Neuro Flashcards
The nervous system consists of
Central nervous system
Peripheral nervous system
Autonomic nervous system
The neuron is
the structural and functional unit of the nervous system. Neurons initiate and transmit impulses to other neurons.
The neuron’s function
Composed of an axon and one or more dendrites.
Axon transmits impulses away from the
cell body to dendrites of other neurons
or directly to the cell bodies of other
neurons.
Dendrites receive impulses and
conduct them toward the nerve cell
body.
Neuron’s have both a
sensory and motor components
synapse
is the junction between neurons where an impulse is transmitted.
axon
long branch, transmits impulses
dendrites
receive impulses from other neurons
synapse
bridge between the axon and dendrites
neurotransmitters
are chemical agents involved in transmission of the impulse across the synapse.
you need these in order for the impulses to go over the bridge.
Myelin Sheath
sheath is a wrapping of a fatty material that protects and insulates the nerve fibers and enhances the speed of impulse conduction.
Afferent Neuron
sensory neuron that transmits impulses from the peripheral receptors to the Central Nervous System (CNS).
Efferent Neuron
is a motor neuron that conducts impulses from the CNS to the muscles and glands.
Myelin Sheath
acts like a wire. has the copper on the inside and a rubber coating that protects it. When that plastic coating breakdown, the wire doesn’t work. Same things happen to a myelin sheath. Sometimes if its not a lot of damage, it can repair itself, but if there is too much damage, then it will bot be able to be repaired.
internuncial neurons
( interneurons) are connecting links between afferent and efferent neurons.
central nervous system is composed of
brain and spinal cord
the brain is composed of
cerebrum, corpus callosum, basal ganglia, Diencephalon, brainstem, cerebellum
how do neurons work
the afferent neuron reports to the brain that there is something wrong. The brain then reports to the efferent neuron to physically change the situation. i.e. if your hand is on a hot stove, the afferent neuron reports this to the brain and then the brain tells the efferent neuron to remove your hand.
internuncial neurons
the links between the afferent and efferent neurons
cerebrum
outermost area is the cortex
Has two hemispheres
Each hemisphere is divided into
four lobes ( frontal, Parietal,
Temporal and Occipital )corpus callosum
large fiber tract that
connects the two hemispheres
basal ganglia
islands of gray matter within
white matter of cerebrum that regulate and
integrate motor activity originating in the cerebal
cortex. Part of the extrapyramidal system.
diencephalon
the connecting part of
the brain between the cerebrum and
the brain stem. It contains the:
a. Thalamus
b. Hypothalamusbrainstem
contains midbrain, pons and
medulla oblongata
respiratory, vasomotor, and cardiac type functions
cerebellum
coordinates muscle tone
and movements and maintains
equilibrium
issues in cerebellum causes ataxia, unsteady gait, surroundings.
frontal lobe
motor function, intellectual function, personality, injury to this lobe changes a person’s personality . Broca’s area is located in the frontal lobe. This is the motorized speech area. Allows us to speak and say what we want to say, be able to communicate. If there is a lesion on the frontal lobe, it causes aphasia and issues with expression through speech.
parietal lobe
sensory stimulation, sensation, touch, pressure, takes info coming in and makes sense of it .
temporal lobe
sensory stimulation, hearing, auditory, receptive, it contains wernicke’s area. This is the sensory speech area. Helps us to understand what someone is saying to us and what is written. If someone has a lesion on wernicke’s area, it causes issues with reception of what we say to them. It’s like we are speaking gibberish.
Occipital Lobe
everything associated with vision. this is where basal ganglia is located. These regulate motor activity that originates in the cerebral cortex. Parkinson’s is caused from this area
spinal cord
Serves as a connecting link between the brain and the periphery
Extends from foramen magnum to the second lumbar vertebra.
Ascending tracts are sensory pathways
Descending tracts are motor pathways
cerebrospinal fluid
Surrounds brain and spinal cord
Offers protection by functioning as a shock absorber
Allows fluid shifts from the cranial cavity to the spinal cavity
Carries nutrients to and from the nerve cells
too much CSF causes ICP, hydrocephalus
certain things cause CSF leakage. Its very clear color. It is very high in glucose when tested.
what is distinct of CSF
The center is clear and the rest is like a yellow halo coming out around it. you can see this if you catch it on a gauze pad
vascular supply of the CNS
Two internal carotid arteries anteriorly
Two vertebral arteries leading to basilar artery posteriorly
These arteries communicate at the base of the brain through the Circle of Willis
Anterior, Middle and Posterior cerebral arteries are the main arteries for distributing blood to each hemisphere of the brain
Brainstem and Cerebellum are supplied by branches of the vertebral and basilar arteries
Venous blood drains into dural sinuses then into internal jugular veins
peripheral nervous system
Spinal Nerves- 31 pairs carry impulses to and from the spinal cord. Each nerve is attached to spinal cord by two roots:
two roots of the peripheral nervous system are
dorsal posterior root, and the ventral anterior root
Dorsal posterior root
contains afferent
sensory nerves
ventral anterior root
contains efferent motor nerve fibers
cranial nerves
12 pairs that carry impulses to and from
the brain. Have sensory, motor or
mixed functions.
The 12 cranial nerves
I Olfactory: Sensory-carries impulses for sense of smell
II Optic: Sensory-carries impulses for vision
III Oculomotor: Motor-muscles for pupillary constriction, elevation of upper eyelid; 4 out of 6 extraocular movements
IV Trochlear: Motor-muscles for downward, inward movement of the eye
V Trigeminal: Mixed-impulses from face, surface of eyes (corneal reflex); muscles controlling mastication
VI Abducens: Motor- muscles for lateral deviation of eye
VII Facial: Mixed- impulses for taste from anterior tongue; muscles for facial movement
VIII Acoustic: Sensory-impulses for hearing (cochlear division) and balance (vestibular division)
IX Glossopharyngeal: Mixed-impulse for sensation to posterior tongue and pharynx ; muscles for movement of soft pharynx (elevation) and swallowing
X Vagus: Mixed- impulses for sensation to lower pharynx and larynx; muscles for movement of soft palate, pharynx, and larynx
XI Spinal accessory: Motor-movement of sternomastoid muscles and upper trapezius muscles
XII Hypoglossal: Motor-movement of tongue
autonomic nervous system
Part of peripheral nervous system
Includes those peripheral nerves (both cranial and spinal) that regulate functions occurring automatically in the body
Regulates smooth muscle, cardiac muscle, and glands.
Components: Sympathetic and Parasympathetic
neurological exam
Mental Status Exam (Cerebral Function)
Appearance and behavior
Level of Consciousness
Intellectual Function
Emotional Status
Thought Content
Language and Speech
Cranial Nerves
Cerebellar Function
Motor Functions
Sensory Functions
Reflexesfive point level of consciousness scale
1 Alert: Normal mental activity, aware,
mentally functional
2 Obtunded/Drowsy: Sleepy, very short
attention span, can respond
appropriately if aroused
3 Stupor: Apathetic, slow moving, blank
expression, staring, aroused only by
vigorous stimuli
4 Light coma: Not oriented to time, place or
person. Aroused only by painful stimuli-
response is only a grunt or grimace or withdrawal
from pain
5 Deep Coma: No response except decerebrate or decorticate
posture
decerebrate posturing
Decerebrate posture is an abnormal body posture that involves the arms and legs being held straight out, the toes being pointed downward, and the head and neck being arched backwards. The muscles are tightened and held rigidly. This type of posturing usually means there has been severe damage to the brain.
decorticate posturing
Decorticate posture is an abnormal posturing in which a person is stiff with bent arms, clenched fists, and legs held out straight. The arms are bent in toward the body and the wrists and fingers are bent and held on the chest.
This type of posturing is a sign of severe damage in the brain. People who have this condition should get medical attention right away.
pupil reaction and eye movement
Observe size, shape and equality of pupils (note size in millimeters)
Test reaction to light—pupillary constriction
Corneal Reflex
Oculocephalic Reflex
motor function
Test movement of extremities
Test muscle strength
MOTOR SCALE
5/5 moves against gravity and resistance
4/5 moves against moderate resistance
3/5 moves against gravity only
2/5 moves but not against gravity
1/5 muscle contracts-no movement
0/5 no visible or palpable movement
