The Somatic SensesBy Reyna Gontaruk, Alex Truong & Stephen Monahan

Introductory Sensory Information● Sensory Receptors

○ Monitor Specific Conditions within the

body or the surrounding environment

■ Touch, Pressure, Temperature

● When stimulated, Sensory receptors pass

information to the Central Nervous System

in the form of action potentials

Introductory Sensory Information Cont.● Sensation

○ Interpretation of Sensory Impulses

● Projection – A feeling comes from the

specific area where the sensation occurs.

○ Ex : Hitting your head off of a desk

Introductory Sensory Information Cont.● Adaptation

○ The reduction in sensitivity to a

stimulus over time

■ Exposure to the stimulus is

constant

● Ex: Cigarette smokers

● Transduction

○ Conversion of a sensory

stimulus from one form to

another.

■ Ex: Light hitting retina of

eye

The Somatic Senses

What is the difference between somatic and special senses?● Special senses: taste, smell, sight, hearing,

balance ● Somatic sense: anything you can feel with

your skin (everything else)

Types of somatic receptors

1. Nociceptors (pain)2. Thermoreceptors (temperature)3. Mechanoreceptors (touch/pressure)4. Chemoreceptors

Nociceptors

Types of pain receptors:● Cutaneous (skin)● Somatic (joints and bones)● Visceral (internal organs)

Sensitivities:● Chemical● Mechanical● Thermal

ThermoreceptorsLocation:● Skin● Cornea● TongueTypes:● Warm (immediately

below skin)● Cold (deeper in dermis)

Mechanoreceptors● 3 types

○ Tactile- touch, pressure, vibration■ distinguish shape and texture■ indicate degree of mechanical

distortion■ pulsing or oscillating pressure

○ Baroreceptors■ changes of pressure in walls

of blood vessels, digestive, reproductive, and urinary tracts

Proprioceptors ● monitor body position- where, direction, speed of

movements● allows knowledge of body conscious and

subconscious (do actions without having to look or think about it)

● 3 groups○ muscle spindles

■ skeletal muscle length■ stretch reflexes

○ golgi tendon■ stimulated my tension in tendon■ monitor external tension during muscle

contraction○ receptors in joint capsules

■ nerve endings detect pressure, tension, movement

Chemoreceptors● respond to chemical stimuli in environment

○ carotid bodies (origin of internal carotid arteries on sides of neck measure)

○ aortic bodies (between major branches of the aortic arch)

● Cardiovascular○ monitor pH, Carbon Dioxide levels,

and oxygen levels in arterial blood● involved in other senses

The Special Senses

1. Taste2. Smell3. Sight4. Hearing5. Balance

QUIZ TIME

QuizWhat receptor for is being used for knowing where various body parts are after doing a backflip in the air?

A. Nociceptors B. ProprioceptorsC. ThermoreceptorsD. Mechanoreceptors

Quiz

What three places are nociceptors found in?

Quiz

What is the relationship between Sensation and Projection? What is an example of this relationship?

THE END