Somatic Sensations 1 Flashcards
Components of the central and peripheral nervous systems that receive sensory information from the external and internal environment:
Somatic Senses
Specific functions making it possible for humans to experience and interact with the enviornment
Special Senses
Special senses:
Grouped in localized areas
Concentrated in specific locations in the head
Complex neural pathways (Vision, Hearing/Balance, Smell, Taste)
Somatic senses:
Widely distributed
Scattered throughout the body
Simple structures (relatively) (Tactile, Thermal, Pain, Proprioceptive, Visceral, “Deep”)
Somatic Senses - Mechanoreception:
Tactile &Position
Somatic Senses - Thermoreception:
Hot & Cold
Somatic Senses - Nociception:
Pain from tissue damage
Somatic Senses - Exteroreception:
Surface of the body
Somatic Senses - Proprioception:
Position of the body
Somatic Senses - Visceral:
Internal organ sensations
Somatic Senses - Deep:
Tissues, muscle, bone, tendons
6 Types of Tactile receptors:
Free nerve endings
Meissner’s corpuscle
Merkel’s Discs
Hair end-organ
Ruffini’s endings
Pacinian Corpscle
What Receptor is associated with - Touch, & Pressure detection (Only receptor found in cornea of the eye)
Free Nerve Endings
What Receptor is associated with - Touch and vibration, is very sensitive, quickly adapts to sensation, is a long encapsulated nerve ending (Large myelinated fibers type AB) Location: non-hairy skin, fingertips, fingernails, lips.
Meissner’s Corpuscle
What Receptor is associated with - “expanded Tip” Iggo dome receptor, Touch localization and texture sensation, determination of continual touch, Strong initial adaptation followed by weak adaptation of stimulus continues, Location: Fingertips, Hairy-parts of the skin, Steady-state signals
Merkel’s Discs
What Receptor is associated with - Protruding epithelium with a collection of Merkel discs creating a “dome”, “Receptor Organ”, Extremely sensitive receptor!, One large myelinated cell (type AB)
Merkel’s Discs - Iggo Dome Receptor
What Receptor is associated with - Interweaving base of hair roots, Touch receptors, Detects movement of the object on the skin and initial contact with the body.
Hair End- Organ
What Receptor is associated with - Deep in the skin layers & internal tissues, Also found in joint capsules (joint rotation), multi branched, encapsulated, slow adaptation (signals continuous states of stimulation), Touch & pressure receptors.
Ruffini’s Endings
What Receptor is associated with - lay beneath the skin & deep into tissues, rapid local compression stimulation, adapt to the compression very QUICK! detects rapid changes & tissue vibration, single myelinated nerve
Pacinian Corpuscles
More critical Receptors:
Transmit signals via Type AB nerve fibers, 30-70m/sec, Precision of location, minute intensity changes, or acute changes in sensation. Meissner’s, Iggo Dome, Hair, Pacinian & Ruffini’s
Not-so critical Receptors:
Transmits signals via Type A delta fibers, 5-30m/sec, Pressure, poorly localized touch & tickle (some FNEs transmit via C fibers, 2m/sec, mainly tickle)
What types of tactile receptors are involve in detection of vibrations?
All tactile receptors, but each detects different frequencies
What tactile receptor detects high frequency vibrations in the 300-800 cycles/se range, has rapid response to deformation, Type AB nerve fiber transmission
Pacinian
What tactile receptor detects slow frequency vibrations in the 2-80 cycles/sec range (slow response to deformation compared to Pacinian)
Meissner’s
Sensory information from our specialized receptors enter the spinal cord through ________ roots of the spinal nerves.
Dorsal
Name the pathway: Stimulus travels through the dorsal roots up to the medulla of the brain in the dorsal columns of the cord. After signals synapse and cross to the opposite side of the cord (decussate), signal continues upward through the brain stem to the thalamus by way of the medial lemniscus.
Dorsal Column-Medial Lemniscal System
Name the pathway: Stimulus travels through the dorsal roots and immediately after entering the spinal cord from the dorsal roots, synapse occurs in dorsal horns gray matter in the spinal cord. Signal crosses over to opposite side of the cord and ascends through the anterior and lateral white lower brain stem to the thalamus.
Anterolateral System (Spinothalamic pathway) (Ventrolateral system) all the same thing..
Name the pathway: Large nerve fibers from mechanoreceptors divide into the medial and lateral branches of the spinal root. (medial branch turns medially into the dorsal root column immediately) (Lateral branch enters dorsal horn gray matter then divides and synapses with other local neurons which can illicit cord reflexes and other tracts)
Dorsal Column Medial Lemniscal System
Dorsal Column Medial Lemniscal System - 1st order neuron:
Enters dorsal columns passing uninterrupted (ipsilateral) to the dorsal medulla where they synapse in the dorsal column nuclei.