CSD 450 Study Guide - Final

Ischemia

reduced blood supply to an organ

infract

small area of dead tissue

ischemic penumbra

area that surrounds the infarct, area of damage

artery

mechanisms that carry oxygenated blood to the brain (capillaries and arterioles)

vein

carries deoxygenated blood back to heart

capillary

terminal extension, very small, blood flows slowly allowing for nutrients exchange, can connect arteries to veins

what are the two major artery systems that carry blood to the brain

carotid system and vertebral basilar system

carotid system splits into…

internal and external carotid arteries

internal carotid artery function

supplies a large part of blood to the brain (splits then enters skull)

internal carotid artery parts

ophthalmic, anterior cerebral, and middle arteries

vertebral basilar system function

provides blood to the posterior circulation systems and brainstem

vertebral basilar system location

arrives through subclavical, arises on each side of neck

circle of Willis function

acts as a safety valve. If injury occurs below circle, circle will allow for alternate circulation

3 category of branches for circle of willis

internal carotid, basilar, connection membranes

parts of internal carotid arteries

anterior and middle cerebral arteries

anterior cerebral arteries (ACA) function

supplies (feeds) orbital and medial cortical surfaces of the prefrontal, frontal, and parietal lobes

%%middle cerebral arteries (MCA) function%%

supplies the lateral cortical surface of each hemisphere.

part(s) of basilar artery

posterior cerebral arteries

parts of connection mechanisms

anterior communicating artery (1), posterior communicating arteries

Posterior Cerebral Artery

Anterior Cerebral Artery (A2 and A1)

Anterior Communicating Artery

Middle Cerebral Artery

Basilar Artery

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Posterior Communicating Artery

signs and deficits associated if there is an issue with the *anterior artery*

loss of somatic sensory issues of contralateral leg and foot, mental impairments: lack of spontaneity, easy distraction, problem solving deficits, cognitive decline

signs and deficits associated if there is an issue with the *middle artery*

sensation difficulties, aphasia, contralateral foot and leg issues, visual spatial deficits

List the areas of the brain that the vertebral arteries supply blood to

medulla, cerebellum, choroid plexus

List the areas of the brain that the basilar artery supply blood to

lateral pons, cerebellum, CNs

signs and deficits associated if there is an issue with the *ventral arteies*

dysphagia, dysarthria, ipsilateral ataxia

signs and deficits associated if there is an issue with the *basilar artery*

facial sensation difficulties, ataxia, vertigo

collateral circulation

important recovery. provides an alternative vascular supply where vascular supplies overlap

problem with collateral circulation

can create areas of vulnerability in the brain

Anastomoses

where capillaries join with other systems through terminal arteries in watershed zone

watershed zones

a boarder zone in the brain where vascular systems overlap

watershed zones - why these areas are vulnerable to damage

these zones are the furthest from the main arterial supply, and are vulnerable to lack of perfusion or reduction from the main arterial supply

What is the yellow area?

anterior cerebral artery

What is the red area?

middle cerebral artery

What is the blue area?

posterior cerebral artery

blood brain barrier definition

a mechanism that regulates arterial permeability in the CNS, is the line of defense

damage to blood brain barrier:

toxins leak into the brain

2 components of blood brain barrier that regular arterial permeability

endothelial cells and astrocytes

cerebrovascular disease

disease of circulation

Two main processes of cerebrovascular disease

atherosclerosis and hypertension

atherosclerosis

arteries are narrow, constricts the amount and ease of blood flow

hypertension

results in chronically elevated blood pressure

cerebrovascular accident occurs when

the disease process intensifies to an occlusion or hemorrhage

Signs of CVA

sudden onset of weakness or numbness on one side, sudden inability to speak or understand others, sudden difficulty seeing with one or both eyes, sudden loss of balance and/or dizziness, headache with no cause

transient ischemic attack

mini stroke, lasts for about a day; elevated risk for full blown stroke

type of a CVA

occlusive, hemorrhage, external pressure

occlusive (2 types)

blockage. thromotic - fixed clot. embolic - travels in the system

hemorrhage (2 types)

bleeding. aneurysm, AVM

aneurysm

weakening or thinning of wall in blood vessel

arteriovenous malformation

(AVM) people are born with a tangle of blood vessels in brain or spine

external pressure (2 types)

reducing blood supply. tumor or intracranial pressure

how does the brain process language? (w/ examples)

receptive (auditory comprehension, reading) and expressive (verbal and written) modalities

^^how does the brain process and comprehend auditory input?^^

**COME BACK TO THIS**

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auditory comprehension of language

auditory input travels through the peripheral auditory system to reach the cortex

what are the structures and pathways involved in understanding auditory input?

Primary auditory cortex, Broca’s area, planum temporale, planum polare, dorsal stream, ventral stream

^^Auditory input - primary auditory cortex^^

where cortical processing begins in the temporal lobe

Auditory input - broca’s area

shows activation with complex syntactic activites

Auditory input - planum temporale

aka wernicke’s area. signal sent here, second, pulls in information about processing semantics and auditory input

Auditory input - planum polare

3rd step. anteriorly. acoustic processing

Auditory input - dorsal stream

supports auditory motor integration,

Auditory input - ventral stream

attachment of meaning to sounds/sound combos

blue line // dorsal pathway 1

wernike’s → premotor cortex

green line // dorsal pathways 2

wernike’s → broca’s

purple line // ventral pathway 1

superior temporal gyrus → broca’s

orange line // ventral pathway 2

anterior superior temporal gyrus → frontal operculum

how does the brain process visual information?

visual information travels through the visual system to reach the cortex

which structures and pathways are involved in the visual process?

Eye, optic chiasm, primary visual cortex, thalamus, geniculocalcarine tract, dorsal stream, ventral stream

^^visual process - optic chiasm^^

^^visual process - primary visual cortex^^

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^^visual process - thalamus^^

visual process - geniculocalcarine tract

carries information from the thalamus to the primary visual cortex

visual process - dorsal stream

to superior occipital lobe and inferior parietal lobe; the “where” objects are located in visual field

visual process - ventral stream

inferior occipital, posterior, and inferior temporal lobes; the “what” objects are

left hemisphere reading systems (3)

parietotemporal, occipitotemporal, anterior

Parietotemporal function

word analysis, sorting words out, comprehension of written and spoken language

Parietotemporal location

on boarder between temporal and parietal lobes (angular gyrus, supramarginal gyrus, posterior portion of superior temporal gyrus)

occipitotemporal function

sight reading, visual word form area

occipitotemporal location

between the temporal and occipital lobes (left inferior occipital area, left inferior-posterior temporal gyrus, fusiform gyrus)

anterior reading system function

word analysis in spoken language and articulation, silent reading, decoding unfamiliar words

anterior reading system location

broca’s area, premotor areas

orange part

anterior reading system

purple part

parietotemporal reading system

blue part

occipitotemporal reading system

sequence of reading system pathways

eye → thalamus → primary visual cortex → occipitotemporal OR parietotemporal reading systems → anterior reading system

oral language production pathway (4 steps)

1. prefrontal cortex → broca’s area
2. broca’s area → SMA
3. SMA → primary motor strip
4. primary motor strip → UMN, LMN, muscles of speech sound production

function of broca’s area (in terms of oral language production pathway)

speech motor/articulation, phonological processing, syntactic processing, cognition

which pathway is this?

oral language production pathway

structures involved in the oral language production pathway

Prefrontal cortex, Broca’s area, UMN, LMN, supplementary motor area, primary motor strip

==oral language production pathway - Prefrontal cortex==

==oral language production pathway - premotor cortex==

==oral language production pathway - UMN==

==oral language production pathway - LMN==

==oral language production pathway - left superior parietal lobe==

==oral language production pathway - supplementary motor area==

==oral language production pathway - primary motor cortex==

written language production pathway

1. prefrontal cortex → broca’s area
2. broca’s area → premotor cortex
3. premotor cortex → primary motor cortex
4. primary motor cortex → UMN, LMN, dominant hand
5. left superior parietal lobe