(E2) Exam 2 - No Pathways Flashcards
Define Sensation
What sensations do humans respond to?
External (exteroception) and Internal (interoception)
Describe External (exteroception)
Describe Internal (interoception)
Describe a unipolar neuron
Describe a bipolar neuron
Describe a pseudounipolar neuron
Describe a multipolar neuron
Sensory neurons in the body: Peripheral branches contain ______
specific receptors
Sensory neurons in the body: Central process/branch projects to ______
CNS
Sensory information from
the body is conveyed via ________ neurons
with cell bodies located in ___________
- pseudounipolar
- dorsal root (spinal) ganglia
Central process forms _________
dorsal roots
Peripheral process courses from ______
receptors
Describe the different classes of sensory fibers in peripheral nerves
Largest diameter axons convey ___________
muscle & joint information for the muscle nerves and types of touch for cutaneous nerves
Smaller diameter axons convey ________
painful information
What receptors do humans have?
Describe Mechanoreceptors
What does unencapsulatated mean?
Free nerve endings
What does encapsulated mean?
What are the 4 glabrous skin receptors?
Meissner
Merkel
Ruffini
Pacinian
Touch receptors are found
throughout the skin
Many axons join to form the
________
peripheral nerve bundle
Describe the Meissner corpuscle
Describe the Merkel Cells
Describe the Pacinian Corpuscle
Describe the Ruffini Corpuscle
What are the deep mechanorecpetors and where are they found?
________ detect muscle
length and other contractile
properties
Muscle spindles
What are the two types of skeletal muscle fiber?
Describe type 1a fibers
Describe type II fibers
Describe the Golgi Tendon Organs ( what are they, what do they detect, how do they convey to the SC)
Few sensory axons enter the ______ spinal cord
sacral
Most motor axons terminate at _____
cervical spinal cord
More white matter in _____ region than _____ region
cervical
sacral
Regions of most gray matter correspond to ______
limbs
Fibers are_________
organized throughout
central nervous system
somatotopically
IMAGE Little human
Image: Somatotopic organization of posterior columns
What is the posterior funiculus?
_______ are columns of axons from body comprising posterior funiculus.
Posterior (dorsal) columns
Gracile fasciculus is______ (its location)
medial
Cuneate fasciculus is________(its location)
lateral
List the axons from mechanoreceptors in the body from the dorsal column
Describe the spinocerebellar pathways
What is another name for the posterolateral tract?
Lissauer’s tract
Describe pain and temperature fibers
Pain and temperature fibers are
unmyelinated or have little
myelin and also ascend or
descend 1 or 2 levels before
synapsing in dorsal horn
Image: Cytoarchitecture of spinal cord
One classification is lamina
What is the periaqueductal gray?
______ neurons are pseudounipolar with
cell bodies located in ganglia
Sensory
Pattern: ______ neuron is located in nucleus within CNS
2nd
Pattern: ____ neuron is located in thalamic nucleus
3rd
Sensation from face is conveyed by
________ and combination of senses is referred to
as trigeminal system
trigeminal nerve (CN V)
Trigeminal nerve emerges from
Pons
3 divisions of trigeminal nerve
True or False: Dermatomes of face are
sharply delineated
True - No overlap like in the rest of the body
Describe this
Describe this
Trigeminal nerve has nuclei
and a ganglion - Name them
Motor root of
trigeminal nerve (CN V)
courses deep to _____
semilunar ganglion
Describe the Motor Nucleus (what is it, where does it exit, and where is it found)
Muscles that the Motor Nucleus Innervates
Describe the semilunar ganglion
What is the Gasserian Ganglion?
Another name for the semilunar (trigeminal) ganglion
Semilunar (trigeminal) ganglion
Large collection of pseudounipolar
neurons from _______
all three divisons of trigeminal nerve
- peripheral processes form individual divisions
- central processes form (sensory root) of trigeminal nerve
What do the 3 divisions of the trigeminal nerve pass through?
Why is the mesencephalic nucleus considered “abnormal”?
Main Sensory Nucelus (of the face): Location, Function and Equivalence
The central processes form the sensory
root of the trigeminal ganglion and
enter the CNS to synapse in the _________
main sensory nucleus
Two regions of main sensory nucleus
Spinal Nucleus: Location, sensation and equivalence
Image: Spinal Trigeminal nucleus somatotopically represented
Axons/fibers conveying pain and temperature
are ________
small in diameter and lightly or
unmyelinated
Dull, aching pain is likely conveyed by
C fibers
Dental hypersensitivity (sharp pain) is likely
conveyed by
Aδ fibers
What is the trigeminal tubercle?
What are the 3 parts of the spinal nucleus of trigeminal nerve?
Pars Caudalis
Pars interpolaris
Pars Oralis
Describe Pars Caudalis
Describe Pars Oralis
Describe Pars Interpolaris
Describe Wallenberg Syndrome
What is a reflex and a simple reflex?
Describe a tendon reflex
Describe a corneal reflex
Cornea has pain receptors that convey
signals via
ophthalmic nerve
Conscious perception of pain from cornea
is conveyed to
cerebral cortex
Cornea Reflex is formed via connections to facial
nucleus _______
bilaterally
(if one cornea is irritated, both eyes blink)
Mesencephalic Nucleus: Location and Function
“sleeve” of neuronal cell bodies
surrounding the cerebral aqueduct
Periaqueductal gray (central gray)
Unconscious proprioception is sent to _______
cerebellum
Mesencephalic nucleus is also
associated with _______ reflex
jaw jerk
Describe the Jaw Jerk reflex
Jaw jerk reflex - Input to motor nucleus is
bilateral
True or False: Unilateral lesion doesn’t result
in loss of jaw jerk reflex
True
_________ information from
periodontal ligament (Ruffini
endings) also feeds back to
motor nucleus neurons
associated with muscles of
mastication to regulate bite force
Proprioceptive
Centers for Pain Modulation
Pain Pathway: Periaqueductal gray (PAG)
uses________ to activate
neurons in nucleus raphe
magnus (NRM) or locus
ceruleus
enkephalin
Pain Pathway: NRM neurons use _____
serotonin
Pain Pathway: Locus ceruleus neurons use _____
noradrenaline
What is enkephalin?
Mechanisms for Pain Modulation
What is this?
Mesencephalic Nucleus
What is this?
1st order processes from distinct tracts within the CNS
What are these?
What are these?
3rd order neurons
What are these?
3rd neuron axons
What is this?
4th order neuron
Lower Motor Neuron Signs of Lesion
What are the 2 neuron pathways for motor neurons?
Describe Lower Motor Neurons
Lower motor neurons in ventral
horn of spinal cord are
somatotopically organized
Flexors more _________ and
distal limbs more ________
- dorsal/posterior
- lateral
Lower motor neurons are primarily _______
α- and/or γ-motor neurons
Describe α- and γ-motor neurons
Where are upper motor neurons?
Cell bodies in layer V of cerebral cortex
Signs of Lesion for Upper Motor Neurons
Define Spasticity
Involuntary or abnormal
muscle contraction
Images of Reflexes
What is the Babinski sign?
Corticospinal tract
Cell bodies are located in layer ____ of the cerebral cortex
Layer V
60% located in frontal lobe
40% located in parietal lobe
Muscles of facial expression in
the upper half of the face are
controlled _________
about equally from
both hemispheres
Muscles in the lower half of
the face are influenced
primarily from the __________
contralateral hemisphere
Glossopharyngeal nerve innervates ______
stylopharyngeus
Vagus nerve innervates ______
pharyngeal,laryngeal, and esophageal muscles
Accessory nerve fibers course with _______
vagus nerve
Nucleus ambiguus receives input ________
bilaterally
Soft palate and uvula innervation is usually just ____
contralateral
___________ sends axons that innervate left uvula
Right precentral gyrus
Hypoglossal nucleus receives input _______
bilaterally
Genioglossus innervation is usually just __________
contralateral
_________ sends axons that innervate left genioglossus
Right precentral gyrus
Accessory nucleus receives input primarily ________
ipsilateral
Innervation Diagram
Functions of extrapyramidal pathways
Modifies impulses
Dampens erratic motion
Maintains muscle tone
Facilitates trunk stability
What are extrapyramidal pathways?
Extrapyramidal pathways: Cranial nuclei coordinate via
interneurons that course in the
medial longitudinal fasciculus (MLF)
Autonomic fibers from hypothalamus, limbic system
and other areas project to parasympathetic nuclei and
IMLCC.
What do the fibers form?
dorsal longitudinal fasciculus (DLF)
Bilateral tracts that do NOT
decussate
Extrapyramidal Pathway: Describe the Vestibulospinal tracts
Extrapyramidal Pathway: Describe the Rubrospinal Tract
Extrapyramidal Pathway: Describe the Reticulospinal Tract
Extrapyramidal Pathway: Describe the Tectospinal Tract
What is the basal nuclei and what disorders are associated with damage to it?
Describe Parkinsons Disease
Describe Huntington’s DIsease
Describe Tourette’s Syndrome
Functions of the Cerebellum
Cerebellar Disorders
What is this?
Precentral Gyrus
Lower motor neurons in ventral horn and cranial
nerve motor nuclei. (list the cranial nerves)
CN III, IV, V, VI, VII,
IX, X, XI, XII
(3,4,5,6,7,9,10,11,12)
