PT9111 - Cerebrum, Vasculature and CSF Flashcards by Robert Graham

How long does the brain continue to undergo myelination? Which regions are the last to become myelinated?

Until the third decade.
Frontal regions (executive functions).

How well did you know this?

Not at all

Perfectly

What percentage of the frontal lobe makes up the cortex? What are its key areas?

40%
-Primary motor area
-Premotor area
-Supplementary motor area
-Frontal eye fields
-Broca’s area
-Prefrontal area

How well did you know this?

Not at all

Perfectly

What are the four main functions of the frontal lobe?

-Movement control (planning and execution)
-Conjugate eye movements
-Speech production (broca’s area)
-Personality

How well did you know this?

Not at all

Perfectly

What does Broca’s area do?

Processes information from the temporal cortex and writes a script for speech execution passed to primary motor cortex

How well did you know this?

Not at all

Perfectly

What are the 5 personality changes associated with frontal lobe damage?

-Hypo-emotionality/de-energization
-Executive disturbances
-Disturbed social behaviour
-Emotional dysregulation
-Distress
-Decision making

How well did you know this?

Not at all

Perfectly

What are symptoms of frontal lobe lesions?

-Hemiplegia (paralysis of one side of the body; contralateral to legion)
-Weakness
-Apraxia (unable to perform learned movements on command)
-Personality disorders
-Aphasia (Broca’s area)

How well did you know this?

Not at all

Perfectly

What percentage of the cortex is made of the parietal lobe? What are its key areas?

20%.
-Primary somatosensory
-Secondary somatosensory
-Association areas

How well did you know this?

Not at all

Perfectly

What are the functions of the parietal lobe?

Sensation (from thalamus) and interpreting somatosensory signals
-touch, pressure, vibration, position, temperature
-Integration of sensory information to allow for motor planning, learning, language, spatial recognition, and stereognosis

How well did you know this?

Not at all

Perfectly

What are symptoms of parietal lobe lesions?

-Loss of sensation
-Sensory apraxia (cannot perceive objects purpose)
-Asomatognosia (denial of existence of body parts)
-Neglect syndrome (failure to recognize the opposite size of the body)

How well did you know this?

Not at all

Perfectly

What percent of the cortex is made of the occipital lobe? What are the key areas?

15%
-Primary visual area
-Visual association area

How well did you know this?

Not at all

Perfectly

What is the function of the occipital lobe?

Visual processing and interpretation (send information to other brain regions)

How well did you know this?

Not at all

Perfectly

What are symptoms of occipital lobe lesions?

Blindness, colourblindness, inability to detect moving objects

How well did you know this?

Not at all

Perfectly

What percent of the cortex is made of the temporal lobe? What are its key areas?

25%
-Primary auditory area
-Secondary auditory area
-Auditory association areas
-Emotions area
-Memory areas
-Speech (Wernicke’s area)

How well did you know this?

Not at all

Perfectly

What are the functions of the temporal lobe?

-Translating and processing sounds and tones
-Phonological representation of words
-Semantic retrieval (meaning to words)
-Semantic memory (remembering thought or objectives that are common knowledge
-Visual perception and facial perception
-Declarative memory (remembering things that have happened or have been learned)
-Familiarity

How well did you know this?

Not at all

Perfectly

What is the diencephalon? What are its key regions?

Division of the forebrain.
-Thalamus, Hypothalamus, Epithalamus, Subthalamus

How well did you know this?

Not at all

Perfectly

What is the thalamus? What sensory information pass through it?

Two oval collections of nuclei.
All sensory information EXCEPT smell

How well did you know this?

Not at all

Perfectly

What are the thalamic subdivisions and what are they responsible for?

Medial genticulate nuclei - hearing
Lateral genticulate nuclei - vision
Ventral posterior nuclei - taste and somatic sensations (pressure)
Anterior nucleus - emotions and memory

How well did you know this?

Not at all

Perfectly

What is the main function of the diencephalon?

Primary relay and processing center for sensory information and autonomic control.

How well did you know this?

Not at all

Perfectly

Through which fibers does cortical communication occur?

Intracortical fibers, association fibers, commissural fibers, and projection fibers

How well did you know this?

Not at all

Perfectly

What do association fibers do?

Connect gyri and sulci from lobe to lobe in the same hemisphere (ex. superior longitudinal fasciculus)

How well did you know this?

Not at all

Perfectly

What do intracortical fibers do?

Connect neurons in a localized area

How well did you know this?

Not at all

Perfectly

What do commissural fibers do?

Connect homologous areas of the two hemispheres (ex. corpus collosum)

How well did you know this?

Not at all

Perfectly

What do projection fibers do?

Connect cortex with subcortical nuclei
Corticofugal (efferent)
Corticopetal (afferent)

What is lateralization of function in the diencephalon?

Contralateral representation of the body in each hemisphere.

Some functions are lateralized to one hemisphere (higher functions, dominant hemisphere - correlates with opposite of dominant hand)

T/F: The gray matter receives greater supply than white matter.

True

What is average cerebral blood flow? What is ischemic?

55ml/100g per minute -Ischemia: 35ml/100g per minute

What is the total intracranial blood turnover rate?

5-7x per minute

Hypoxia and/or hypercarbia result in _____

vasodilation

Hypocarbia results in _______

vasoconstriction

What are factors that relate to passing through the BBB?

Molecular size, lipid miscibility, degree of ionic dissociation

What is the purpose of the anterior communicating artery?

Joins the two anterior cerebral arteries and supplies of corpus collosum -Important source of blood flow if one internal carotid is blocked

What is the function of the anterior cerebral artery? What part of the somatotopy is affected?

Supplies inferior and medial surface of frontal and parietal lobes. -Lower extremity (more medial)

What is the function of the middle cerebral artery?

Supplies most of lateral surface of frontal, parietal, and temporal lobe.

What happens if the middle cerebral artery becomes occluded?

-Sensorimotor deficits in the contralateral face and upper limb -global aphasia in dominant hemisphere (receptive and expressive language, auditory and visual comprehension) -Neglect syndrome

What is the function of the posterior inferior cerebellar artery?

Supplies large parts of the cerebellum

What syndrome results from stroke of the posterior inferior cerebellar artery? What are it's symptoms?

Wallenberg syndrome: -ipsilateral loss of pain and temperature sensation of the face -contralateral loss of pain and temperature sensation in the limbs, trunk and neck -ipsilateral Horner syndrome (drooping eyelid and constricted pupil) -hoarseness, vertigo, double vision, ipsilateral cerebellar ataxia (coordination and balance impaired), ipsilateral loss of taste

What arteries supply the spinal cord?

-single anterior spinal artery -paired posterior spinal arteries -radicular and segmental branches

What does the superior cerebellar artery supply?

-Supplies dorsal surface of cerebellum and midbrain

What do the pontine arteries supply?

Pons

What does the anterior inferior cerebellar artery supply?

Superior cerebellum and pons

What does the posterior cerebral artery supply?

The medial/inferior surface of temporal and occipital lobe; small strip on lateral surface occipital lobe -Supplies the calcarine artery (primary visual area)

What symptoms arise if stroke occurs in the posterior cerebral artery?

Contralateral homonymous hemianopsia (entire visual field on the opposite side of the stroke is affected) -If damage occurs in dominant hemisphere, reading and writing are impaired

What arteries make up the circle of willis? Where is it located?

Anterior communicating, anterior cerebral, internal carotid, posterior communicating, posterior cerebral, basilar -Located on the ventral surface of the brain

What is the purpose of the circle of willis?

Insurance policy; vascular shunt

Where do the venous sinuses drain into?

Sigmoid sinus and then into the internal jugular vein. Then to brachiocephalic veins which merge to form the superior vena cava.

What are the three venous sinuses?

-Inferior sagittal sinus -Superior sagittal sinus -Transverse sinus

What happens when a cerebral venous sinus thrombosis occurs?

Hemorrhage; caused by bacterial infection or malignancy, pregnancy and oral contraceptives are risk factors

Where are the venous sinuses located?

Between the periosteal and meningeal layer of the dura mater.

What are the three dural folds? What are their function?

Provide support to the brain and dural venous sinuses 1. Falx Cerebri (vertical, cerebral) 2. Tentorium Cerebelli (horizontal, cerebellum) 3. Falx Cerebelli (vertical, cerebellar)

What is a subarachnoid hemorrhage usually caused by?

-Cerebral arteries; often caused by aneurysm rupture

What is a subdural hemorrhage usually caused by?

Cerebral veins

What is an epidural hemorrhage usually caused by?

Meningeal vessels running on inside surface of cranium

Where is CSF produced, what are its functions, and where is it found?

-Produced in cells of the choroid plexus located in lateral third and fourth ventricles -Acts as a cushion, removes metabolic waste, and maintains a stable ionic environment -Found in the subarachnoid space

How much CSF is produced by the choroid plexus? What is the total volume and what is the turnover rate?

-Produces about 500mL per day -Total volume is 150mL -Replenished 3-4x/day

What is the flow of CSF?

Lateral ventricles, interventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, median/lateral aperture, subarachnoid space around brain and spinal cord, absorbed into dural venous sinuses

What is hydrocephalus?

-Obstruction of CSF pathway causing stagnation of flow; results in dilation of parts of ventricular system

Whats the differences between obstructive and communicating hydrocephalus?

Obstructive is within ventricles (congenital malformation, tumor); communicating is outside the ventricles (ex. subarachnoid space; hemorrhage or infection) Shunt can be inserted