Nervous Sys. Flashcards
what are the 3 major functions of the nervous system
- sensory
- integrative
- motor
what kind of neurons are sensory neurons ?
afferent
what kind of neurons are motor neurons ?
efferent
What is the meaning of the term afferent?
carry the signals detected by the sensory receptors to the brain and spinal cord
What is the meaning of the term efferent?
carrying information away from the brain
what is the integrative function of the nervous system ?
analyzing + storing sensory information –> then making appropriate responses
what are the components of the CNS?
- Brain
- Spinal Cord
what are the components of the PNS ?
all the other nervous system outside the CNS = EVERYTHING else
what are the 2 subdivisions of the nervous system?
- Central nervous sys
- Peripheral nervous sys
what are the components of the PNS?
- Cranial nerves and their branches
- Spinal nerves and their branches
- Ganglia
- Sensory receptors
what are ganglia ?
what are Neurons
electrically excitable nerve cells
what are neuroglial cells
supportive + protective cells in nervous tissue
what is a nerve
bundles of neurons
what are the structural components of a neuron
- dendrites
- myelin sheath
- axon
- axon terminal
- cell body
what are the 3 functional classification of neurons?
- sensory
- motor
- interneurons
what function do interneurons serve in the nervous sys ?
integrative
what are the 2 subdivisions of the PNS?
- Somatic (SNS)
- Autonomic (ANS)
what 3rd subdivision is apart of the PNS but considered to fall under the ANS division?
enteric nervous sys (ENS)
what is the function of the ENS?
involved in regulating the digestive system
what PNS subdivision is under involuntary control?
autonomic
what PNS subdivision is under voluntary control?
somatic
what are the 2 subdivisions of the ANS?
- sympathetic
- parasympathetic
what subdivisions functions are associated with “fight or flight”
sympathetic
what subdivisions functions are associated with “rest and digest”
parasympathetic
what are the 2 cell types of nervous tissue?
- neurons
- neuroglia
what sys is often called “the brain of the gut”
enteric nervous sys
what are 3 structural classifications of neurons
- bipolar
- multipolar
- unipolar
what are the characteristics of a multipolar neuron?
- Several dendrites
- 1 axon
Most neurons in
the CNS are what…?
multipolar neurons
what are the characteristics of a bipolar neuron?
- 1 main dendrite
- 1 axon
the majority of special senses neurons are what…?
bipolar neurons
what are unipolar neurons
are sensory neurons that during development have a fused axon and dendrite
can neuroglia cells generate AP?
NO
what are the 4 types of neuroglia cells in the CNS ?
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells
what are the 2 types of neuroglia cells in the PNS ?
- Schwann cells
- satellite cells
astrocyte function =
creates “blood brain” barrier to protect neurons
oligodendrocytes function =
form myelin sheath around CNS axons
microglia function =
function as phagocytes
ependymal cells function =
produce + maintain circulation of cerebrospinal fluid
Schwann cells function =
myelinated a single PNS axon
satellite cells functions =
facilitates the exchange of substances between neurons + extracellular environment
what is the Myelin sheath ?
is when axons are covered by a lipid and protein layer generated from oligodendrocytes/Schwann cells
define Unmyelinated
means axons that do NOT have a myelin sheath
define Demyelinated
means axons that have LOST/destroyed their myelin sheath
what is the Node of Ranvier
the gaps formed between the myelin sheaths where the axons are left uncovered
what does it mean if an axon IS covered by a myelin sheath
that the neuron is myelinated
what are the 2 purposes of myelination ?
1) To electrically insulate the axons of neurons
2) To increase speed of nerve impulse conduction
Node of Ranvier function =
how electrical signals in myelinated neurons jump from one node to the next
what cells produce myelin sheaths in the CNS
oligodendrocytes
what cells produce myelin sheaths in the PNS
Schwann cells
what disease can the destruction of myelin sheaths occur in?
multiple sclerosis
what is an autoimmune disease?
when your immune system is overactive = caused it to attack and damage your body’s own tissues
Where is gray matter located in the CNS
in the brain in the outermost layer
Where is gray matter located in the spinal cord?
concentrated in the middle of the spinal cord
What is the composition of gray matter?
mostly neuronal cell
bodies and unmyelinated axon
What is the composition of white matter?
mostly myelinated axons
What is a neural network?
Groups of neurons organized into circuits
what is neural plasticity ?
Organizations of neuronal
networks continually breaking and reforming
what is the conduction of an AP?
when nerve impulses travel from one area of the body to another down an axon
what neurons does continuous conduction occur in?
unmyelinated neurons
what neurons does saltatory conduction occur in?
myelinated neurons
which conduction is faster + why?
- saltatory conduction
- why = neurons signal jumps from one node of Ranvier to the next
Pre-synaptic neuron function =
neuron sending the message
Post-synaptic neuron function =
neuron receiving the signal
what are the 3 components of the brain stem ?
- medulla oblongata
- pons
- midbrain
what are the 3 components of the diencephalon?
- thalamus
- hypothalamus
- epithalamus
what is the largest part of the human brain?
cerebrum
what are the 4 main regions of the brain?
- cerebrum
- diencephalon
- brain stem
- cerebellum
what are nuclei in regards to the brain?
Clusters of neuronal cell bodies with similar
functions
what are tracts in regards to the brain?
Pathways of axons heading in the same direction
what is the role of cranial meninges + the skull + CSF + blood-brain barrier ?
to protect the contents of the brain and spinal cord
what are the 3 cranial + spinal meninges?
- dura mater (outer)
- arachnoid mater (middle)
- pia mater (inner)
what are ventricles in the brain?
CSF filled cavities in the brain
what are the 4 ventricles within the brain?
- 2 lateral ventricles
- third ventricle
- fourth ventricle
what is cerebrospinal fluid ?
clear liquid that continuously circles through cavities of the brain + spinal cord
What vital functions are controlled by the medulla oblongata?
heart + respiratory rhythm
Why may injury to the medulla oblongata be fatal?
if functions maintaining heart and respiratory
rhythm are compromised
How is the cerebellum separated from the cerebrum?
by a deep groove = the
transverse fissure
What are folia in the cerebellum ?
a superficial layer arranged in thin parallel ridges
How is the cerebellum attached to the rest of the brain?
by the cerebellar peduncles
functions of the cerebellum =
- evaluating effectiveness of movement
- sending feedback to cerebral cortex to correct motor errors
- regulation of posture and balance
What is ataxia?
is when damage to the cerebellum disrupts/inhibits muscle co-ordination
functions of the hypothalamus =
- regulation of the pituitary function
- regulation of emotional and behavioral patterns
- regulation of eating and drinking
- control of body temperature
- regulation of circadian rhythms and states of consciousness
what is the cerebral cortex?
Outer rim of gray matter of the cerebrum
define fissure
folds
what is the cerebral hemisphere?
the R and L halves of the cerebrum
define gyri
elevated ridges
define sulci
crevices
what component of the diencephalon is the pineal gland a part of ?
Epithalamus
what are the 4 lobes of the cerebrum
- Frontal lobes
- Parietal lobes
- Occipital lobes
- Temporal lobes
what are the 12 cranial nerves?
- olfactory
- optic
- oculomotor
- trochlear
- trigeminal
- abducens
- facial
- vestibulocochlear
- glossopharyngeal
- vagus
- accessory
- hypoglossal
what cranial nerve is this I ?
olfactory
what cranial nerve is this II ?
optic
what cranial nerve is this III ?
oculomotor
what cranial nerve is this IV ?
trochlear
what cranial nerve is this V ?
trigeminal
what cranial nerve is this VI ?
abducens
what cranial nerve is this VII ?
facial
what cranial nerve is this VIII ?
vestibulocochlear
what cranial nerve is this IX ?
glossopharyngeal
what cranial nerve is this X ?
vagus
what cranial nerve is this XI ?
accessory
what cranial nerve is this XII ?
hypoglossal
what is the major function of cranial nerve I ?
smell
what is the major function of cranial nerve II ?
sight
what is the major function of cranial nerve V ?
touch + pain + thermal sensation
what is the major function of cranial nerve VIII ?
hearing/balance
what is the major function of cranial nerve X ?
- taste
- touch
- pain
- temperature
- slows heart rate
what is the location of cranial nerve II ?
optic foramen
what is the location of cranial nerve I ?
olfactory foramina of cribriform plate
what is the location of cranial nerve V (3 branches) ?
- superior orbital fissure
- foramen rotundum (maxillary)
- foramen ovale (mandibular)
what is the location of cranial nerve VIII ?
internal acoustic canal (meatus)
what are the 3 protective structures of the Spinal Cord ?
- vertebrae/spinal column 2. Meninges
- CSF
what is the location of cranial nerve X ?
jugular foramen
how many pairs of cervical nerves are there ?
8 pairs
how many total pairs of spinal nerves are there ?
31 pairs
how many pairs of thoracic nerves are there ?
12 pairs
how many pairs of lumbar nerves are there ?
5 pairs
how many pairs of coccygeal nerves are there ?
1 pair
how many pairs of sacral nerves are there ?
5 pairs
what are the cervical plexus?
C1-C5
what are the brachial plexus
C5-T1
what are the lumbar plexus?
L1-L4
what are the sacral plexus?
L4-S4
What spinal nerves do not form a plexus?
thoracic nerves = T2-T12
what muscle does the phrenic nerve innervate?
diaphragm
what muscle does the axillary nerve innervate?
deltoid + teres minor
what muscle does the musculocutaneous nerve innervate?
anterior muscles of the arm
what muscle does the ulnar nerve innervate?
flexor carpi ulnaris
what muscle does the median nerve innervate?
muscles of ANTERIOR forearm
what muscle does the radial nerve innervate?
muscles of POSTERIOR arm + forearm
what muscle does the femoral nerve innervate?
- iliacus
- quadriceps femoris
- sartorius
- pectineus
ANTERIOR leg
what muscle does the obturator nerve innervate?
- adductor longus + brevis + magnus
- gracilis
LATERAL side of leg
what muscle does the sciatic nerve innervate?
muscles of the POSTERIOR leg
what plexus is the phrenic nerve from?
cervical
what plexus is the axillary nerve from?
brachial
what plexus is the musculocutabeous nerve from?
brachial
what plexus is the ulnar nerve from?
brachial
what plexus is the median nerve from?
brachial
what plexus is the radial nerve from?
brachial
what plexus is the femoral nerve from?
lumbar
what plexus is the obturator nerve from?
lumbar
what plexus is the sciatic nerve from?
sacral
what are the 5 external components of the spinal cord?
- Cervical enlargement
- Conus medullaris
- Cauda equina
- Lumbar enlargement
- Filum Terminal
what is shingles ?
an acute infection of the PNS by herpes zoster
can the spinal
cord integrates some of its own information?
YES
what is the response from spinal integration called?
spinal reflex
the pathway followed in the spinal reflex is called ?
reflex arc
what are the 5 components/pathway of the reflex arc?
- sensory receptor
- sensory neuron
- integrating center
- motor neuron
- effector
monosynaptic reflex arcs have how many synapses + interneurons ?
- 1 synapse = between sensory and motor neuron
- NO interneuron
polysynaptic reflex arcs have how many synapses + interneurons?
- 2 or more synapses
- 3 or more interneurons
what is the CT that surrounds the whole nerve?
epineurium
what is the CT that surrounds a fascicle?
perineurium
what is the CT that surrounds as individual axon?
endoneurium
