Exam 2 Flashcards
Dorsal Primary Rami
Do not merge to form plexi
Motor: muscles of the deep back muscles
Sensory: innervate joint capsules/ligaments
Ventral Primary Rami
Merge to form plexi
Stay segmental in thoracic region
Cervical Plexus
C2, C3, C4 Phrenic nerve (C3-C5)
Brachial Plexus
C5-T1
Ulnar, radial, median
Lumbar Plexus
L1-L4
Femoral, obturator
Sacral Plexus
L4-S3
Common peroneal, tibial
Afferent fiber
Usually unipolar
Receptor
Peripheral process
Efferent fiber
Axon
Synaptic terminal
Sequence of membranes surrounding afferent/efferent fibers
Axon, axolemma, myelin, neurilemma, endonerium, perinerium, epinerium
Neurilemma
Covers the myelin sheath
Endonerium
Covers each individual nerve fiber. Contains blood vessels that supply oxygen and nutrients
Perinerium
Surrounds bundles of nerve fibers
Epinerium
Surrounds entire nerve
Peripheral nerve cutaneous innervation
Areas of skin supplied by more than one spinal cord level
Superficial sensations (exteroceptors)
Responsible for pain, temperature, and fine touch
Examples of exteroceptors
Free nerve endings Hair follicles Merkel's discs Meissner's corpuscles Krause end bulbs
Deep receptors (proprioceptors)
Responsible for joint position, kinesthetic awareness, vibration, muscle length and muscle tension, skin movements, and deep pressure
Examples of deep receptors
Muscle spindles GTOs Ruffini corpuscles Pacinian corpuscles Golgi ligament endings
What do free nerve endings detect?
Pain, touch, tickle, itch, temperature
What is the axon reflex?
The superficial heat stimulates temperature receptors in the skin, then a branch of the peripheral process synapses on cutaneous blood vessels which causes dilation
Ruffini Endings detect
joint angles at end range
Continuous stretch on skin
Hair follicle receptor organs
Combination of hair follicle and nerve fiber
Responsible for superficial touch
Krause end bulb
Responsible for touch, light pressure, and cold temperature sensations
Meissner’s corpulscles
Detects moving 2 point discrimination and low frequency vibration
Pacinian corpuscles
Detects pressure and high frequency vibration
Merkel’s Discs
Detects texture, localized touch, and static 2 point discrimination
Babinski reflex
Stroke along heel and along 5th metatarsal and then across the metatarsal heads
Oppenhein reflex
Stroking down the medial side of the tibia causes 1st toe extension
Chaddock reflex
Stroking along the lateral ankle/lateral aspect of foot causes 1st digit extension
Type I Mechanoreceptors
Ruffini endings - static end range position; speed/direction of active/passive movement; continuous stretch
Type II mechanoreceptors
Detect sudden movement
Type III mechanoreceptors
Golgi ligament endings (ligament receptors)
Type IV Mechanoreceptors
Free nerve endings
Who is the father of neuroscience? What did he propose?
Ramon y Cajal
Proposed the neuron doctrine - that the nervous system was composed of individual neurons instead of all neurons being connected
Parts of the CNS
Brain (cerebellum, cerebru, and brainstem) and spinal cord (rootlets/roots & spinal nerves)
Parts of the PNS
Cranial nerves
Dorsal and ventral primary rami
Parts of the ANS
Parasympathetic
Sympathetic
Somatic nervous system
Voluntary skeletal muscle
Visceral nervous system
Nerve supply of organs
Ganglia
Cluster of nerve cell bodies located outside the CNS
Exception to ganglia definition
Dorsal root ganglia
Nuclei
Cluster of nerve cell bodies located within the CNS
Exception to nuclei definition
Basal root ganglia
Tracts
Bundles of axons carrying similar information (axons with same origin and common termination)
Other names for tracts
Lemniscus, fasiculus, peduncle, column, and capsule
Sensation
Awareness of stimuli
Perception
Interpretation of stimuli into meaningful information
Unipolar neurons
Only one projection extending off of the cell body
Seen in peripheral sensory neurons
Bipolar neurons
A single primary dendrite and a single axon extending off the cell body
Found in retina, vestibular nerve, cochlear nerve
Multipolar neurons
One axons and 2 or more dendrites
Most motor and CNS interneurons
Anterograde transport
From the cell body to the terminus
Retrograde transport
From the terminus to the cell body
Paresis
Partial loss of voluntary contraction
Paralysis
Complete loss of voluntary contraction
Myoclonus
Involuntary contractions
Hypotonia
Abnormally low resistance to passive stretch
Flaccidity
Lack of resistance to passive stretch
Resting membrane potential
-70 mv
Astrocytes
Add structure, part of BBB, maintain potassium levels, guide migrating neurons Transmit information (transmit calcium to other astrocytes and has 2 way communication with neurons) Scar in CNS injury
Oligodendrocytes
Myelinate axons in CNS (1 segment of multiple axons)
Antibodies attack these in MS
Schwann cells
Myelinate axons in PNS (1 segment of 1 axon)
Antibodies attack these in Guillian-Barre
Microglia
Phagocytes
Activated in Alzheimer’s and AIDS
Ependymal Cells
Line the ventricles and central canal
Ependymomas
Protoplasmic astrocytes
Located in the gray matter
Fibrous astrocytes
Located in white matter
Axo-dendritic synapses
most numerous; usually excitatory
Axo-somatic synapses
usually inhibitory
Axo-axonic
Presynaptic inhibition or facilitation; either reduces or increases calcium influx
Glutamate
The major excitatory NT in CNS
GABA
The major inhibitory NT in CNS
GABA-a & GABA-c: increase calcium influx
GABA-b: increase potassium efflux
Substance P
Released by sensory neurons transmitting pain
Endorphins and enkephalins
Inhibit neurons involved in perception of pain
Glycine
Prominent inhibitory neurotransmitters in the spinal cord
Serotonin
Produced by neurons in the raphe nuclei of the brainstem; axons project to spinal cord, telencephalon, and diencephalon
Dopamine
Produced by neurons in the substantia nigra and ventral tegmental area of the midbrain; axons project to basal ganglia, frontal cortex, amygdala, and hippocampus
Myasthenia Gravis
Antibodies are produced against Ach receptors in muscle cell membranes
Characterized by weakness of levator palpebrae superioris, EOMs and limb muscles which becomes worse with excercise
