ch. 13, 14, 16 Flashcards
what are the enlargements of the spinal cord
cervical and lumbar
supplies nerves to shoulder and arms
cervical
supplies nerves to pelvis and legs
lumbar
what are the two longitudinal grooves of the gross anatomy of the spinal cord
posterior median sulcus
anterior median fissure
how many segments are part of the spinal cord
31
what comes out of each of these segments
each gives rise to a pair of spinal nerves
2 nerve roots that emerge from the spinal cord
dorsal root with sensory neurons
ventral root with motor (efferent) neurons
what is contained within a dorsal root ganglion
cell bodies of these neurons
what forms a spinal nerve
the dorsal w sensory neurons and ventral root w motor neurons
how does the spinal nerve get out from the vertebrae
mixed nerves both sensory and motor
what happens after the spinal nerve passes through the vertebrae
through intervertebral foramen and branches to form peripheral nerves
provide necessary physical stability
shock absorption
carry blood vessels to deliver nutrients and O2 to spinal cord
function of spinal meninges
location of spinal meninges
between bone and soft tissue of cord and brain
protective specialized membranes surrounding spinal cord and brain
spinal meninges
three layers of spinal meninges
dura mater
arachnoid mater
pia mater
outermost
dura mater
dense collagen fibers so it is very tough
dura mater
middle layer
arachnoid mater
epidural space- anesthetics injected into this space to block nerve function
dura mater
subarachnoid space- under this layer
arachnoid mater
filled with CSF
arachnoiod mater
innermost
pia mater
firmly bound to neural tissue underneath
pia mater
very thin and follows contours of spinal cord
pia mater
blood vessels servicing spinal cord run along surface of what kind of mater
pia mater
what is the subarachnoid space filled with
CSF (cerebral spinal fluid)
shock absorber and diffusion medium for dissolved gases, nutrients, chemical messengers and wastes
CSF
mostly cell bodies of neurons (interneurons), neuroglia and unmyelinated axons
gray matter in the spinal cord
how is the gray matter in the spinal cord structured
butterfly shaped with projections (“wings”) called horns
with somatic and visceral sensory neurons
posterior horn
somatic motor (efferent) neurons
anterior horn
visceral motor (efferent) neurons
lateral horn
horizontal bar that connects “wings”; has axons that cross from 1 side of cord to the other
gray commissure
contains CSF and is continuous with brain ventricles
central canal
bundles of myelinated axons
white matter
how is the white matter in the spinal cord structured
divided into 3 regions called columns (posterior anterior and lateral)
bundles of axons that are similar and relay the same type of info in the same direction
nerve tracts
sends sensory info to the brain
ascending tracts
send motor info to the spinal cord
descending tracts
region of the skin surface thats monitored by a single pair of spinal nerves
deratomes
clinical importance of deratomes?
damage or infection of a spinal nerve or dorsal root ganglion will produce a characteristic loss of sensation to its corresponding region of the skin
complex, interwoven networks of nerves and are combinations of spinal nerve branches
nerve plexus
what are the four nerve plexus
cervical plexus
brachial plexus
lumbar plexus
sacral plexus
innverate muscles of neck and also control diaphragm
cervical plexus
innervates shoulder and arms
brachial plexus
innervate pelvic area and legs
lumbar and sacral plexuses
rapid automatic responses to specific stimuli
reflexes
function: preserve homeostasis by making rapid adjustments in the function of organs or organ systems
reflexes
2 tips of reflexes
spinal and cranial
those processed in spinal cord
spinal reflexes
those processed in the brain
cranial reflexes
suckling, tracking objects with eyes, chewing, withdrawal reflex
innate reflexes
knee-jerk, postural reflexes
somatic reflexes
pupillary reflec, respiration, cardiovascular function, swallowing, coughing
visceral (autonomic) reflexes
- receptor at end of sensory neuron is activated
- sensory neuron is activated and carries nerve impulse into CNS via doral root
- interneurons processes info and sends it on
- motor neuron is activated and carries nerve impulse out of CNS via ventral root
- effector (muscles or gland) responds
reflex arc
4 major brain regions
cerebrum
cerebellum
dicencephalon
brain stem
4 major parts of diencephalon
thalamus
hypothalamus
pituitary
pineal
3 parts of the brain stem
midbrain
pons
medulla oblongata
4 connected chambers within cerebral hemispheres and brain stem
brain chamber ventricles
what are brain chamber ventricles filled with
CSF
4 brain ventricles
lateral
3rd
4th
within corpus callosum
lateral ventricles (right and left)
within diencephalon
3rd ventricle
between brain stem and cerebellum
4th ventricle
continuously circulates between ventricles, central canal, and subarachnoid space
CSF is located in the nervous system
3 cranial meninges
dura mater
arachnoid mater
pia mater
how is the dura mater different from the spinal dura mater
cranial dura mater has 2 layers to it here with outer layer fused to skull interior- no epidural space
function of the cranial meninges
protection from mechanical forces
stabilizes and supports brain
completely surrounds and bathes exposed surfaces of cns
CSF
how much CSF do we have
150 mL
cushions CNS structures
supports brain - brain floats in CSF
trnasports nutrients, chemical messengers and wastes
function of CSF
what is the formation of CSF
secreted by tiny masses of specialized neuroglial cells and capillaries
where is CSF formed
choroid plexus- project into ventricles and empty the CSF there
how many cranial nerves originate in the medulla oblongata
5
how many cranial nerves originate in pons
4
how many cranial nerves originate in the midbrain
2
loosely organized mass of gray matter that is throughout the brain stem
reticular formation
where is reticular formation located
medulla oblongata
2 reflex centers located in the medulla oblongata
cardiovascular center
respiratory rhythmicity centers
contains cell bodies of neurons associated with 4 cranial nerves
has centers that control respiratory-rate and death
process and relay info heading to or from cerebellum
function of pons
reflex movement of eyes, head, and neck
reflex responses to visual stimuli
reflex movements of head neck and trunk
reflex responses to auditory stimuli
2 hemispheres connected by vermis in midline
cerebellum
mostly branching white matter but has a thin layer of gray matter on the surface
cerebellum
allows the cerebellum to communicate with the rest of CNS via nerve tracts
cerebellar peduncles
adjusts postural to maintain balance and equilibrium
programs and fine-tines body movements to make them smooth
integrates sensory information from receptors in muscles, tendons, joints, eyes, and ears to help make adjustments as needed
cerebellum
fx: secretes melatonin
pineal gland
fx: secretes many hormones
pituitary gland
central relay point for incoming sensory information and channels them to appropriate regions of cerebral cortex for interpretation
also filters information- only passing on a portion of what arrives
thalamus
autonomic functions the hypothalamus controls
heart rate, bp, respiration, digestive fx
2 hormones secreted by the hypothalamus
ADH (antidiuretic hormone) and oxytocin
several structures together (functional grouping)
limbic system
primarily in the diencephalon
limbic system
largest region in the brain that has 2 cerebral hemispheres separated by longitudinal fissures
cerebrum
connected by deep bridges of nerve fibers
corpus callosum
5 lobes in the cerebrum
insula frontal parietal occipital temporal
thin blanket of gray matter that covers cerebrum and contains nearly 75% of all neuron cell bodies in CNS
cerebral cortex
three axons found in white matter of cerebrum
association
commissural
projection
interconnect area of cortex within a single hemisphere
association fibers
interconnect and permit communication between the hemispheres; includes corpus collasum
commissural fibers
links cerebral cortex to rest of the brain and spinal cord
projection fibers
primary motor cortex
frontal lobe
fx. direct voluntary control of skeletal muscles
frontal lobe
primary sensory cortex
parietal lobe
fx. receives info of touch, pressure, pain, vibrations, taste, and temp
parietal lobe
visual cortex
occipital lobe
fx. receives visual info
occipital lobe
auditory and olfactory cortex
temporal lobe
fx. receives info about hearing and smell
temporal lobe
gustatory cortex
insula
fx. receives info about taste
insula
regions of the cortex that interpret incoming data or coordinate a motor response
association area
fx. monitors activity in the primary sensory cortex
somatic sensory association area
fx. monitors activity of visual cortex and interprets results
visual association area
fx. monitors activity of auditory cortex; word recognition occurs here
auditory association area
fx. coordinates learned movements
somatic motor association area
areas that receive info from many association areas and direct complex motor activities
integrative cortex
receives info from all sensory association areas and integrates sensory info and coordinates access to complex visual and auditory memories
general interpretive area
wernicke’s area
regulates pattern of breathing and vocalization; needed for normal speech
speech center (broker’s area)
coordinates info from association area of the entire cortex and performs abstract intellectual
prefrontal cortex
in what hemisphere is the general interpretive area and speech areas found
left hemisphere
contains general interpretive and speech centers
left side
responsible for language based skils
left side
performs analytical tasks
left side
reading, writing, speaking, math calc, logical decision making
left side
involved with spatial visualization
right side
allows identification of objects by touch, smell, sight, taste or feel
right side
involved with emotions and intuition
right side
structure that allows the 2 hemispheres to mix
corpus callosum
how many cranial nerves are there
12
sensory; smell
olfactory
sensory; vision
optic
motor; eye movements (4/6 extra ocular muscles)
oculomotor
motor; eye movements (only one extra-ocular muscles)
trochlear and abducens
mixed; sensory- cornea, eyelids, forehead, facial skin, teeth, lips, and gums
motor- chewing muscles
trigeminal
mixed; sensory-taste
motor- facial expression muscles, lacrimal, and salivary gland secretions
facial
sensory; balance/equilibrium and hearing
vestibulocochlear
mixed; sensory-pharynx, tongue, carotid arteries
motor-salivary gland secretions, swallowing/throat muscles
glossopharyngeal
mixed; sensory-throat, diaphragm, visceral organs of throat and abdomen
motor- speech and swallowing muscles, heart, smooth muscles, and glands of visceral organs of thorax and abdomen
vagus
motor; muscles of throat, neck, and back
accessory
motor; move tongue
hypoglossal
create visceral reflexes with sensory origins from receptors to regulate autonomic activities via motor nerve fibers to visceral effectors
ANS
adjusts our basic life supports without conscious control
ANS
what type of nerve fibers are all ANS fibers
motor
2 divisions of the ANS
sympathetic and parasympathetic
readies body for crisis that may require sudden, intense physical activity; fight or flight
sympathetic
conserves energy and promotes sedentary activities such as digestion; rest and digest
parasympathetic
2 regions of the spinal cord that nerve fibers of the sympathetic division originate
thoracic and lumbar region
2 regions of the spinal cord that nerve fibers of the parasympathetic division originate
brain stem and sacral regions
2 neurotransmitters used in the sympathetic division
ACh
norepinephrine
neurotransmitter used in the parasympathetic division
ACh
2 hormones that play a part in sympathetic division
epinephrine (adrenaline) and norepinephrine (noradrenaline)
what hormones play a part in the parasympathetic division
no hormones
