Sensory Inputs & Motor Outputs of Brain: Distal Spinal Cord Function Flashcards
what are the 3 basic functions of the neurons
1. sensory input: neurons that collect info about external environment and internal conditions of body
2. integration: recieve sensory input, analyze it and make decisions about appropriate response to make
3. motor output: neurons carry out instructions that result from integration by impulses sent to various effector organs that include muscles and glands
what is sensation
physical feeling or perception for something that happens to or comes into contact with body
what is the funciton of a spinal nerve
carries signal between spinal cord and body
has both sensory + motor fibres
cell body is in dorsal ganglion
what is the function of a cranial nerve
carries signal between forebrain or brainstem and mainly head and neck
what are the receptor types
sensory endings of peripheral branches of sensory fibres
- touch
- temperature
- movement
- chemicals
- pressure
- light
- sound
what are the classifications of receptors
- anatomical
- location
what are the locations of receptors
1. exteroreceptors: near surface of body –> sensitive to change in external environment
2. proprioceptors: sensitive to movement of muscles, tendons, and joints
3. interoceptors: located within viscera –> sensitive to change in internal environment
what is a somatic afferent
dendritic zone is on or near the surface of the bod
what is visceral afferent
dendritic zone in the wall of various viscera of the body
how can the somatic afferent fibres be subdivided
- general somatic afferent (GSA)
- speical somatic afferent (SSA)
what are general somatic afferent (GSA)
touch, temperature, proprioception and noxious stimuli
cranial nerve V for the head
spinal nerves for the rest of the body
what is a special somatic afferent (SSA)
vision: cranial nerve II
sound: cranial nerve VIII
input from outside
what can visceral afferent fibres can be subdivided into
- general visceral afferent (GVA)
- special visceral afferent (SVA)
what are general visceral afferent (GVA)
organ content, distention, chemicals
cranial nerves VII, IX, and X to visceral structures in the head
cranial nerve X, and spinal nerves to the viscera and blood vessels of the rest of the body
what are special visceral afferent (SVA) and the nerves
taste: cranial nerves VII, IX, and X
olfaction: cranial nerve I
summarize the classification of the sensory portion of the PNS
what are the functional classifications of the cranial nerves
what are the brainstem nuclei
all info comes in from cranial nerves with different fibres
sensory nuclei are in the dorsal lateral surface
what are the sensory spinal tracts
what is the fasciculus gracilis
proprioceptive information from pelvic limbs
what is fasciculus cuneatus
proprioceptive information from thoracic limbs
what is dorsal and ventral spinocerebellar tracts
information to cerebellum for coordination
what is spinothalamic tracts
information to thalamus about pain, itch, touch and temperature
what is the motor function
movement involving muscular component
what is a lower motor neuron (LMN)
neurons located in either the ventral horn of the spinal cord or cranial nerve nuclei of the brainstem with motor function
come out of CNS to bring info to muscle
motor info goes out of ventral part
what is upper motor neuron (UMN)
motor neurons originate in the motor region of the cerebral cortex or the brain stem and carry motor information down to the lower motor neurons
doesn’t leave CNS –> only activates LMN that will leave CNS and activate muscles
doesn’t leave spinal cord
spinal reflexes clincally
what can the motor portion of the PNS can be classified based on the location of the dendritic zone in the body
- general somatic efferent (GSE)
- general visceral efferent (GVE)
what is general somatic efferent (GSE)
dendritic zone in striated muscle throughout the body
cranial nerves: all of them except from I, II and VIII
ventral nerve roots and spinal nerves for the rest of the body
what are general visceral efferent (GVE)
dendritic zone in involuntary smooth muscle of visera
cranial nerves: III, VII, IX, X and XI
spinal nerves for rest of body
what is the functional classification of cranial nerves
what are the functional classification of cranial nerves
what are the motor outputs of the brain
what are the motor outputs of the brain
what is the corticospinal tracts (pyramidal system)
motor spinal tracts
motor information directl from cerebral cortex
poorly developed in domestic animals
what is the rubrospinal tracts (extrapyramidal)
motor information from red nucleus in the brain stem
motor spinal tracts
what is the reticulospinal tracts (extrapyramidal system)
motor information from reticular formation in the brainstem
what is the vestibulospinal tracts (extrapyramidal system)
motor information from vestibular nuclei in the brainstem
what are the tectospinal tracts (extrapyramidal)
motor information from the tectal region in the brainstem
what are ways to assess proprioception
- proprioceptive placing (knuckling response)
- hopping reaction
- hemiwalking
- wheelbarrowing
- extensor postural thrusting
- hip sway
- visual and tactile placing
how can motor function be assessed
- gait
- muscle tone and muscle bulk
- patellar reflex
- withdrawal (flexor) reflex
what are the clinical differences between UMN and LMN signs
how do we assess severity of motor and sensory function
different susceptibility to damage of the different tracts
motor function: normal –> back pain –> weakness –> total paralysis
sensory function: normal –> loss of proprioception –> loss of superficial pain perception –> loss of deep pain perception
what are the grades of spinal injuries
- normal
- pain (no neurological deficits)
- ambulatory paresis
- non-ambulatory paresis
- plegia
- plegia with absent deep pain sensation
