Final Exam (based off review) Flashcards
Lecture & Lab
What are the 4 Somtosensory Conscious Pathways?
- Dorsal Column Upper Tract (Cuneatus)
- Dorsal Column Lower Tract (Gracilis)
- Anterior Spinothalamic Tract
- Lateral Spinothalamic Tract
Somatosensory Conscious Pathways Order:
1st order neuron (DRG) >DR> 2nd order (medulla) neuron > 3rd order neuron (VP thalamus) > internal capsule > corona radiata > postcentral gyrus
Dorsal Column Pathway (Lower tract, fasciculus gracilis):
DRG (1st cell body)
DR
Fasciculus gracilis (first axon)
Nucleus gracilis (2nd cell body)
Medial lemniscus (second axon “decussate”)
VP thalamus (3rd cell body)
Internal capsule (third axon)
Corona radiate
Postcentral gyrus
Dorsal Column Pathway (Upper tract, fasciculus cuneatus):
DRG (1st cell body)
DR
Fasciculus cuneatus (first axon)
Nucleus cuneatus (2nd cell body)
Medial lemniscus (second axon “decussate”)
VP thalamus (3rd cell body)
Internal capsule (third axon)
Corona radiata
Postcentral gyrus
Anterior Spinothalamic Tract Pathway:
DRG > DR > DH > AST > VP Thalamus > Internal Capsule > Corona Radiata > Postcentral gyrus
Lateral Spinothalamic Tract Pathway:
DRG > DR > DH > LST > VP Thalamus > Internal Capsule > Corona Radiata > Postcentral gyrus
Where do the dorsal column tracts 2nd order neuron decussate?
medulla (medial lemniscus)
What type of sensations are the dorsal column tracts responsible for?
fine touch and proprioception
What type of sensations is the anterior spinothalamic tract responsible for?
crude touch and pressure
What type of sensations is the lateral spinothalamic tract responsible for?
pain and temperature
What are the 2 Somatosensory Unconscious Pathways?
- Anterior Spinocerebellar Tract
- Posterior Spinocerebellar Tract
Anterior Spinocerebellar Tract:
DRG > DR > DH > lateral column (deccusate) > AST > inferior peduncles > cerebellar cortex
Posterior Spinocerebellar Tract:
DRG > DR > DH > lateral column (deccusate) > PST > superior cerebral peduncles > cerebellar cortex
What type of sensations are the Posterior & Anterior Spinocerebellar Tract Pathways responsible for?
Subconscious proprioception
What are the 3 Somatomotor Conscious Pathways? (pyramidal tracts)
corticospinal pathway
anterior corticospinal tract
lateral corticospinal tract
corticobulbar tracts
What are the somatomotor pathways responsible for?
subconscious movement of muscle
What type of sensations is the anterior corticospinal tract responsible for?
gross motor
What type of sensations is the lateral corticospinal tract responsible for?
fine motor
Corticospinal pathway:
What type of sensations is the corticospinal tract responsible for?
subconscious movements of the body
Lateral corticospinal pathway: (Contralateral) 75%-90% Fine Motor
Precentral gyrus (UMN) >
Corona radiata >
Internal capsule >
Cerebral peduncles >
Pyramids >
LCT >
Lateral Column >
Ventral horn (LMN)
Anterior corticospinal pathway: (Contralateral) 10%-25% Gross Motor
Precentral gyrus (UMN) >
Corona radiata >
Internal capsule >
Cerebral peduncles >
Pyramids >
ACT >
Lateral Column >
Ventral horn (LMN) (decussate)
Corticobulbar tract pathway:
Precentral gyrus (UMN) >
Corona radiata >
Internal capsule >
Cerebral peduncles >
Motor nuclei of cranial nerves 3-12 (LMN)
What type of sensations is the corticobulbar tract responsible for?
subconscious movements of the head
What are the 4 Somatomotor Unconscious Pathways? (extrapyramidal tracts)
rubrospinal tract
reticulospinal tract
vestibulospinal tract
tectospinal tract
Rubrospinal tract pathway:
red nucleus (UMN) > rubrospinal tract > VH (LMN)
Reticulospinal tract pathway:
reticular formation (UMN) > reticulospinal tract > VH (LMN)
Vestibulospinal tract pathway:
vestibular nucleus (UMN) >vestibulospinal tract > VH (LMN)
Tectospinal tract pathway:
tectum (UMN) > tectospinal tract > VH (LMN)
Which 3 somatomotor unconscious pathways go through the anterior white column?
vestibulospinal tract
reticulospinal tract
tectospinal tract
What is the only somatomotor unconscious pathway that goes through the lateral white column?
rubrospinal tract
Stretch postural reflex:
a protective mechanism that causes muscles to contract when stretched passively
Example of stretch reflex:
occurs when a muscle is stretched and as a result that same muscle contracts. An example of this in the human body is the “knee-jerk” reflex (tap the patellar with a small hammer).
Golgi tendon reflex:
a protective feedback mechanism to control the tension of an active muscle by causing relaxation before the tendon tension becomes high enough to cause damage.
Flexor/withdrawal reflex example:
if one steps on a tack, the involved lower limb flexes to remove the foot from the stimulus.
Crossed extensor reflex example:
The spinal reflex occurs, but additionally, the extensor muscles of the contralateral limb will contract to maintain stability against the force of gravity to ensure the person does not fall after withdrawing the limb from the painful stimulus.
Nerve that supplies the biceps brachii and brachialis muscles, and provides sensation to the lateral forearm
Musculocutaneous nerve
Nerve that supplies the flexor muscles and the skin of the palm and the two outer fingers
Median nerve
supplies the small muscles of the hand
Ulnar nerve
Nerve that supplies the shoulder muscles and the overlying skin
Axillary nerve
Nerve that supplies the extensor muscles and the skin of part of the arm and hand
Radial nerve
Brachial Plexus Injuries & Disorders:
Avulsion- the nerve is torn away from its attachment at the spinal cord; the most severe type.
Rupture- the nerve is torn, but not at the spinal cord attachment.
Neuroma-
Neurapraxia-
Erb’s Palsy-
Global Palsy-
Horner Syndrome-
Neurolysis-
CNS Injuries:
Injuries:
Stroke
Hematoma
Aneurysm
Thrombosis
Hemorrhage
Angioma (arteriovenous malformation)
CNS Disorders:
Neuropsychological and language disorders
Degenerative disorders of the neuromuscular system
Disorders of the basal nuclei
Disorders of the cerebellum
Somatosensory loss
Lower and upper motor neuron lesions
Cranial nerve lesions
What are the 2 motor compartments of the upper limb?
Anterior & Posterior
What are the 3 sensory compartments/patches of the upper limb?
Lateral
Medial
Posterior
The motor component of the anterior brachium is supplied by ______, and the posterior brachium is supplied by ______ nerve.
musculocutaneous; radial
The motor component of the anterior antebrachium is supplied by the _____ nerve except to 1 ½ mm, and the posterior antebrachium is supplied by the _____ nerve.
median; radial
The motor component of the anterior hand is supplied by the _____ nerve except to 1 ½ m groups.
ulnar
The sensory component of the upper lateral cut is supplied by the _____ nerve; The lower lateral cut is supplied by the _____ nerve; The posterior cut is supplied by _____ nerve.
axillary; radial; radial
The sensory component of the medial antebrachial cut and the lateral antebrachial cut is supplied by the _____ nerve. The posterior antebrachial cut is supplied by the _____ nerve.
musculocutaneous; radial
The sensory component of the hand is supplied by the terminal ____ nerve.; terminal _____ nerve.; terminal _____nerve.
ulnar; median; radial
What are the nerves to the true upper limb?
terminal branches (mixed nerves)
What does the true upper limb consist of?
arm
forearm
hand
The arm (brachium) has what type of sensory patches
brachial cutaneous nerves
The forearm (antebrachium) has what type of sensory patches
antebrachial cutaneous nerves
The hand (manus) has what type of sensory patches
cutaneous terminal branches of median, ulnar, and radial nerves
the distribution of all motor and sensory nerve fibers from one spinal cord segment.
segmental innervation
the sensory distribution to the specific area of skin from one spinal cord segment
dermatomes
Each nerve branch that comes off the brachial plexus is known as a
peripheral nerve
these nerves can be motor nerves, sensory nerves (cutaneous), or mixed nerves
peripheral nerves
What are the motor peripheral nerves to the upper limb?
Dorsal Scapular Nerve
Long Thoracic Nerve
Nerve to Subclavius
Suprascapular Nerve
Lateral Pectoral Nerve
Medial Pectoral Nerve
Upper Subscapular Nerve
Middle Subscapular (Thoracodorsal) Nerve
Lower Subscapular Nerve
What are the sensory (cutaneous) peripheral nerves to the upper limb?
Musculocutaneous Nerve
Median Nerve
Ulnar Nerve
Axillary Nerve
Radial Nerve
What are the mixed peripheral nerves to the upper limb?
Intercostobrachial Nerve (First intercostal nerve)
Upper Lateral Brachial Cutaneous Nerve (Axillary)
Lower Lateral Brachial Cutaneous Nerve (Radial)
Posterior Brachial Cutaneous Nerve (Radial)
Medial Brachial Cutaneous Nerve
Lat. Antebrachial Cut. N. (Musculocutaneous)
Medial Antebrachial Cutaneous Nerve
Posterior Antebrachial Cutaneous Nerve (Radial)
Terminal (cutaneous) branches of Median Nerve
Terminal (cutaneous) branches of Ulnar Nerve
Terminal (cutaneous) branches of Radial Nerve
the more proximal the nerve, the higher the spinal level that contributes axons to that _____.
nerve
Axillary nerve dermatomes:
C5 & C6
supplies the lateral (thumb side) arm and forearm
Radial dermatomes:
C5-C8
supplies the lateral arm, forearm, and whole hand
Musculocutaneous dermatomes:
C5-C7
supplies the lateral arm, forearm, thumb, and 2nd/3rd digits
Median dermatomes:
C5-T1
supplies the lateral/medial arm, forearm (except for the armpit), and the whole hand
Ulnar dermatomes:
C8 & T1
supplies the medial arm, forearm, half of the 4th digit, and the 5th digit (pinky)
What is a reflex arc? What are the components of a reflex arc?
A simple spinal reflex is the least complicated spinal reflect arc, and it includes the sensory and motor neurons working as a unit at the spinal level.
A reflex arc that involves one synapse between two neurons, an afferent (sensory) and an efferent (motor)
monosynaptic reflex arc
A reflex arc that involves multiple synapses (at least two) between an efferent neuron, an afferent neuron, and at least one interneuron.
polysynaptic reflex arc
What is an example of a monosynaptic reflex arc?
stretch-postural reflex
What is an example of a polysynaptic reflex arc?
flexor/withdrawal reflex
cross-extensor reflex
What is an example of a complicated polysynaptic reflex that occurs in conjunction with one of the simple spinal reflexes?
cross-extensor reflex
descending motor pathways from the brain that can inhibit or incite motor neurons of lower levels making it easier or more difficult for a reflex to occur. These influences are responsible for voluntary and some automatic control of the lower motor neurons.
supraspinal influences
What is an example of a neurological test for a supraspinal lesion?
Babinski reflex
What are the five regions of the brain?
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Mylencephalon
Name white/gray matter structures in the telencephalon:
White matter:
1. corona radiata
2. corpus callosum
Gray matter:
1. caudate nucleus- execution of movement
2. putamen- learning and motor control, including speech articulation
Name white/gray matter structures in the diencephalon:
White matter:
1. internal capsule
2. fornix
Gray matter:
1. thalamus-regulates consciousness, arousal, and attention
2. hypothalamus- maintains body temperature, metabolic rate, etc
Name white/gray matter structures in the mesencephalon:
White matter:
1. cerebral peduncles
2.
Gray matter:
1. tectum- auditory and vision
2. substantia nigra
Name white/gray matter structures in the metencephalon:
White matter:
1. corticospinal tract- voluntary motor function
2. spinothalamic tract- pain and temperature conscious
Gray matter:
1. pneumotaxic center- preventing overdistention of the lungs
2. apneustic center- controls the intensity of breathing and delay
Name white/gray matter structures in the myelencephalon:
White matter:
1. fasciculus gracilis- discriminative touch and conscious proprioceptive information from the lower half of the body to the brain
2. fasciculus cuneatus- discriminative touch and conscious
proprioceptive information from the upper half of the body
Gray matter:
1. nucleus gracilis- discriminative touch and conscious proprioceptive information
2. nucleus cuneatus- discriminative touch and conscious proprioceptive information
the ability of neurons to change their function, the quantity and types of neurotransmitters that they produce (i.e. their chemical profile), and/or their structure.
neuroplasticity
During motor learning, what happens to the number of active regions in the brain?
there is a reduction in the amount of active regions in the brain.
the act of attempting to decrease the exaggerated neural response to a stimulus.
habituation
Examples of Habituation:
- PT/OT treatment for tactile defensiveness-stimulating the child’s skin with gentle stimulation at first, then gradually increasing the stimulation, in an effort to cause the patient to be able to tolerate the tactile stimulation (and thereby achieve habituation).
- people with tinnitus. Hearing aids can be used to habituate to the ringing over a prolonged period of time.
- a learned experience in paying attention to certain important stimulations (like listening to a lecture) while tuning out certain other less important stimulations (like the itchiness of a sweater).
In adults, how is recovery from injury promoted in the CNS?
through neuroplasticity. Neuronal communication sites are continuously being created and broken.
Why does functional regeneration of axons occur more frequently in the peripheral nervous system (PNS) than in the CNS?
Because of the production of nerve growth factor by Schwann cells, the clearing of debris, and residual Schwann cell sheaths that guide peripheral axonal regrowth to the target. Schwann cells don’t exist in the CNS. If rehabilitative exercise begins 5 days after a (neurological injury) peripheral nerve lesion it can increase axonal regeneration and innervation of a muscle.
What are some rehabilitation mechanisms that can promote beneficial neural plasticity?
- Initiating therapy early after injury (for example rehabilitative exercise beginning 5 days after a peripheral nerve lesion), while avoiding vigorous use or overuse of the impaired extremity (such as in the upper limb).
- Practicing many repetitions of specific tasks to elicit beneficial adaptive neuroplasticity (such as in habituation and motor cortical reorganization)
- The use of transcranial magnetic stimulation (TMS) to enhance or inhibit motor learning and memory formation.
- Using evidenced-based therapy for chronic strokes such as task-specific training (for example forced use training (FUT)/ constraint-induced movement therapy (CIMT).
Upper Motor Neuron Lesions:
Spastic paralysis
*hyperreflexia
*hypertonia
*spasticity
Lower Motor Neuron Lesions:
Flaccid Paralysis
* hyporeflexia
*hypotonia
*atrophy
*flaccidity
Dorsal Column lesions:
Multiple Sclerosis, loss of proprioception in the hands and fingers, Astereognosis
Spinothalamic lesions:
Syringomyelia, loss of pain & temp awareness, Charcot’s joints
Blood supply to the brain:
The circle of Willis:
distributing vessels
vertebral arteries
internal carotid arteries
Blood supply to the spinal cord:
Anterior spinal arteries (anterior cord)
Left/Right posterior spinal arteries (posterior cord)
Left/Right radicular arteries (lateral cord)