The Nervous System

HomeostasisWhat is it?

Homeostasis: the process of keeping internal conditions relatively constant.

The Nervous System

What does it do?

• Controls functions in the body

• responds to internal and external stimuli.

The Nervous System

What does it do?

• maintains homeostasis

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The Nervous System

What is it?

Nervous system:

• Complex network

of specialized cells that transmit messages in the body

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The Nervous System

Two halves• CNS = Central Nervous System• PNS = Peripheral Nervous System

The Nervous System

Two halves• CNS = Central Nervous System

–Brain–Spinal cord

The Nervous System

Two halves• CNS = Central Nervous System• PNS = Peripheral Nervous System

–Cranial nerves (nerves off brain)–Spinal Nerves (off the spinal cord)

The BRAIN

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Parts of the Brain• Cerebrum

–responsible for all voluntary activities

Parts of the Brain• Cerebrum

–Two hemispheres•Left and Right hemispheres

•Right hemisphere controls left side of body, left controls the right

Parts of the Brain

Parts of the Brain• Cerebrum

–Four lobes

Frontal lobe

Parietal lobe

Temporal lobe

Occipital lobe

• Cerebellum–means “little

brain”–controls

coordination–Let’s see how

well your cerebellum works…..

Parts of the Brain

• Brainstem– connects brain to

spinal cord

– Controls heart rate, breathing, and swallowing

– Also vomiting, hiccupping, coughing and sneezing

Parts of the Brain

• Parts of the Brainstem–Midbrain–Pons–Medulla

oblongatta

Parts of the Brain

Parts of the Brain

Parts of the Brain• Thalamus and Hypothalamus

Parts of the Brain• Thalamus: receives messages from the

sense organs

• Hypothalamus: control center for hunger, thirst, fatigue, anger and body temp.

• So, the hypothalamus maintains what?

Parts of the Brain

The Nervous System

• CNS = Central Nervous System–Brain–Spinal cord

• PNS = Peripheral Nervous System–Cranial nerves (nerves off brain)–Spinal Nerves (off the spinal cord)

Spinal Cord• Main communication link

between brain and rest of body• Protected by...• 31 pairs of nerves branch off• Reflex happens within the

spinal cord

the vertebral column

Reflex• When an impulse skips going to the brain and just

comes right back out the spinal cord

The Neuron

Start by labeling a neuron

Neurons:

Axon terminals

A nerve cell

3

1

2

4

5

Schwann’s cellsNode6

7

8

The Nerve ImpulseNerve Impulse: flow of electrical charges along the neuronStarts at the dendrite, travels to cell body or soma, down the axon and then the axon terminal. Then a neurotransmitter will carry the impulse across the synapse

The Neuron

Electrical flow of the nerve impulse:Dendrites Soma Axon Axon Terminals

The next slide shows what it will look like

when you put several neurons in a row (in other words a nerve)

The Neuron

Three types of neurons…

1. Sensory neuron– Sends impulse from sense organs toward

brain2. Motor neuron

– Away from brain/spinal cord to muscles/organs

3. Interneuron– Connect sensory to motor neurons– Found only in the spinal cord

Synapse• Gap between one

neuron and the next neuron

• Where the impulse jumps to the next neuron

Neurotransmitter:

Chemicals used to pass the impulse

Let’s label the picture:

Axon

Soma

Axon terminal

Neurotransmitter

Synapse

Transport protein

Neurotransmitter

Synapse

Neurotransmitters

One common neurotransmitter is: ACETYLCHOLINE

Cranial nerves

• Cranial nerves: nerves that branch directly off of the brain–Most of them are sensory

–Others are motor

1. Olfactory:2. Optic3. Oculomotor4. Troclear5. Trigeminal6. Abducens7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

1. Olfactory: smell2. Optic3. Oculomotor4. Troclear5. Trigeminal6. Abducens7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor4. Troclear5. Trigeminal6. Abducens7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal6. Abducens7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear: eye movement5. Trigeminal6. Abducens7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal: feeling in face (3 branches)6. Abducens7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear: eye movement5. Trigeminal: feeling in face (3 branches)6. Abducens:eye movement7. Facial8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal: feeling in face (3 branches)6. Abducens7. Facial: face movements, saliva, tear ducts8. Auditory (vestibulocochlear)9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal: feeling in face (3 branches)6. Abducens7. Facial: face movements, saliva, tear ducts8. Auditory/vestibulocochlear: hearing, balance9. Glossopharyngeal10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal: feeling in face (3 branches)6. Abducens7. Facial: face movements, saliva, tear ducts8. Auditory/vestibulocochlear: hearing, balance9. Glossopharyngeal: taste back 1/3 of tongue 10.Vagus11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal: feeling in face (3 branches)6. Abducens7. Facial: face movements, saliva, tear ducts8. Auditory/vestibulocochlear: hearing, balance9. Glossopharyngeal: taste back 1/3 of tongue 10.Vagus: control organs11.Accessory12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear5. Trigeminal: feeling in face (3 branches)6. Abducens7. Facial: face movements, saliva, tear ducts8. Auditory/vestibulocochlear: hearing, balance9. Glossopharyngeal: taste back 1/3 of tongue 10.Vagus: control organs11.Accessory: muscles of neck and shoulders 12.Hypoglossal

Cranial Nerves1. Olfactory: smell2. Optic: vision (forward and peripheral)3. Oculomotor: eye movement, constricts pupil4. Troclear: eye movement5. Trigeminal: feeling in face (3 branches)6. Abducens: eye movement7. Facial: face movements, saliva, tear ducts8. Auditory/vestibulocochlear: hearing, balance9. Glossopharyngeal: taste back 1/3 of tongue 10.Vagus: control organs11.Accessory: muscles of neck and shoulders 12.Hypoglossal: tongue movements

The Nervous System

• Central Nervous System (CNS) –Brain–Spinal cord

• Peripheral Nervous System (PNS)–Cranial nerves (nerves off brain)–Spinal Nerves (off the spinal cord)

Spinal Nerves

• Nerves that branch off the spinal cord

• ____ pair

• Travel to …

every part of the body

Cervical

Thoracic

Lumbar

Sacral

The Neuron

The Nervous System

• Central Nervous System (CNS) –Brain–Spinal cord

• Peripheral Nervous System (PNS)–Cranial nerves (nerves off brain)–Spinal Nerves (off the spinal cord)

All made of neurons

Neurons:

Axon terminals

A nerve cell

3

1

2

4

5

Schwann’s cellsNode6

7

8

The Nerve ImpulseNerve Impulse: flow of electrical charges along the neuron

The Neuron

Electrical flow of the nerve impulse:Dendrites Soma Axon Axon Terminals

The Neuron

Three types of neurons…

1. Sensory neuron– Sends impulse from sense organs toward

brain2. Motor neuron

– Away from brain/spinal cord to muscles/organs

3. Interneuron– Connect sensory to motor neurons– Found only in the spinal cord

Synapse• Gap between one

neuron and the next neuron

• Where the impulse jumps to the next neuron

Neurotransmitter:

Chemicals used to pass the impulse

Let’s label the picture:

Axon

Soma

Axon terminal

Neurotransmitter

Synapse

Transport protein

Neurotransmitter

Synapse

Virtual Pig Dissection