The Sensory sysems -

Sensory systems

20 August, 2024

Draw

Give a check mark in the matrix for the senses that are used in each of the activities listed.

LESSON OBJECTIVES

1. Define the sensory nervous system and describe

the various types of receptors.

2. Summarize the common sensory systems relating

each to the type of receptor involved and basic
neural pathway.

Multiple Choice

Transmits nerve impulses; a neuron

• sensory receptor

• nerve cell

• brain

• behavior

• stimulus

THE SENSORY NERVOUS SYSTEM

A sensory system is the part of the
nervous system that detects and
processes information from the
environment.

consists of sensory neurons,
interneurons, and parts of the brain
involved in sensory perception

THE SENSORY NERVOUS SYSTEM

Common sensory systems are those
for vision, hearing, touch/pressure,
temperature, taste, smell, and
balance.

Multiple Choice

An organ with nerve endings that responds to stimulation

• sensory receptor

• nerve cell

• brain

• behavior

• stimulus

Parts of the brain are responsible for different senses

Stimuli - ( Stimulus - singular )

Stimulus: A stimulus is anything in the environment that causes a response or reaction
in an organism. It can be something you see, hear, smell, taste, or touch.

Touching a Hot Stove: When you accidentally touch a hot stove,
you quickly pull your hand away. The heat is the stimulus, and
pulling your hand away is the response.

Hearing a Loud Noise: If you hear a loud noise, you might jump or
feel startled. The loud noise is the stimulus, and your reaction
(jumping or feeling startled) is the response.

Smelling Food: If you smell delicious food, your mouth might start to
water. The smell of the food is the stimulus, and your mouth
watering is the response.

Smell can strongly elicit memories (olfactory memory)

SENSORY RECEPTORS
Sensory systems can detect
type, intensity, location, and
duration of stimuli.

Different types of sensory
neurons have different
sensory receptors that
respond to different kinds of
stimuli.

SENSORY RECEPTORS

The nervous system detects changes in our

environment (known as stimuli) through cells called

receptors.

When receptors detect certain stimuli, they
signal to the central nervous system (CNS)
through initiating an electrical impulse through
a neuron (nerve cell).

Multiple Choice

What receptor allows you to see a rainbow?

• Photoreceptor

• Thermoreceptor

• Mechanoreceptor

• Gravitonreceptor

Multiple Choice

What is a thermoreceptor?

• Responds to body position

• Responds to changes in temperature

• Responds to physical forces including touch and pressure

• Responds to squirrels running outside

Multiple Choice

Which receptor helps you hear your favorite band?

• Mechanoreceptor

• Band eceptor

• Thermoreceptor

• hearingreceptor

Multiple Choice

What receptor indicates change in body positions? (Hint: helps us with balance, walking, dancing, etc.)

• Geogravity receptors

• Proprioreceptors

• Chemoreceptors

• Photoreceptors

Multiple Choice

"You feel a mosquito biting your arm". This is because you have ....................... in your skin.

• Thermoreceptors

• Photoreceptors

• Mechanoreceptors

• Electroreceptors

MECHANORECEPTORS

Mechanoreceptors detect mechanical forces.

● touch
● Pressure
● Vibration
● Pain
● Sound Hair Cells in the Inner Ear:

These specialized mechanoreceptors are located
in the cochlea of the inner ear. They detect sound
waves (vibrations in the air) and convert them into
electrical signals that are sent to the brain,
allowing us to hear.

Touch receptors

Your inner ear has two tasks: Making it
possible for you to hear and helping you

keep your balance.

Semicircular canals help
maintain balance.

Semicircular canals
contain fluid and hair
cells.

Multiple Choice

The sense of equilibrium is maintained by the:

• Cochlea

• Semicircular canals

• Olfactory epithelium

• Retina

The hair cells is
mechanoreceptors
which sent to the
brain

CHEMORECEPTORS

Chemoreceptors detect
chemical stimuli:

● Smell (Odors are molecules in the air bind to these receptors,

sending signals to the brain that are interpreted as specific odors.)

● Taste (Sweet,Sour, Salty, Bitter, Umami (savory or meaty taste)
● Oxygen concentration (changes in the

levels of oxygen (O₂), carbon dioxide (CO₂), and the pH (acidity) of the blood.)

● Pain ( These receptors can detect certain chemicals

that come in contact with the skin, such as acids or toxins,
which might cause a sensation like burning or itching )

Multiple Choice

Which of the following is a primary taste sensation?

• Sour

• Bitter

• Umami

• All of the above

PHOTORECEPTORs
Photoreceptorsare specialized cells in the retina of the eye detect light,

allowing us to perceive images, colors, and the intensity of light.

Multiple Choice

The receptor cells responsible for vision are called:

• Olfactory cells

• Rods and cones

• Taste buds

• Hair cells

The iris is the colored part of the eye that surrounds
the pupil

the iris is a muscle that plays a crucial role in controlling the
amount of light that enters the eye by changing the size of
pupil

Iris relaxes (

dilate )

=> letting
more light

Iris contracts
=> letting less

light

Light travel through clear structure called the lenses.
The retina is an area at the back of the eye that has
photoreceptors

Photoreceptors includes:
●

Rod-cells : detect shapes

and low levels of light.
They are important for

night vision

●

Cone cells: detect colors
and function best in bright

light

Multiple Choice

The transparent, biconvex structure that focuses light on the retina is the:

• Cornea

• Lens

• Iris

• Sclera

Focusing light

The curved

shapes change
the direction of
light and focus it
onto the retina.

If the corneas or lenses are not curved exactly right, the
eyes will have trouble focusing image.

THERMORECEPTORS

Thermoreceptors detect varying temperature.

● body temperature
● pain

NOCICEPTORS

Nociceptors detect potentially damaging stimuli.

● temperature
● pressure
● chemical

Location: Nociceptors are found throughout the body, including the skin, joints,
muscles, bones, and internal organs. They are particularly abundant in areas where
injury is more likely to occur.

●

Mechanical Nociceptors: Respond
to physical damage, such as cutting or

pressure.

●

Thermal Nociceptors: Respond to
extreme temperatures, either hot or

cold.

●

Chemical Nociceptors: Respond to
chemicals, which may be released by
damaged tissues or present in harmful

substances.

2. How Nociceptors Work

●Detection of Pain:When a harmful stimulus (like a burn or a cut) occurs, nociceptors detect it and
generate electrical signals.

●Transmission to the Brain:These signals are then transmitted through nerve fibers to the spinal cord
and up to the brain.

●Pain Perception:The brain processes these signals and interprets them as pain, allowing you to recognize and

respond to the injury (e.g., pulling your hand away from a hot surface).

SENSORY SYSTEMS
VISUAL SYSTEM

Two types of photoreceptors in the eye detect visible light.

1. Rods are stimulated at

low levels of light and
detect shapes.

2. Cones are stimulated by

different wavelengths of
light and detect color.

VISUAL SYSTEM

Information is sent through the optic
nerve to the occipital lobe of the brain.

AUDITORY SYSTEM
Hair cells in the cochlea of the inner ear
are mechanoreceptors that are
stimulated by vibrations caused by
sound waves.

Information is sent through the auditory
nerve to the temporal lobe of the brain.

SOMATOSENSORY SYSTEM

The somatosensory system detects
changes at the surface or inside the
body.

● mechanoreceptors,

chemoreceptors, thermoreceptors,
and nociceptors all over the body

Information about touch and pain is
processed in the parietal lobe of the brain.

GUSTATORY SYSTEM

Chemoreceptors located in taste buds in
the mouth detect information about flavors.

Information is
sent to the frontal
lobe of the brain
by multiple
nerves.

OLFACTORY SYSTEM

Chemoreceptors in the nasal cavity detect
odors and information is received by the
olfactory bulb.

Multiple parts of the brain, including the
frontal lobe, process the information.

VESTIBULAR SYSTEM

Mechanoreceptors in the semicircular
canals of the inner ear detect balance and
rotational movements.

Information about balance is sent to the multiple
parts of the cerebellum and cerebrum by the
vestibular nerve.

ADDITIONAL RESOURCES

AumSum - How do ears help with balancing?

AumSum - Taste Buds

AumSum - How can we smell things?

Bozeman Science - Sensory System