ANAPHY: U9.1 Sensory System (Integration of Nervous System Functions)

Senses

The means by which the brain receives information about the environment and body

Sensation

The process initiated by stimuli acting on sensory receptors

Perception

Conscious awareness of the stimuli received by sensory neurons; brain constantly receives sensations as action potentials

Action Potentials

How does the brain receive sensations as?

General Senses & Special Senses

2 Basic Groups of Senses

General Senses

One of the basic groups of senses that has receptors distributed over a large part of the body

Somatic Senses & Visceral Senses

2 Types of General Senses

Somatic Sense

Type of general sense that is associated with the skin, muscle, joints; includes senses of touch, pressure, temperature, pain, proprioception

Skin, muscle, joints

What parts of the body is the somatic sense associated with?

Touch, pressure, temperature, pain, proprioception

What are the 5 senses included in the somatic sense?

Proprioception

Sense of body’s position and movement

Visceral Sense

Type of general sense that is associated with the internal organs; primarily includes senses of pain and pressure

Internal Organs

What part of the body is the visceral sense associated with?

Pain & pressure

What are the 2 senses included in the visceral sense?

Special Senses

One of the basic groups of senses that is localized to specific organs that have specialized receptors; include smell, taste, sight, hearing, balance

Smell, taste, sight, hearing, balance

5 Types of Special Senses

(1) Type of stimulus they detect

(2) Location in the body

(3) Receptor structure

What are the 3 criteria sensory receptors are classified by?

Mechanoreceptors, Chemoreceptors, Thermoreceptors, Photoreceptors, Nociceptors

5 Types of Sensory Receptors

Mechanoreceptor

Type of sensory receptor that responds to mechanical force/movement, such as touch, pressure, proprioception, hearing, and balance (majority of the special senses)

Chemoreceptor

Type of sensory receptor that responds to chemicals; depended on by smell and taste

Thermoreceptor

Type of sensory receptor that responds to changes in temperature at the site of the receptor and are necessary for the sense of temperature

Photoreceptor

Type of sensory receptor that responds to light striking the receptor cells; necessary for vision

Nociceptor

Type of sensory receptor that responds to pain (extreme mechanical, chemical and thermal stimuli); some are capable of responding to more than one type of stimuli

Free Nerve Endings, Merkel Discs, Hair Follicle Receptors, Meissner Corpuscles, Ruffini End Organs, Pacinian Corpuscle

6 Types of Touch Receptors from the Skin

Free Nerve Endings

Type of touch receptor from the skin that detects sensations of pain and temperature

Cold Receptor, Warm Receptor, Pain Receptor

What are the 3 types of free nerve endings for temperature specifically?

0-12 degrees Celsius

What temperature range activates the Cold Receptor (free nerve endings for cold temperature)?

25-47 degrees Celsius

What temperature range activates the Warm Receptor (free nerve endings for warm temperature)?

Less than 12 degrees Celsius & More than 47 degrees Celsius

What are the 2 temperature ranges that activate the Pain Receptor (free nerve endings for extreme temperature)?

25-35 degrees Celsius

What is the temperature range when both warm and cold receptors (free nerve endings for warm and cold temperatures) are activated?

Merkel Disc

Type of touch receptor from the skin that are superficial nerve endings for light touch

Also known as tactile disks; senses light touch and superficial pressure

Hair Follicle Receptors

Type of touch receptor from the skin that senses light touch

Responds to slight bending of hair and involved with light touch; sensation isn’t very well localized since dendritic tree

Meissner Corpuscles

Type of touch receptor from the skin that responds to fine, discriminative touch

Sensations of light touch and superficial pressure

Ruffini End Organs

Type of touch receptor from the skin that responds to pressure senses

Important in responding to continuous touch or pressure; responds to pressure on skin directly superficial to the receptor and to stretch of adjacent skin

Pacinian Corpuscle

Type of touch receptor from the skin that responds to deep senses/pressures

Responsible for deep cutaneous pressure and vibration; those associated with the joints help relay proprioceptive information about joint positions

Righting Reflex

Keeps the body in an upright position on even or uneven grounds

Pain sensation

An unpleasant perceptual or emotional experience

Localized and Diffuse Pain

2 Types of Pain Sensation

Localized Pain

Type of pain sensation in which pain is sharp, pricking, and cutting

Rapid action potential

Diffuse Pain

Type of pain sensation in which pain is burning and aching

Slower action potential

Local & Generalized Anesthesia

2 Types of Pain Control

Local Anesthesia

Type of pain control in which action potentials are suppressed from pain receptors in local areas of the body; chemicals are injected near sensory nerve

General Anesthesia

Type of pain control in which there is a loss of consciousness; chemicals affect reticular formation

Referred Pain

Pain felt in a body region that is not the source of the pain stimulus

Felt when internal organs are damaged or inflamed; occurs because both area of skin to which the pain is referred and the visceral area that is damaged are innervated by neurons that project to the same area of the cerebral cortex

One has a heart problem and is experiencing chest pain

Example of referred pain