Nervous System Flashcards
1
Q
What are the two parts of the nervous system?
A
- central nervous system (cns)
- peripheral nervous system (pns)
2
Q
What are the structures of the CNS?
A
- brain
- spinal cord
3
Q
What structures make up the PNS?
A
all cell bodies and nerve fibers outside of the brain & spinal cord
4
Q
What are the functions of the nervous system?
A
- sensory (afferent) system: sends sensory information to the brain via CNS
- motor (efferent) system: sends motor impulses from the brain to muscles & glands
5
Q
What is the sensory (afferent) nervous system?
A
- somatic sensory system provides sensation of touch & pain to muscles/joints
- visceral sensory system provids pain & reflex information sesnsation from viscera of body cavities
6
Q
What is the motor (efferent) nervous system?
A
- somatic motor system supplies the skeleta; muscle (voluntary)
- visceral motor system (autonomic) supplies smooth muscles, glands, and heart (involuntary)
7
Q
What do the sensory (afferent) and motor (efferent) systems have in common?
A
both consist of somatic & visceral components
8
Q
What are neurons?
A
- structural & funcational units
- provide rapid communication within the nervous systems
9
Q
What are the components of a neuron?
A
- cell body
- dendrites
- axon
- myeline
- synapse
10
Q
What is a cell body?
A
main body of a neuron with extensions (aka dendrites)
11
Q
What are dendrites?
A
- extensions from the cell body
- receiving end of the neuron
12
Q
What is an axon?
A
- carries impulse to & from the cell body & sending end of the neuron
13
Q
What is a myelin?
A
- forms a sheath that surrounds some axons
- increases the speed of impulse conduction
14
Q
What is a synapse?
A
point where neurons communicate with each other
15
Q
What are neuroglia?
A
- support neurons
- non-neural cells
- forms a major part of the nervous system
16
Q
What are the structures of the PNS?
A
- bundles of nerve fibers
- connective tissue sheaths
- blood vessels (vasa nervorum)
17
Q
What are the components of an indivdual nerve fiber?
A
- axon
- neurolemma
- endoneurium
18
Q
What are the types of nerve fibers?
A
- myelinated
- unmyelinated
19
Q
What are the components of connective tissue sheaths?
A
- endoneurium
- perineurium
- epineurium
20
Q
What is the endoneurium?
A
layer that surrounds the neurolemma/axon of nerve fiber
21
Q
What is the perineurium?
A
layer that surrounds bundle of nerve fibers
22
Q
What is the epineurium?
A
Outermost covering of a nerve
23
Q
What are the two major types of peripheral nerves?
A
- cranial nerves
- spinal nerves
24
Q
Describe cranial nerves
A
- originates from the brain
- exits cranial cavity via foramina
- 12 pairs (aka 24 nerves)
25
Where do the 12 pairs of cranial nerves arise rom?
- 11 pairs arise from brain
- 1 pair arises from ** superior spinal cord**
26
Describe the spinal nerves
- originates from the spinal cord
- exits the **intervertbral formaina** of vertebral column
- 31 pairs (aka 62 nerves)
27
What are the categories of spinal nerves?
- cervical (8)
- thoracic (12)
- lumbar (5)
- sacral (5)
- coccygeal (1)
28
What are the structures of the spinal cord?
1. nerve rootlets
2. nerve root
3. spinal nerve
4. divides into two branches
5. dermatomes
6. myotomes
7. visceral motor fibrs of sympathetic nervous system
29
What are the structures of the spinal nerve (medial to lateral)?
1. nerve rootlets
2. nerve root
3. spinal nerve
4. divides into two branches
30
What is a nerve rootlet?
- arises from spinal cord
- converges & forms a nerve root (beginning formation)
31
What are the two types of nerve roots?
- anterior (ventral) root
- posterior (dorsal) root
32
What is the function of the anterior/ventral root?
- motor (efferent) fiber
- conducts motor output from brain
33
What is the function of the posterior/dorsal root?
- sensory (afferent) fiber
- receives and sends sensory information to brain
34
Describe the anterior & posterior roots
- **form a spinal nerve**
- two roots unite at **intervertebral foramen**
35
What the the two nerve branches?
- originate from spinal nerve
- creates **posterior dorsal rami** & **anterior rami**
36
What type of nerve is a spinal nerve?
mixed (sensory & motor)
37
What is the posterior (dorsal) rami?
supplies the following
- joints of the vertebrae
- deep muscles of the back
- overlying skin
38
What is the anterior rami?
supplies the following:
- anterior & lateral regions fo the trunk
- upper extremities (via brachial plexus)
- lower extremities (via lumbrosacral plexus)
39
40
What is a dermatome?
- somatic **sensory** fibers
- located throughout the body
- provides sensation posterior & anterior
41
What is a myotome?
- somatic **motor** fibers
- located throughout the body
- provides sensation posterior & anterior
42
How are dermatomes labeled?
from head to toe
43
Describe how spinal injuries are described using dermatomes & myotomes?
- patient is described by their last working dermatome/myotome
- ex: someone with a C7 injury is labeled as a C6
44
True or False:
A person with damaged dermatomes will have damaged myotomes.
False
- someone with damaged dermatomes may have functional myotomes (or vice versa)
45
What is the Asia Scale?
- system that classifies the severity of spinal cord injuries
- uses a 5-point scale (A-E) from most severe to typical function
46
What are the different levels of spinal cord injuries within the Asia Scale?
A: Complete injury, with no sensory or motor function in the sacral segments S4-S5
B: Sensory incomplete injury, with preserved sensation below the neurological level of injury and in the sacral segments S4-S5
C: Motor incomplete injury, with preserved motor function below the neurological level and most key muscles below the neurological level having a muscle grade of less than 3
D: Motor incomplete injury, with preserved motor function below the neurological level and most key muscles below the neurological level having a muscle grade of greater than or equal to 3
E: Normal injury, with normal sensory and motor functions
47
What is the autonomic nervous system (ANS)?
- aka visceral motor system
- contains afferent & efferent muscle fibers
- 2 divisions
48
What do the visceral efferent motor fibers stimulate?
- smooth muscle
- cardiac muscle
- glands
49
What is the function of the visceral afferent sensory fibers?
- conductor of pain
- helps regulate the visceral function
50
What are the two divisions of the ANS?
- sympathetic division
- parasympathetic division
51
Describe the sympathetic division of the ANS
- thoracolumbar division
- flight or fight response for stress
- **primary function:** regulate blood vessels
52
Describe the parasympathetic division of the ANS
- craniosacral division
- rest & digest
- energy conserving
53
How do you treat a compressed or crushed nerve?
- non-surgical treatment
- no surgery is required bc connective tissue sheath is **intact** & guides grown axon to anatomical destination
54
What diagnosis could cause a compressed or crushed nerve?
carpal tunnel syndrome
55
How do you treat a lacerated nerve?
- surgery is required
- surgeon reattaches nerve at **epineurium**
- bundles of nerve fibers are aligned to encourage regeneration
56
Describe the healing process for lacerated nerves
- longer regeneration for proximal injuries
- healing begins **after 4 weeks** at 1mm per day or an inch a month
57
What are common nerve conditions/injuries?
- carpal tunnel syndrome
- cubital tunnel syndrome
- radial nerve palsy
58
What is carpal tunnel syndrome?
- occurs when the median nerve in the wrist is compressed
- causes pain, numbness, tingling, or weakness in the hand or wrist
59
What is cubital tunnel syndrome?
occurs when the ulnar nerve, which passes through the cubital tunnel on the inside of the elbow, becomes inflamed, swollen, and irritated
60
What is radial nerve palsy?
- occurs when there is injury to the radial nerve
- includes loss of sensation & weakness along the posterior aspect of arm, forearm, and hand
