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Chapter 35 –

The Nervous System

Section 35-1

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35–1 Human Body Systems

A. Organization of the Body

1. Cells – specialized!

2. Tissues

a. Epithelial

b. Connective

c. Nervous

d. Muscle

3. Organs – made of all 4 tissues!

4. Organ Systems – there are ELEVEN!

B. Maintaining Homeostasis

1. A Nonliving Example

2. In the Body – 37C (98.6F)

a. Hypothermia (under heat)

b. Hyperthermia (over heat)

Section 35-1

Section Outline

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Room temperature increases

Thermostat senses temperature

change and switches on heating

system

Thermostat senses temperature

change and switches off heating

system

Room temperature decreases

Section 35-1

Examples of Feedback Inhibition

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Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Section 35-1

Figure 35-2 Human Organ Systems Part I

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Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Section 35-1

Figure 35-2 Human Organ Systems Part I

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Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Section 35-1

Figure 35-2 Human Organ Systems Part I

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Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Section 35-1

Figure 35-2 Human Organ Systems Part I

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Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Section 35-1

Figure 35-2 Human Organ Systems Part I

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Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Section 35-1

Figure 35-2 Human Organ Systems Part 2

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Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Section 35-1

Figure 35-2 Human Organ Systems Part 2

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Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Section 35-1

Figure 35-2 Human Organ Systems Part 2

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Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Section 35-1

Figure 35-2 Human Organ Systems Part 2

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Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Section 35-1

Figure 35-2 Human Organ Systems Part 2

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Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Section 35-1

Figure 35-2 Human Organ Systems Part 2

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35–2 The Nervous System

A. Neurons – cells that transmit impulses – bundles of neurons

make up nerves

(**structure next slide**)

1. Sensory – from environment to brain

2. Motor – from brain to muscles & glands

3. Interneurons – connect sensory & motor

B. Parts of a Neuron

1. Cell Body – nucleus here; most metabolic activity

2. Dendrites – small “branches”

3. Axon – a long “tail”

4. Myelin sheath – creates gaps called nodes

Section 35-2

Section Outline

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Axon terminals

Myelin sheath

Nodes

Cell body

Axon

Nucleus

Dendrites

Section 35-2

A Neuron

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35–2 The Nervous System (continued)

C. The Nerve Impulse

1. The Resting Neuron – balance of sodium and potassium

ions in cell (sodium out; potassium in) **next slide**

2. The Moving Impulse – begins with a stimulus from

environment or another neuron **advance 2 slides**

3. Threshold – all or nothing **domino example**

a. A few milliseconds after firing a neuron cannot receive

an impulse and then requires a stronger impulse to fire

again – only a few milliseconds before back to “normal”

Section 35-2

Section Outline

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Section 35-2

Figure 35-6 Resting Potential

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Section 35-2

Figure 35-7 An Impulse

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Section 35-2

Figure 35-7 An Impulse

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Section 35-2

Figure 35-7 An Impulse

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Section 35-2

Figure 35-7 An Impulse

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35–2 The Nervous System

C. The Nerve Impulse

1. The Resting Neuron – balance of sodium and potassium

ions in cell (sodium out; potassium in)

2. The Moving Impulse – begins with a stimulus from

environment or another neuron

3. Threshold – all or nothing

D. The Synapse

1. Axon to dendrite – between neurons

2. Use neurotransmitters to send impulse

Section 35-2

Section Outline

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Vesicle

Axon

Axon

terminal

Synaptic cleft

Neurotransmitter

Receptor

Dendrite of

adjacent neuron

Direction of Impulse

Section 35-2

Figure 35-8 The Synapse

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35–3 Divisions of the Nervous System

A. The Central Nervous System

1. Brain & Spinal Cord

2. Wrapped in meninges & surrounded by

cerebrospinal fluid

B. The Brain

1. The Cerebrum – voluntary activities of the brain

2. The Cerebellum – coordinates muscles

3. The Brain Stem – controls unconscious activity

a. Pons – upper part – sensory control

b. Medulla Oblongata – lower part – unconscious

control

4. The Thalamus and Hypothalamus

Section 35-3

Section Outline

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35–3 Divisions of the Nervous System (continued)

C. The Spinal Cord

D. The Peripheral Nervous System

1. Sensory

2. Motor

1. The Somatic Nervous System

2. The Autonomic Nervous System

1. Sympathetic

2. Parasympathetic

Section 35-3

Section Outline

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Concept Map

which consists of

is divided into

that make up

which is divided into

Section 35-3

The Nervous

System

Sensory

nerves Motor

nerves

Autonomic

nervous system

Somatic nervous

system

Central nervous

system

Peripheral

nervous system

Sympathetic

nervous system

Parasympathetic

nervous system

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Pons

Pituitary gland

Hypothalamus

Cerebrum

Medulla oblongata Spinal cord

Cerebellum

Pineal

gland

Thalamus

Section 35-3

Figure 35-9 The Brain

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Spinal nerve

Central canal Gray matter

White matter

Meninges

Section 35-3

Cross Section of the Spinal Cord

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Section 35-3

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35–4 The Senses

A. Vision

B. Hearing and Balance

1. Hearing

2. Balance

C. Smell and Taste

D. Touch and Related Senses

Section 35-4

Section Outline

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Choroid

Retina

Blood vessels

Optic nerve

Fovea

Vitreous humor

Sclera

Ligaments

Iris

Pupil

Cornea

Aqueous humor

Lens

Muscle

Section 35-4

Figure 35-14 The Eye

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Cerebral cortex

Nasal cavity

Taste bud

Smell

sensory area

Taste

sensory

area

Thalamus

Olfactory

(smell) bulb

Olfactory

nerve

Smell

receptor

Taste

pore

Taste

receptor

Sensory

nerve fibers

Section 35-4

The Senses of Smell and Taste

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Auditory canal

Tympanum Round window Eustachian tube

Bone

Cochlea

Cochlear nerve

Semicircular canals

Oval

window Stirrup Anvil

Hammer

Section 35-4

Figure 35-15 The Ear

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35–5 Drugs and the Nervous System

A. Drugs That Affect the Synapse

1. Stimulants

2. Depressants

3. Cocaine

4. Opiates

5. Marijuana

6. Alcohol

7. Alcohol and Disease

B. Drug Abuse

Section 35-5

Section Outline

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Used to increase alertness,

relieve fatigue

Used to relieve anxiety,

irritability, tension

Used to relieve pain

Stimulants

Depressants

Opiates

Amphetamines

Barbiturates

Tranquilizers

Morphine

Codeine

Increase heart and respiratory rates;

elevate blood pressure; dilate pupils;

decrease appetite

Slow down the actions of the central

nervous system; small amounts cause

calmness and relaxation; larger

amounts cause slurred speech and

impaired judgement

Act as a depressant; cause

drowsiness, restlessness, nausea

Section 35-5

Commonly Abused Drugs

Drug Type Medical Use Examples Effects on the body

Internet

Go Online

The latest discoveries in the nervous and immune systems

Interactive test

Articles on the human body

For links on the nervous system, go to www.SciLinks.org and enter the Web Code as follows: cbn-0352.

For links on the human brain, go to www.SciLinks.org and enter the Web Code as follows: cbn-0353.

For links on the senses, go to www.SciLinks.org and enter the Web Code as follows: cbn-0354.

For links on drugs and drug abuse, go to www.SciLinks.org and enter the Web Code as follows: cbn-0355.