Clin Phys 5 Flashcards
(80 cards)
1
Q
What are the two divisions of the nervous system?
A
peripheral nervous system
central nervous system
2
Q
What is the function of the peripheral nervous system?
A
detects a stimulus and relays it to the central nervous system (sensory)
3
Q
What is the function of the central nervous system? Describe the cascade of events.
A
integrates information from PNS –> a response –> carried to effectors (muscles, glands, blood vessels) via the peripheral nervous system (motor)
4
Q
What composes the central nervous system?
A
brain & spinal cord
5
Q
What are neruons? What is their function?
A
excitable cells that receive a stimulus from a neuron or a receptor in the dendrites –> integrates it in the cell body/axon hillock –> passes it along to another stimulus if its is adequately stimulated in the axon
6
Q
Label 1-7 of this neuron.
A
1: dendrites
2: cell body (soma)
3: axon
4: oligodendrocyte
5: node of ranvier
6: myelin sheath
7: synapse
7
Q
What is the function of the myeline sheath?
A
provides extra insulation that allows for quick passage of stimulus transmission
8
Q
What is the function of the node of ranvier?
A
allows generation of fast electrical pulse
9
Q
Axons are carried in __ called __ in the PNS and __ in the CNS
A
bundles; nerves; tracts
10
Q
What are bundles of axons/their function?
A
cables that carry electrical impulses b/w brain & body
11
Q
Most neuronal cell bodies reside in the __.
A
CNS
12
Q
What are 3 exceptions to neuronal cell bodies only residing in the CNS? What are there functions?
A
- dorsal root ganglia: neuronal cell bodies for the axons that bring most sensory info from PNS –> CNS
- autonomic ganglia: helps regulate activities of ANS (ex., breathing)
- enteric ganglia: help regulate activity of the gut
13
Q
What is the cerebral cortex responsible for?
A
formation, storage, retrieval of memory, speech, language, abstract thinking, math, planning, and executing plans, perception, voluntary movements (simplex + complex)
14
Q
What are the contents of the cerebral cortex?
A
- frontal lobe
- parietal lobe
- temporal lobe
- occipital lobe
15
Q
What is the frontal lobe responsible for?
A
- simple movements: pre-central gyrus
- complex motor plans: anterior portions + pre-central gyrus
- motor aspects of speech: anterior & inferior to pre-central gyrus
- planning, abstract thinking, social behaviour (executive functions): distributed throughout frontal and parietal lobes
16
Q
What is the parietal lobe responsible for?
A
- perception of touch, temperature, vibration: post-central gyrus
- Perception of “where our limbs are” (proprioception): post-central gyrus
- memory, executive functions, abstract reasoning - distributed throughout the parietal lobe
17
Q
What is the temporal lobe responsible for?
A
- hearing
- scent, taste
- recognition of speech
- memory: cooperates w/ limbic structures
18
Q
What is the occipital lobe responsible for?
A
- vision
- areas that relate visual stimuli to “actual things” (i.e., association cortex)
- memories related to what has been seen
19
Q
What are memory processors?
A
structure of limbic lobe below temporal lobe - hippocampus, amygdala
20
Q
Where is memory stored?
A
in the cortex close to sensation associated w/ them
21
Q
What are basal ganglia?
A
structure that lie below cortex, close to middle of parietal and temporal lobes: striatum, globes pallidus, sub thalamic nuclei
22
Q
What is the function of basal ganglia?
A
to refine & regulate behviours or movements
23
Q
What does basal ganglia inhibit?
A
tics, unnecessary movements, non-speech vocalizations
24
Q
What does basal ganglia encourage?
A
intended movements
25
Basal ganglia is impaired in several diseases causing?
- tremors, rigidity, difficulty initiating movements
- random, purposeless movements
- tics, vocal utterances
- personality changes
26
What is the function of the thalamus?
- relays information from sensory receptors in PNS --> cortex
- relays info from brain areas --> refine motor planning
27
What type of information does the thalamus relay?
- joint/limb position & movement
- pain, touch, temperature
28
What is the function of the hypothalamus?
- controls much of endocrine system and pituitary gland
- regulates temperature activity of ANS, fluid balance
- some thalamic nuclei modulate emotion and memory formation
29
T/F: cerebellum is about 50% of mass of brain
False, 10%
30
What is the highly folded complex structure of the brain?
the cerebellum
31
What is the function of the cerebellum?
compares information from receptors that sense joint position + movement and gravity + equilibrium
32
How does the cerebellum use info to adjust movements that are formulated in the prefrontal cortex?
error-corrects movements that are planned by comparing them to data from receptors
33
What passes through the brainstem?
ALL pathways that bring sensory information into brain (from PNS) or send motor information out of the brain (to PNS) pass through
34
T/F: Neurons or axons regenerate after damage
False, they do not
35
Dorsal components of the spinal cord carry __ __ to the __.
sensory information; brain
36
What isolates the spinal cord rom the peripheral nervous system and rest of
the body?
meninges
37
What is the spinal cord bathed in?
cerebrospinal fluid
38
Ventral components of the spinal cord carry __ __ away from __ to __.
motor information; brain; effectors (muscles)
39
What is gray matter made of?
mostly cell bodies w/ unmyelinated or lightly myelinated axons
40
What does it mean to be myelinated?
the change or maturation of certain nerve cells whereby a layer of myelin forms around the axons which allows the nerve impulses to travel faster
41
Gray matter is divided into 2 horns, what are they? What do they do?
ventral horns: cell bodies of neurons that activate skeletal muscles
doral horns: cell bodies of neurons that rely and integrate sensory information to the brain
42
What is white matter made of?
myelinated axons
43
White matter is divided into columns, what are they? What do they do?
- dorsal columns: proprioception, vibration sense, fast pain fibres - sensory to brain
- anterior & lateral columns: pain, temp, itch - sensory to pain
- anterior columns: motor information --> skeletal muscles
44
The corticospinal tract is a major neuronal pathway providing voluntary ___ function
Motor
45
Describe the pathway of the corticospinal tract.
motor plan formed (prefrontal cortex) --> activation of neurons in the primary motor cortex (prefrontal lobe) axons travel through the brainstem (medullary pyramids) & cross over to the opposite side --> activation of primary motor neurons in the ventral horn that stimulate skeletal muscle contraction OR activation of motor neurons in the ventral horn that modify reflexes
46
What is the lateral corticospinal tract responsible for?
fine movements of extremities
47
What is the anterior corticospinal tract responsible for?
movements of trunk
48
What accounts for about 90% of the output of the corticospinal tract?
to shut down reflexes that would oppose voluntary movements
49
How does the cerebellum modify motor plans?
Cerebellum integrates information from proprioceptors (spinocerebellar tract) & inner ear (vestibulocerebellar tract) to keep cerebellum “up-to-date” on position of body --> Compares this info w/ info from motor “plan” generate by frontal lobe (relayed through the pons) --> Cerebellum “adjusts” motor plan by communicating via thalamus w/ frontal lobe and refining the movements relayed by corticospinal tract
50
What does the motor system depend heavily on?
input from receptors about the position of a joint, tension across a joint, and tension in a skeletal muscle (aka proprioceptors)
51
What do proprioceptors do?
inform the cortex, the cerebellum and neurons in the spinal cord about the actual position of the body
52
What is the pathway of the dorsal column-medial lemniscal system?
proprioceptor --> dorsal horn --> dorsal column --> thalamus --> post-central gyrus of parietal lobe
53
What is the pathway of the spinocerebellar system?
proprioceptor --> dorsal horn --> dorso-lateral columns --> cerebellum
54
What is a reflex?
fast, involuntary sequence of muscular movements
55
A motor reflex does not need __ __ __, brainstem or spinal cord circuits are adequate.
higher brain centres
56
T/F: reflex are complex
False, simple
57
Reflexes have a __ / __ function
protective / stabilizing
58
What needs to happen to reflexes in order to perform purposeful complex movements?
they need to be inhibited
59
What is a muscle spindle?
a proprioceptor that sense muscle strength
60
As a muscle is stretched, what happens?
activates the muscle to contract against the stretch by stimulating the motor neuron in the ventral horn, inhibits antagonist muscle
61
What is a stretch reflex?
helps to maintain posture
62
what is a tendon reflex?
- When a tendon is stretched, the antagonist muscle contracts and the agonist relaxes
- Thought to help prevent tearing the tendon during excessive force generation
63
What is a withdrawal reflex?
in response to a painful stimulus, muscles of flexion are activated to withdraw a limb
64
What is a plantar reflex?
in response to an irritating stimulus (lateral form stroke of foot), the foot plantar flexes (foot flexes "down") and toes curl
65
What are deep tendon reflexes (DTRs)?
These are simple stretch reflexes activated by striking the tendon with a reflex hammer→contraction of the agonist muscle
66
What are examples of deep tendon reflexes (DTRs)?
patellar reflex, triceps reflex
67
What are causes of absent deep tendon reflexes (DTRs)?
- normal variation (some people are really difficult to get reflexes from)
- damage to sensory or motor nerves innervating the muscle being tested
68
What are causes of excessive deep tendon reflexes (DTRs)?
- loss of inhibition of reflexes from higher brain centres – usually the corticospinal tract (so damage to the corticospinal tract)
69
When are reflexes easier to interpret?
when they are asymmetrical - one side greater/less than the other side
70
What reflex develops as we learn to walk?
plantar reflex
71
What does it mean if the foot dorsiflexes and the toes spread during a plantar reflex exam?
corticospinal input to the lower limb is poor
72
T/F: an “upgoing” plantar reflex is usually a normal finding
False, abnormal
73
What does the cerebellar tests include in the neurological exam?
▪ rapid alternating movements (RAMS)
▪ point-to-point movements (i.e. patient touches his nose then rapidly touches your finger, and repeats)
▪ heel to shin movements
▪Gait – how coordinated is the patient’s gait?
74
What do the cerebellar tests of the neurological exam rely on?
rely on the ability of the cerebellum to evaluate the body’s position and provide feedback to the rest of the motor system
75
if the cerebellum has lost function than the movements of the cerebellar test will be?
clumsy, uncoordinated, and slow
76
What does the Romberg test evaluate?
function of dorsal columns - Sensory input from proprioceptors to the cerebellum and the parietal cortex – key for joint and limb position sensing
77
Describe the Romberg test.
- Patient stands with feet together and closes her eyes
- If the patient loses balance and starts to fall (support the patient!), indicates that the dorsal columns could be damaged
- visual input is no longer available to help the patient keep her balance
78
How can the brain structures in the corticospinal tract be damaged?
- stroke, trauma, demyelinating disease, tumours
- structures include the precentral gyrus and prefrontal
cortex
79
What is the result of corticospinal tract damage?
pattern of loss of muscle strength – extensors and supinators of the arm are weaker than the pronators or flexors
80
How do you test the corticospinal tract (i.e., pronator drift)?
- Patient stands with arms outstretched, palms up, hand open, eyes closed
- The arm “drifts” to a more pronated position, the hand closes, and the arm tends to descend
