Exam #2 Flashcards
1
Q
What spinal nerves make up the brachial plexus?
A
C5-T1
2
Q
What are the 3 connective tissue sheaths of a peripheral nerve?
A
endoneurium
perineurium
epineurium
3
Q
The epineurium surrounds the ______ and the perineurium surrounds ______ and the endoneurium surrounds _______.
A
peripheral nerve; fascicle; and individual axon
4
Q
Peripheral nerves connective tissue sheaths:
A
- Protect the axons and glia
- Support changes in length during movement
Connective tissues stretch
Axon unfolding
Fascicle gliding - Innervated with nociceptive free nerve endings
5
Q
Peripheral nerves blood supply:
A
- Peripheral nerves supplied by arterial branches that enter the nerve trunk
- Movement promotes the flow of blood through the nerves
- Blood supply is needed:
Nutrition
Oxygen
Waste removal - Movement promotes the flow of axoplasm through the axons
Axoplasm thickens at rest
Movement thins it
Facilitates axoplasmic transport
6
Q
where motor axons synapse with muscle fibers and have a 1:1 ratio (axon to fiber)
A
neuromuscular junction
7
Q
Neuromuscular Junction:
A
These synapses only require depolarization of the motor axon to release ACh and depolarize the muscle membrane
No summation of action potentials is needed to depolarize the postsynaptic membrane
Inhibition is not possible
Miniature end-plate potentials
8
Q
Peripheral nerve dysfunction: sensory changes
A
Decreased, altered, or lost sensation
(E.g., hyperalgesia, dysesthesia, paresthesia, allodynia)
9
Q
Peripheral nerve dysfunction: autonomic changes
A
- Single severed nerve: Lack of sweating, loss of control of sympathetic control of vascular smooth muscle fibers
- Many affected nerves: impotence, HR & BP regulation issues, bladder/bowel dysfunction
10
Q
Peripheral nerve dysfunction: motor changes
A
- Paresis or paralysis
- Muscle atrophy
- Fibrillation (spontaneous contraction of individual muscle fibers)
11
Q
Peripheral nerve dysfunction: trophic (nutritional) changes
A
- Damaged nerves do not provide nutrition to the target tissues (remember those mini end-plate potentials?)
(E.g., muscle atrophy, shiny skin, dystrophic nails, thickening subcutaneous tissue, poor wound healing, blood supply changes,
lack of movement, loss of sensation, etc)
12
Q
What does the spinal region consist of?
A
Spinal cord
Dorsal and ventral roots
Spinal nerves
Meninges
13
Q
What does the gray matter consist of?
A
dorsal horn
ventral horn
lateral horn
14
Q
What does the white matter consist of?
A
Propriospinal neurons
Tract cells
* Sensory
* Upper motor neurons
15
Q
what gray matter horn is primarily sensory information
A
dorsal horn
16
Q
what gray matter horn is primarily motor information
A
ventral horn (cell bodies of lower motor
neurons)
17
Q
what gray matter horn is primarily autonomic information
A
lateral horn
18
Q
axons of LMN cell bodies from a single segment
A
ventral root
19
Q
sensory axons
A
dorsal root
20
Q
carry all of the motor, autonomic, and sensory axons of a single segment.
A
spinal nerve
21
Q
innervate paravertebral muscles, posterior vertebra, & overlying cutaneous areas
A
dorsal rami
22
Q
innervate the skeletal, muscular, and cutaneous areas of the limbs; anterior & lateral trunk
A
ventral rami
23
Q
the dorsal nerve root and ventral nerve root merge to form
A
spinal nerve
24
Q
what two things branch off of the spinal nerve
A
dorsal ramus and ventral ramus
25
Segmental organization of the spinal cord:
medulla-> L1-L2 intervertebral space
26
Where does C1-C7 spinal nerves exit?
above the corresponding vertebra
27
C8 exits below ______ because there are no C8 vertebrae.
C7
28
Thoracic, lumbar, sacral spina nerves exit
below the
corresponding vertebra
29
Meningies:
Pia mater closely adheres to spinal cord
---- CSF in subarachnoid space ----
Arachnoid
---- Subdural space ----
Dura tough outer layer
---- Epidural space ----
Vertebrae
30
nerve compression injury (myelin injured) grade 1
neuropraxia
31
axonotmessis
32
neurotmesis
33
Neuropathy symptoms:
unusual sensation
numbness
34
nerve that is motor in the brachial part of the upper extremity and when it crosses the elbow it becomes sensory.
musculocutaneous nerve
35
ulnar nerve
36
radial nerve
37
Interneurons:
Integrate activity from multiple
inputs
Adjust output of lower motor
neurons
Influence whether a motor neuron
fires
Inhibitory interneurons provide:
* Reciprocal inhibition
* Recurrent inhibition
38
also known as claw hand
ulnar nerve palsy
39
decreases antagonist
opposition to the action of
agonist muscles
Reciprocal inhibition
40
focuses motor activity
Recurrent inhibition
41
a group of nerve fibers that share common origins, terminations, and functions
spinal tract
42
pathways that carry impulses from pain, thermal, tactical, muscle, and joint receptors to the brain
ascending pathways
43
What are the 3 neurons in ascending tracts?
1st order neuron
2nd order neuron
3rd order neuron
44
1st order neuron:
Enters the spinal cord through the dorsal root (cell body in the dorsal root ganglion)
Stays on the ipsilateral side of the spinal cord
Terminates in a synapse with 2nd order neuron either in spinal grey matter OR medulla
45
2nd order neuron:
Cell body in the spinal cord or medulla
Axon decussates to contralateral side
Ascends to thalamus and terminates with 3rd order neuron
46
3rd order neuron:
Cell body in the thalamus
Axon passes to the somatosensory cortex of the ipsilateral hemisphere
47
a tract that carries information about
touch and proprioception to
the ipsilateral side of the body
dorsal column tract
48
Where does the dorsal column decussate?
medulla
49
a tract that carries information about pain, thermal sensations, pressure, &
non-discriminate touch.
spinothalamic tract
50
a tract that carries information from
muscle spindles to the cerebellum and serve to control posture and coordination
spinocerebellar tract
51
tracts that originate from cerebral cortex and brain stem that controls movement, muscle tone, spinal reflexes, spinal autonomic functions, and modulation of sensory transmission to higher centers
descending tracts
52
a tract that is the central motor relay pathway – voluntary, selective,
discrete, skilled movements
corticospinal tract
53
reticulospinal tract
54
a tract that receive information about head movement and
position from the inner ear
Vestibulospinal tract
55
Autonomic system function:
1. Maintain homeostasis of the internal environment
2. Regulates reproduction
56
a hematoma that results from arterial bleeding between the skull and the dura mater. Most often this hematoma occurs when the middle meningeal artery is torn by a fracture of the temporal or parietal bone.
epidural hematoma
57
bleeding is slow in this hematoma because the hematoma is produced by venous bleeding, where the blood pressure is less than in arteries.
subdural hematoma
58
Epidural and Subdural Hematoma:
both types of hematoma are potentially life-threatening because neural tissue is compressed and displaced
59
A CSF disorder where CSF circulation is blocked, and pressure builds in the ventricles
hydrocephalus
60
a type of hydrocephalus that's present at birth
congenital hydrocephalus
61
a type of hydrocephalus that occurs after birth
acquired hydrocephalus
62
a type of hydrocephalus where the ventricular system is intact (communicating), and a blockage exists beyond the fourth ventricle.
communicating hydrocephalus
63
a type of hydrocephalus (also called obstructive) where the blockage is within the ventricular system itself, most often the cerebral aqueduct
noncommunicating hydrocephalus
64
inflammation of the meninges that surround the brain and/or spinal cord
meningitis
65
a type of stroke that occurs when an embolus or thrombus lodges in a vessel, obstructing blood flow. Typically, an embolus abruptly deprives an area of blood, resulting in almost immediate onset of deficits
brain infarction
66
a type of stroke deprives the downstream vessels of blood, and the extravascular blood exerts pressure on the surrounding brain. Generally, hemorrhagic strokes present with the worst deficits within hours of onset; then improvement occurs as edema decreases and extravascular blood is removed
hemorrhage
67
What are the two types of strokes?
brain infarction
hemorrhage
68
If the axon diameter is large the conduction speed will be ______.
fast
69
If the axon diameter is small the conduction speed will be ______.
slow
70
a plexus emerges between the anterior and middle scalene muscles, passes deep to the clavicle, and enters the axilla
brachial plexus
71
What are the terminal branches (nerves) of the brachial plexus?
musculocutaneous
axillary
median
ulnar
radial
72
condition or injury that impacts nerves
outside the brain and or spinal cord
peripheral nerve injury
73
How does movement impact the health of peripheral nerves?
optimizes the health of nerves by promoting the flow of blood throughout the nerves and the flow of axoplasm through the axons by facilitating retrograde and anterograde transport
74
What are some sensory changes of peripheral nerve damage?
decreased or lost sensation and/or abnormal sensations:
hyperalgesia
dysesthesia
paresthesia
allodynia
75
What are some motor changes of peripheral nerve damage?
paresis (weakness) or paralysis
76
What are some autonomic changes of peripheral nerve damage?
difficulty regulating:
blood pressure
heart rate
sweating
bowel and bladder functions
77
What are some trophic changes of peripheral nerve damage?
muscle atrophy
shiny skin
brittle nails
thickening of subcutaneous tissues
78
Mechanisms of peripheral injuries:
laceration
compression
stretch
79
What are the symptoms of neuropathy?
tingling
numbness
burning
unusual sensations
pain from light touch
balance problems
twitching
muscle cramping
80
What muscles does the radial nerve innervate?
o Triceps
o Brachioradialis
o ECRL
o ECRB
o Supinator
81
Radial nerve injuries:
wartenbergs syndrome
radial nerve palsy
82
a radial nerve injury that causes radial nerve compression and symptoms of paresthesia (pins and needles)
wartenbergs syndrome
83
a radial nerve injury that causes the inability to lift the wrist or fingers (wrist drop)
radial nerve palsy
84
What muscles does the median nerve innervate?
o PT
o FCR
o PL
o FDS
85
Median nerve injuries:
carpal tunnel syndrome
AIN palsy
ape hand
hand of benediction
86
a type of median nerve injury that causes median nerve compression at the carpal tunnel (paresthesia, weak grip, sleep disruption)
carpal tunnel syndrome
87
a median nerve motor impairment that causes the inability to make the "okay" sign
AIN palsy
88
a median nerve injury that causes wasting of the thenar eminence 2/2 median nerve palsy and inability to abduct and oppose the thumb
ape hand
89
high median nerve injury at the level of elbow/forearm that impacts digits 2 and 3
hand of benediction
90
What muscles does the musculocutaneous nerve innervate?
Coracobrachialis
Biceps
Brachialis
91
What muscles does the ulnar nerve innervate?
FCU
FDP RF/SF
AddPol
FPB – deep head
Interossei Muscles: Dorsal, Palmar
Lumbricals RF/SF
Hypothenar Group
92
Ulnar nerve injuries:
cubital tunnel syndrome
ulnar tunnel syndrome (guyon's canal)
ulnar nerve palsy (claw hand)
93
ulnar nerve compression at
medial elbow (cubital tunnel) that causes paresthesia, weak grip, and medial hand pain
cubital tunnel syndrome
94
ulnar nerve compression at
Guyon’s canal that causes weakness and/or numbness ulnar side of hand/hypothenar area (gripping handle bars)
ulnar tunnel syndrome
95
Ulnar nerve injury:
MPJ hyperextension
Intrinsic paralysis: interossei, lumbricals
Intact extrinsic tendons: flexors, extensors
ulnar nerve palsy (claw hand)
96
How does movement impact the health of peripheral nerves?
movement optimizes the health of nerves by promoting the flow of blood throughout the nerves and the flow of axoplasm through the axons (facilitates anterograde and retrograde)
97
The musculocutaneous nerve innervates the following muscles in the arm: (Flexors)
Biceps brachii
Brachialis
Coracobrachialis
98
The axillary nerve innervates the following muscles of the arm:
Deltoid
Teres minor
Part of the triceps
99
The median nerve innervates the following muscles of the arm:
muscles in the forearm, hand, and intrinsic hand muscles (e.g. flexor carpi radialis, thenar muscles, abductor pollicis brevis, etc)
100
The ulnar nerve innervates the following muscles of the arm:
muscles in the forearm, hand (e.g. Flexor carpi ulnaris, Palmaris brevis, lumbricals, hypothenar muscles, etc)
101
The radial nerve innervates the following muscles of the arm:
many muscles in the arm and forearm, including: Triceps brachii, Brachioradialis, Extensor carpi radialis longus, etc)
102
Associate axon diameter with conduction speed and innervated structures.
peripheral axons are classified into groups according to their speed of conduction and their diameter. Myelinated axons are generally much faster than unmyelinated.
103
Explain how to determine if a lesion that causes motor, autonomic, and somatosensory signs and symptoms in the lower limb is in the peripheral or central nervous system.
prominent muscle atrophy, fasciculations, and reduced reflexes point toward a peripheral nerve lesion, while increased reflexes, spasticity, and a more diffuse sensory loss might indicate a central nervous system lesion
104
Compare and contrast the neuromuscular junction with other synapses in the nervous system:
NMJ: synapse that connects a motor neuron to a muscle fiber
Other synapses: large postsynaptic membrane with a high concentration of acetylcholine receptors
105
Describe the anatomic relationship between spinal cord segments and vertebrae in adults.
Because the spinal cord in the adult is significantly shorter than the vertebral column, the levels of spinal cord segments below C2 do not correspond with vertebral levels.
106
What skeletal muscles does C2 innervate? (head & neck movements)
sternocleidomastoid
trapezius
107
What skeletal muscles does C3 innervate? (breathing)
diaphragm
108
What skeletal muscles does C4 innervate? (scapular elevation & retraction)
levator scapulae
rhomboids
109
What skeletal muscles does C5 innervate?
Supraspinatus
Serratus anterior
Biceps
Brachialis
Deltoid
Pectoralis major
110
What skeletal muscles does C6 innervate?
Supinator
Pronator teres
Latissimus
Long extensors of wrist/fingers
Pectoralis major
111
What skeletal muscles does C7 innervate?
Triceps
Supinator
Pronator teres
Latissimus dorsi
Long extensors of wrist/fingers
Pectoralis major
Serratus anterior
112
What skeletal muscles does C8 innervate?
Long flexors of wrist and fingers
Serratus anterior
Latissimus dorsi
Pectoralis major
Triceps
113
What skeletal muscles does T1 innervate?
Hand intrinsics
Long flexors of wrist and fingers
Pectoralis major
Triceps
114
What two tracts are located on the right side of a cross-section of the spinal cord?
dorsal column
lateral spinothalamic tract
115
What tract is located on the left side of a cross-section of the spinal cord?
lateral corticospinal tract
116
Dorsal Column:
Origin: Peripheral receptors
Decussation: Medulla
Function: light touch/conscious proprioception
117
Spinothalamic tract:
Origin: Dorsal horn
Decussation:
Function: Pain and temperature
118
Lateral corticospinal tract:
Origin: Motor/Premotor/Primary motor cerebral cortex
Decussation:
Function: motor control of hand movements
119
Reticulospinal tract:
Origin: Reticular formation in the medulla/pons
Decussation:
Function: Posture & gross movements
120
Vestibulospinal tract:
Origin: Vestibular nuclei in the medulla and pons
Decussation:
Function:
121
A type of inhibition where a muscle relaxes on one side of a joint to allow the opposing muscle to contract. This prevents muscles from working against each other when an external load is applied.
Reciprocal inhibition
122
A type of inhibition where a population of neurons excites another population, which then inhibits the activity of the first population
Recurrent inhibition
123
Describe autonomic and somatic control for normal bladder filling and emptying
Autonomic:
*Sympathetic- regulates urine storage in the bladder
*Parasympathetic- relaxes the internal urethral sphincter allowing the bladder to empty.
Somatic:
external urethral sphincter keeps the bladder closed and prevents emptying. During urination (voiding), this tonic activity is temporarily inhibited, allowing the external sphincter muscle to relax
124
Reflexive bladder function:
a bladder that empties automatically when it's full, without conscious control. This happens when the bladder stretches and sends signals to the spinal cord, which then sends a message back to the bladder to contract and release urine
125
A bladder dysfunction that causes a paralyzed bladder to overfill with urine, and when the bladder cannot stretch any further, urine dribbles out.
flaccid bladder function
126
Explain the effects on sexual functioning in males and females above T12 spinal cord lesions:
affects psychogenic arousal in both, meaning they may not be able to achieve arousal through thoughts or mental stimulation
127
Explain the effects on sexual functioning in males and females with between T12 & S1 spinal cord lesions:
may still allow for some psychogenic arousal but primarily rely on reflexogenic arousal
128
Explain the effects on sexual functioning in males and females with below S1 spinal cord lesions:
significantly impact both psychogenic and reflexogenic arousal, leading to major difficulties with sexual function
129
What impact does spinal cord injury have on male and female fertility?
fertility returns to normal after a few months and they can conceive and often have a normal pregnancy; however, they frequently require cesarean delivery due to impaired sensation and volitional control and to prevent autonomic dysreflexia.
130
What impact does spinal cord injury have on male and female fertility?
131
affects only one spinal cord segment
segmental dysfunction
132
Signs of segmental dysfunction:
* lose of sensation in a dermatome
* decreased or lost of muscle power in a myotome
* decreased of lost of phasic stretch
133
affects everything below the lesion
vertical tract dysfunction
134
Signs of vertical tract dysfunction:
* altered or lost of sensation below the level of the lesion
* altered or lost of descending control of BP, pelvic viscera, or thermoregulation
135
a spinal region syndrome that is typically caused by a disruption of blood flow in the anterior spinal artery. The ischemia damages the anterior two-thirds of the spinal cord, affecting ascending spinothalamic tracts and descending upper motor neurons.
Anterior cord syndrome
136
a spinal region syndrome that usually occurs at the cervical level as a result of trauma
Central cord syndrome
137
a spinal region syndrome that results from a hemisection of the cord. Segmental losses are ipsilateral and include loss of lower motor neurons and all sensations
Brown-Séquard syndrome
138
a spinal region syndrome that indicates damage to the lumbar and/or sacral spinal roots, causing sensory impairment and flaccid paresis or paralysis of lower limb muscles, bladder, and bow
Cauda equina syndrome
139
a rare neurological condition caused by inflammation (swelling) of the spinal cord
Transverse myelitis
140
a narrowing of the spinal canal that puts pressure on the spinal cord and nerves
spinal stenosis
141
Symptoms of spinal stenosis:
tingling, prickling, burning, and/or electrical sensations), pain, and numbness, along with myotomal (lower motor neuron) distribution of weakness and atrophy in the upper limb
142
Label a diagram of a spinal segment and explain how these:
143
Describe the role of the autonomic nervous system in maintaining homeostasis:
regulating the activity of internal organs and vasculature including circulation, respiration, digestion, metabolism, secretions, body temperature, and reproduction
144
What are the two routes used to transmit information from visceral receptors to the central nervous system?
1. spinal cord
2. cranial nerves “glossopharyngeal (CN 9) and vagus nerves (CN 10)
145
Describe the spinal cord route used to transmit information from visceral receptors to the central nervous system:
visceral afferent fibers travel through spinal nerves to the spinal cord, then ascend to the brain via the spinothalamic tract (responsible for visceral information from the thoracic organs)
146
Describe the cranial nerves route used to transmit information from visceral receptors to the central nervous system:
carries signals directly to the brainstem via the nucleus of the solitary tract (responsible for visceral sensations from the abdominal and pelvic regions)
147
How does afferent autonomic information can cause referred pain?
nerve fibers carrying visceral (organ) sensations converge with somatic (skin) sensory fibers at the same spinal cord level, causing the brain to misinterpret the pain signal as originating from the somatic area instead of the visceral organ, leading to pain felt in a seemingly unrelated body region
148
What is the role of the pons in the regulation of autonomic functions?
regulating respiration
149
What is the role of the medulla in the regulation of autonomic functions?
regulates heart rate, respiration, vasoconstriction, and vasodilation via signals to autonomic efferent neurons in the spinal cord and by signals conveyed in the vagus nerve
150
What is the role of the hypothalamus in the regulation of autonomic functions?
master control of HOMEOSTASIS, influences cardiorespiratory, metabolic, water reabsorption, and digestive activity by acting on the pituitary gland, control centers in the brainstem, and spinal cord
151
What is the role of the emotion/motivation system in the regulation of autonomic functions?
produce autonomic responses. For example, we have increased BP due to anxiety.
152
Compare the somatic motor system with the autonomic efferent system:
1. Unlike with the somatic nervous system, regulation of autonomic functions is typically nonconscious and can be exerted by hormones.
2. Unlike skeletal muscle, many internal organs can function independently of central nervous system input. Examples include independent activity of the heart and the GI tract.
3. Somatic efferent pathways have one neuron in the peripheral nervous system; autonomic efferent pathways usually comprise two neurons that synapse outside the central nervous system.
153
Sympathetic (Fight or Flight):
increases heart rate, dilates pupils, inhibits digestion, stimulates sweating, releases adrenaline, prepares the body for immediate action in a stressful situation
154
Parasympathetic (Rest and Digest):
slows heart rate, constricts pupils, stimulates digestion, promotes urination, conserves energy, relaxes the body after a stressful event.
155
Explain the autonomic responses to threat:
prepares the body for action in response to a perceived threat through a process called the fight-or-flight response. The ANS activates the sympathetic nervous system (SNS), which triggers a series of physiological changes that help the body cope with danger
156
Compare sympathetic and parasympathetic effects on organ function:
Heart rate: The SNS increases heart rate, while the PNS slows it down.
Blood pressure: The SNS increases blood pressure, while the PNS decreases it.
Breathing: The SNS increases breathing rate, while the PNS slows it down.
Digestion: The SNS slows digestion, while the PNS increases it.
Pupils: The SNS dilates pupils, while the PNS constricts them.
Bronchi: The SNS dilates bronchi, while the PNS constricts them.
Blood vessels: The SNS constricts blood vessels, while the PNS stimulates vasodilation.
157
Identify the types of receptors in the autonomic system and their clinical significance.
158
Identify the types of receptors in the autonomic system and their clinical significance.
cholinergic receptors (which bind to acetylcholine)
adrenergic receptors (which bind to norepinephrine and epinephrine)
159
Cholinergic Receptors:
Nicotinic receptors: Found at all autonomic ganglia, stimulating neurotransmitter release from postganglionic neurons; clinically, nicotine can activate these receptors, leading to effects like increased heart rate and blood pressure.
Muscarinic receptors (M1-M5): Primarily located on target organs innervated by the parasympathetic nervous system, responsible for functions like slowing heart rate, increased salivation, and smooth muscle contraction; medications targeting these receptors can be used to treat conditions like overactive bladder or glaucoma.
160
Adrenergic Receptors (also called "Alpha" and "Beta" receptors):
Alpha-1 receptors: Primarily cause vasoconstriction when stimulated, leading to increased blood pressure; alpha-blockers are used to treat hypertension.
Alpha-2 receptors: Generally have inhibitory effects, including decreasing norepinephrine release; can be targeted for managing blood pressure.
Beta-1 receptors: Located mainly in the heart, increasing heart rate and contractility when stimulated; beta-blockers are used to treat conditions like tachycardia.
Beta-2 receptors: Primarily found in smooth muscle of the lungs and blood vessels, causing relaxation (bronchodilation and vasodilation) when activated; beta-2 agonists can be used to treat asthma.
161
Describe trophic skin changes.
Skin: Thinning, wasting away, or glossy skin
Nails: Brittle nails or changes in the nail beds
Hair: Thickening or thinning of hair, or excess growth
Sensation: Loss of sensation, particularly pain and temperature
Healing: Slower healing
162
Define autonomic dysreflexia and describe common causes and appropriate interventions.
Medical emergency affecting people with SCI above T6
Occurs when an unperceived noxious stimulus BELOW the level of injury causes sympathetic overactivity
Sweating/flushing above the lesion
Pounding headache
High blood pressure
Pallor below the lesion level
Lower HR
Common
163
What are the common causes of autonomic dysreflexia?
Overstretched bladder or rectum
Unperceived pain or infection of a pressure ulcer
164
Position the patient upright
Loosen tight clothing
Monitor vital signs
Medications
Preventative measures:
*Regular bladder catheterization
*Bowel management program
*Skin care to prevent pressure ulcers
*Patient education on identifying triggers and managing symptoms
165
occurs when the autonomic nervous system (ANS) fails to regulate blood pressure in response to standing up
Neurogenic orthostatic hypotension
166
Explain the causes of neurogenic orthostatic hypotension.
Spinal region disorders
Autonomic degenerative disorders
e.g., Parkinson’s disease
Peripheral neuropathies
e.g., Diabetes, toxin exposures,
nutritional deficiencies
