CNS Flashcards
ALS attacks what?
MS attacks what?
ALS - motor neurons
MS - myelin
Where does reciprocal inhibition occur?
At the spinal cord level.
What are directional terms unique to the CNS and what do they mean?
Rostral - towards the nose
Caudal - towards the back
Spinal cord: Functions: - \_\_\_\_\_\_\_ and \_\_\_\_\_\_ innervation - Provides \_\_\_-way conduction pathway between body and brain - major centre for \_\_\_\_\_\_
Location:
- Runs through the ______ _____
- Extends from the _______ ______ to the level of vertebra ___ or ___
Motor and sensory innervation
2 way
Reflexes
Vertebral canal
foramen magnum
L1 or L2
What is the conus medullaris?
Where the spinal cord comes to an end
What is the filum terminale?
What does it prevent?
tiny, part of pia matter that anchors the spinal cord caudally or inferiorly
- anchors it to the sacrum/coccyx to prevent anterior/superior displacement
What are cervical/lumbar enlargements?
Nerves that supply upper/lower limbs
What is the cauda equina?
When the spinal cord reaches the conus medullaris, lots of nerves splay out in the form of a horses tail
What does the gray matter of the spinal cord consist of?
Neuron cell bodies, neuroglia, unmyelinated axons.
How is the grey matter of the spinal cord divided?
Divided according to somatic and visceral regions.
SS
VS
VM
SM
Describe the white matter of the spinal cord.
What does it consist of?
What does it allow?
Composed of myleniated axons.
Allows communication between spinal cord and brain
Incoming sensory information comes in _______ to the spinal cord, outgoing motor information leaves ________.
dorsally
ventrally
What are the different things that protect the spinal cord?
CSF
Meninges
Vertebrae
What are the three meningeal layers?
Dura mater
Arachnoid mater
Pia mater
Describe the dura mater.
What tissue type does it have?
Strongest, outermost, leathery layer surrounding spinal cord
Composed of dense fibrous CT.
Where is the arachnoid mater located?
Deep to the dura mater.
Describe the pia mater?
Where does it extend to?
What are denticulate ligaments?
Innermost layer
Delicate layer of CT
Extends to the coccyx
Denticulate ligaments - lateral extensions of the pia mater
Where is the CSF located in the meninges?
Subarachnoid space
What does the epidural space contain?
Fat
What do the dendiculate ligaments do?
Anchor the spinal cord medially and laterally.
What are the four regions of the brain?
Cerebrum
Diencephalon (thalamus, hypothalamus, epithalamus)
Brain stem (pons, medulla oblongata, midbrain)
Cerebellum
What are modifications to the brain to increase surface area?
Ridges and convolutions
Organization of the brain:
- Centrally located ____ matter
- Externally located _____ matter
- Additional layer of _____ matter external to the ____ matter
- _____ - outer layer of gray matter
- Formed from neuronal ____ _____
- Located in _______ and _________
gray white gray white cortex cell bodies cerebrum cerebellum
Cerebral cortex:
- Home of our _______ mind
- Composed of _____ matter
- approx. ___% of brain’s mass
conscious
grey
40
Cerebrum:
- Divided into ________, accounts for __% of brain mass
– _____ - deep grooves, which separate major regions of the brain
— _______ ______ - separates cerebrum and cerebellum
— ________ ______ separates cerebral hemispheres
- _______ - shallow groove
- ______- raised area of the brain
- Deeper sulci divide the cerebrum into ______
- ______ are named for the skull bones overlying them. What are they?
______ lies deep in the lateral sulcus.
- _______ sulcus separates the frontal and parietal lobes
hemispheres, 83%
fissures
transverse fissure
longitudinal fissure
sulcus/sulci
gyri/gyrus
lobes
lobes
- parietal, temporal, frontal, occipital
insula
central
What does the longitudinal fissure separate?
What does the transverse fissure separate?
Longitudinal - hemispheres
transverse - cerebrum and cerebellum
What is the central sulucs bordered by?
What cortices are located there?
Two major sulci:
Precentral gyrus - primary motor cortex
Postcentral gyrus - primary somatosensory cortex
Where is the primary somatosensory cortex located?
What is it involved in?
Postcentral gyrus
Involved in spatial discrimination
Involved in conscious awareness of general somatic senses (touch, pressure, pain, etc.)
Where are the special somatic senses located?
What are they?
Primary visual cortex - occipital
Primary auditory cortex - temporal
- Vestibular (eqb) cortex - insula
Where is the primary motor cortex located?
What is it involved in?
Precentral gyrus
Involved with controlling somatic motor functions
- (voluntary movements of skeletal muscle)
Homunculus:
Sensory:
- amount of ________ cortex devoted to a body region is related to the sensitivity of that region (i.e. the _____ of ______ ______)
- most sensitive parts = what?
Motor:
- amount of ______ cortex devoted to a body region is related to the ability to what?
- most skilled and delicate parts are the what?
Sensory homunculus:
somatosensory
number of sensory receptors
- lips and fingertips
Motor homunculus:
- motor
- ability to perform precise, skilled movement = number of motor neurons
- face and hand
Why can chimps and apes perform large feats of strength but we cannot?
We have a neural limit to how many muscles we can use at once.
Where does the somatosensory association cortex lie?
Posterior to primary somatosensory cortex
Somatosensory association cortex:
- _______ different sensory inputs into a comprehensive understanding of what is being felt:
- _____ and ______
- Draws upon stored ________ of past sensory experiences
Provide an example of this.
Integrates - touch and pressure
memories
ex: feel keys and know what they are without seeing them
Premotor cortex:
Location?
Function:
- ______ and ______ complex movements to relay to what?
Receives processed ______ information
- these include _____, _____ and general ______ sensory
- controls voluntary actions depending on ______ feedback about ______ relations.
Anterior to primary motor cortex or precentral gyrus
- Plans and coordinates - relay to primary motor cortex
receives processed sensory info
- including visual, auditory and general somatic sensory
sensory feedback - spatial relations
The two hemispheres of the brain are _________.
Damage to the left side causes what?
Damage to the right side at the same area causes what?
Contralateral
left - aphasia - inability to use/comprehend words
right - speech without emotional inflection
If you are left brain dominant, you are _____ handed.
What are characteristics of this?
What if you were right brain dominant?
left brain - right handed - analytical
right brain - left handed - creative
Why is it better to be dominant on one side of the brain?
Don’t waste energy communicating with the other side - generally retarded if you do.
Diencephalon:
- Surrounded by the cerebral _______ and borders the _____ ______
Composed of _____ matter and three paired structures. These are?
hemispheres
third ventricle
gray
thalamus, hypothalamus, epithalamus
Thalamus
- __% of the diencephalon
- _____ impulses converge on the thalamus
- Acts as a _____ _____ for incoming sensory messages
- _____ part of the brain communicating with the cerebral cortex relays signals through the thalamus
80
sensory
relay station
every part
The hypothalamus is the main ______ control center of the body
- ______ glands protrude inferiorly from here
Give two functions.
visceral
pituitary
Control of ANS
Regulation of body temperature
Epithalamus
- Forms part of the “roof” of the _____ ventricle
- includes the _____ gland
- secretes the hormone _______
- – this gland is under the influence of the _______
- _______ signals the body to prepare for sleep
third
pineal - melatonin - hypothalamus controlled - melatonin - sleep
How is melatonin secreted?
Light stops hitting the optic nerve, triggers melatonin release preparing us for sleep.
How does melatonin secretion get messed up?
Jet lag
blue light
up north with 6 months of light
Brainstem
- passageway between the ________ and ______ ______
Produces automatic behaviours responsible for _______
Comprised of what structures?
cerebrum - spinal cord
survival
medulla oblongata, pons, midbrain
What centres does the medulla oblongata contain?
cardiac, (vasomotor), respiratory
What does the pons coordinate?
What two brain structures does it bridge?
voluntary movement
cerebellum and brainstem
The midbrain relays information between what two CNS structures.
What reflexes does it integrate?
Which structures correspond to each?
cerebrum and spinal cord
visual, auditory
- visual - superior colliculi
- auditory - inferior colliculi
Cerebellum
What are the two main structures? What matter are they composed of?
Functions to ______ body movements and maintain _____.
Also involved in _____ memory (the best kind of memory :)
Cortex - gray matter
arbor vitae - internal white matter
Functions - smooth out body movements and help maintain posture
muscle memory
Why can’t you tickle yourself?
cerebellum integrates commands from cerebrum and is thus aware of actual actions to yourself.
The brain is protected by what four components?
Skull
CSF
Meninges
BBB
Meninges Functions:
- Cover and protect the ____
- Enclose and protect the ______ vessels that supply the CNS
- contain the ____
CNS
blood
CSF
The dura matter is the ______ of the meninges.
It is composed of two layers:
- _______ layer - inner surface of skull bones
- ______ layer - external covering of the brain
strongest
periosteal
meningeal
Arachnoid mater - Located where? - Subarachnoid space contains what and is located where? What are arachnoid villi? - where do they project? - what do they allow?
Below dura matter (deep to)
CSF and between pia and arachnoid
Arachnoid villi
- project through dura matter into sinuses
- allow CSF to pass into the dural blood sinuses
Pia mater
- Delicate ____, which is _____ vascularized
- Clings tightly to the surface of the _____
- Follows all the _______ of the brain (ex: gyri, sulci, fissues)
CT, highly vascularized
brain
convolutions
From the skin down, what are the layers of the brain?
skin periosteum spongy bone of skull periosteal layer of dura matter meningeal layer of dura mater arachnoid subaracnoid pia
What are the different kinds of hematomas?
Epidural - dura matter rips away
Subdural - between dura and arachnoid
intercerebral hematoma
What is the danger with brain hematomas
Swelling of brain with no place to go, leads to death of brain tissue
Describe a concussion.
Hit head, brain slams against skull and recoils on the other side.
leads to bruising of brain
What is the major issue with whiplash?
Tendons and ligaments of neck and back are overstretched, effects last a while.
Why does punching a boy in the jaw make him get KO’d?
farther from the muscles that can brace
Ventricles of the brain:
- Expansions of the brain’s ______ cavity
- lined with ______ cells
- __________ with each other and with the ______ _______ of the spinal cord
central
ependymal
continuous - central canal
CSF
- surrounds CNS in _______ space
Describe some fuctions.
subarachnoid
Nourishes CNS and removes wastes
Where is the CSF formed?
Where is that located and what is it composed of?
choroid plexuses in the brain ventricles
- located in all four ventricles
- composed of ependymal cells and capillaries
What does the CSF arise from?
arises from blood plasma through filtration from the capillaries and passes through the ependymal cells into the ventricles
What does the BBB prevent from getting in?
What can get in?
Impermeable capillaires that prevent blood-borne toxins from getting in.
Allows nutrients and oxygen in, as well as nicotine and alcohol.
