nervous system

The Nervous SystemThe Nervous System

Functions of the Nervous SystemFunctions of the Nervous System

1.1. Control center for all body activitiesControl center for all body activities

2.2. 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 Neuron

Each neuron contains:Each neuron contains:

- - Cell bodyCell body with with nucleusnucleus

- - DendritesDendrites : fibers that : fibers that receive messages from receive messages from other neuronsother neurons

- - AxonsAxons : fibers that : fibers that send messages to other send messages to other neuronsneurons

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

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

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

Brain TeaserBrain Teaser

If you were running a race, and you passed If you were running a race, and you passed the person in 2the person in 2ndnd place, what place would place, what place would you be in now?you be in now?

SecondSecond

Two Major Divisions Two Major Divisions of the Nervous of the Nervous

SystemSystem


BrainBrain : 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

Anatomy of the BrainAnatomy of the Brain

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

Retrieval of a MemoryRetrieval of a Memory

A memory is not a A memory is not a snapshot stored in the snapshot stored in the brain – it must be put brain – it must be put together from together from information stored in information stored in various parts of the various parts of the brainbrain


Cerebellum : at base of brain

-Responsible for:

- Muscle coordination

- Balance

- Posture


Brain 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


Spinal 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


A H I M N O T U V W

Which of the letters above does not belong with the rest?

N It is not a mirror-image of itself

Peripheral Nervous SystemPeripheral Nervous System

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

-Responsibilities:-Responsibilities:

- - Sensory nervesSensory nerves - - carry messages from carry messages from body to brain (pain, body to brain (pain, pressure, temperature)pressure, temperature)

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


There is a town where 5% of all the people There is a town where 5% of all the people living there have unlisted phone numbers. living there have unlisted phone numbers. If you selected 100 names at random from If you selected 100 names at random from the town’s phone directory, on average, the town’s phone directory, on average, how many of these people would have how many of these people would have unlisted phone numbers?unlisted phone numbers?

0 They would not be in the phone book if 0 They would not be in the phone book if their number was unlistedtheir number was unlisted

nervous system

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