Sensory, Motor, & Integrative System Ch 16

Sensation: The conscious or subconscious awareness of external or internal stimuli. Perception: The conscious awareness and the interpretation of meaning of sensations.

Exteroceptors vs Interoceptors

General Senses vs. Special Senses Taste Smell Vision Hearing Balance Pain Temperature Light touch Pressure Sense of body and limb position

Sensory Receptors Mechanoreceptors Thermoreceptors Photoreceptors Chemoreceptors Nociceptors Osmoreceptors

General Senses Unencapsulated Encapsulated Nerve Nerve Endings vs Free nerve endings Naked nerve endings surrounded by one or more layers Pacinian corpuscle skin, bones, internal organs, joints Deeper tissue, muscles

Unencapsulated Nerve Endings pain, light touch, and temperature Free Nerve Endings - Pain & Temperature Merkel’s Discs - Light Touch & Pressure Root Hair Plexuses - Light Touch

Encapsulated Nerve Endings Pacinian Corpuscles - Deep Pressure Meissner’s Corpuscles - Discriminative Touch in Hairless Skin Areas Krause’s End-Bulbs - Discriminative Touch in Mucous Membranes Ruffini’s Corpuscles - Deep Pressure & Stretch (Proprioception)

The Epidermis Merkel Cells- slow mechanoreceptors (basal layer)

Skin Receptors free nerve endings Merkel disc Meissner’s corpuscles Ruffini corpuscle root hair plexus Pacinian corpuscles

Encapsulated Nerve Endings Muscle Spindles - Skeletal Muscle Stretching (Proprioception) Golgi Tendon Organs - Tendon Stretching (Proprioception)

Muscle Spindle & Tendon Organ

Pain- protective function Somatic Pain-results from injuries to skin, muscle, joints, tendon vs. Visceral Pain- pain in body organs

Referred Pain- felt on the body surface

Somatic Sensory Pathway

Ascending Spinal Cord Tract

2nd order neuron- to thalamus or cerebellum Ascending Spinal Cord Tract Conducts sensory impulses upward through 3 successive chains of neurons 1st order neuron-cutaneous receptors of skin and proprioceptors  spinal cord or brain stem 2nd order neuron- to thalamus or cerebellum 3rd order neuron- to somatosensory cortex of cerebrum

Descending Spinal Cord Tract

Direct pathway- regulates fine and fast movements Descending Spinal Cord Tract Descending tract delivers impulses efferently from brain to spinal cord Direct pathway- regulates fine and fast movements Indirect pathway- maintains balance by varying postural muscle tone

Primary Somatosensory Cortex & Primary Motor Area

Primary Sensory Cortex Motor Areas and Sensory Areas of the Cebral Cortex

Primary Motor Cortex Motor Areas and Sensory Areas of the Cebral Cortex

Importance of Sleep Slow-wave sleep (NREM stages 3 and 4) is presumed to be the restorative stage People deprived of REM sleep become moody and depressed REM sleep may be a reverse learning process where superfluous information is purged from the brain Daily sleep requirements decline with age Stage 4 sleep declines steadily and may disappear after age 60

Stages of Sleep

Sleep Disorders Narcolepsy Insomnia Sleep apnea Lapsing abruptly into sleep from the awake state Insomnia Chronic inability to obtain the amount or quality of sleep needed Sleep apnea Temporary cessation of breathing during sleep

Learning & Memory Stimulus Sensory organs perception Sensory Memory (millisecond-1)   attention Short-Term Memory Working Memory (< 1 minute) forgetting repetition Long-Term Memory ( days, months, years)

Learning & Memory Sensory Memory: A sensory memory exists for each sensory channel: iconic memory for visual stimuli echoic memory for aural stimuli haptic memory for touch Information sensory memory short-term memory by attention, thereby filtering the stimuli to only those which are of interest at a given time.

Learning & Memory Short-term Memory: acts as a scratch-pad for temporary recall of the information under process can contain at any one time seven, plus or minus two, "chunks" of information lasts around twenty seconds.

Warning- next slide short term memory test

Short-term Memory Quiz (30 sec) eggs drawing rock apple focus mission favor ice brain flag trial partner house life chair

Learning & Memory Long-term Memory: intended for storage of information over a long time. Short-termlong-term (rehearsal) Little decay Storage Deletion- decay and interference Retrieval-recall and recognition

Learning & Memory Long-term Memory: Why we forget: fading (trace decay) over time interference (overlaying new information over the old) lack of retrieval cues.

Learning & Memory Encoding in Long-term Memory: Organizing Practicing Spacing Making meaning Emotionally engaging

INQUIRY Where are merkel cells located? What do proprioceptors sense? What type of stimulus triggers a response in nociceptors? How much information can short term memory hold at any one time? Where are second order neurons located? What is phantom limb pain? Give ways to store info in long-term memory.