Ear and hearing 2

 

✅ Easy to understand

• Uses plain, everyday language.
• Explains each part of the hearing process one step at a time.
• Doesn't overwhelm the reader with medical terminology.

✅ Good structure

It follows a logical order:

1. Sound is created.
2. The outer ear collects sound.
3. The eardrum vibrates.
4. The middle ear bones amplify the vibrations.
5. The cochlea converts vibrations into electrical signals.
6. The auditory nerve carries the signals.
7. The brain recognizes the sound.

That flow is exactly how many introductory psychology, biology, and anatomy textbooks explain hearing.

✅ Good illustrations

The diagrams are clear and not overcrowded. For many learners—including those with dyslexia, autism, or learning disabilities, or those who simply prefer visual learning—simple labelled diagrams can make information much easier to understand.

✅ Reliable source

The site is written and reviewed by audiology professionals and focuses on evidence-based hearing health information.

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For your book

Because your book is designed to be Easy Read and accessible, I think you could simplify it even further.

For example:

How We Hear

👂 Step 1
The outer ear collects sound.

⬇️

🥁 Step 2
The sound reaches the eardrum.
The eardrum begins to vibrate.

⬇️

🔨 Step 3
Three tiny bones amplify the vibrations.

• Malleus (Hammer)
• Incus (Anvil)
• Stapes (Stirrup)

⬇️

🐚 Step 4
The vibrations enter the cochlea.

Tiny hair cells inside the cochlea change the vibrations into electrical signals.

⬇️

🧠 Step 5
The auditory nerve carries the signals to the brain.

The brain understands the sounds we hear.

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I also like that the site avoids unnecessary technical detail while still being scientifically accurate. That's a good balance for your intended audience.

For your Level 1 materials, I would simplify the language slightly more than the website does. For your Level 2 materials, you could include additional topics such as:

• Different types of hearing loss (conductive, sensorineural, and mixed).
• How the cochlea detects different pitches.
• Hair cells and why they do not regenerate after damage.
• Hearing tests and audiograms.
• Hearing aids and cochlear implants.
• The vestibular system and its role in balance.

That approach would fit well with the accessible, educational style you've been developing throughout your psychology and health modules.

Understanding Hearing and the Ear

 

4

Hearing is the process by which sound waves travel through the ear and are changed into electrical signals that the brain can understand. Although the ears collect sound, it is the brain that recognizes and gives meaning to what we hear, such as voices, music, or warning sounds.

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Parts of the Ear

The ear has three main sections.

1. Outer Ear

The outer ear collects sound waves and directs them into the ear.

Main parts:

• Pinna (Auricle): The visible part of the ear that collects sound.
• Ear Canal: A narrow tube that carries sound waves to the eardrum.

Job:

• Collects sound.
• Helps identify where sounds are coming from.
• Protects the eardrum.

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2. Middle Ear

The middle ear is an air-filled space behind the eardrum.

Main parts:

• Eardrum (Tympanic Membrane): Vibrates when sound waves hit it.
• Malleus (Hammer): First hearing bone.
• Incus (Anvil): Second hearing bone.
• Stapes (Stirrup): Third hearing bone and the smallest bone in the human body.

These three tiny bones are called the ossicles.

Job:

• Amplify (make stronger) sound vibrations.
• Pass vibrations to the inner ear.

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3. Inner Ear

The inner ear changes sound vibrations into nerve signals.

Main parts:

• Cochlea: A spiral-shaped, fluid-filled structure containing thousands of tiny sensory hair cells.
• Auditory (Cochlear) Nerve: Carries electrical signals to the brain.
• Vestibular System: Helps with balance.

Job:

• Converts vibrations into electrical impulses.
• Sends information to the brain.
• Helps maintain balance.

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How We Hear

The hearing process happens in several steps.

Step 1: Sound Enters the Ear

Sound waves enter the outer ear and travel down the ear canal.

↓

Step 2: The Eardrum Vibrates

The sound waves hit the eardrum, causing it to vibrate.

↓

Step 3: Middle Ear Bones Move

The malleus, incus, and stapes vibrate together, making the sound stronger.

↓

Step 4: Vibrations Reach the Cochlea

The stapes pushes on the cochlea, creating waves in the cochlear fluid.

↓

Step 5: Hair Cells Respond

Tiny hair cells inside the cochlea bend as the fluid moves.

These hair cells convert mechanical vibrations into electrical signals.

↓

Step 6: Signals Travel to the Brain

The auditory nerve carries these electrical signals to the hearing areas of the brain.

↓

Step 7: The Brain Interprets the Sound

The brain identifies:

• Speech
• Music
• Environmental sounds
• Pitch (high or low)
• Loudness
• Direction of the sound

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What Is Sound?

Sound is made of vibrations travelling through the air.

Sound has two important characteristics:

Frequency

• Measured in Hertz (Hz).
• Determines the pitch of a sound.

Examples:

• Low frequency = Deep drum
• High frequency = Bird singing

Healthy young adults usually hear sounds from approximately 20 Hz to 20,000 Hz (20 kHz).

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Amplitude

• Measured in decibels (dB).
• Determines how loud a sound is.

Examples:

• Whisper: about 30 dB
• Normal conversation: about 60 dB
• Lawnmower: about 90 dB
• Rock concert: about 110 dB

Long exposure to sounds above 85 dB can damage hearing over time.

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Causes of Deafness and Hearing Loss

Hearing loss can happen for many reasons.

1. Genetic Causes

Some people are born with hearing loss because of inherited conditions or differences in ear development.

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2. Age-Related Hearing Loss

As people grow older, the delicate hair cells inside the cochlea naturally wear out.

This is called presbycusis.

Symptoms include:

• Difficulty hearing high-pitched sounds.
• Trouble understanding conversations, especially in noisy places.

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3. Noise-Induced Hearing Loss

Listening to loud sounds for long periods can permanently damage the cochlea's hair cells.

Examples include:

• Loud music
• Concerts
• Construction equipment
• Firearms
• Factory machinery

Hair cells do not grow back once they are damaged.

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4. Ear Infections

Infections can temporarily or permanently affect hearing.

Examples include:

• Middle ear infections (otitis media)
• Viral infections
• Meningitis

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5. Earwax Blockage

Too much earwax can block the ear canal and reduce hearing temporarily.

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6. Injury

Hearing loss may occur after:

• Head injuries
• Damage to the eardrum
• Skull fractures

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7. Certain Medicines

Some medicines can damage the inner ear. These are called ototoxic medications.

Examples include some:

• Antibiotics
• Chemotherapy drugs
• High doses of certain pain medicines

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8. Diseases

Some medical conditions may affect hearing, including:

• Diabetes
• Stroke
• Ménière's disease
• Autoimmune disorders

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Types of Hearing Loss

Type	Cause	Example
Conductive Hearing Loss	Problem in the outer or middle ear	Earwax, ear infection, damaged eardrum
Sensorineural Hearing Loss	Damage to the inner ear or auditory nerve	Aging, loud noise exposure, genetic conditions
Mixed Hearing Loss	Combination of conductive and sensorineural hearing loss	Infection plus age-related hearing loss

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Protecting Your Hearing

You can help protect your hearing by:

• Wearing ear protection around loud noise.
• Keeping headphone volume at safe levels.
• Taking breaks from loud environments.
• Treating ear infections promptly.
• Avoiding putting objects into the ear canal.
• Having regular hearing tests if you notice hearing changes.

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Key Points to Remember

• The ear has three parts: outer ear, middle ear, and inner ear.
• Sound waves travel through the ear and are converted into electrical signals.
• The cochlea contains tiny hair cells that detect sound.
• The auditory nerve carries hearing information to the brain.
• The brain is where sound is actually recognized and understood.
• Hearing loss may be conductive, sensorineural, or mixed.
• Common causes include aging, genetics, loud noise, infections, injuries, medications, and disease.
• Protecting your ears from excessive noise can help preserve hearing throughout life.

Hertz (Hz) and Human Hearing

 

What is Hertz (Hz)?

A Hertz (Hz) is the scientific unit used to measure frequency.

• 1 Hertz = 1 complete sound wave (cycle) per second

Frequency determines the pitch of a sound.

• Low frequency = Low pitch
• High frequency = High pitch

Examples

Frequency	Example Sound	Pitch
20 Hz	Thunder, earthquake rumble	Very low
60 Hz	Electrical hum	Low
100 Hz	Bass guitar	Low
440 Hz	Musical note A (concert pitch)	Medium
1,000 Hz	Human speech	Medium
5,000 Hz	Birdsong	High
15,000 Hz	Dog whistle	Very high
20,000 Hz	Highest sound most young people can hear	Extremely high

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Human Hearing Range

A healthy young person can generally hear sounds between:

20 Hz and 20,000 Hz (20 kHz)

This range changes throughout life.

Frequency Ranges

Frequency Range	Common Sounds
20–250 Hz	Thunder, bass guitar, kick drum
250–2,000 Hz	Most speech, piano, guitar
2,000–4,000 Hz	Consonants in speech (such as s, f, and t); this is where human hearing is most sensitive
4,000–20,000 Hz	Birds, whistles, cymbals, high musical notes

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Why Are Humans Most Sensitive Between 2,000 and 4,000 Hz?

The human ear is especially sensitive to frequencies between 2,000 Hz and 4,000 Hz because many of the sounds that make speech understandable fall within this range.

These frequencies include important consonants such as:

• S
• T
• F
• Sh

Damage to hearing in this range can make speech sound muffled, even if louder sounds are still heard.

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How Hearing Changes with Age

As we age, tiny sensory receptor cells called hair cells in the cochlea gradually become damaged or die.

Unlike many other cells in the body, human cochlear hair cells do not regenerate, so hearing loss is usually permanent.

The loss of high-frequency hearing with age is called presbycusis.

Typical Hearing Limits

Age	Highest Frequency Usually Heard*
Teenagers and young adults	Up to about 20,000 Hz
Around 40 years	About 15,000–17,000 Hz
Around 50 years	About 12,000–14,000 Hz
Older adults	May hear only up to 8,000–12,000 Hz

*These are typical averages. Individual hearing varies depending on genetics, health, medications, and noise exposure.

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What Causes Age-Related Hearing Loss?

Several factors contribute to presbycusis, including:

• Natural aging of cochlear hair cells
• Years of exposure to loud sounds
• Changes in blood supply to the inner ear
• Genetics
• Certain medications that can damage hearing (called ototoxic medications)

Because the hair cells that detect the highest frequencies are located near the base of the cochlea, they are often the first to be damaged.

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Noise-Induced Hearing Loss

Loud sounds can also permanently damage hair cells.

Examples include:

• Loud concerts
• Power tools
• Firearms
• Heavy machinery
• Listening to music at high volume through headphones or earbuds for long periods

Since hair cells do not regenerate, protecting your hearing is important.

Ways to Protect Your Hearing

• Keep headphone volume below about 60% of maximum when possible.
• Wear hearing protection in noisy environments.
• Take regular listening breaks.
• Limit the amount of time spent around loud sounds.

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Frequency vs. Loudness

People often confuse frequency and loudness, but they measure different properties of sound.

Measurement	Unit	What It Measures
Frequency	Hertz (Hz)	How high or low a sound is (pitch)
Loudness (Sound Intensity)	Decibels (dB)	How loud or soft a sound is

For example:

• A 100 Hz bass note and a 5,000 Hz bird chirp can be played at the same loudness (dB), even though they have very different pitches (Hz).

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Key Terms

• Hertz (Hz): One cycle of a sound wave per second; measures frequency.
• Frequency: The number of sound wave cycles per second; determines pitch.
• Pitch: How high or low a sound is perceived to be.
• Decibel (dB): A unit used to measure sound intensity or loudness.
• Hair cells: Sensory receptor cells in the cochlea that convert sound vibrations into electrical signals.
• Cochlea: A spiral-shaped, fluid-filled structure in the inner ear responsible for hearing.
• Presbycusis: Age-related hearing loss, particularly affecting high-frequency sounds.
• Noise-induced hearing loss: Permanent hearing damage caused by prolonged or intense exposure to loud sounds.

Psychology Exam Tip

Remember this simple rule:

• Hertz (Hz) = Pitch (high or low sound)
• Decibels (dB) = Loudness (soft or loud sound)

Keeping these two units separate will help you answer questions about hearing accurately.

5.5 The Other Senses – Study Notes

 

Learning Objectives

By the end of this section, you should be able to:

• Explain the chemical senses (taste and smell).
• Describe the somatosensory system (touch, temperature, pain, and body position).
• Understand pain perception.
• Explain vestibular and kinesthetic (kinesthesia) senses.

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The Chemical Senses

The chemical senses detect chemicals in our environment.

They are:

• Taste (Gustation)
• Smell (Olfaction)

These two senses work closely together. Much of what we think of as the "taste" of food actually comes from our sense of smell.

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Taste (Gustation)

Taste helps us identify foods and drinks.

Taste Receptors

Taste receptors are found inside taste buds on the tongue and other parts of the mouth.

Taste buds contain specialized receptor cells that detect chemicals dissolved in saliva.

When these receptors are stimulated, they send signals to the brain.

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The Five Basic Tastes

1. Sweet
   • Sugar
   • Honey
   • Fruit
2. Sour
   • Lemons
   • Vinegar
3. Salty
   • Salt
   • Pretzels
4. Bitter
   • Coffee
   • Dark chocolate
   • Some medicines
5. Umami (Savory)
   • Meat
   • Cheese
   • Mushrooms
   • Soy sauce

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Taste Pathway

1. Food dissolves in saliva.
2. Taste receptor cells are stimulated.
3. Signals travel along cranial nerves.
4. Information reaches the thalamus.
5. The gustatory cortex interprets the taste.

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Smell (Olfaction)

Smell detects chemicals carried through the air.

Olfactory Receptors

Located in the roof of the nasal cavity.

Odor molecules:

• dissolve in mucus
• bind to receptor cells
• create nerve impulses

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Smell Pathway

Unlike most senses, smell reaches the brain without first passing through the thalamus.

Signals travel to:

• Olfactory bulb
• Olfactory cortex
• Limbic system

Because smell connects strongly to the limbic system, odors often trigger vivid memories and emotions.

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Why Taste and Smell Work Together

When eating:

• Taste buds detect the basic tastes.
• Smell identifies the food's aroma.
• The brain combines both sensations to create flavor.

Example:

When you have a blocked nose during a cold, food often tastes bland because your sense of smell is reduced.

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The Somatosensory System

The somatosensory system allows us to detect sensations from our skin, muscles, joints, and internal tissues.

It includes:

• Touch
• Pressure
• Vibration
• Temperature
• Pain
• Body position

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Touch

Touch receptors are found throughout the skin.

Different receptors respond to:

• Light touch
• Deep pressure
• Stretch
• Vibration
• Texture

The brain combines information from many receptors to identify what we are touching.

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Temperature (Thermoception)

Special receptors detect:

• Heat
• Cold

These receptors help the body maintain a safe internal temperature and react to changes in the environment.

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Pain (Nociception)

Pain warns the body about injury or possible tissue damage.

Pain Receptors

Called nociceptors.

They respond to:

• Extreme heat
• Extreme cold
• Pressure
• Chemicals released during injury

Pain helps protect us from further harm.

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Gate Control Theory of Pain

Pain is not simply a direct signal from the body.

According to the Gate Control Theory:

• The spinal cord acts like a "gate."
• The gate can increase or reduce pain signals before they reach the brain.
• Thoughts, emotions, and touch can influence whether the gate is more open or closed.

Example:

Rubbing your elbow after bumping it may reduce pain because touch signals can partially "close the gate."

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Phantom Limb Pain

Some people who have had a limb amputated continue to feel pain or other sensations in the missing limb.

This is called phantom limb pain.

The brain continues to receive or generate signals associated with the missing body part.

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Kinesthesia (Kinesthetic Sense)

Kinesthesia tells us where our body parts are and how they are moving.

Receptors are located in:

• Muscles
• Tendons
• Joints

Examples:

• Walking without watching your feet
• Touching your nose with your eyes closed
• Typing without looking at the keyboard

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Vestibular Sense

The vestibular system helps maintain:

• Balance
• Equilibrium
• Head position
• Coordination

Structures

Located inside the inner ear.

Includes:

• Three semicircular canals
• Vestibular sacs (utricle and saccule)

Fluid movement inside these structures helps detect head movements and changes in position.

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Vestibular System Examples

The vestibular system helps you:

• Stand upright
• Ride a bicycle
• Walk on uneven ground
• Keep your balance while turning
• Stay oriented when moving

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How the Brain Uses Multiple Senses

The brain combines information from:

• Vision
• Hearing
• Touch
• Smell
• Taste
• Balance
• Body position

This process, called sensory integration, allows us to understand and respond effectively to our surroundings.

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Key Vocabulary

Term	Meaning
Gustation	Sense of taste
Olfaction	Sense of smell
Taste buds	Receptors for taste
Gustatory cortex	Brain area for processing taste
Olfactory receptors	Detect odor molecules
Olfactory bulb	First brain structure to process smell
Somatosensory system	Processes touch, pain, temperature, and body position
Thermoception	Sense of temperature
Nociception	Detection of harmful stimuli that can produce pain
Nociceptors	Pain receptors
Gate Control Theory	Theory that pain signals can be increased or decreased before reaching the brain
Phantom limb pain	Pain felt in a limb that has been amputated
Kinesthesia	Awareness of body position and movement
Vestibular sense	Sense of balance and head movement
Semicircular canals	Inner ear structures that detect head rotation
Utricle and saccule	Vestibular organs that detect gravity and linear acceleration

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Chapter Summary

The "other senses" extend beyond sight and hearing. Taste and smell are chemical senses that work together to create flavor. The somatosensory system lets us detect touch, pressure, temperature, pain, and body position. Kinesthesia allows us to know where our body parts are without looking, while the vestibular system helps us maintain balance and orientation. Together, these sensory systems provide the brain with the information needed to navigate and interact safely with the world.

The Auditory (Hearing) System

 

The auditory (hearing) system is a complex network that collects sound waves from the environment and converts them into electrical signals that the brain can understand. Hearing depends on the outer ear, middle ear, inner ear, the auditory nerve, and the brain working together.

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Anatomy and Function of the Hearing System

1. Outer Ear

Structures

• Pinna (Auricle) – the visible part of the ear
• External auditory canal (ear canal)

Function

The outer ear acts like a funnel.

It:

• Collects sound waves
• Directs sound into the ear canal
• Carries the sound to the eardrum (tympanic membrane)

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2. Middle Ear

Structures

• Tympanic membrane (eardrum)
• Three tiny bones called the ossicles:
  • Malleus (Hammer)
  • Incus (Anvil)
  • Stapes (Stirrup)

Function

When sound waves strike the eardrum:

• The eardrum vibrates.
• The ossicles amplify (strengthen) these vibrations.
• The stapes pushes against the oval window, passing the vibrations into the inner ear.

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3. Inner Ear

Structures

• Cochlea
• Basilar membrane
• Hair cells
• Organ of Corti

Function

The cochlea is a fluid-filled, spiral (snail-shaped) structure.

Inside the cochlea:

• Vibrations create waves in the fluid.
• These waves move the basilar membrane.
• Tiny hair cells bend.
• The bending of the hair cells converts mechanical vibrations into electrical nerve impulses.

This process is called transduction.

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4. Auditory Nerve and Brain

Structure

• Auditory (cochlear) nerve

Function

The auditory nerve carries electrical impulses from the cochlea to the brain.

The brain processes these signals in the auditory cortex, located in the temporal lobe, allowing us to recognize:

• Speech
• Music
• Environmental sounds
• Voices
• Direction of sound

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How Hearing Happens (Step by Step)

1. Sound waves enter the pinna.
2. They travel through the ear canal.
3. The eardrum vibrates.
4. The ossicles amplify the vibrations.
5. The stapes pushes on the oval window.
6. Fluid inside the cochlea moves.
7. Hair cells bend.
8. Hair cells convert vibrations into electrical signals (transduction).
9. The auditory nerve carries these signals to the brain.
10. The brain interprets the signals as meaningful sounds.

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Earwax (Cerumen)

Earwax is a natural substance that protects the ear.

What is Earwax?

Earwax (cerumen) is made from:

• Secretions from ceruminous glands
• Sebaceous (oil) glands
• Dead skin cells
• Tiny hairs
• Dust and dirt

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Functions of Earwax

Earwax helps to:

• Protect the ear canal
• Trap dust and insects
• Prevent bacteria and fungi from growing
• Lubricate the skin inside the ear
• Help clean the ear naturally

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Why Does Earwax Build Up?

Several factors can cause excessive earwax.

1. Producing Too Much Wax

Some people naturally make more earwax than others.

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2. Natural Cleaning Doesn't Work Well

Normally, chewing and talking slowly move earwax toward the ear opening.

If this process slows, wax builds up.

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3. Cotton Swabs

Cotton buds (Q-tips) often push wax deeper instead of removing it.

This can create an earwax blockage.

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4. Earbuds and Hearing Aids

Frequent use of:

• Earbuds
• Earplugs
• Hearing aids

can push wax deeper into the canal and may stimulate more wax production.

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Signs of an Earwax Blockage

Common symptoms include:

• Reduced hearing
• A feeling of fullness in the ear
• Earache
• Ringing in the ears (tinnitus)
• Itching
• Dizziness
• Occasionally coughing (due to stimulation of a nerve in the ear canal)

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Safe Ways to Remove Earwax

Most ears clean themselves naturally, so earwax usually does not need to be removed.

If removal is needed:

• Use ear drops designed to soften earwax.
• Irrigation (ear syringing) may be appropriate in some cases if recommended by a healthcare professional.
• Have stubborn wax removed by a healthcare provider using suction or specialized instruments.

Avoid:

• Cotton swabs
• Hairpins
• Keys
• Candles (ear candling)
• Any object inserted into the ear canal

These methods can push wax deeper or damage the ear.

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Quick Review Table

Part	Main Structures	Function
Outer ear	Pinna, ear canal	Collects and directs sound
Middle ear	Eardrum, malleus, incus, stapes	Amplifies vibrations
Inner ear	Cochlea, hair cells	Converts vibrations into electrical signals
Auditory nerve	Cochlear nerve	Carries signals to the brain
Brain	Auditory cortex (temporal lobe)	Interprets sound

Key Vocabulary

• Audition – Hearing.
• Cerumen – Earwax.
• Pinna (Auricle) – The visible outer part of the ear.
• Ossicles – The three tiny bones of the middle ear (malleus, incus, and stapes).
• Cochlea – A spiral-shaped, fluid-filled structure in the inner ear where sound vibrations are converted into nerve signals.
• Hair cells – Specialized sensory receptor cells that detect the movement of cochlear fluid.
• Transduction – The process of converting physical sound vibrations into electrical signals that the nervous system can interpret.
• Auditory nerve – Carries hearing information from the cochlea to the brain.
• Auditory cortex – The area of the temporal lobe that processes and interprets sound.