9. Systems in the NS. Sensory III - the SOMATOSENSORY SYSTEM Flashcards
SENSATION is the PHYSIOLOGICAL REACTION to the SURROUNDING WORLD
what are the PURPOSES of SENSATION
- BALANCE & PHYSICAL ORIENTATION
- RESPONSE to constant CHANGES in the Environment
- PLEASURE/PAIN
- SAFETY - Reflex Movements away from harm
TYPES of SENSATION
SOMATOSENSORY / CUTANEOUS Senses:
Touch, Pressure, Vibration, Temperature, Pain, Proprioception
SPECIAL SENSES: Smell, Taste, Hearing, Sight
AUTONOMIC SYSTEM
what are the SPECIALISED Cutaneous Receptors
- PACINIAN
-MERISSNER’S CORPUSCLE - MERKEL’S DISCS
- RUFFINI
- Mechanoreceptors
what are the UNSPECIALISED Cutaneous Receptors
- FREE NERVE ENDINGS
- HAIR FOLLICLE RECEPTORS
what does the SPECIALISED CUTANEOUS RECEPTOR -
PACINIAN CORPUSCLES detect
PRESSURE
RAPID VIBRATIONS (200-300 Hz)
what does the SPECIALISED CUTANEOUS RECEPTOR -
MEISSSNER’S CORPUSCLES detect
- 50 Hz MECHANORECEPTOR
- LIGHT TOUCH
- TEXTURE
- RAPID ADAPTION
- HIGH SENSITIVITY
what does the SPECIALISED CUTANEOUS RECEPTOR -
MERKEL’S DISCS detect
SUSTAINED TOUCH & PRESSURE
what does the SPECIALISED CUTANEOUS RECEPTOR -
RUFFINI ENDINGS detect
SLOW ADAPTING MECHANORECEPTORS
- DEEP SKIN TENSION / SENSION
- JOINT ANGLE CHANGE
- MODULATES GRIP
- DEEP THERMAL PAIN (deep thermal Burns loss of pain)
what does the SPECIALISED CUTANEOUS RECEPTOR -
MECHANORECEPTORS detect
TOUCH, PRESSURE, STRETCH
what does the UNSPECIALISED CUTANEOUS RECEPTOR -
FREE NERVE ENDINGS detect
PAIN
TEMPERATURE
MECHANICAL DEFORMATION
CHEMICAL
what does the UNSPECIALISED CUTANEOUS RECEPTOR -
HAIR FOLLICLE RECEPTORS detect
TOUCH
which CUTANEOUS RECEPTOR MODULATES GRIP
RUFFINI
which CUTANEOUS RECEPTOR detects RAPID VIBRATIONS (200-300)
PACINIAN CORPUSCLES
which CUTANEOUS RECEPTOR detect SUSTAINED TOUCH & PRESSURE
MERKEL’S DISCS
which CUTANEOUS RECEPTOR detects DEEP SKIN TENSION/STRETCH, JOINT ANGLE CHANGE, MODULATES GRIP, DEEP THERMAL PAIN
RUFFINI
which CUTANEOUS RECEPTOR detect PRESSURE & RAPID VIBRATIONS
PACINIAN
which CUTANEOUS RECEPTOR detect LIGHT TOUCH, TEXTURE, RAPID ADAPTION, HIGH SENSITIVITY
MEISSNER’S CORPUSCLE
which CUTANEOUS RECEPTOR detects PAIN, TEMPERATURE, MECHANICAL DEFORMATION, CHEMICAL
FREE NERVE ENDINGS
(unspecialised)
what are the 2 primary PROPRIOCEPTION STRETCH RECEPTORS:
- MUSCLE SPINDLES
- GOLGI TENDON APPARATUS (for REFLEX ARC)
(Muscle spindles are sensory receptors within the belly of a muscle that primarily detect changes in the length of this muscle)
where can you find VISCERAL STRETCH RECEPTORS
- HEART
- CAROTID
- LUNG
- GUT
sensory signals of PROPRIOCEPTION are sent to brain via which ASCENDING PATHWAYS:
- SPINOCEREBELLAR
- MEDIAL LEMINISCUS
how is PROPRAGTATION DETECTED/ACTIVATED at the NERVE ENDING / RECEPTOR
DEFORMATION of the CONNECTIVE TISSUE COVERING the Nerve ENDING
- ACTIVATES MECHANICALLY-GATED ION CHANNELS
- DEPOLARISES the RECEPTOR to reach THRESHOLD for ACTION POTENTIAL
there are 2 ADAPTATIONS of IMPULSES: FAST & SLOW
how is the RESPONSE of the FAST ADAPTATION
BRIEF (short) RESPONSE
there are 2 ADAPTATIONS of IMPULSES: FAST & SLOW
how is the RESPONSE of the SLOW ADAPTATION
continues to RESPOND to STIMULUS LONGER
(important for when you need to know that you are continuously being stimulated)
but will Eventually FATIGUE
how are TYPE A FIBRE types
- LARGE
- FAST
- MYELINATED
how are TYPE B FIBRE types
- SMALL
- MYELINATED
- SLOW / LOW CONDUCTION VELOCITY
how are TYPE C FIBRE types
- SMALLEST
- UNMYELINATED
- SLOW / LOW CONDUCTION VELOCITY
SLOW PAIN
which FIBRE TYPE are MUSCLE PROPRIOCEPTORS
A ALPHA
which FIBRE TYPE are SKIN MECHANORECEPTORS for NON-NOXIOUS (non-harmful) STIMULI
A BETA
which FIBRE TYPE are NOXIOUS MECHANICAL STIMULUS, for PAIN & TEMPERATURE
A - DELTA
which FIBRE TYPE are for SLOW PAIN, NOXIOUS HEAT and CHEMICAL STIMULI
C fibres
in SOMATOSENSORY PATHWAYS there are PRIMARY, SECONDARY, TERTIARY NEURONS.
where are their CELL BODIES LOCATED
In DORSAL ROOT GANGLION,
SPINAL CORD,
THALAMUS
name of the SOMATOSENSORY PATHWAY / SENSORY PATHWAY of the CNS
DORSAL COLUMN MEDIAL LEMINISCAL PATHWAY
how are ASCENDING PATHWAYS to the THALAMUS
MOSTLY DECUSSATED (cross over)
some IPSILATERAL
which TRACT is for PAIN & TEMPERATURE
SPINOTHALAMIC TRACT
- most decussate
which TRACT is for VIBRATION & PROPRIOCEPTION
POSTERIOR COLUMNS
- Most Ipsilateral
what CLINICAL FINDINGS present in a SPINAL CORD LESION
- IPSILATERAL WEAKNESS
- IPSILATERAL LOSS of VIBRATION & PROPRIOCEPTION
- COTRALATERAL LOSS of PAIN/TEMP at or few levels below lesion
in SPINOTHALAMIC TRACT for PAIN & TEMPERATURE are neurones ipsilateral or do they decussate
MOST DECUSSATE
in POSTERIOR COLUMNS for VIBRATION & PROPRIOCEPTION are neurones ipsilateral or do they decussate
MOST IPSILATERAL
how is the REFLEX ARC RESPONSE
RAPID RESPONSE when DANGER/HARM
to SPINAL CORD - RELAY NEURON - MOTOR NEURON
efferents from spinal cord, doesn’t relay to brain for immediate response
what are the CENTRAL PATHWAYS
- MEDIAL LEMINISCUS
- MEDULLA
- THALAMUS
- CORTEX - PRIMARY SENSORY AREA
-> cerebellum for posture, balance - CORTICAL ASSOCIATION PATHWAYS
the POSTERIOR PARIETAL CORTEX is for what
PROPRIOCEPTION
(where the body is in space)
in which LOBE are the PRIMARY MOTOR CORTEX and SOMATOSENSORY CORTEX
FRONTAL LOBE
example of REFERRED PAIN is CARDIAC PAIN being felt in the…
ARM
as dorsal root ganglion are connected so there is stimulation of adjacent areas
example of REFERRED PAIN is ANGINA PECTORIS being felt in the…
ARM, JAW
example of REFERRED PAIN is PLEURITIS (inflammation of Diaphragm) being felt in the…
SHOULDER
example of REFERRED PAIN is PLEURITIS (inflammation of Diaphragm) being felt in the…
SHOULDER
example of REFERRED PAIN is URINARY TRACT INFECTION being felt in the…
BACK, ABDOMEN
example of REFERRED PAIN is AORTIC ANEURYSM being felt in the…
BACK
example of REFERRED PAIN is CHOLECYSTITIS (galbladder inflamation) being felt in the…
RIGHT SHOULDER / SCAPULAR AREA
what is PHANTOM LIMB PAIN
LONG-LASTING NOXIOUS INPUT to the LIMB
- DEVELOPMENT of CORTICAL PAIN MEMORY and
ENHANCED EXCITABILITY
result in AMPUTATION
(reorganisation of the amputation zone in somatosensory cortex)
what are ANALGESICS / chemicals released for PAIN MODULATION
- KININS & SEROTONINS released at site of injury
- ENDORPHINS - block plain perception
MECHANICAL forms of PAIN MODULATION, Non-painful sensory stimuli:
- RUBBING
- HEAT or COLD
- CHEMICAL STIMULI eg CAPSAICIN (RED PEPPER)
other stimuli to try and mask the painful pathway