click below
click below
Normal Size Small Size show me how
Neuroanatomy
Neuroanatomy final
Term | Definition |
---|---|
Central Nervous System | Cerebrum, cerebellum, brainstem, spinal cord, thalamus, etc. |
Peripheral Nervous System | Spinal nerves, cranial nerves, sensors |
autonomic (visceral) | Involuntary body functions of visceral muscles (cardiac, glandular secretions, digestive function) |
somatic | Voluntary body functions |
Autonomic NS Innervations | Glands, smooth muscle, cardiac muscle |
Somatic NS | Motor control is largely dictated by the precentral region of the cerebral cortex with nerve impulses conveyed thru descending motor tracts (efferent) of the brain and spinal cord. |
Nerve Tracts | The mode of communication from the brain and spinal cord to the rest of the body |
Sensory (Afferent) | Info received from the environment and sent to the brain for processing (constant regulation of vital abilities - HR, body temp) |
Motor (Efferent) | Convey info from the cerebral cortex out to the periphery |
3 Types of Nerve Tracts | Projection, Association, and Commisural |
Projection | tract from cortex to brainstem |
Association | provide communication between regions of same hemisphere |
Commisural | Communication between right and left hemisphere |
Efferent (motor) pathways | Pyramidal & Extrapyramidal |
Pyramidal | Corticobulbar and corticospinal |
Corticobulbar | from the motor cortex to the brainstem; motor cranial nerves for speech |
Corticospinal | from the motor cortex, pre-motor cortex and SMA to the spinal nerves in the spinal cord |
Extrapyramidal | basal ganglia and reticular formation (originate in the cerebral cortex, but moves outside the medulla; provide background tonicity; reflexes |
Afferent (sensory) pathways | Spinothalmic |
Spinothalmic | from environment to higher brain centers; pain and thermal regulation |
Grey Matter | Neuronal bodies |
White Matter | Mylinated axons |
Upper Motor Neurons (UMN) | connect the brain to the appropriate level in the spinal cord or brainstem, from which point nerve signals continue to the muscles by means of the lower motor neurons |
Lower Motor Neurons (LMN) | Final Common Pathway |
Gyri | mountains of the brain |
Sulci | valleys of the brain |
Fissure | deeper groove of the brain |
Surface of the cerebral cortex of the brain doubles on itself, surface becomes convoluted -Function of this? | Increased surface area for neuron power |
Lateral Sulcus | "Sylvian Fissure" divides the temporal lobe from the frontal lobe |
Central Sulcus | "Rolandic Fissure" divides frontal lobe from the parietal lobe |
Broadmann's Areas | He brain mapped - diff parts of the brain have specific functions |
Dura Mater | Superficial layer of protection; more inelastic (fibrous/rigid) |
Arachnoid Mater | middle layer; many of the blood vessles for the brain pass through - where cerebral spinal fluid flows |
Pia Mater | thin cobering of the brain itself; major arteries/veins that serve the cerebral cortex are here |
Falx cerebri | separates the two hemispheres of the cerebrum into R and L, down to the corpus collosum |
Falx cerebelli | separates the two hemispheres of the cerebellum into R and L |
Tentorium cerebelli | Horizontally divides the cerebrum into superior (cerebral) and inferior (cerebellar) regions |
Diaphragma sella | separates the pituitary gland, hypothalamus, and optic chiasma |
Cerebrum - Dura Mater Infolds | Falx cerebri, falx cerebelli, tentorium cerebelli, and diaphragma sella |
Cerebrospinal fluid | protection, nutrition, waste removal |
Hydocephalus | occlusion of the cerebral spinal fluid pathway. literally "water on the brain". Most common obstruction is cerebral aqueduct -btw the 3rd and 4th ventrical) Treatment = meds and shunt. |
CSF originates? | in the ventricles and is absorbed by the venous system of the brain |
Ventricular System | CSF and 2 paired lateral ventricles, 3rd ventricle, 4th ventricle, and choroid plexus |
3rd Ventricle | sits around the thalamus |
4th Ventricle | flows through cerebral aquaduct |
choroid plexus | aggregate of tissue that produces cerebro spinal fluid |
Venus System | Choroid plexus moves the subarachnoid space and bathes the brain in CSF and then gets eliminated via the venus system |
Cerebrovascular system | complex interconnected vascular system (arteries, veins) blood carries oxygen to the organs including the brain |
Vascular system of the brain | the brain constitutes 2% of our overall body weight but requires 20% of the oxygen needs of the body due to its high metabolic requirements. Blood carries this O2 thru the brain. |
Arteries | Carry oxygenated blood away from the heart; aorta |
Veins | Carry deoxygenated blood back to the heart; vena cavas |
Circle of Willis | encircles the optic chiasma and is a series of vessels that provide collateral blood flow to the left and right hemispheres of the brain as well as the anterior posterior aspects. |
What is the Circle of Willis? | The carotid and vertebral systems are joined by communicating arteries that help ensure equilized distribution of blood and safeguard against vascular accidents |
What are the 2 primary arteries involved in the Circle of Willis Anterior? | Carotids and vertebrals |
Common Carotid arteries of the circle of willis -anterior branch to... | the internal and external carotids (only internal CA supply blood) |
Internal Carotid Arteries (ICA) branch off to... | the anterior cerebral artery (ACA) and the middle cerebral artery (MCA) |
Anterior Cerebral Artery (ACA) | frontal/ parietal lobes, copus callosum, BG (basal ganglia) regions |
Middle cerebral artery (MCA) | temporal lobe, motor strip, Broca's, Wernicke's, sensory regions |
What does the Middle Cerebral Artery do? | supply blood to areas critical for speech, language and hearing. It is the largest and courses laterally thru the lateral sulci |
Lenticulostrate arteries | arteries of the middle cerebral artery that branch off and supply blood to the Basal Ganglia and internal capsule |
Watershed area | Diffuse symptoms, not as severe, but more widespread speech lang deficits. |
The Circle of Willis -Posterior | The basilar artery divides to become the left and right posterior cerebral arteries (PCA) |
Basilar Artery | Left and right vertebral arteries join to form the basilar artery |
Posterior cerebral arteries | serve the inferior temporal and occipital lobes, primary visual cortex, cerebellum (supply blood to back part of brain) |
Posterior communicating arteries (PCOM) | connect the PCA to the MCA (2 of them) |
Anterior communicating artery (ACOM) | connects the ACAs |
Venous system | blood drains into the cisterns (both superficial and deep). It returns to the general bloodstream via the jugular veins and eventually the superior vena cava |
Spinal Vascularization | Anterior/posterior spinal arteries supply the spinal cord. Radicular arteries serve the spinal nerves |
Cerebrum | "bark" outer surface of the brain. Made up of 6 cell layers with 2 basic cell types (pyramidal -pyramid shaped involved in motor funciton. And non-pyramidal cells-star shaped, involved in sensory information or intercommunication btw cells) |
Right hemisphere of the cerebrum | mostly devoted to creativity |
Left hemisphere of the cerebrum | mostly devoted to logic abilities. |
Corpus collosum | bundle of axons which connect the 2 hemispheres; information/communication highway |
What is the cerebrum | It controls voluntary functions. Considered the seat of consciousness and it is the most highly evolved and organized structure of the body. (includes: gray matter, white matter, and gyri & sulci) |
Intra-axial hemorrhages | occur within the brain tissue, due to trauma or stoke 3 types: intraventricular, intraparenchymal, intracerebral |
Intraventricular | bleeding into ventricals |
Intraparenchymal | bulk of the brain tissue |
Intracerebral | intraxial hemorrhage (general term) |
Extra-axial hemorrhages | occurs outside of the brain tissue; can be due to trauma 3 types: epidural hematoma (EDH), subdural hematoma (SDH), subarchnoid hemorrhage (SAH) |
Frontal Lobe | Largest of the lobes, accounts for 1/3 of the cerebral cortex. Executive functioning, language, motor control of body. Includes: precentral gyrus-motor strip, SMA/Pre-motor area, Pre-frontal cortex, and Broca's area |
Homunculus | Topographic organization |
Parietal Lobe | Post-central gyrus is the sensory counterpart to the motor strip - primary site of sensory input; distribution of sensory function by body region is closely related to the motor strip. Supramarginal gyrus-motor planning for speech. Impairments here=autism |
Angular gyrus of the Parietal lobe | important in comprehension of written language |
Temporal Lobe | Auditory and receptive language processing; auditory reception, memory acquisition. |
Superior Temporal Gyrus (Heschl's gyrus) | auditory information is projected. Posterior area = Wernicke's Area |
Wernicke's Area | auditory comprehension and processing |
Arcuate Fasciculus | Tract of nerve fibers running from Broca's to Wernicke's area. |
Occipital Lobe | Posterior limit of the brain. Primary Visual cortex |
Insular Cortex | Plays a role in consciousness, emotion, homeostasis, cognitive functioning, perception, self awareness, and hand eye coordination |
Cerebellum | Older than the cerbrum. 2 Hemispheres, highly folded surface. Regulation/coordination of movement, posture and balance. Plays a role in memory for motor function. Ataxia |
Subcortical Structures | Basal ganglia, thalamus, hippocampu, hypothalamus, amygdala. Functionally, compose the limbic system. |
Basal Ganglia | Composed of the caudate nucleus, putamen, substantia nigra and globus pallidus. Movement disorders |
Lentiform | Globus pallidus and putamen together |
Striatum | Putamen and caudate nucleus together. |
Thalamus | Situated deeply in the forebrain. Sensory and motor function. Last relay site for sensory info be4 reaches cerebrum. Reticular activating system - sleep/wake and attention |
Hypothalamus | Inferior/ventral to the thalamus. Homeostasis, autonomic responses, thirst/hunger, emotion, reproduction, dysautonomia. (Primative emotions) |
Hyppocampus | In proximity of the temporal lobe. Learning and short-term memory. Recall spacial relationships in world, communicates with the hypothalamus. Retrograde amnesia and anterograde - due to damage in this area |
Amygdala | Located in the temporal lobe. Involved in memory, emotion, and fear. Autism |
Brainstem | Consists of the medulla oblongata, pons and midbrain. Intermediate stage of organization. Originates site of cranial nerves. Midbrain, pons, medulla oblongata. |
Spinal Cord | Begins at foramen magnum and courses inferiorly thru the vertebral column. Has both efferent & afferent components. Relays motor info, relays sensory info, & coordinates reflexes |
Synaptic Pruning | C1q is secreted by neurons to identify "un-needed" synapses |
Theory of autism | sensory overload (diminished amnt of C1q) |
Alzheimers/Dementia | Increased amnts of C1q |
Neuroplasticity | ability of the brain to regenerate neuronal pathways &/or find alternate neuronal pathways to compensate for damage |
Left Hemisphere of brain | characterized by language deficits |
Right Hemisphere of brain | higher level cognitive deficits (thinking, planning, organize, STM, processing) and visual deficits |
Communication Disorders | Aphasias, cognitive-communicative disorders, apraxia, dysarthria, cognitive-communicative disorders |
ALS | Happens where UPN and LMN connect (damage to nerve cells and glial cells |
MS | Demylination of axons (damage to nerves) |
PD | damage in the basal ganglia (damage to glial cells) |
Cerebral hemisphere neuropathologies | Encephalitis, brain injury, and dementia |
Disruption of supporting systems of the CNS (blood supply, meningeal coverings and ventricular systems) | Meningitis, hydocephalus, and stoke |
Meningitis | #1 cause=ear infections. Inflammation of the meninges (pia and arachnoid) Including the subarachnoid space and CSF. Microorganisms enter the CSF |
Hydocephalus | Blockage/obstruction usually from the ventricles. Inadequate drainage results in increased intracranial pressure causing brain tissue to shift out of the way |
Stroke | vascular disease interrupting the blood supply to various CNS tissues |
Ischemic | Type of stroke common in the MCA (80% of stokes) can be thrombotic or embolic |
Ischemia | decrease in oxygen and glucose to brain tissue |
Thrombotic Stroke | gradual buildup of plaque that occludes |
Embolic Stroke | material that travels in the blood stream until it gets to an artery/capillary that's too narrow |
Hemorrhagic stroke | (20% of stokes) a burst in the vessel. Results in bleeding on the brain |
TIA (transient ischemic attack) | mirrors symptoms of a stoke, but resolves - sign you may have a stroke soon |
Common locations of a stroke | meningeal layers (epidural, subdural, subarachnoid) and Intracerebral/parenchymal (subcortically) |
Antecedents of a stroke | Hypertension (malignant or chronic) Aneurysm (weakening of an artery wall resulting in ballooning out over time) |
Arteriovenus Malformation | abnormally formed capillary beds |
Encephalitis | inflammation of generalized brain tissue causing swelling, usually in the temporal lobes; viral - herpes |
Traumatic brain injury | brain damage as a result of physical trauma. Can be penetrating (open head injury that pierces thru brain matter) or non-penetrating (closed injury as a result of blunt trauma or rotational acceleration) |
Discrete lesions | concussion, contusion, hematoma, ischemic brain damage |
Diffuse lesions | diffuse axonal injury and hypoxic/anoxic. May have more lasting effects |
concussion | most minor of brain injuries. alteration of consciousness for a short time. visual and vestibular deficits |
contusion | minor hemorrhage or tearing of blood vessel at the site of impact (coup, contrecoup) |
hematoma | accumulation of blood (epidural, subdural) |
ischemic brain damage | ACA or MCA distribution (see in soldiers) |
diffuse axonal injury | damage to nerve fibers (axons); shearing of white matter |
hypoxic/anoxic | decreased oxygenation of tissue (hypotension, high intracranial pressures, seizures, cardiopulmonary compromise) |
Mechanisms of Traumatic Brain Injury | Discrete lesions and diffuse lesions |
Dementia | disease characterized by a progressive decline in cognitive abilities that typically strikes in later years. Memory decline and one more: apraxia, agnosia, aphasia, executive function impairment |
Cortical dementia | atrophy of the cerebral cortex (alzheimers and frontotemporal |
Subcortical dementia | degeneration of the basal ganglia. often vascular or multi-infarct. Huntington's disease |
causes of dementia | build up of tau proteins causing cell death; primarily affects the temporal lobes, hippocampus. Genetics |
Aphasia | Loss of language skills. Expressive-difficulty with speaking or writing. Receptive - difficulty understanding or reading |
Dysarthria | motor speech deficits |
Apraxia | motor planning deficits |
cognitive-communicative disorders | thinking skills deficits (attention, memory, problem solving) |
Wernicke's aphasia | Receptive aphasia - fluent sounding speech that is meaningless/not on topic. Damage due to the left posterior aspect of the superior temporal gyrus and surrounding areas |
Broca's aphasia | non-fluent effortful/telegraphic speech. A stoke in the left hemisphere of the frontal region. |
Conduction Aphasia | arcuate fasciculus. Difficulty repeating, literal substitutions |
Global aphasia | damage to both Wernicke's and Broca's areas resulting in expressive and receptive deficits |
Anomic aphasia | mildest of aphasias; difficulty with word retrieval (tip of tongue) |
Motor speech lesions | Dysarthria (flaccid, spastic, ataxic, mixed) and Apraxia (SMA, insula, frontal/parietal lobes) can be oral (swallowing or non speech movements-can't stick out tongue) or Verbal (speech movements-can't do multisyllabic words) |
cognition | attention, organization/sequencing, problem-solving, memory and higher level processing |
executive functioning | attention, self-regulation, self-inhibition, self-awareness, insight into deficits, reasoning |
pragmatics | social appropriateness - eye contact, verbosity, personal space, turn-taking |
Right hemisphere dysfunction | impairments in attention and integration. Attention supports all other cognitive functions; significant L neglect |
Chronic traumatic encephalopathy (CTE) | a progressive neurodegenerative syndrome resulting from multiple concussed episodes and characterized by an increase in tau protiens and resulting in early onset dementia, decreased emotional regulation, and depression |
Locked in syndrome | a paralysis of voluntary muscles of the body while consciousness remains relatively unaffected. Caused by a lower brainstem injury |
Telencephalon | cerebral hemispheres, basal ganglia, olfactory tracts, verntricles |
Diencephalon | thalamus, hypothalamus, pituitary gland, optic tract, ventricles |
Mesencephalon | mid brain |
metencephalon | pons, cerebellum, ventricle |
myelencephalon | medulla oblongata, ventricle |