Neuroanatomy & Function I Flashcards
basic overview
structural breakdown of nervous system
CNS, PNS
autonomic and somatic
parasymp. symp
efferent v afferent
CNS = brain and spinal cord
PNS = peripheral nevers, cranial nerves, spinal nerver roots & ganglia (cell bodies in groups)
Somatic: voluntary control
motor (Efferent) moving toward the CNS
sensory (Afferent) moving away from the CNS
Autonomic: invountary control (happens automatic)
parasymp: rest/digest
sympa: fight & flight
Afferent = often means toward from a region (like away from the CNS TOWARD the stimuli)
Efferent = often means away from a region (like away from the stimuli towards the CNS)
afferent sensory: sensation from the areas to the CNS
motor = efferent : gores from the CNS to the area
aspects of the autonomic and somatic NS can be found both centrally and peripherally
Neuron Cell Anatomy Overview
Neuronal Body
- cell body/soma/perokaryon
Dendrite = intake the information
- branches of dendrites have spines on the ends = responsible for intaking information, adjusting and creating new connections/receptors with memory, learning & increased sleep
Axon = transferrs information away from the cell body towards the synapse to pass it along
- Hillock = closest aspect towards the cell body
- initial segment = first part
- branches/telodendria = which connect to the synpase
neurons contain a nucleus and all other normal aspects of a cell !!
input of singal –> dendrites –> cell body –> axon –> synpase
- orthodromic transmission of signal = forward
- antidroic passing of a signal (backwards) is rarely normal & commonly pathological
types of neurons
bipolar: seen in special senses (visual and vistubular systems and smell)
- one dendrite, one axon and multiple branches off each
Psudeo-unipolar : seen in peripheral nerves mostly, in the sensory ganglia of spinal and cranial nerves
- contain a peripheal axon “dendrite” and central axon
Multipolar: seen in the CNA and PNS, most common type of nerve
- one axon, many branches & multiple dendrites
neurons
nerve fiber
fasciale
& the covering
(where are the blood vessels?)
neurons = single nerve cell
nerve fiber = refers to the axon
multiple axons together = fascicle
multiple fasciles = nerve
nervous tissue = contains the nerve, neurons an the glial cells
blood vessels: vasa nervosum = contained within the connective tissue sheaths= each layer
Epineurum = surrounds the nerve
Perineurium = around a fascicle
Endoneurium = around each axon
what type of glial cells are found within the CNS
what type are found within the PNS
CNS Gial Cells
- glial cells: those responsible for chemical and physical support to neruons
- astrocytes
- microglia
- oligodendrocytes
- ependymal cells
PNS glial Cells
- Schwann cells
- Satellite cells
seen to be equal in number to the amount of neurons in brain
Astrocytes
- what are they & where are they found
- function
ASTROCYTES
- found within the CNS : Glial Cell
responsible for…
- NT (glutamate) clearance from the synpase (becuase it cannot be left there (toxic!))
- glycogen storage = energy for the neurons
- BBB component (strengthens)
- pH balancer: alkaline
- stabilzie and cushion the neurons within the CNS
Microglia
- what are they & where are they found
- function
MICROGLIA
- CNS glial cell
responsible for….
- immune function within the brain!!! = seen as the immune cells of the brain as the BBB blocks any immune cells from body to enter it
- innate immune responders: phagocytosis, antigen presenting abilites
- become active during inflammation, trauma, degeneration and space occupying lesions of the brain
- function even when not “activated”
- can be initially protective in neurodegeneration, but over time play a role in autoimmune processes
Oligodendrocytes
- what are they & where are they found
- function
OLIGODENDROCYTES
- CNS glial cells!
responsible for…
- the production of mylein in the CNS!!
- mylein: coats the axons of nerves making signals pass much faster through them
Ependymal Cells
- what are they & where are they found
- function
EPENDYMAL CELLS
- CNS glial cells
Responsible for…
- found within the choroid plexus of ventricles in the brain (choroid plexus is what makes CSF; a network of blood vessels)
- these cells are what actively make the CSF within the plexus
- can be found also in the spinal cord’s central canal
(common pediatric tumor = ependymoma)
Schwann Cells
- what are they & where are they found
- function
SCHWANN CELLS
- PNS: glial cells
responsible for…
- mylein production for the neurons within the PNS
- surround most of the axons of the body: but thye only direclty myleinate some of them
what is mylein
grey matter v white matter within the brain
mylein
- an insulating layer of lipid material which is produced from schwaan cells & oligodndrocytes in the nervous system to surround axons of nerves and increase signal conduction
- increase velocity and strength of the signal
WHITE MATTER: myleinated axons from nerves within th ebody
GREY MATTER: the cell bodies of the neurons
primarily, the cortex is grey matter, with white matter deep to that (but grey matter returns in the deepest areas of the brain (thalmus, hypothalm, etc.)
Neurolgical Lesions
- examples
- focal v diffuse?
what about a seizure
Lesion = injury to a body part
Types of Lesions
- strokes (ischemis or hemorrhagic)
- TBI
- Space Occupying Lesions (neoplasms, tumors)
- Infections
- Progressive/genetic Conditions (Huntington’s Disease)
Focal
- damange to a SPECIFIC AREA: inturruptinga SPECIFIC FUNCTION
DIffuse
- damage which results in large deficts in function
- seen with a hemorrhage (bleed) or space occupying lesion as it inturrupts multiple parts of the brain & results in multiple symptoms
Seizures are NOT lesions: there is no “damange” but rather just spontaneous excitatory neuron discahrging/firing
Anatomical Directions as it relates to the brain
Anterior posterior = the same (front back)
superioe inferior = the same (top bottom)
Dorsal and ventral (top bottom)
- dorsal = top
- ventral = bottom
Rostral = toward the front & up (frontal cortex)
Caudal = toward back and down (occipial lobes)
components of the cerebral cortex & Lobes
(draw them out or describe where they are)
The Cerebral Cortex: a grey matter covering of the brain which is divided into lobes dependent on location and function
contain gyri and sulci: folds and grooves within the cortex which illustrate individal locations and demarcations of the brain
Frontal Lobe
- separated from the paritel lobe via the Central Sulcus
Precentral gyrus: the primary motor area
postcentral gyrus: the primary sensory area
Lateral Suluc (Sylvian Fissure) separates the temporal lobes from the frontal
longitudinal fissure: separates right from left hemispheres
the corpus collusum:network of white matter connecting the two hemispheres
key landmarks from the ventral view of the brain
- and their assocaited functions
Uncinate Process
- commony area of the brain to herniate during a brain hernaition (down through the skull to spine)
Parahippocampal gyrus
- memory center
Lingual gyrus
- vision center
Fusiform Gyrus
- Facial Recognition
Inferior temporal gyrus
- vision
inferior occipital gyrus
- vision
key landmarks from the medial view of the brain
corpus callosum
- white matter connecting left to right hemispheres
Cingulate Gyrus & sulic
- limbic system (emotion and behavior regulation)
Superior Front gyrus
Paracentral Lobuble
precuneus
cuneus (visual processing in occipital)
lingual gyrus (vision)
hippocampal gyrus
fusiform gyrus (facial recognition)
inferior temproal gyrus
uncus (memory, smell & emotions)
Fornix (white matter for memory connection to hippocampus)
Frontal Lobe
- boundaries
- vascular supply
- functions
Boundaries
- from the central sulcus to the frontal pole of the cerebral cortex to the edges of the later fissure (inferior boundary is the roof of the eyes)
Vasculature
- internal carotid branches to anterior cerebral artery & middle cerebral artery
Functions
- primary motor function : at the precentral gyrus
- higher order thinking (initaive, judgement, abstract reasoning, creativity, etc.)
Broca’s Area
- location
- Broadmann’s number
- function
- connection
BROCAS AREA
- located in the frontal lobe (most commonly) on the left sided inferiorly (if individual is right-handed they are mostly left brain dominant)
function = production of coherant motor speech
connected to Wernicke’s area (angualr gyrus) via the arcuate fasiculus
Broadmann’s Area = 44 & 45
injury to Broca’s Areas = results in no issues with comprehension of speech but issue with motor production of speech leading to delayed speech but logical and comprehensive words, just fewer words spoken, less inflection in tone, etc.
Parietal Lobe
- location
- boundaries
- blood supply
- strucuture within
- function
PARIETAL LOBE
- from the central sulcus to the parieto-occipital fissure and then laterally to the lateral fissure
BLOOD = MCA and some effect of the ACA
Structures
- postcentral gyrus: primary sensory cortex
Function
- sensory function: touch, taste, and temperature
- an intergration location: integrating sensory function to produce images and understanding of the world around
Temporal Lobe
location & boundaries
Blood supplt
function
Location & Boundaries
- sits below the lateral fissure, then extendds back to the parieto-occipital fissure and meets in the middle
BLOOD = MCA from the internal carotid
Function
- processing auditory information
- memory
- speech
- vision
Werinicke’s Area
location
function
broadmanns area numbers
Wernicke’s Area: located in the temporal lobe (some overlap into the parietal lobes) on the left side of the brain – or whichever side the individal is brain dominant (usually left)
Function
- word processing and language input : understanding words (receptive speech)
Broadmann’s Areas
- 22 (superior temproal)
- 39 (angualr gyrus)
- 40 (supramarginal gyrus)
injury to the wernicke’s area of the brain results in word salad speech: in which the patient has no problem speaking, but the contents of speech has no meaning
Occiptial Lobe
location & boundaries
fuction
blood supply
Location & Boundaries
- sitting behind the pariteo-occiptial fissure
BLOOD = basilar artery gives rise to teh Posterior cerebral artery (PCA)
Function
- processing visual imput
Visual Pathways
input from the left and right visual fields
to the optic nerves
o the optic chiasm (where the left nasal visual field and the right nasal visual field cross over)
to the optic tracts (each having information from either the right or left visal fields
to the lateral geniculate body (of the thalmus)
to the optic radiations (which seperate vision into the quadrants
to the occiptial visual cortex
(so information at the left visial cortex is the information taken in from the right visual field (via the right nasal and left temporal rentina))
some of the fibers also transmit signals from the optic tracts to the superior colliculus in midbrain on the same side of which they arise then go to the frontal eye fields (frontal lobe) to the vertical gaze center in midbrain, to the horizontal gaze in the pons and then to control eye an neck moving
Insular Lobe
function
location
Location
- deep to the temporal lobe
Function
- integration center
- emotional center
- consciousness
- homeostasis
- pain
- vestibular
- gustatory
Broadmann Area 4
Pre-Central Gyrus = location
Primary Motor Cortex = function
Broadmann area’s 3,1 & 2
Location: Postcentral Gyrus
Function: Primary Somatosensory
Brodmann’s Area 6
Location = Rostral to the primary motor cortex (just above and in front)
Function = Motor Planning: premortor area for extrenally motivated activies (laterally) & Supplementary Motor: form internally motivated movements (medically)
Broadmann’s Area
17
Location = posterior to the calcarine sulcus (just below the cuneus)
Function = visual cortex
Brodmann’s Area
22
39
40
22 = superior temporal gyrus
39 = angular gyrus
40 = supramarginal gyrus
all responsible for wernicke’s area and speech receptive
brodmann’s area
41, 42
Location = within the lateral fissure just medial to area 22
Function = auditory areas
Brodmann’s Area
44 & 45
Location = inferior frontal gyrus
Function = Broca’s Area for Motor Speech
Tracts v Commisures
Tracts
- axons, myleinated which typically travel in a vertical fashion
- also called fasciculus or pathways
Commisure
(cross overs)
- axons, myleinated or unmyleinated
- usually cross over to the contralateral side
- can be in the brain or spinal cord
- also called decussation
Key White Matter Pathways to know
INTERNAL CAPSULE
Internal Capsule
- a tract/pathway which travels from top to bottom of a single hemisphere of white matter
- goes from the cortex to the brainstem
- supplied by the MCA
parts
- anterior limb: front/pariteo pontine fibers
- genu: the turn: corticobulbalr tracts
- posterior limb: decending voluntary motor pathways and acending pathways from thalmus to basal ganglia
Key White Matter Pathways to Know
CORPUS CALLOSUM
corpus callosum
- connects the two hemispheres together at the cortical elvel
Key White Matter Pathways to Know
ANTERIOR AND POSTERIOR COMMISURES
Anterior Commisure
- ventral to the rostral area of teh corpus callosum
- used for smell and limbic function
posterior commisure
- connect prenucli (midbrain) to each other from each hemisphere
- good for pupillary reflex
Parts of the diencephalon
thalmus
hypothalmus
epithalamus
subthalamus
The Thalmus
two egg shaped things in the diencephalon
contain different nucli for differnt functions and tracts
Functions
- Sensory nuclei
- Motor nucli (with cerebellear influence)
- associative nuclei (ghih level congnition)
- limbic nuclei (mood and motivation)
- reticular and intralaminar nuclei (arousal and nociception)
The Hypothalmus
Functions
- autonomic control
- hormonal control (to the pituitary)
- circadian rhythm
- hunger
- emotions
also contains specific nuceli which are invovled in specific pathways
PItuitary Gland
anterior pituitary
- true gland: with portal system of blood where the signal from the hypothalmus is transported down infundibulum into capillary of pituitary & hormones (pro-hormones) are released to enter general circulation (bypass BBB)
- from arcuate, paraventricualr, periventricualr and suproptic nuceli in the hypothalmus
Posterior pituitary
- a neurohypophysis: meaning an extension tract of the hypothalmus itself
- supraoptic and paraventricaulr nuclei in the hypothalmus have axons which pass through here
- release oxytocin & vasopressin (ADH) which go directly into the systemic vasculature
Epithalamus & Subthalamus
Epithalamus = pineal gland (secretes melatonin) & habenular nuclei (reward pathway; negative reward)
Subthalamus = at midbrain; part of basal ganglia for motor control
Parts of the brainstem
midbrain
pons
medulla oblongata
- connects spinal cord to diencephalon
all parts of the brainstem contain nuclei tracts for….
- motor and sensory pathways
- arousal and consciousness
- autonomic and vital functions (breathing, peeing)
- cranial nerves
- pathways to/from thalmus, hypothalmus, cortex, cerebellum & spinal cord
Brainstem Orientation based on Region
basal, tegmentum, tectum
Basal/basilar Region: of the midbrain, pons and medulla are all ventral (bottom) think base
Tegmentum: of midbrain, pons and medulla are all dorsal (highest up) ( this area is a motor relay center)
Tectum: in the midbrain, is dorsal and posterior to the cerebral aqueduct ( for reflexs to audiory or visual stimuli)
