CNS/sensory 1 - intro Flashcards
name major divisions of the nervous system
afferent - sensory input
efferent - motor output
describe afferent
sensory input
cell bodies outside of CNS
sends axons into CNS
which nerves go into cns
cranial nerves
spinal nerves
describe cranial nerves
somatic
visual
olfactory
taste
auditory
vestibular
send into brain directly
describe spinal nerves
somatic sensation = touch, temp, pain
visceral = sensation inside you - input
send into cns
describe efferent
motor output
cell bodies in CNS
WHAT IS cns
brain and spinal cord
name efferents
somatic efferent
autonomic efferent
enteric
describe somatic efferent
innervates skeletal muscle
only excitatory - ACH
motor neurons
what is ach
neurotransmitter at neuromuscular junction
describe autonomic efferent
innervates interneurons
and attach to other things = smooth and cardiac muscle
excitatory and inhibitory - causes muscles to contract
describe enteric
nervous system
neurons that control digestive system
what is cerebrum
cortex
2 halves
outside
what is corpus callosum
connecting of 2 sides - 2 halves
what is thalamus
on top of brainstem
what is brainstem - parts
midbrain
pons
medulla
what is frontal lobe
motivation
Consciousness
what is parietal lobe
integrates sensory info from different modalities
name 4 lobes of brain
frontal
parietal
temporal
occipital
what is occipital lobe
visal areas
what is central sulcus
separates primary motor gyrus and primary somatosensory gyrus
what is cerebellum
below cortex
motor control and movement
what is gyrus
fold in cerebrum = increased surface area
more cerebral cortex
what is sulcus
cracks
sulci
what are ventricles
little opening called ventricles
produce cerebral spinal fluid
openings/cavities
what is gray matter
cell bodies of neuron’s are in 2 mm band on surface
cell bodies
dendrites
synapses
what is white matter
myelinated axons
what is basal nuclei
basal ganglia
collection of cell bodies all together
name divisions of spinal cord
cervical nerves
lumbar nerves
thoracic nerves
sacral nerves
coccygeal nerves
how many spinal segments
31
what is between vertebrae
spinal nerves
what is spinal segment
hockey puck shape
bunch of spinal cord and corresponding 2 spinal nerves coming off on either side
describe cervical nerves
8 pairs
spinal nerves innervate = neck, shoulders, arms, hands
describe lumbar nerves
lower abdominal wall, hips, legs
describe sacral nerves
genitals and lower digestive track
what is difference in matter of brain and spinal cord
gray matter on inside of spinal cord
white matter on outside
opposite of brain
describe dorsal horn (spinal cord)
wings of butterfly
Afferent
sensory info comes in
behind ventral horn
describe ventral horn (spinal cord)
efferents
cell bodies = ventral horn of gray matter
motor info comes out
describe gray matter (spinal cord)
neurons form circuitry
butterfly shaped
describe central canal (spinal cord)
Opening in middle of gray matter
where csf is
describe dorsal root (spinal cord)
afferent
describe ventral root
efferent
describe white matter (spinal cord)
axons going up and down cord
grouped together in tracts
describe dorsal root ganglion (spinal cord)
bulge = cell bodies of neurons that form afferents that send axons into cns
innervates skin and other tissue = as part of somatosensory input
cell bodies located close to spinal cord = in dorsal root or dorsal root ganglion
describe cranial nerves - detailed
12 pairs
olfactory and optic nerves - 2 project other places in brain - do not go through brainstem
10 of them project into brainstem
trigeminal nerve innervates face
share both sensory and motor info coming in and out of cranial nerves
describe brain edema
increased intercranial pressure pushes brain out base of skull (pushes brain out through only opening)
compresses brain stem and cranial nerves that regulate pupillary response
like how during concussion or head injury = doctor will shine light in eye - looking for pupillary reflex
describe early development of the nervous system - up to week 1
fertilized egg - ovum
divides and becomes ball of cells
after one week = blastocyst - week 1 (blastocyst - ball of cells, starts to take shape = hollow cavity on inside)
inner cell mass = inside - bunch of developing cells - eventually becomes you and nervous system
describe early development of the nervous system - week 2 and 3 - basic
week 2 - blastocyst = more definition of blastocyst and inner cell mass will grow
week 3 - blastocyst - embryonic disk forms - important layer of cells in blastocyst - neural plate forms
describe early development of the nervous system - week 4 - basic
if chop it= look down on embryonic disk –> where specialization starts to form - which cells become nervous system and which cells become everything else
describe week 3 of development of neural tube - in detail
3 layers of neural plate - ectoderm, mesoderm, endoderm
neural plate had 2 layers - bunch of cells growing and dividing
starts to form neural groove
describe week 4 of development of neural tube - in detail
neural groove starts to form neural tube
Neural crest becomes part of PNS and CNS - part of ectoderm - dorsal root ganglia afferent
sensory input
mesoderm forms dura
neural tube becomes CNS and part of PNS
describe neural tube
vesicles develop during week 4 - neural tube forms little bulges
~week 4/5 = forms whole nervous system
what does neural tube become
forebrain
midbrain
hindbrain
extension of neural tube = spinal cord
describe parts of CNS - from neural tube
fore brain = cerebral hemispheres, thalamus
midbrain = midbrain
hindbrain = cerebellum, pons, medulla
inside neural tube = hollow - cavity becomes ventricles and central canal - csf fluif produced and flows
what do ventricles contain
150 ml of cerebral spinal fluid - csf
name important ventricles
lateral ventricles
third ventricle
4th ventricle
describe lateral ventricles
2 large ventricles - curve around temporal lobes
large
most of csf
describe choroid plexus
lining of ventricle
oozes csf into ventricle all the time
what are foramens
ventricle connected to each other through little connections
describe formation of csf
Produced by the choroid plexus (in the four ventricles, but mainly the two lateral)
rate of 500 ml/day
must leave brain since more than max
describe function of csf
supports and cushions cns - specific gravity pf csf and brain are equal
provides nourishment to brain
removes metabolic waste through absorption at the arachnoid villi (organ that takes csf out of brain)
describe composition of csf
sterile
colourless
acellular fluid
contains glucose
describe circulation of csf - general
passive - not pumped
oozes out of choroid plexus and moves around - absorbed by arachnoid villi
dumped back into venous blood supply
what is entire pathway of csf
foramen of munro - where 2 lateral ventricles attach into 3rd ventricle
dump csf into 3rd ventricle (can also produce some csf)
then goes behind midbrain via cerebral aqueduct - midbrain
fourth ventricle (between brainstem and cerebellum) - still produces some csf
central canal - csf flows passively
csf leaves out foramens of lushka (2 lateral) and magendie
csf enters subarachnoid space - now goes outside of brain and spinal cord
cavity collects csf through arachnoid villi - takes out and dumps into venous blood supply (connects at midline)
what is subarachnoid space formed by
produced by one of coverings of CSF - meninges aka membranes
what is hydrocephalus
too much water in brain - too much csf
csf pushed brain out towards skull
name types of hydrocephalus
communicating
non communicating
describe communicating hydrocephalus
problem is absorption of csf by arachnoid vili or block in subarachnoid space
but all ventricles are communicating and all foramens ok
describe noncommunicating hydrocephalus
problem in ventricle or foramen is blocked
what are meninges
membranes
what do meninges cover
brain and spinal cord
what are 3 meninges of cns and describe
dura mater - protects brain, thick leather
arachnoid membrane - thinner, creates subarachnoid space
pia mater - very thin, lays flat on gray matter
what is subarachnoid space = meninges of cns
between arachnoid membrane and pia mater
composed of trabeculae = little foot processes that create space between arachnoid membrane and pia mater
contains csf and blood vessels - dive down and perfuse neural tissu
describe dural - venous - sinus
csf returns to blood at dural sinus (dura opens to form this)
csf collected and returned to venous blood supply
arachnoid vili = line dural sinus
csf = subarachnoid space and move into dural sinus via arachnoid villi
describe thoracic nerves
down thoracic segments
shoulder, chest
upper abdominal wall
12 pairs
how many pairs of coccygeal nerves are there
1 pair
what does ectoderm become
pns and cns systems between week 3 and 4
what does mesoderm do
Becomes muscles and internal parts of body
what does endoderm do
will fold up into tube and form digestive system
what happens if neural tube is not formed properly
problem for baby
neural tube deficits
