nervous system Flashcards
involves release of neurotransmitters
1.Chemical Synapse
pre- and postsynaptic neurons are
bound by gap junctions; rare; found
in the brain and eyes
Electrical Synapse
*serve as the integrating and
processing area
*“decision making”
* color is due to cell bodies and
dendrites of neurons
GRAY MATTER:
superficial layer of gray matter in the brain
cortex
cluster of neuron cell bodies within the CNS
center
center that displays discrete anatomic boundaries in the CNS
nucleus
relay nerve signals
*provides means for information to
be transmitted throughout the
body
*color is due to myelinated
axons
WHITE MATTER:
bundles of axon within the CNS that shares a common origin and destination
tract
Innermost layer
tightly adheres to the brain and follows every contour of the brain
help form CSF in the
ventricles
pia matter
deep to it is the
subarachnoid space, which
contains CSF
support cerebral arteries and
veins within subarachnoid
space
Arachnoid
Mater
toughest meninges
the 2 layers are usually fused
but separate in some
1.Periosteal Layer
2. Meningeal layer
dura matter
toughest meninges
the 2 layers are usually fused but separate in some
dura matter
drain blood from brain
Dural Venous Sinus
contains the arteries and veins that
nourish the meninges and bones of the
cranium.
Epidural Space
positioned between the arachnoid
mater and the dura mater
Subdural Space
double layers of dura mater
These membranous partitions separate specific
parts of the brain and provide additional
stabilization and support to the brain.
Cranial Dural Septa
clear, colorless liquid that circulates within the ventricles
and subarachnoid space
Cerebrospinal Fluid
Created by the choroid plexus
Cerebrospinal Fluid
Circulates from ventricles to subarachnoid
space
500mL per day
reabsorbed in arachnoid villi and returned to
the blood
Cerebrospinal Fluid
gatekeeper to control which materials pass from the blood into the
brain.
prevent exposure of neurons in the brain to drugs, waste products in
the blood, and variations in levels of normal substances that could
adversely affect brain function.
Blood-Brain Barrier
However, this barrier is not absolute. Thus, lipid-soluble molecules
such as nicotine, alcohol, & some anesthetics, can diffuse across
the endothelial plasma membranes
It is markedly reduced or missing in three distinct locations in the
CNS: the choroid plexus, hypothalamus, and pineal gland
Blood-Brain Barrier
conscious thought processes and the origin of all
complex intellectual functions.
center of your intelligence, reasoning, thought,
memory, and judgment, voluntary control of skeletal
muscle movement and conscious perception of your
senses (i.e., vision, hearing, touch, smell, taste, and
proprioception)
Cerebrum
: It usually contains the Wernicke’ and Broca’s area. It is specialized
for language abilities and is important in performing sequential and
analytical reasoning tasks, such as those required in science and
mathematics.
left hemisphere of the brain
it is concerned with visuospatial relationships and analyses. It is
the seat of imagination and insight, musical and artistic skill, perception
of patterns and spatial relationships, and comparison of sights, sounds,
smells, and taste
right hemisphere of the brain
Voluntary motor functions including speech,
concentration, verbal communication, decision
making, planning, personality
Frontal Lobe
control voluntary skeletal muscle movement
Primary Motor Cortex
coordinating learned, skilled motor activities
Premotor Cortex
(Motor speech area)
Movements for vocalization
Broca’s Area:
General sensory input from both the skin and body
position
Parietal Lobe
receiving, processing, and storing somatic sensory
information.
We typically are conscious of the sensations received
by this cortex.
Primary somatosensory cortex
interprets sensations to determine the texture,
temperature, pressure, and shape of objects
Somatosensory association area:
Hearing and smell
Temporal Lobe
receives, processes, and stores auditory information.
Primary auditory cortex:
integrates and interprets the characteristics of sounds and
compares them to memories of sounds heard in the past
Auditory association area
receives, processes, and stores odor information.
Primary olfactory cortex:
Processing incoming visual information and
storing visual memories
Occipital Lobe
receives, processes, and stores incoming visual information
Primary Visual Cortex
integrates and interprets all of the incoming visual
information by analyzing color, movement, and form, and
uses this information to identify the things we see.
Visual Association Area:
Memory and interpretation of taste
Insula
Receives, processes, and stores taste information.
Primary gustatory cortex:
Associated with many higher intellectual functions such
as complex thought, judgment, expression of
personality, planning future behaviors, and decision
making.
Evaluates potential consequences of one’s actions, and
in so doing will modulate one’s behavior based on
societal norms
Prefrontal Cortex
typically located only within the left hemisphere.
Involved in recognizing, understanding, and
comprehending spoken or written language.
The Wernicke area and the motor speech area must
work together for fluent communication to occur.
It helps us to comprehend Words.
Wernicke’s Area
In general, the cerebral nuclei primarily help regulate
motor output initiated by the cerebral cortex, to help inhibit
unwanted movements.
Cerebral Nuclei
participates in the expression of emotions, control of
behavioral activities, and development of moods
Enables you to feel fear especially in threatening
situations.
Amygdala
Primarily focused on motor control, movement regulation,
and procedural learning
Basal Nuclei (Basal Ganglia)
Diencephalon
Epithalamus,
Thalamus
Hypothalamus
sandwiched between the 2 cerebral hemispheres
“in-between brain
Diencephalon
Epithalamus
PINEAL GLAND
HABENULAR NUCLEI
Endocrine gland
secretes melatonin
Melatonin regulates
circadian rhythm
(day-night cycles)
PINEAL GLAND
relay signals from the
limbic system to the
midbrain
involved in visceral &
emotional responses
to odors
HABENULAR NUCLEI
is essential for sorting, filtering, and
relaying sensory and motor information to the
appropriate areas of the brain. By doing this, it helps
focus attention on important stimuli while filtering out
unnecessary information.
acts as an information filter
Thalamus
It regulates the flow of sensory information, filtering out
unnecessary or irrelevant signals before passing the
important ones to the cortex.
In a noisy environment, the thalamus can help prioritize the
sounds that are most important (like a conversation) while
filtering out background noise.
Thalamus
also receives input from the basal nuclei
and cerebellum, which are involved in motor coordination,
and sends this information to the motor cortex to help
regulate voluntary movement.
It also ensures that only the relevant motor signals are
processed and passed on for execution, preventing
overactive or unwanted motor activity.
Thalamus
plays a role in regulating alertness and
consciousness by modulating the flow of sensory
information during sleep and wakefulness.
During sleep, it reduces the amount of sensory
information reaching the cortex, allowing for deeper sleep
and preventing you from reacting to every small stimulus
Thalamus
Master control of the autonomic nervous system
Master control of the endocrine system
Thermoregulation
Control of food intake
Control of water intake
Regulation of Circadian rhythm
Control of emotional behavior
Hypothalamus
Master control of the autonomic nervous system
influence activities such as heart rate, blood pressure,
digestive activities, respiration
Master control of endocrine system
oversees most of the endocrine system
secretes hormones that control secretory activities in
the anterior pituitary gland
Produces ADH & oxytocin
Hypothalamus
Thermoregulation
contains the body’s thermostat
detects altered blood temperatures and signal other
control mechanisms of heat and cold.
Control of Food Intake
Monitor levels of nutrients such as glucose and amino
acids in the blood
Produces sensation of hunger
Hypothalamus
Control of Water Intake
monitors concentration of dissolved substances in the blood to
regulate sensation of thirst
if dehydration is detected–> thirst is stimulated
Regulation of Circadian Rhythm
directs the pineal gland to secrete melatonin
Hypothalamus
Control of emotional behavior
hypothalamus is located in the center of the limbic system which
controls emotional responses such as pleasure, aggression, fear, rage,
contentment, and sex drive
Hypothalamus
BRAINSTEM
Midbrain
Pons
Medulla Oblongata
connects the cerebrum, diencephalon, and cerebellum to
the spinal cord
bidirectional passageway for all tracts between brain and
spinal cord
It houses many autonomic centers and reflex centers
required for survival
BRAINSTEM
“Mesencephalon”
Contains visual and auditory reflex centers
Contains subcortical motor centers
Contains nuclei for cranial nerves III and IV
Midbrain
Substantia nigra: houses neurons that produces the
neurotransmitter dopamine
Dopamine: control movement, emotional response,
ability to experience pleasure & pain
Tegmentum: issues involuntary motor commands to the
erector spinae to help maintain p
Midbrain
Contains nuclei of cranial nerves V, VI, VII
Relays information from cerebrum to cerebellum
Pons
regulate skeletal muscles of breathing
regulate smooth transition between breathing in & breathing
out
Pontine Respiratory Center
Contains a lot of autonomic nuclei necessary for vital
functions.
continuous with the spinal cord inferiorly
Involves in coughing, sneezing, salivation, swallowing,
gagging, vomiting reflex
contains CN nuclei associated with CN 8, 9, 10, 11, & 12
site of crossover of pyramids: decussation of pyramids
Medulla Oblongata
Cardiovascular Center: Cardiac Center + Vasomotor Center
Cardiac Center: regulates heart rate and force of contraction
to alter cardiac output
Vasomotor Center: controls contraction & relaxation of
smallest blood vessels
Medulla Oblongata
2nd largest part of the brain
Coordinates and fine-tunes skeletal muscle movement
that were initiated by the cerebrum
Ensures that skeletal muscle contraction follows the correct
pattern–> smooth, coordinated movements
Responsible for Proper Balance & Posture
Receives proprioceptive information from body joints and
use this information to regulate body position
CEREBELLUM
storing memories and forming long-term memory. Research
suggest neurogenesis in this area
Hippocampus
involved in several aspects of emotion, especially fear. It can also
help store and code memories based on how a person
emotionally perceives them—for example, as related to fear,
extreme happiness, or sadness.
storing memories and forming long-term memory. Research
suggest neurogenesis in this area
particular odors can provoke certain emotions or be associated
with certain memories
Olfactory bulbs, Olfactory tracts, and Olfactory cortex
Oh, Oh, Oh, To, Touch, And, Feel, Very, Good, Vagina, Ah,
Heaven
CN I
2.CN II
3.CN III
4.CN IV
5.CN V
6.CN VI
7. CN VII
8. CN VIII
9. CN IX
10. CN X
11. CN XI
12.CN XII
CN I
Olfactory
CN II
Optic
CN III
Oculomotor
CN IV
Trochlear
CN V
Trigeminal
CN VI
Abducens
CN VII
Facial
CN VIII
Vestibulocochlear
CN IX
Glossopharyngeal
CN X
Vagus
CN XI
Accessory
CN XII
Hypoglossal
Conducts olfactory (smell) sensation from the nose to the brain
Nerve Damage: Anosmia (partial or total loss of smell)
How to Test: Test smell (have patient close eyes, close one
nostril, and inhale an odor with the other nostril)
Olfactory (Sensory)
conducts visual information from the retina of the eye to the
brain
Nerve Damage: Anopsia (visual defects)
How to Test: Test vision (cover one eye and have patient view a
visual acuity chart with the other eye).
optic (Sensory)
innervates 4 of the 6 extrinsic eye muscles, an upper eyelid muscle,
and intrinsic eye muscles (smooth muscles in the eye)
Nerve Damage: Ptosis, Diplopia, Strabismus, Mydriasis
How to Test: Determine if the upper eyelid droops, examine eye
movement (have patient follow a moving object with eyes), examine
if pupil constricts in response to light
Oculomotor (motor)
innervates superior oblique muscle w/c moves eye inferiorly &
laterally
Nerve Damage: Diplopia, Strabismus
How to Test: Examine eye movement (have patient follow a moving
object with eyes)
Trochlear (motor)
Innervates muscles of mastication/chewing
Sensory stimuli for this nerve are touch, temperature, and pain.
Nerve Damage: Trigeminal Neuralgia (Tic Douloureux) which
results in intense, pulsating pain lasting from minutes to several
hours.
How to test: Have patient close mouth against resistance; also
have patient close eyes and then determine if an object (such
as a feather) moved along the face can be felt
Trigeminal (Both)
Innervates 1 extrinsic eye muscle (Lateral Rectus which moves
eye laterally)
Nerve Damage: Limited eye movement; Diplopia
Examine eye movement (have patient follow a moving object
with eyes) and determine if the eye is able to be abducted.
Abducens (Motor)
transmits taste sensation from anterior 2/3 of tongue
relay motor outputs to muscle of facial expression, lacrimal
gland, salivary gland.
Nerve Damage: Dry Eye, Dry Mouth, Bell’s Palsy
How to test: Have patient smile, frown, blink, squint, pout
Facial (both)
transmits equilibrium & auditory sensations from inner ear to
brain
Nerve Damage: loss of balance, N/V, Dizziness, loss of hearing
How to Test: Hearing Test
Vestibulocochlear (Sensory)
transmits taste and touch sensation from posterior 1/3 of tongue
general sensation of most pharynx, relays information from
chemoreceptors and baroreceptors
Nerve Damage: Dry Mouth, Loss of taste sensation
How to test: Have patient open mouth and say “ahhh”—the soft palate
should elevate and the uvula should remain in the midline under
normal conditions
Glossopharyngeal (both)
contracts trapezius & sternocleidomastoid muscle; assists CN X
Nerve Damage: Muscle paralysis
How to test: Elevate or shrug the shoulders; turn head to opposite
sides
Accessory (motor)
contracts intrinsic & extrinsic tongue muscles to move tongue
Nerve Damage: swallowing & speech difficulties
How to Test: Have patient protrude (stick out) tongue: If a single
hypoglossal nerve (either left or right) is paralyzed, a protruded
(stuck-out) tongue deviates to the side of the damaged nerve.
Hypoglossal (motor)
Provide an essential structural and functional link between the brain
and the torso and limbs of the body.
Sensory input is relayed from sensory receptors within the torso and
limbs to the brain, and motor output is relayed from the brain to the
effectors of the torso and limbs
Spinal Cord
do not require the involvement of the brain, but instead have the
spinal cord as the integration center.
Spinal reflexes initiate our quickest reactions to a stimulus.
spinal cord exhibits some functional independence from the brain.
spinal cord
Connective tissue
Epineurium
Perineurium
Endoneurium
structural
Nerve
cranial nerves
spinal nerves
functional nerve
sensory
mixed
motor
Houses sensory neurons that extends from
sensory receptors to spinal cord
the dendrites form the sensory receptors, the
axons extends to the spinal cord
Cell bodies are located outside the spinal cord
POSTERIOR GANGLION ROOT
Houses motor neurons that extend to effectors
Does not contain a ganglion along its length
Motor neuron axons extend from the spinal cord
within the anterior root and continue through
the spinal nerve to their terminal ends, which
innervate an effector
ANTERIOR ROOT
Function: Responsible for sensory processing.
Role:
They receive incoming sensory information (e.g., pain,
temperature, touch) from the body through sensory neurons.
These signals are then relayed to the brain for processing or
trigger reflex actions.
Location:
Found toward the back of the spinal cord.
DORSAL HORNS
innermost MENINGES
Pia Mater
external to pia mater
Subarachnoid space: where CSF circulates, where CSF is
removed through lumbar puncture
Arachnoid mate
one layer in the spinal cord
merge with epineurium
Subdural Space: between arachnoid & dura mater
Epidural Space: External to the dura mater
Dura mater
rapid, preprogrammed, involuntary responses of muscles or glands to a
stimulus.
Reflexes
.A stimulus activates a sensory receptor
2.The sensory neuron transmits a nerve signal to the CNS.
3.Information from the nerve signal is processed in the integration
center by interneurons
4.The motor neuron transmits a nerve signal from the CNS to an
effector.
5.The effector responds to the nerve signal from the motor neuron.
Reflex Arc
Helps maintain muscle tone and posture by automatically adjusting
muscle length.
Stretch Reflex
The autonomic nervous system includes involuntary motor
output to cardiac muscle, smooth muscle, and glands, and
responds to sensory input from visceral sensory components.
regulated by hypothalamus, brainstem, spinal cord
Autonomic Nervous System
fight-flight response
Activated in response to stress, danger, or intense physical activity.
When triggered, it helps the body to mobilize energy & react quickly.
Prepares the body to face a threat or escape danger by increasing
energy availability, boosting alertness, and optimizing physical
performance.
Widely coordinated response
Arises from the thoracolumbar regions
Sympathetic Nervous System
Neurotransmitters of sympathetic
norepinephrine and epinephrine (adrenaline)
Physiological Effects of Sympathetic Nervous System
Increased heart rate
Dilated pupils
Bronchodilation
Inhibition of digestion
Release of glucose
Sweat production
rest-digest system
The PNS supports rest, relaxation, and digestion, promoting
recovery and conservation of energy.
Becomes more active during calm, non-stressful times, promoting
maintenance activities like digestion, growth, and tissue repair.
Localized, specific response
Arises from the craniosacral regions
Parasympathetic Nervous System
Neurotransmitters
acetylcholine (Muscarinic receptors)
Physiological Effects of parasympathetic nervous system
Decreased heart rate
Constricted pupils
Bronchoconstriction
Stimulation of digestion/urination
Stimulation of
salivation/lacrimation
Structures innervated by SNS ONLY:
A-B-E
Adrenal Medulla/Adipose Connective Tissue,
Blood Vessels
Effectors of Skin
