainhuman brain

- Responsible for:- Responsible for: - Thought- Thought - Language- Language - Senses- Senses - Memory- Memory - Voluntary movement- Voluntary movement

CEREBELLUMCEREBELLUMCerebellum : at base of

brain-Responsible for: - Muscle coordination - Balance - Posture

BRAIN STEMBRAIN STEMBrain StemBrain Stem : connects : connects

brain to spinal cordbrain to spinal cord-Responsible for:-Responsible for: - Breathing- Breathing - Swallowing- Swallowing - Heartbeat- Heartbeat - Blood pressure- Blood pressure

Central Nervous SystemCentral Nervous SystemSpinal CordSpinal Cord : Column of : Column of

nerves from brain to nerves from brain to tailbone – protected by tailbone – protected by vertebrae of spinevertebrae of spine

- Responsible for:Responsible for: - Conducting - Conducting

impulses between the impulses between the brain and the rest of brain and the rest of the bodythe body

*Impulses may travel as *Impulses may travel as

fast at 268 miles/hrfast at 268 miles/hr

Peripheral Nervous SystemPeripheral Nervous SystemNervesNerves : visible bundles of : visible bundles of

axons and dendrites that axons and dendrites that entend from the brain and entend from the brain and spinal cord to all other parts spinal cord to all other parts of the body of the body

-Responsibilities:-Responsibilities: - - Sensory nervesSensory nerves - carry - carry

messages from body to brain messages from body to brain (pain, pressure, temperature)(pain, pressure, temperature)

- - Motor nervesMotor nerves – carry – carry messages from brain to body messages from brain to body to respond to respond