A & P - Neuro Flashcards
vessels under the skull and in the dura
- middle meningeal artery
- branch off of external carotid artery
- feeds meninges
vessels on top of the brain and in the arachnoid
- anterior, middle and posterior cerebral arteries
- branches of the circle of Willis
- feed the brain
5 layers (superficial to deep) of scalp
- skin
- connective tissue
- aponeurosis
- loose areolar tissue
- pericranium
nerve supply of scalp
- supratrochlear and supraorbital: CNV1
- zygomaticotemporal: CNV2
- auriculotemporal: CNV3
- greater, lesser and third occipitals: C2+3 spinal nerves
MENINGES 3 layers
- DURA MATER
- ARACHNOID MATER
- PIA MATER
middle meningeal artery tear
- blow to the side of the head
- epidural hematoma
- compresses cerebrum = bad
cerebral vein tear
- elderly who falls and hits head
- subdural hematoma
- compresses cerebrum = bad
cerebral artery tear
- ruptured aneurysm
- Weakened area of arterial wall
- Worst headache of my life
- subarachnoid hemorrhage
- compresses cerebrum = bad
Cerebrospinal Fluid (CSF)
- physical support
- pressure diffuser
- immunological shield
- carries away metabolites
- made in the ventricular system by specialized cells called the choroid plexus
- fills the subarachnoid space
- filters thru subarachnoid granulations into the venous sinus (drainage) system of the brain
- Hydrocephalus is a condition caused by abnormalities of CSF production, flow or drainage.
- CSF is the fluid obtained from a Lumbar Puncture
CEREBRUM
outermost portion is cortex, containing sulci and gyri and 4 lobes;
split into R+L hemispheres
executive function, personality
CEREBELLUM
contains 2 lobes and 3 peduncles
DIENCEPHALON
thalamus + hypothalamus
STEM
midbrain + pons + medulla oblongata
sulcus
a depression or fissure in the surface of the brain
gyrus
an upfolding of the brain cortex
superior temporal gyrus
Wernicke’s Area, the sensory speech area
angular gyrus
comprehension of visually presented materials (reading)
inferior frontal lobe
pars triangularis,
Broca’s Area, the
motor speech area
precentral gyrus
primary motor
area, the motor strip
postcentral gyrus
primary sensory area,
the sensory strip
supramarginal gyrus
language perception and processing
MOTOR PATHWAYS
-The outside of the brain is gray matter, made up of neuron cell bodies.
-The inside of the brain is white matter, where all the cell body axons travel.
-Axons travel together from cortex to cord as the corona radiata (aka projection fibers).
-Specifically, the motor axons from the corona radiata come together as the internal
capsule
internal capsule
- the motor fiber passageway thru the caudate, thalamus and lentiform nucleus, on the way to the midbrain’s crus cerebri.
- Forms the main highway for the main highway for the input and output fibres of the cerebral cortex
- It is “V” shaped on horizontal section with the concavity directed laterally
- Traced below the capsular fibres occupy the crus cerebri of the mid brain, passes through the pons and forms the pyramid of medulla oblogata.
- In the lower medulla about 80% fibres decussate and enter into the cotralateral lateral funiculus of the cord as the lateral cortico-spinal tract.
- 18% fibres descend uncrossed as the anterior cortico- spinal tract, which however terminate in the opposite spinal grey matter after crossing in the anterior white commissure
- 2% fibres descend and terminate uncrossed in the lateral cortico-spinal tract
Motor fibers
- run down to the crus cerebri, and make their way thru the pons to the medulla.
- Here they are called the pyramidal tracts (pyramid), and they cross (decussate): Left Cortical Fibers cross to the right of the cord, and Right Cortical Fibers cross to the left of the cord.
- Actually, only ~80% cross over, and 20% continues down on the same side. The ones that cross over in the medulla become the cord’s Lateral Corticospinal Tract.
- The ones that stay on the same side become the cord’s Ventral Corticospinal Tract, which crosses over in the cord.
BRAIN VENTRICLES
spaces deep within the brain, CSF factory and drainage system
Nerve Fibres of the Cerebrum
- Association fibres
- Commissural fibres
- Projection fibres
Association Fibres
- Fibres connect the cortical areas of the same hemisphere
- Short- connects adjacent gyri
- Long- connects gyri separated from one another by considerable interval, eg:
- Cingulum-: fibres of the limbic lobe and lies within the cingulate gyrus, forms a part of the papez circuit
- Uncinate (arcuate) fasciculus-: hooks around the floor of the stem of lateral sulcus. Connects Broca’s area and the orbital surface of the frontal lobe with the temporal pole
Commissural Fibres
- Connect wide areas of cerebral cortex of the two hemispheres across middle line
- Fibres may be homotopical ie. connect identical areas or heterotopical ie. Connect non-identical areas
- Five sets of commisural bands are present:
- Corpus callosum, ant, hippocampal, habenular, and post commisure,
Corpus Callosum
- Rostrum: consists of fibres connecting the orbital surface
- Genu : consists of fibres(forceps minor) connecting the medial and lateral surfaces of the frontal lobes
- Trunk : consists of fibres connecting wide areas of cerebral cortex
- Splenium : consists of fibres (forceps major) connecting the occipital lobes.
- Makes information stored in the cortex of one hemisphere available to corresponding cortical areas of the opposite hemisphere
- Corpus callosum operates cooperatively at the superficial level
- Anterior commissure unifies the emotional responses of the two sides of the brain
Projection Fibres
- Fibres connect the cerebral cortex with the sub-cortical grey matter of the basal ganglia, thalamus, and with the nuclei of the brain stem and spinal cord
- Corona radiata : fibres from the entire cortex converge to the periphery of the corpus striatum.The fan shaped arrangement of the fibres is called corona radiata
- Traced below the fibres are continuous with the fibres of the internal capsule