intro to neuro Flashcards
what are the two types of CNS tissue
-Grey matter -white matter
what is grey matter
neuron cell bodies
what is white matter
axons and supporting cells
where is grey matter located
in the cortex of the cerebrum and cerebellum
where is white matter locate
it is centrally located in the cerebrum and cerebellum
how is the position of the white and grey matter different in the spinal cord
the location of the grey and white matter are reversed
what is the cerebrum
- comprised of two hemispheres which communicate via a tract called the Corpus Callosum (CC)
Gyri:
- elevated folds of the convolution
Sulci
- depressed grooves
what is the surface of the cerebrum comprised of
grey matter: also known as the Cerebral cortex
what are the two main jobs of the cerebrum
- concious perception and association of sensory input (thoughts and reasoning)
- Initiation of conciousness movement
- Note reflex pathways do not utilize the cortex
what are the 3 regions of the cerebrum
- Cerebral cortex
- Basal nuclei
- Internal capsule
what layer is the cerebral cortex
the outer layer of grey matter
what sensory fields are associated with the cerebral cortex
conscious perception of stimuli
what motor areas are associated with the cerebral cortex
voluntary initiation of skeletal muscle
what association areas are in the cerebral cortex
integration of sensory information and planning of voluntary movement, memory, reasoning, verbalization, judgment and emotion
what layer of there cerebrum is the basal nuclei
- the inner layer of grey matter
- cell bodies within the deeper regions of the cerebrum
what is the function of the Basal nuclei
regulation of movement
(i.e. balance, posture)
what type of neural tissue makes up the internal capsule
white matter
what is the internal capsule of the cerebrum
projections of tracts from the brain stem (thalamus) to the cerebrum
What is the function of the internal capsule of the cerebrum
all sensory information except smell is directed to the cortex via the thalamus
what are the functions of the thalamus
- all conscious sensory info except olfaction is relayed through the thalamus before reaching the cerebral cortex via the internal capsule
- relay for certain motor reflexes
- associated with wakefulness
what are the five cortical lobes of each cerebral hemisphere
- occipital
- parietal
- frontal
- temporal
- piriform
what is the function of the occipital lobe
- conscious perception of visual information
- cortical event, not an ocular event
- Reception Vs. perception
The ________ lobe has widespread connections to other parts of the brain as well
occipital lobe
what is visual preception
what color is the dress
how can lesions associated with the visual cortex of the occipital lobe affect visual perception.
These lesions may cause cortical blindness but the pupillary reflex will remain due to the pupillary light reflex pathway normally goes to the brain stem
How might an occipital lesion affect the menace response
a lesion on the occipital lobe may cause absent menace response since the menace response requiring cortical perception and is not a reflex
what does the parietal lobe contain
the somatosensory cortex
what type of information is perceived at the parietal lobe
- sensory input from skin, skeletal m., ligaments, tendons and joints
- Pain and touch are perceived here
- the integration of sensory information to produce a 3D “map” of the body’s location in space
- this is called proprioception
Proprioception
this is the integration of sensory info to produce a 3D map of the body’s location in space
what are some symptoms of loss of cutaneous proprioception
defined by deficits in postural reactions
what are some of the less common symptoms of parietal lobe lesions
- lesions here can produce bizarre abnormalities of spatial perception
- -awareness of certain parts of the space around the body is lost or altered
- unilateral lesions produce “hemineglect”
- failure to perceive half of one’s environment
- unilateral lesions produce “hemineglect”
what functions are the frontal lobe responsible for
- initiating voluntary motor functions
- this does not include fine-tuning motor activities
what behaviors are associated with the frontal lobe
judgment and behavior
what are some of the symptoms of frontal lobe lesions
- lesions produce abnormalities of voluntary movement
- CS: delay or inability to initiate movement
- “Phineas gage”
Phineas Gage definition
alteration in attitude/ personality due to a lesion of the frontal lobe
how would unilateral lesions of the frontal lobe be visualized in CS
- would be seen with contralateral clinical signs
- if the right frontal lobe is lesioned, initiation of movement on the left side of the body will be effected
What sensory cortex is in the Temporal lobe
the auditory cortex
what is the function of the auditory cortex
perception and interpretation of auditory (cochlear) info
what in the temporal lobe allows info from both ears to reach both auditory cortices
-Multiple decussations
will the destruction of one auditory cortex produce deafness
no not even in one ear due to the cochlea being represented in both hemispheres
how would damage to the temporal lobe affect auditory info perception
damage to temporal lobe would result in reduced perception of sound
what sensory information does the piriform lobe process
-Preception of olfactory info
what is unique about the olfactory information in the piriform lobe
it is the only sensation that does not relay through the thalamus
the Piriform lobe has a strong connection with the limbic system which is important for
- Autonomic (visceral) reflexes and emotional responses
- plays a major role in survival
how will lesions of the piriform affect sensory perception
a lesion of the piriform lobe will result in reduce sense of olfaction
where is the cerebellum located
centrally located vermis with left and right hemisphere caudal to the transverse fissure
how is the cerebellum made up of CNS tissue
white matter is deep to an outer layer cortex of grey matter
what are the functions associated with the cerebellum
- coordination and fine-tuning of movement
- control rate, range, and force of movement
how does the cerebellum communicate with other parts of the CNS
via nerve tracts, called the cerebellar peduncles (CP)
what makes up the brain stem
- what remains after the cerebrum and cerebellum have been removed
- thalamus
- Hypothalamus
- optic tract/optic chiasm
- Epithalamus
- Corpora quadrigemina
- Pons
- Medulla oblongata
what is the function of the thalamus
it is the relay center for all afferent sensory info except smell
what is the function of the hypothalamus
- essential in the maintenance of homeostasis
- has a direct connection to the pituitary gland
what is the function of the epithalamus
connects the limbic system to the rest of the brain
what gland is in the epithalamus
pineal gland
what is the function of the pineal gland
- melatonin secretion
- photo periodicity
- circadian rhythms
- estrus timing
what two parts make up the corpora quadrigemina
- rostral colliculus
- caudal colliculus
what reflexes are processed by the rostral colliculus
visual reflexes
what reflexes are processed by the caudal colliculus
auditory reflexes
what do the fibers of the pons form
- fibers of the pons form the cerebellar peduncle
what is the function of the cerebellar peduncle
carry signals from cerebrum to cerebellum
what is the importance of the medulla oblongata
- the junction between the brain and spinal cord
- all ascending/descending tracts pass through the medulla
What is the importance of the Obex in the Medulla oblongata
CSF connection between the 4th ventricle and the central canal of the spinal cord
what is the limbic system
- not a discrete anatomical lobe
- group of structures
- functions in emotional and survival drives
- pathway forms a ring around the brainstem
the limbic system involves connections between which other major structures in the brain
- Hypothalamus
- Amygdala
- Hippocampus
- Cingulate gyrus
- Thalamus
what are the 4 F’s of the limbic function
- Fighting
- feeding
- fleeing
- Ducking (sex)
what is the primary blood supply to the spinal cord
ventral spinal artery
what is the secondary arterial supply to the spinal cord
from the paired dorsal spinal arteries
the_______ unity of L/R vertebral arteries with ventral spinal artery
Basilar A.
what is another name for cerebral arterial circle
circle of willis
what arteries feed the cerebral arterial circle
fed by the basilar artery and internal carotid arteries in most species
what does the cerebral arterial circle supply
the cerebrum and cerebellum
what species of animals do not have an extra-cranial internal carotid artery
- adult cats
- pigs
- ruminants
in these species that lack an extra-cranial internal carotid artery what supplies the cerebral arterial circle with the basilar artery
Rete Mirabile
what supplies the rete mirabile
by the branches of the maxillary aa.
how many layers of dura are there
2 layers of dura
wherein the skull do the 2 layers separated
the only place the 2 layers of dura separate is at the dural reflection
at the dural reflection what happens to the deeper layer of dura
the deeper layer dives between hemispheres and between cerebrum/cerebellum
at the dural reflection what happens to the superficial dural layer
the superficial layer of dura remains immediately adjacent to the periosteum inside the skull
what separates the dura of the spinal cord from the periosteum of the vertebrae
the dura of the spinal cord is separated from the periosteum of the vertebrae by a layer of fat in the epidural space
what is in the Arachnoid/subarachnoid space
CSF: cerebrospinal fluid
where is the Pia located
it adheres closely to the CNS
what is the space called that is formed inside a dural reflections
sinus
where is the dorsal sagittal sinus:
- within the falx cerebri
- between the 2 cerebral hemispheres
- in the longitudinal fissure
where is the transverse sinus
- within the tentorium cerebelli
- between cerebellum and cerebrum
- in the transverse fissure
Falx cerebri
dural reflection between the two cerebral hemispheres
Tentorium cerebelli
transverse dural reflection between the cerebrum and cerebellum
Venous return from the brain is via the _______
dorsal sinus
where are the dural sinuses located
they are spaces formed where the inner and outer dural layers separate
how do the dural sinuses achieve the venous return
all the fluid in the brain is collected at the dural sinuses which is ultimately drained into the vein of the head
what fluids are collected in the dural sinuses
- Venous blood
- CSF
- via arachnoid villi
what is the function of the CSF in the subarachnoid space
provides a fluid cushion of protection and space for vessels to travel
What are/where are arachnoid trabeculae
- Located in the subarachnoid space
- spiderweb-like beams
what is Pia matter
it is the inner most meningeal layer
where is the pia matter located
- intimately follows the brain’s gyri and sulci
- grossly, pia is seen as a very thin membrane on the surface of the brain after the dura and arachnoid are removed
what is the importance of the pia matter
pia is the region of CSF production
what produces the CSF in the pia matter
choroid plexus found in the ventricles
what is the flow that is associated with the CSF
- csf is produced by choroid plexus which if surrounded by the PIA mater
- CSF is circulated through ventricles and central canal
- the CSF is finally reabsorbed into venous blood at the Dural sinuses
what are cisterns
cisterns are relatively large collections of fluid
what is another name for Cerebellomedullary cistern
cisterna magna
where is the cisterna magna located
- between the cerebellum and the brain stem
- an enlargement of the subarachnoid space
- near the atlanto-occipital joint
- can be used for CSF collection
what layers make up the spinal meninges
the same three layers as the cranial meninges
what is the difference between the spinal and cranial meninges
There is an epidural space located between the dura and the bony vertebral canal in the spinal meninges
what is the clinical importance of the epidural space
it is a target for epidural anesthesia placement
