Table of ContentsChapter Preview

15.1 How the Nervous System Works

15.2 Divisions of the Nervous System

15.3 Sight and Hearing

15.4 Smell, Taste, and Touch

15.5 Alcohol and Other Drugs

Chapter 15 Preview Questions

1. Which part of the skeletal system protects the brain?

a. spine

b. pelvis

c. skull

d. joint

Chapter 15 Preview Questions

1. Which part of the skeletal system protects the brain?

a. spine

b. pelvis

c. skull

d. joint

Chapter 15 Preview Questions

2. Which muscles can you control voluntarily?

a. heart muscles

b. leg muscles

c. diaphragm

d. stomach muscles

Chapter 15 Preview Questions

2. Which muscles can you control voluntarily?

a. heart muscles

b. leg muscles

c. diaphragm

d. stomach muscles

Chapter 15 Preview Questions

3. What is the smallest unit of any body system?

a. structure

b. organ

c. tissue

d. cell

Chapter 15 Preview Questions

3. What is the smallest unit of any body system?

a. structure

b. organ

c. tissue

d. cell

Chapter 15 Preview Questions

4. What is the eye designed to receive from the environment?

a. light rays

b. vibrations

c. lenses

d. motion

Chapter 15 Preview Questions

4. What is the eye designed to receive from the environment?

a. light rays

b. vibrations

c. lenses

d. motion

You smell a delicious aroma. You walk into the kitchen and see a bag of popcorn in the microwave. You hear some kernels still popping. Then you think to yourself, “Snack time!” Which body systems enabled you to smell, walk, see, hear, and think? How did each system play a part in your response?

How do organs and other structures enable the nervous system to function?

Section 15.1: How the Nervous

System WorksWhat are the functions of the nervous system?What is the structure of a neuron and what kinds of neurons are found in the body?How do nerve impulses travel from one neuron to another?

 Jobs of the nervous system:

1. The nervous system receives information (Stimulus) about what is happening both inside and outside our bodies.

2. It directs how we react to our environment (Response)

3. It maintains homeostasis.

 

Kinds of NeuronsSensory Neurons: carries messages from receptors to the interneuron within the brain or spinal cord.

Interneurons: connect sensory and motor neurons. (brain and spinal chord)

Motor Neurons: sends impulses to muscles.

The Structure of a Neuron:

Cell body= with a nucleus

Dendrite = an extension that carries messages to the cell body.

Axon = carries messages away from the cell body.

 

How a Nerve Impulse Travels

A nerve impulse must cross the gap between the axon and the next structure this is the synapse

The axon tips release chemicals that carry

the impulse across

the gap.

Section 15.2: Divisions of the Nervous System

What are the structures and functions of the central nervous system?What are the structures and functions of the peripheral nervous system?What is a reflex?What are two ways in which the nervous system can be injured?

Divisions of the Nervous System

The Central Nervous System:

Control center of the body.

Brain and Spinal Cord

 

The Peripheral Nervous System:

Branches out and connects to the CNS

Somatic nerves control voluntary actions

Autonomic nerves control involuntary actions

 The Brain:

100 billion neurons (all interneurons)

3 main regions

 

Cerebrum:

largest

Two halves

Think/remember/speak

The senses

 

2. Cerebellum:

Balance

Posture

 

Brainstem/Medulla

Controls involuntary processes

Heartbeat/blood pressure

Breathing

Divisions of the Nervous System

The Central Nervous System:

Control center of the body.

Brain and Spinal Cord

 

The Peripheral Nervous System:

Branches out and connects to the CNS

Somatic nerves control voluntary actions

Autonomic nerves control involuntary actions

 

Central Nervous System

The central nervous system is the control center of the body. It includes the brain and spinal cord.

Peripheral Nervous System

• Branches out and connects to the CNS• Somatic nerves control voluntary actions• Autonomic nerves control involuntary

actions

 

The Brain There are three main regions of the brain

1. Cerebrum:• largest • Two halves• Think/remember/speak• The senses

 

2. Cerebellum:

Balance

Posture

 

3. Brainstem/Medulla

Controls involuntary processes

Heartbeat/blood pressure

Breathing

Reflexes

A reflex is an automatic response that occurs very rapidly and without conscious control.

Reflexes

A reflex is an automatic response that occurs very rapidly and without conscious control.

Section 15.3: Sight and Hearing

How do your eyes enable you to see?How do you hear and maintain your sense of balance?

Vision

You eyes respond to the stimulus of light. They convert that stimulus into impulses that your brain interprets, enabling you to see.

VisionLight coming from an object enters your eye and is focused by the lens.

The light produces an upside-down image on your retina.

Receptors in your retina then send impulses to your cerebrum, which turns the image right-side up.

Hearing and Balance

Your ears are the sense organs that respond to the stimulus of sound. Ears convert the sound to nerve impulses that your brain interprets.

Sound Intensity

Sound intensity, or loudness, is measured in units called decibels. The threshold of hearing for the human ear is 0 decibels. For every 10-decibel increase, the sound intensity increases ten times. Thus, a 20-decibel sound is ten times more intense than a 10-decibel sound. A 30-decibel sound is 100 times more intense than a 10-decibel sound. Sound levels for several sound sources are shown in the bar graph.

Sound Intensity

Decibels, or sound level; type of sound

Reading Graphs:

What unit of measure is represented on the y-axis? What is represented on the x-axis?

Section 15.4: Smell, Taste, and

Touch

What are the functions of the nervous system?What is the structure of a neuron and what kinds of neurons are found in the body?How do nerve impulses travel from one neuron to another?.

Touch

Touch receptors are the nerve cells that tell your brain about tactile sensations. There are two groups

(1) mechanoreceptors that tell you about sensations of pushing, pulling or movement,

(2) thermoreceptors that tell you about sensations of temperature.

SMELL

Smell and Taste

The senses of smell and taste work closely together.

Both depend on chemicals in food or in the air.

The chemicals trigger responses in receptors in the nose and mouth.

Section 5: Alcohol

and Other Drugs

What are the functions of the nervous system?What is the structure of a neuron and what kinds of neurons are found in the body?How do nerve impulses travel from one neuron to another?

Illegal (Controlled) DrugsMarijuana

Methamphetamine

Cocaine

Narcotics

Hallucinogens

Depressants

Steroids

Inhalants

Tobacco • Kills More than all Other

Drugs Combined! 430,000 + Every Year!

• Second Hand Smoke

• Cancer, Heart Attacks

• Smokers’ Face/Breath/Teeth

• No Safe Way To Use

Alcohol

Alcohol is a drug found in many beverages, including beer, wine, cocktails, and hard liquor. Alcohol is a powerful depressant and affects every system of the body.

Alcohol • Health Risk• Fitness for Duty• Accidents• Drinking & Driving• Violence / Family• Underage Drinking

Excessive Drinking can Cause Problems with... Work, Family, Friends, Society, and Self

ALCOHOL IS A DEPRESSANT-IT SLOWS THE ACTIONS OF THE CENTRAL NERVOUS SYSTEM.

Marijuana• Strong

• Available

• 30 Million Users

• Reputation as a “safe” drug

• 15 Times Stronger than ‘70s

• Keeps People from Achieving Their Potential

• Often Laced w/ Other Drugs

• Hooks into Fat Cells

Cocaine & MethamphetamineIncreases

• Heart Rate

• Blood Pressure

• Activity

• Insomnia,

• Euphoria followed by Depression

• Neural Disruption

• “Wired”, Addiction

COCAINE vs. Methamphetamine

Crack vs. ICECoke=> Shorter, Bigger Surge

Ice=> Voices & Bugs, Paranoia, Violence

Cocaine

• Highly Addicting

• Dealing & Stealing

• High Dying Potential

• Often in Up/Down Combos => w/ Heroin

Methamphetamine - “Ice”

• High Potential for Violence, Addiction, & Death

• The Drug of Choice in Hawaii

• 2-3 Months Addiction Time

• Losing One’s Mind & Will

Ecstasy (Methamphetamine) vs.

Herbal Ecstasy (Ephedrine)

Ecstasy: Powerful Stimulant &

Hallucinogen

HallucinogensTherapeutic Use

Street Abuse

Army Testing Begins in 1989

Users Easy to Spot

Effects= Focus, Distortions, Nausea, Disorientation, Performance , Communications , Panic, TRAUMA

Hallucinogens

Effects: Focus X, Distortions, Nausea, Disorientation, Performance X, Communications X, Panic, TRAUMA

Depressants1950’s - Sleeping Pills1960’s - Barbiturates(Seconal & Phenobarbital)

Slowed Down, Sleepy; Impaired Thinking, Coordination; MoodSwings, Stressed heart

NARCOTICS

The Naturals: Opium, Morphine, Heroin

The Synthetics: Percodan, Demerol, Codeine

InhalantsThe Hidden Addiction:

Readily Available => Gas, Glue, Sprays, Paint, Polish, Cleaning Fluid, Medications, Poppers, White Out, Scented Pens....

InhalantsEffects: Feeling Light-Headed, Light-Sensitive, Sores, Nose Bleeds => Organ Damage, Bone Marrow, Increasing Dysfunction, Withdrawal, Addiction, Overdose

Inhalants

Things to Remember:

Very Short High,

Very High Dosage Rate,

High Addiction & Overdose Potential

Anabolic SteroidsInvented in 1935 – SYNTHETIC CHEMICALS SIMILAR TO HORMONES

Widely Used & Promoted in the ‘50s

Discouraged Use - 1960-1990

Non-Athlete Use: 1990s

Anabolic Steroids

• Effects= Building Muscle Mass

• stronger and faster.

• Puffy Face, Acne, Jaundice,

• Organ Damage,

• ROID RAGE !#@*#!

“Long Term use = Death” Excess Use Causes Too Many Changes, Too Fast

For The Body to Handle

Drug Abuse

Drug abuse can have serious consequences. However, there are ways to tell if someone is abusing drugs and ways to help that person.