Midterm 1 - Functional Anatomy of CNS Flashcards
what does the brain consist of
cerebrum
diencephalon
cerebellum
brain stem
components of brain stem
mesencephalon
pons
medullar oblongata
components of diencephalon
thalamus
hypothalamus
what is the cerebrum often referred to
forebrain
what part of the brain evolves latest
cerebrum
what does the CNS receive
continuous flow of info - from inside and outside of body
what does the CNS do with information
analyzes and interprets - makes sense of internal and external info
what does the CNS send commands for
maintain function of vital systems and organs (homeostasis)
respond to external environment
how can the brain be organized
structural (anatomical) features and function
what maintains structural support in CNS
meninges
what are the meninges
3 layers surrounding the brain and spinal cord
what is the outer meninx
dura mater
what is the middle meninx
arachnoid
what is the inner meninx
Pia matter
what is the dura mater composition
thick and tough - attached to skull bone
what does the dura mater do
protects and supports the brain
where is the dura mater
inserted between cerebral hemisphere
what does the dura mater form
venous sinus
what does the dura mater collect
most of the blood and cerebrospinal fluid from brain
where is the Pia mater
tightly attached to the neural tissue
where is the sub-arachnoid space
between arachnoid and Pia mater
what is the subarachnoid space filled with
cerebrospinal fluid
where is cerebrospinal fluid (CSF) formed
by capillaries of specialized areas of the Pia mater called choroid plexus
where does CSF circulate
from brains ventricles down to the central canal of the spinal cord
where does the CSF diffuse
from 4th ventricle to the subarachnoid space and circulates around the brain and spinal cord
what happens to CSF before entering blood circulation
it is drained into venous sinus
what are the roles of the CSF
provides nutrients to CNS
protection (shock absorber)
ionic concentration ideal for optimum neuronal function
where is the blood -CSF barrier
at choroid plexus
what is the blood - CSF barrier responsible for
uptake of nutrients and drugs in CSF
what does the blood-brain barrier allow to diffuse
only liposoluble substances such as gases
why can no cells or proteins diffuse through blood-brain barrier
it has tight junctions which are surrounded by basal lamina to prevent any leakage/free movement
what does the cerebral cortex consist of
grey matter
what is the most superficial layer of the cerebrum
cerebral cortex - acquired late in evolution
what is the cerebral cortex responsible for
the conscious experience of sensory input
what is the cerebral cortex a site of
high nervous association
what is the cerebral cortex marked by
a high degree of educability (learning/reflex)
where do you hit an animal if you want to render it unconscious
cerebral cortex - primary cortical areas have been mapped
what is beneath the cortex
white matter
what does white matter include
association fibers between parts of cortex
commissural fibers between 2 hemispheres
projection fibers
what do projection fibers in white matter connect
cortex to other brain structures and spinal cord
where is the basal nuclei
deep within the cerebrum (close to thalamus)
what is the basal nuclei
paired nuclei composed of large pools of neurons
what does the basal nuclei control
complex semi-voluntary movements i.e walking/running
for movements that will always be the same, where is this info stored
basal nuclei
what does the basal nuclei work in conjunction with
the cortex and cerebellum - still requires consciousness
what does the basal nuclei also control in birds
voluntary movements
where does the cerebellum receive info from
inner ear
proprioceptive receptors
cortex
inner ear info
equilibrium
proprioceptive receptors
muscles, tendons, joints
cortex info
visual and motor
what is the main role of the cerebellum
prevent distortion of intended movement
how does the cerebellum work
receive info regarding body status intended movement
makes adjustments for smooth completion
how does the cerebellum send corrective signals
via thalamus to the cortex and spinal nuclei commanding the muscles
what type of animal is the cerebellum well developed
animals requiring precise adjustment for locomotion (air, ground, water)
what happens when there is damage to the cerebellum
bad posture
wobbly
cannot control movement
what is the diencephalon also called
interbrain
what does the diencephalon consist of
hypothalamus
thalamus
epithalamus
what is the thalamus
relay station for sensory information, cerebellum, basal ganglia, cerebral cortex
what does the epithalamus contain
olfactory correlation centre and the pineal gland
what is the epithalamus involved in
circadian rhythm
what does the hypothalamus produce
neuropeptides that control anterior pituitary
neurohormones released by posterior pituitary
what is the principal regulator of the autonomic nervous system
hypothalamus
with the brain stem, the hypothalamus is the most important region for the control of…
homeostasis
what does the brain stem contain
nuclei that govern body function by reflexes
large amount of white matter (conveyors)
what is the deepest part of the brain
brainstem
what is the brain stem the control centre for
cardiovascular and respiratory systems
what is the mesencephalon
visual and auditory reflex centre
how does the mesencephalon work as the visual reflex centre
receive visual info
control eye movement (for focus)
how does the mesencephalon work as the auditory reflex system
turns head for noise
what is well developed in birds to process visual info
the mesencephalon
what is the size of most mammals’ midbrains
very small and covered by cortex
what do the pons and medulla oblongata contain
center for postural reflexes
respiratory movements
examples of postural reflexes
hopping
righting
placing
what is the medulla oblongata crucial for the control of
heart activity
blood pressure
relative distribution of blood to organs
how many pairs of cranial nerves are there
12
which are the only purely sensory nerves that remain in the brain
I (olfactory) and II (optic)
where do cranial nerves III - XII exit from
brain stem and innervate structures of the head and neck
what are cranial nerves III - XII mostly
sensory and motor (mixed)
what is the cranial nerve that is the exception
X - Vagus nerve
what makes cranial nerve X the exception
most widely distributed nerve throughout the body, from neck to abdomen
what is the vagus nerve (X)
parasympathetic fibers to visceral structures in the thorax and abdomen
what must the spinal cord be
flexible - intervertebral disc
what are the regions of the spinal cord
cervical
thoracic
lumbar
sacral
coccygeal
does the number of vertebra differ between species
yes
where is the cervical/thoracic region
neck/chest
where is the lumbar region
abdomen
where is the sacral region
pelvis
where is the coccygeal region
tail
how do you access CSF
spinal tap
in the spinal cord, what does white matter contain
myelinated and unmyelinated axons
how is white matter arranged in the spinal cord
in columns or tracts
what does grey matter contain in spinal cord
cell bodies and dendrites
what is the grey matter shaped like in the spinal cord
a butterfly
what is the dorsal horn of grey matter responsible for
sensory
what is the ventral horn of grey matter responsible for
motor (skeletal muscles) and autonomic fibers
what is the middle zone of grey matter
association
what is the number of spinal nerves dependent on
the number of vertebrae
what is the entry/exit of neurons from spinal cord
spinal nerves
where are spinal nerves formed
by joined dorsal and ventral roots merged within spinal canal
where do spinal nerves emerge from
intervertebral foramina
how do spinal nerves predict the effect of spinal cord injury
each spinal segment receives sensory info from skin section and send info to muscles
how do spinal nerves receive sensory info from skin
dermatomes
how do spinal nerves send info to muscles
myotomes
