SENSES

Ability to perceive stimuli

Sense

Conscious awareness of stimuli received by sensory neurons

Sensation

Sensory nerve endings that respond to stimuli by developing action potentials

Sensory receptors

Receptors distributed over a large part of the body

General senses

Receptors localized within specific organs

Special senses

Receptors found throughout the body, including joints and organs

General senses

Specialized receptors located in specific organs: eye, ear, nose, mouth

Special senses

What are the types of senses?

• General senses

• Somatic senses

• Visceral senses

• Special senses

This type of sense provide information about body and environment.

Somatic senses

Information from skin, muscles, and joints and organ capsules.

Somatic senses

This type of sense provide information about internal organs, blood, and body fluids

Visceral senses

What are the types of information under somatic senses?

• Touch

• Pain (nociception)

• Temperature

• Proprioception

What are the types of information (examples) under visceral senses?

• Blood pressure

• pH of fluids

• Osmolarity of fluids

• Stretch receptors in organs

Name the special senses

Smell, taste, sight, hearing, and balance

Name the types of sensory receptors

• Thermoreceptors

• Nociceptors

• Mechanoreceptors

• Photoreceptors

• Chemoreceptors

Where are nociceptors located?

All tissues and organs except the brain

Where are mechanoreceptors located?

Skin, ears, muscles

Where are photoreceptors located?

Eyes

Where are chemoreceptors located?

Tongue, nose

Where are thermoreceptors located?

Skin, hypothalamus

This sensory receptors detect temperature changes

Thermoreceptors

Sensory receptors that detect pain

Nocireceptor

Sensory receptors that detect movement

Mechanoreceptors

Sensory receptors that detect light

Photoreceptors

Sensory receptors that detect chemicals, like odors and taste

Chemoreceptors

What are the types of mechanoreceptors?

• Hair follicle receptors

• Pacinian corpuscle

• Meissner corpuscle

This type of mechanoreceptor is extremely sensitive and detects light touch

Hair follicle receptors

This type of mechanoreceptor is the deepest receptor, associated with tendons and joints, and can detect deep pressure, vibration, and position

Pacinian corpuscle (lamellated)

This type of mechanoreceptor is located deep in the epidermis and have a localizing tactile sensations.

Meissner corpuscle

What are the types of touch receptors?

Merkel's disk and ruffini corpuscle

This type of touch receptors detect light touch and superficial pressure

Merkel's disk (tactile disks)

What's another term for Merkel's disk?

Tactile disks

Type of touch receptors that is located deep in the epidermis; detects continuous pressure on the skin.

Ruffini corpuscle

An unpleasant perceptual and emotional experience

Pain

Pain can be localized, how?

• Sharp, pricking, cutting pain

• Rapid action potential

Pain can be diffused, how?

• Burning, aching pain

• Slower action potentials

Perception of pain location differs depending on the?

Depending on the types of receptors involved

Superficial pain sensations in the skin are?

Highly localized; simultaneous stimulation of pain receptors and tactile receptors.

Highly localized and simultaneous stimulation of pain receptors and tactile receptors.

Superficial pain sensations on the skin

Not highly localized; absence of tactile receptors in the deeper structures.

Deep or visceral pain sensations

Pain control with action potentials that are suppressed from pain; chemicals are injected near sensory nerve

Localized anesthesia

Pain control that results to loss of consciousness; chemicals that affect reticular formation

General anesthesia

What are the 2 types of pain control?

• Localized anesthesia

• General anesthesia

Originates in a region that is not a source of pain

stimulus and felt when internal organs are damaged or inflamed

Referred pain

Sensory neurons from the superficial area and neurons of source pain converge onto ____?

Onto the same ascending neurons of spinal cord

Give an example of referred pain

• Heart attack (left arm or jaw pain)

• Gallbladder inflammation (right shoulder pain)

• Ruptured spleen (Kehr's sign) (shoulder pain)

• Pancreatic issues (back pain)

• Brain freeze (forehead pain)

Pain that comes on suddenly, usually the result of trauma, injury, surgery, or something similar, and is relieved when cause is treated

Acute pain

How many months do acute pains last?

Lasts 6 months or less

Pain thay comes on gradually, usually the result of conditions that are difficult to treat or diagnose, and difficult to find lasting relief

Chronic pain

Sense of smell; occurs in response to odorants

Olfaction

How many smells can we detect?

10,000 different smells

Where is the Olfaction located?

In superior portion of the nasal cavity

Which lobes processes odor?

Frontal and temporal lobes

Sensory structures thay detect taste

Taste buds

Where are taste buds located?

On papillae on tongue, hard palate, throat

How many taste cells are in each taste buds?

40 taste cells

Each taste cell has ___ _____ thay extend into _____ _____.

Taste hairs, taste pores

Which senses both use chemoreceptors?

Taste and smell

Meissner corpuscle

Olfactory receptors are located where?

In roof of the nasal cavity

In olfaction, chemicals must be ______ in ______ for detection.

Dissolved, muscus

The olfation has neurons withh long?

Long cilia

The impulses in olfaction are transmitted through which nerve?

Olfactory nerve

This houses the receptors organs

Taste buds

Where is the location of taste buds?

• Most are on tongue

• Soft palate

• Cheeks

The tongue is covered with?

Projection, or papillae

Papillae in the tongue that is sharp with no taste buds.

Filiform papillae

Papillae in the tongue that is rounded with taste buds

Fungiform papillae

Papillae in the tongue that is large with taste buds

Circumvallate papillae

Where are taste buds found?

On the sides of papillae

What’s the structure of taste buds?

• Have gustatory hairs (long microvilli)

• Hairs stimulated by chemicals dissolved in saliva

Name the types of tastes

Sweet, sour, salty, bitter, umami

Salty receptors allows modulating diet for _________ balance

electrolyte

Where do taste cells send taste stimuli to?

Taste hairs

What do you call the hairlike processes that taste cells contain?

taste hairs

This protects you from sweat and provide shade from the sun

eyebrow

This protects your eye from foreign objects; lubricates by blinking

Eyelid/eyelashes

How many percent of sensory receptors are in the eyes?

70%, only see 1/6th of eye

Each eye has how many nerve fibers?

over a million nerve fibers

Meets at medial and lateral canthus (crease)

Eyelids

Modified sebaceous glands that produce an oily secretion to lubricate the eye.

Mebomian glands

Modified sweat glands between the eyelashes

Ciliary glands

Accessory structure of the eye that is a thin membrane that covers inner surface of eyelids

Conjunctiva

Commonly known as “pink eye”; an inflammation or infection of the conjunctiva

conjunctivitis

A body system that produces, spreads, and drains tears

Lacrimal apparatus

What is the pathway of the tear?

Lacrimal glands → excretory ducts → eye → lacrimal canals → lacrimal sac → nasolacrimal duct

These provide a critical first line of immune defense against bacteria and viruses on the surface of the eye.

Antibodies (Immunoglobulins)

Muscles that attach to the outer surface of the eye; produces eye movements

Extrinsic eye muscles

The wall of the eye is composed of three tunics, what are they?

• Fibrous tunic

• Vascular tunic

• Nervous tunic

Outermost tunic

Fibrous tunic

Seen anteriorly as the “white of the eye”

Sclera

Helps maintain eye shape, provides attachment sites for muscles, protects internal structures

Sclera

Transparent structure that covers iris and pupil

cornea

allows light to enter and focuses light; repairs itself easily

cornea

It is the middle tunic; contains blood supply; pigment prevents light from scattering

Vascular tunic

It is the black part of the eye (melanin); delivers O2 and nutrients to retina

Choroid

This part of eye helps hold lens in place

Ciliary body

colored part of the eye; surrounds and regulates pupil

iris

rounded opening in the iris

pupil

Controls the shape of the lens via suspensory ligaments

ciliary muscle