CH12/13 Flashcards
(103 cards)
1
Q
CNS, Central Nervous System
A
- Brain (cerebrum, cerebellum, brainstem)
- Spinal cord
2
Q
PNS, Peripheral Nervous System
A
all nerves and sensory structures outside the brain and spinal cord
- 12 pairs of cranial nerves
- 31 pairs of Spinal nerves
- Ganglion: small masses of tissue; (clusters of nerve cell bodies)
- Sensory Receptors (in skin)
3
Q
Ganglion
A
small masses of tissue; (clusters of nerve cell bodies)
4
Q
Somatic Nervous System
A
Voluntary (skeletal muscles)
5
Q
Autonomic Nervous system
A
Involuntary (smooth muscle, cardiac, glands)
- Includes the sympathetic, parasympathetic, enteric nervous systems
6
Q
Sympathetic Nervous System
A
Increase Heart Rate, supports exercise, emergency situations, ‘flight or flight response’
- You sympathize
7
Q
Parasympathetic Nervous System
A
slow heart rate; ‘rest and digest’ response/activities
8
Q
Enteric nervous System
A
Regulates GI function/motility, neurons that extend the GI Tract.; Sensory neurons of ENS monitor stretching of GI Tract walls
9
Q
Sensory Function
A
detection of stimuli
- sense changes through sensory receptors (changes in the internal/ external environment)
- process begins in the PNS and sent to the CNS
- Sensory neurons serve this function
10
Q
Integration function
A
- Decision making; analyzing incoming sensory information
- The CNS determines the response to stimuli
- Association and interneurons serve this function
11
Q
Motor Function
A
response to stimuli, initiates action
- From the CNS, motor output signals target effectors (muscles and glands) in the PNS.
- stimulate tissues to control body movement and gland secretion.
- Motor neurons serve this function
12
Q
Which part of the neuron is the endoplasmic reticulum?
A
Nissil Bodies - rough ER, constantly replaces the cell membrane (normal process of growth and repair)
13
Q
What do the dendrites do?
A
Tree like branches that receive or input of information
14
Q
Which type of neuron has several dendrites and one axon?
A
Multipolar
* Most common type!
* Several dendrites extending from the cell body, one axon
* motor and interneurons, which make up most of the brain and spinal cord.
15
Q
Define Neuroglia
A
- specialized tissue cells that support the neuron. Also known as glial cells
- attaches neurons to blood vessels; “acts as glue”
- produces myelin sheath around the axon
- carries out phagocytosis
16
Q
Define Neuron
A
- functional cell of the nervous system (nerve cell)
- have the property of electrical excitability!
- Cellular Structures
17
Q
What type of glial cell is found on the cell body in the PNS?
A
Schwann cells:
wrap around neuron axons in the PNS forming myelin sheaths
satellite cells: maintain the health of neurons and protect them
18
Q
Satellite cells
A
wrap around the neuron cell body
19
Q
Define myelination
A
process of wrapping around axons to form layers of myelin
20
Q
Glial cell of the CNS
A
- Astrocytes
- Oligodendrocyte
- Microglial cells
- Ependymal cells
21
Q
Astrocytes
A
- Extension wrap around capillaries in brain to regulate blood entering CNS.
- Removal of excess neurotransmitters
- Looks like a star
22
Q
Oligodendrocyte
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Creates myelin sheath
23
Q
Microglial cells
A
phagocytosis
24
Q
Ependymal cells
A
creates & circulates cerebrospinal fluid (CSF)
cushions and nourishes the brain and spinal cord
25
Parkinson’s Disease
Neurons in CNS breakdown/die, Tremors, affects movements
26
Alzheimer’s Disease
plaques found in the brain. Atrophy of brain/ breakdown of energy production within the cells.
memory loss
27
Guillain-Barré syndrome
demyelination PNS
a condition in which the body's immune system attacks the nerves. It can cause weakness, numbness or paralysis
28
Multiple Sclerosis
* Myelin around neurons is loss in the CNS (demyelination occurs)
* difficulties walking, visual problems, pain
29
Stroke
* blood supply to brain is stopped. Neurons die (lack of oxygen)
* sudden weakness, loss of speech
30
ALS- Amyotrophic Lateral Sclerosis
* motor neurons from brain and spinal cord (CNS) to the voluntary muscles; motor neurons stop functioning.
* muscle weakness
31
Lyme Disease
* Bull's eye rash
* bacteria spread by ticks; bacteria enters bloodstream via tick attachment.
* chills, fever, neurological problems (facial palsy, stiff neck)
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Spina Bifida
* failure of the spinal cord to develop properly
* paralysis, bladder & bowel difficulties; spine disorder
33
Nerve Fibers
bundles of axons classified according to their diameter and degree of myelination
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Type A Nerve FIber
* Motor neurons that innervate skeletal muscles
* large diameters = highly myelinated
* Action potential: very fast conduction
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Type B Nerve FIber
fibers are lightly myelinated; intermediate diameters
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Type C Nerve FIber
unmyelinated; smallest diameters: slowest conduction
37
Define Propagation
process by which an electrical impulse travels along the membrane of a nerve cell
38
Factors that affect Propagation
* axon diameter
* amount of myelination
* Temperature
39
# True or False
Myelin sheath increase from birth to maturity
T
40
Nodes of Ranvier
* Also known as neurofibril nodes
* Gaps between the myelin sheath
* Plasma membrane exposed
41
Define a synapse
where neurons connect and communicate with each other
42
How many cranial and spinal nerves are there?
12 pairs of cranial nerves and 31 pairs of spinal nerves
43
Meninges
Protective 3-layer covering that run continuously around the spinal cord and brain
44
# Meningeal Layers
Pia Mater
thin delicate inner layer; denticulate ligaments are thickenings of pia mater that suspend the spinal cord
45
# Meningeal layers
Arachnoid mater
middle spider web-like layer
46
# Meningeal layers
Dura mater
tough protective outer layer; extends to cover and protect the pairs of spinal nerves that extend from the cord at the level of each vertebra
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Epidural space
outside of the dura mater is a space filled with fat and large blood vessels; adipose tissue contributes to the protection of the spinal cord
48
Cerebrospinal fluid
* Clear and colorless fluid; produced by the choroid plexus of the brain.
* Acts as a cushion to help prevent injury.
* CSF is found in the subarachnoid space (between the arachnoid and pia mater).
* Spinal Tap: is done to withdraw CSF for diagnostic purposes
49
Arachnoid villi role?
* facilitate the reabsorption of cerebrospinal fluid (CSF) from the subarachnoid space back into the venous circulation.
* This process helps maintain intracranial pressure and ensures proper brain function
50
Where does the spinal cord begin?
Continuation of the medulla oblongata and ends at L1-L2 in adults, in children ends at L3-L4
51
Where does the spinal cord end?
End of the spinal cord is called Conus medullaris: tapered portion of the spinal cord
52
What is cauda equina?
Where the spinal roots hang off the end of the spinal cord, means horse’s tail
53
Grey matter
* cell bodies and unmyelinated axons
* butterfly-shaped (H Shape)
* Involved in integration of the lower motor neurons that give rise to the axons that control muscle
* dorsal horn(s) and ventral(horns) regions
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Posterior (dorsal) horns
contain cell bodies of sensory neurons from the root ganglia
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Anterior (ventral) horns
Large cell bodies of the lower motor neurons (LMN). Axons of these lower motor neurons exit each spinal segment as ventral roots
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White Matter
* Surrounds the grey matter (H or butterfly shape), made up of myelinated axons
* ascending sensory pathways
* sensory receptors to the brain
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ascending sensory pathways
* delivering sensory information
* sensory receptors to the brain
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descending motor pathways
carrying motor commands from the brain to the muscles
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Motor Tracts
Efferent: descending tracts
Found in anterior and lateral corticospinal tract
carry electrical impulses from brain to body parts, muscles, sometimes glands
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Sensory tracts
* Afferent: ascending tracts, known as spinothalamic tracts
* Found in dorsal column
* Action potential travels to sensory neuron carries electrical impulses from body to brain
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Role of dorsal horn?
Receives and relays sensory information from body to brain; pain, temperature, touch
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Ipsilateral pathway
traveling on the same side of the stimulus or muscle
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Contralateral pathway
traveling on the opposite side
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Motor pathway
efferent, alpha motor neuron; carry electrical impulses from brain to body parts, muscles, sometimes glands
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Sensory pathway
afferent, Action potential travels to sensory neuron carries electrical impulses from body to brain
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Decussation
crossing within brainstem or spinal cord
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Three order neurons
1. First-order sensory neurons: delivers information from the receptor to spinal cord
2. Second-order sensory neurons: information will cross over within the thalamus
3. Third-order sensory neurons: project the location on the brain where stimulus was perceived
68
How many neurons are involved in sensory pathways?
3 neurons
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What are the two main routes of the sensory pathway?
1. Spinothalamic tract: carries information about pain and temperature
2. Posterior column tract: carries general somatosensory (touch, pressure, pain, temp.) and proprioceptive (body position/movement) information
70
Two circuit neuron
Involved in motor pathways
- UMN (Upper Motor Neurons) and LMN (Lower Motor Neurons)
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UMN (Upper Motor Neurons)
originate in cerebral cortex and travel down to brainstem or spinal cord, then transfers to LMN in ventral horn of spinal cord
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LMN (Lower Motor Neurons)
begin in spinal cord (ventral horn) and send efferent information to muscles/glands
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Where does the lateral corticospinal tract decussate at?
Also known as pyramidal tract will decussate in the medulla (at pyramids)
74
What are the 4 extrapyramidal tracts?
Tectospinal Tract
Vestibulospinal tract
Rubrospinal tract
Reticulospinal tract
75
Tectospinal Tract
involves reflexive movements of the head, equilibrium, and coordination of visual reflexes
## Footnote
Tech IT, using their eye coordination
76
Vestibulospinal tract
controls muscle tone and posture that responds to vestibular input from the inner ear allowing us to maintain balance
## Footnote
Vestibular issues make you tilt
77
Rubrospinal tract
controls limb movement on the basis of cerebellar processing and originates in red nucleus in the brain
## Footnote
Rubro=ruby=red nucleus
78
Reticulospinal tract
controls body posture as a response to reticular system of the brain; controls level of alertness
79
Connective tissue coverings of the nerve
* Epineurium: cover the outside of the nerve.
* Perineurium: layer covering the fascicles.
* Endoneurium: layer covering the nerve fiber.
80
Four main nerve plexuses in the human body
* Cervical plexus supplies nerves to the posterior head and neck, (and diaphragm).
* Brachial plexus supplies nerves to the arm.
* Lumbar plexus supplies nerves to the anterior leg.
* Sacral plexus supplies nerves to the posterior leg
81
# Plexus and the nerve they control
Cervical plexus
* receives input from spinal nerves C1-C5, and phrenic nerve
* Phrenic Nerve: controls diaphragm
* Any damage above C5 will involve mechanical ventilation
82
# Plexus and the nerve they control
Brachial plexus
peripheral nerves of arm
* Axillary, radial, median, and ulnar nerves
83
Brachial plexus avulsion
Shoulder dystocia: during birth sometimes baby’s shoulders get stuck. From this force this can cause damage to brachial plexus leading to motor and sensory impairments of the arm
| Injury
84
# Plexus and the nerve they control
Lumbar and sacral plexus
Lumbar: femoral nerve, obturator nerve, and sciatic nerve (large nerves)
85
Tactile sensations
* Tactile epithelial cells (merkel cells): light touch, stratum basale of epidermis
* Lamellated (Pacinian) corpuscles: deep pressure, encapsulated endings in hypodermis
* Tactile (Meissner) corpuscle: light touch, encapsulated endings
* Hair root plexus: detect movement of hair at surface of skin (ex: insect on your skin)
* Bulbous corpuscles (Ruffini corpuscles; type II cutaneous mechanoreceptors): stretch receptors
86
Thermal Sensations
2 types of somatosensory signals: pain and temperature (free nerve endings)
* Temperature: uses thermoreceptors
* Pain: uses nociceptors
87
Pain Sensations
Nociceptors are in every tissue of the body except brain
- Nociception in the sensation of potentially damaging stimuli
* Mechanical, chemical, thermal or photo (bright light) stimuli beyond a set threshold will elicit the pain sensation
88
Fast pain
Fast or acute pain occurs rapidly, within 0.1 seconds after a stimulus is applied. myelinated Type A nerve fiber
89
slow pain
Slow pain is processed and propagated by the unmyelinated Type C nerve fibers. Slow pain tends to increase in intensity and can last a longer time
90
Dermatome
an area of the skin that provides sensory input via the spinal nerves and one cranial nerve to the central nervous system
91
# Proprioception testing
Simple tests
touching the nose with a finger or touching a location on the skin after it has been touched by the clinician
92
# Proprioception testing
Gait observation
observing the patient’s gait (the way that they walk) or walking heel to toe
93
# Proprioception testing
Romberg test
overall measurment of balance
94
Hyporeflexia
absent diminished reflex
95
Hyperreflexia
repeating reflexes; hyperactive
96
Babinski sign
toes dorsiflex and fan out
* In adults: positive babinski sign = upper motor neuron damage
* In infants: positive Babinski sign is normal (due to incomplete myelination in newborns)
97
# Spinal Cord Injury effects
Paresis:
partial paralysis or weakness of a limb
98
# Spinal cord injury effects
Paraplegia:
paralysis of the lower extremities
99
# Spinal cord injury effects
Quadriplegia:
paralysis of all four limbs
100
# Spinal cord injury effects
Hemiplegia
paralysis of one side of the body
101
Shingles
a virus known as varicella-zoster virus (VZV); causes chickenpox
* Affects your nerves
102
Brown- Se'quard syndrome
results in weakness and paralysis on one side of the damage and loss of pain and temperature sensations on the opposite side.
* The left side or the right side of the spinal cord is transected (severed)
103
Spina Bifida
birth defect of spinal cord, neural tube does not completely close
* Spina bifida myelomeningocele - most severe, projection of meninges and spinal cord through skin
