Function of the CNS Flashcards
one of the first to document brain dissections
Leonardo da Vinci
da Vinci’s theory on brain activity
it occurs in ventricles
phrenology
belief that bumps in the skull correspond to particular brain functions
how thick is the cerebral cortex
a few millimeters
3 broad functions of the cerebral cortex
- sensory perception
- motor control
- cognitive functions
2 functions of basal ganglia
- movement initiation
2. inhibition of antagonist muscles
thalamus function
sensory switchboard which relays specific sensory signals to the cortex
what is another name for the hypothalamus
head ganglion of the ANS
2 functions of hypothalamus
- homeostasis
2. fight or flight response
3 cerebellum functions
- motor timing, scaling, coordination, learning
- balance and gait
- eye movements
4 brainstem functions
- cardiovascular, respiratory, digestive control
- sleep/wake cycle and arousal
- balance and posture
- locomotor initiating center
spinal cord function
locomotor pattern generator
meninges
3 membranes covering the brain and spinal cord
3 meninges
- dura mater
- arachnoid
- pia mater
dura mater
tough outer layer
arachnoid
spidery intermediary mesh
pia mater
delicate inner layer
meningitis
infection of the meninges
where is cerebrospinal fluid produced
inner walls of brain ventricles
how is cerebrospinal fluid absorbed
reabsorbed into venous blood
what happens if cerebrospinal fluid reabsorption is blocked
causes hydrocephalus (water on the brain) - swollen head
how is hydrocephalus treated
surgically with drainage tubes
2 functions of cerebrospinal fluid
- bath and support neural tissue
2. maintain electrolyte balance around neurons
glia
supportive cells in CNS
ratio of glia cells to neurons
~ 1:1
4 types of glia cells
- astrocytes
- oligodendrocytes
- ependymal cells
- microglia
astrocytes functions (5)
- physically support neurons
- form blood-brain barrier
- repair by forming scar tissue
- turnover (recycle) neurotransmitters
- maintain electrolyte balance
what happens when astrocytes repair neuron
they form scar tissue which prevents regeneration
how is astrocyte scar tissue dealt with
broken down by enzymes
function of oligodendrocytes
form myelin sheaths that electrically insulate axons
function of ependymal cells
produce cerebrospinal fluid
function of microglia cells
scavengers that ingest bacteria and debris
2 types of brain tumors
- gliomas
2. meningiomas
gliomas
tumor of glia cells
meningiomas
tumor of meninges
do neuronal tumors exist?
no, because neurons can’t divide
how do capillaries in the CNS compare to the rest of the body
they are less porous
3 functions of blood-brain barrier
- protects neurons from chemical fluctuations and harmful agents
- provides oxygen and glucose
- selectively transport needed molecules to the brain
does the brain have glucose stores
no
problems with blood-brain barrier
presents a problem for drug delivery like dopamine in Parkinson’s patients
sensory afferent axons
convey sensory inputs to the CNS
motor efferent axons
convey motor commands from the CNS
which 2 types of signals does the spinal cord convey
- sensory receptors to the brain
2. brain to effectors
neuronal circuitry
generates reflexes and simple rhythmical movements
how many spinal nerves?
31
breakdown of the spinal nerves
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
dermatome
specific area of skin innervated by a spinal nerve
myotome
specific set of muscles innervated by a spinal nerve
shingles
bands of sores and intense pain due to a spinal cord virus
how are shingles related to dermatomes
dermatomes are used to identify which part of the spinal cord is infected
what happens when the spinal cord is damaged at a given level
sensation and motor control below that level are fucked up
what comprises central grey matter in spinal cord tracts
motoneurons, interneurons, dendrites, and axons
what is white matter composed of
bundles of axons (tracts)
function of white matter
convey sensory signals going to and from the brain
where do sensory afferents enter the spinal cord
through dorsal roots
what happens after sensory afferents enter the spinal cord
they bifurcate into ascending and descending columns
bifurcate
split
what do descending branches do
travel caudally 2-3 spinal segments
what occurs in the first 2-3 spinal segments
every millimeter, axons send branches into grey matter of the spinal cord
where are motoneurons located
the ventral horn