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CNS
central
brain, spinal cord
PNS
peripheral
nerves
neuron
specialized cell that conduct signal processes from nerves
"excitablle cells"
sensory
receptor -> CNS
Motor
CNS -> effector
somatic
body wall, aware and voluntary
somatic sensory
feel temperature on the skin
somatic motor
causes to biceps to contract
autonomic/automatic/visceral
organs & vessels/ involuntary control and less aware
autonomic sensory
senses blood pressure
autonomic motor
lowers heart rate (cardiac muscle)
sympathetic
fight or flight (increasing energy)
parasympathetic
rest and digest (calming)
neuroglia
supporting cells
neuropil
background of cytoplasmic extensions of all nervous cells
Steps of neurotransmitter
synpase
axon terminal forms with another cell
nerve
bundle of axons that are wrapped together (mixed function)
multipolor (motor)
interneurons - between each other in the brain
bipolar (special sensory)
special senses
go on in our head usually
unipolar (general sensory)
forms long nerves
neurilemma
only on axon protective coating
astrocyte cells
microglial cells
phagocytic / destory pathogens (digest) debris
ependymal cells
oligodendrocytes
white matter
mostly myelinated axons & dendrites, paler color
gray matter
mostly cell bodies & synapses, darker color (most synapses occur)
Schwann cells
neurilemma sheath
multiple ones wrap axons
myelin sheath
repeated flat layers of lipid membrane of schwann cell
-mylein insulates, protects axons, increases speed of conduction of nerve impulse
neurilemma
ring of flattened cytoplasm & nucleus of schwann cell
unmyelinated
ion exchange continuous/slow
myelinated
few ion exchanges at nodes -> FAST
multiple functions
many axons
At rest
-70 mV inside axons (0 on outside) -> resting membrane potential
dendrities
stimulates neuron at?
ligand
chemical - neurotransmitter/hormone/ion
voltage gates
respond/open based on charge
initial stimulus
usually chemical -> to dendrite
depolarization
(sodium first …. increases charge inside)
potassium out (repolarize)
hyperpolarize
more (-) negative inside
depolarization wave progresses
dendrites -> cell body membrane -> graded potential: could weaken OR stop
insidie axon cytoplasm
transport of cargo
anterograde -> (body to synapse)
vesicles of neutrotransmitter/mitochondria/microtubules
-retrograde (synapse -> cell body)
parts to recycle
extra neurotransmitters
anterograde
cell body to synapse (axon terminal)
retrograde
(axon terminal) synapse to cell body
-carry old membraine parts to recycle and extra neurotransmitters
layers that protect brain
meninges of brain
dura mater, arachnoid, pia mater
dura mater
outer meninges
A - periosteal (inner periosteum)
B - meningeal (inner)
duran sinuses w/ blood (low O2 - veins) in between
arachnoid mater
webbly with vessels
pia mater
on surface of brain
inner meninges
falx cerebri
between right & left cerebrum
tentorium cerebelli
divides cerebrum from cerebellum
falx cerebelli
divides right & left cerebellar (cerebellum)
Dural sinuses
veins
superior & inferior sagittal sinus
all drain into the jugular vein to leave the skull
CSF
in subarachnoid space and made in ventricles (cavities)
choroid plexus
in ventricles -> capillaries (blood) + ependymal cells
creates cerebrospinal fluid
Circulation pattern of CSF
3 primary divisions of embryonic brain neural tube
prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)
Forebrain (prosencephalon)
telencephalon - cerebrum (higher level)
+
diencephalon (2nd) thalamus & epithalamus, hypothalamus
Midbrain (mesencephalon)
(brainstem) - basic vital functions
hind brain (rhombencephalon)
metencephalon - (pons) cerebellum (brainstem)
+
myelencephalon - (medulla oblongata)
shape/expansion changes in brain
week 5 - flexures (bends) - midbrain 1st, cervical 2nd (as the head develops)
week 13 - expansion of telencephalon (envelops diencephalon)
week 26 - surface folds in outer cerebrum & expanded + folded cerebellum
week 39 (birth) - complex cerebral cortex - (gray matter) -> synapses (major)
sulci/sulcus
grooves
gyri/gyrus
bumps
forebrain & hindbrain
adult brain shows mostly?
lateral view
cerebrum (4 lobes)
cerebellum (posterior)
superior view
only cerebrum
R + L hemispheres
all gray matter of cortex
frontal, parietal, temporal, occipital lobes
precentral (motor) gyrus
frontal lobe
postcentral gyrus (sensory)
parietal
3 functional areas of cerbral cortex
motor areas - control voluntary movement
sensory areas - conscious awareness of sensation
association areas - integrate diverse information
cerebral cortex
motor control (voluntary, conscious - somatic_
mostly frontal lobe, also temporal lobe
primary motor cortex
precentral gyrus - fine muscle control
-conscious control of precise, skilled, voluntary movements
-depicated as a "motor homunculus"
premotor cortex
pattern/repetitive
-learned, repetitive, patterned, sequential motor skills
Broca's area (left side)
speech production
frontal eye field
voluntary eye movements
prefrontal cortex - frontal lobe
most complex area, coordinates multiple inputs & outputs
sensory cortex
process info from all receptiors (parietal, occipital, temporal)
special senses
Wernicke's area
understanding and interpreting language (temporal lobe)
sensory homunculus
proportionally more cerbral sensory cortex is devoted to
-hands (finger and thumb)
-mouth (tongue)
-eyes
-genitalia
-internal organs
limbic system
responsible for feeling emotions
cingulate gryus
emotional impact -> memories and affect behavior decisions
capgras delusion/imposter syndrome
-lesion in limbic system
-recognize a relative as someone u know but believe they are an imposter bc there is no emotional impact associated w the person
white matter tracts of cerebrum
L hemipshere
language, math, logic, abstract physical tasks
R hemisphere
artistic, visual spatial, intuition
Diencephalon
thalamus, hypothalamus, epithalamus
"gateway to cortex" - directs neuron tracts
Epithalamus
pineal gland - melatonin
hypothalamus
autonomic NS
control basic viseral functions
(BP, HR, hunger, body temp, sleep;
endocrine (hormone secretion)
pituitary gland -> "master" endocrine
a) hormones for reproduction
b) fluid balance -> kidneys
Thalamus
encloses 3rd ventricle
Mesencephalon
midbrain (least elaborated region of brain & part of brainstem)
-> corpora quadrigemina
a) superior colliculi
-visual reflexes
b) inferior colliculi
-auditory reflexes
(a & b are fast autonomic protective)
cerebral aqueduct
connection between 3rd and 4th ventricles of the brain
pons (brainstem)
breathing & swallowing
some facial expression
breathing rate + rhythm
metencephalon
cauda equina
collection of nerves at the end of the spinal cord that resembles horse tail
myelencephalon
medulla oblongata
controls autonomic reflexes
-cardiovascular center: blood pressure, heart rate, vascoconstriction
-respiratory center: generate rhythm, coughing, sneezing
spinal cord
beings at foramen magnum in vertebral canal