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137 Cards in this Set
- Front
- Back
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What does the brain include?
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Cerebrum, brainstem, and cerebellum
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What does the frontal lobe do?
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Motor control
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What does the parietal lobe do?
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Senses of pain and touch
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What does the temporal lobe do?
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Auditory complex
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What does the occipital lobe do?
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Visual cortex
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What is the white matter below the cortex made up of?
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Myelinated axons
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What does the gray matter in the cerebral cortex do?
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It is responsible for highly complex aspects of mental functioning including language, memory, and visual spatial relationships.
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How is sensory information sent to the cortex?
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Through the thalamus
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What lobe is responsible for the comprehension of language?
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The inferior parietal lobe along with the temporal lobe. (This is Wernicke's area)
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What lobe is responsible for spatial orientation and directing attentinon?
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Parietal cortex
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What are gyri?
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The elevated convolutions
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What are gyri separated by?
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by shallow grooves called sulci and deeper grooves called fissures
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What is the corpus callosum?
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a band of 200-250 million neurons that connect the right and left hemisperes
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What is the frontal lobe's function?
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Motor
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Where is Broca's area?(Frontal lobe)
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Located in the inferior frontal gyrus of one hemisphere usually the left.
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What is Broca's area function? (Frontal lobe)
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In the production of written and spoken language.
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What is the pre-frontal cortex's function? (Frontal lobe)
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involved in executive functions (personality, insight, and foresight)
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IF you damage the frontal area, what might a person have trouble doing?
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trouble with voluntary and purposeful movements
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What is the pre-central gyrus's function? (Frontal lobe)
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Are all involved with initiation of voluntary movements; contain cells of origin of descending motor pathways
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What's the temporal lobe's funciton?
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auditory
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Where is Wernicke's area located?
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Posterior portion of superior gyrus of one hemisphere (usually left)
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What is the occipital's lobe's function?
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Visual
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What part of the occipital lobe contains the primary visual cortex?
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Calcarine sulcus
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What makes up the limbic system?
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Limbic Lobe plus hippocampus and other interconnected structures
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What is the limbic system involved in?
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involved in emotional responses, drive-related behaviors and memory
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What makes up the dicephalon?
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Thalamus
Hypothalamus Epithalamus Subthalamus |
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What type of information does the thalamus send to the cerebral cortex?
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All sensory information except olfactory synapse at thalamic nuclei on the way to the cerebral cortex
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Where is the thalamus located?
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Interventricular foramen and third ventricle
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What pathways go through the thalamus?
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Motor systems with pathways between the cerebellum and cerebral cortex and between the cerebral cortex and basal ganglia often involve thalamic nuclei
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Does the limbic system information pass through the thalamus?
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Yes
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where is the hypothalamus located?
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Inferior to the thalamus. Forms the floor of the third ventricle
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What is the infundibular stalk?
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the connection between the hypothalamus and the posterior pituitary gland= neurohypophysis
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What does the hypothalamus control?
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Control ANS, endocrine and involve in limbic system
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What is the epithalamus involved in?
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regulation of circadian rhythms
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Tumors in the epithalamus affect what?
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Tumors tend to affect eye movements and pupillary reactions as well as cause changes in sexual development
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Where is the subthalamus located?
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Inferior to the thalamus and lateral to the hypothalmus
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What is the subthalamus transversed by?
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traversed by somatosensory pathways on their way to the thalamus
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What does the limbic system control?
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Controls emotional behavior and motivational drives, memory and learning. Limbic structures serve as a bridge between autonomic and voluntary changes in the environment
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Give an life example of how the limbic system works?
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Ex. Response to a chilly room: autonomic response is coordinated by the hypothalamus- cutaneous vasoconstriction and shivering; voluntary response by us is to put on more clothes as we become consciously aware of the chill.
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What are the structures of the limbic system?
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Hypothalamus
Paraolfactory area Anterior nuclei of the thalamus Portions of the basal ganglia Hippocampus Amygdala |
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How does the hypothalamus work in regards with the limbic system?
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Center of the limbic system
Controls visceral activity (ie. ANS) Elicits phenomena associated with emotions Exerts influence through the nervous system (neural component-synapes) and circulatory system (endocrine component-blood) |
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The hypothalamus plays important role in self preservation and preservation of the species (maintain homeostasis). What does it influence??
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Water balance
Food intake Endocrine system Reproduction Sleep Behavior The entire autonomic nervous system |
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What part of the hypothalamus controls vasopressin and oxytocin release?
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Supraoptic nucleus(vasopressin release)
Paraventricular nucleus (oxytocin release) |
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What is the function of the hippocampus?
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Key role in memory and learning
Receives all types of information from the sensory association areas Important information is repeatedly sent by the hippocampus over a neural circuit until it is stored permanently Inputs information to the hypothalamus |
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Damage to the hippocampus does what?
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Damage to either one or both hippocampi leads to short-term memory deficit (anterograde amnesia); damage can occur with severe hypoxia; long term memory and intelligence remains intact
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What has been removed to treat epilepsy?
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Portions of the hippocampus have been removed for treatment of epilepsy
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What is Alzheimer's disease associated with?
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Alzheimer disease is associated with a loss of neurons in the hippocampus
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What is the amydala's role? What does damage to the amydala cause?
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Plays important role in behavior and emotions
Provides input to the hypothalamus and thalamus Damage leads to behavioral alterations, especially a loss of fear |
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What does the amydala associate and give an example?
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Associates experiences with consequences and then programs the appropriate behavioral response to the experience
Ex. Crave food in response to pleasant aroma, induce nausea/vomiting in response to foul odor |
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What is the basal ganglia's function?
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Instrumental in the initiation of voluntary movements and the control of postural adjustments associated with voluntary movements
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What abnormalities are associated with the basal ganglia?
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Abnormalities are associated with movement disorders like Parkinson and Huntington diseases
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What is the corpus striatum?
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It is part of the basal ganglia. It consists of the caudate nucleus and putamen(lentiform nucleus)
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What structures in the basal ganglia contain dopaminergic receptors?
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The corpus striatum's caudate nucleus and putamen.
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What is the substantia nigra?
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Largest nuclear mass of the midbrain
Contains neurons filled with melanin |
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Input to the basal ganglia is through what structure? What neurotransmitter?
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Input is to the corpus striatum and subthalamic nucleus; input is excitatory (Glutamate)
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Output from the basal ganglia is through what structure? What neurotransmitter?
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Output is from the globus pallidus and the substantia nigra; output is inhibitory (GABA)
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What is the cerebellum?
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The large bilaterally symmetric “little brain” in the posterior cranial fossa
Its afferent and efferent connections influence the timing and force of contractions of voluntary muscles that result in smooth, coordinated movements |
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Where is the gray and white matter of the cerebellum?
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Similar to cerebral cortex in that its outer layer is gray matter with white matter beneath called cerebellar nuclei
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Where are all the cranial nerves except 1 and 2 located?
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In the brainstem
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What does the brainstem consist of?
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Midbrain
Pons Medulla |
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What is the brainstem's function?
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Transmits somatosensory impulses from all parts of the body to the forebrain
Transmits motor impulses for voluntary movements from forebrain |
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What is another name for the midbrain?
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Mesencephalon
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Where is the midbrain located?
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Between the pons and forebrain
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What crainial nerves does the midbrain contain?
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3 and 4
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What centers does the midbrain have?
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Centers associated with auditory, visual, and pupillary reflexes.
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What major aqueduct does the midbrain contain and why is it some important?
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It contains the cerebral aqueduct. This is the only exit route for CSF from the forebrain ventricles to the 4th ventricle.
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What cranial nerves does the pons contain?
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5, 6, and 7
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What control centers is the pons associated with?
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Contains centers associated with mastication, eye movements, facial expression, blinking, salivation, equilibrium, and audition
Contains the 2 respiratory centers that work with the medulla to produce a regular breathing pattern |
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What cranial nerves does the medulla contain?
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8,9, 10, 11, and 12
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What control centers is the medulla associated with?
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Contains centers associated with equilibrium, audition, deglutition, coughing, vomiting, salivation, tongue movement, respiration, and circulation
Serves as a decussation center for spinal cord impulses to cross to the other side of the brain |
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What controls respiration and how is it controlled?
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MEdulla.
Receives input from central chemoreceptors carried by glossopharyngeal (9) and vagus nerves (10) |
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What inhibits inspiration?
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Pneumotaxic center is located in the dorsolateral pons and inhibits the inspiratory phase of respiration
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What induces sleep?
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Anterior hypothalamus
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What induces arousal?
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Posterior hypothalamus
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Wakefulness and arousal are a result of what?
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Result of activation of the cerebral cortex
Dependent on the influence of the reticular formation on the cerebral cortex via the ascending reticular activating system (ARAS) |
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Who is at risk for wakefulness in anesthesia. Know about the BIS monitor.
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Acute trauma
Cardiac surgery Cesarean section under GA Bronchoscopy/ laryngoscopy Difficult intubation ASA status 3, 4, 5 patients Chronic use of benzodiazepines or opioids Heavy alcohol use Patients an beta blockers- no increase in HR |
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What happens if you have a loss of CSF in the spine?
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It decreases amount of fluid for brain to float in leading to an intracranial headache.
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What makes up CSF (molecules)?
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H20
protein O2 and CO2 K+ Na++ Ca++ Mg+ Cl- glucose |
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How much CSF is in the CNS?
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125-150mls
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How much CSF is in the ventricles?
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25ml
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How much CSF is in the subarachnoid space around brain and spinal cord?
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25-35ml
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What structure in the brain makes CSF?
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choroid plexus
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How much CSF does the choroid plexus make per hour? Per day?
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30ml/hr
500-700ml/24 hours |
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Where is most CSF formed?
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two lateral ventricles (most production),third ventricle, and forth ventricle by combination of active transport and diffusion
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Explain the cycle of CSF circulation.
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choroid plexus(formed)
lateral ventricles foramina of munro third ventricle aqueduct of sylvius forth ventricle foramina of lushka and magendie subarachnoid space brain arachnoid villi(absorbed) |
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What is the mnemonic for CSF circulation?
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clap loud for the angry fat furious Stacy Brandy Anderson
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How do you inhibit CSF formation?
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Furosemide – inhibits sodium and chloride transport
Acetazolamide (diamox)- carbonic anhydrase inhibitor that decreases bicarbonate transport Mannitol:- osmotic diuretic, changes gradient so fluid is pulled from brain to blood to decrease brain edema; does not cross blood brain barrier |
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What substances is the BBB permeable to?
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Permeable to water, CO2, O2, and most lipid soluble substances including alcohol and anesthetics
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What can break down of the BBB lead to ?
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Breakdown of barrier can lead to brain edema= brain swelling
Can lead to decreased blood flow and brain tissue destruction from ischemia |
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What is the cranial vault and how does it affect CSF pressure?
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Brain= 80%
Blood= 12% CSF= 8% |
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What does the Monroe Kellie hypothesis state?
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Monroe Kellie hypothesis: an increase in the volume of any one of these requires a corresponding decrease in the volume of the other two compartments (brain, blood, csf)
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What is normal ICP?
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10- 12 mmHg. (supratentorial pressure)
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What could cause increased ICP?
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With obstruction by hemorrhage, infection or tumor of villi, pressure may be as high as 40 mm hg. Causing papilledema (optic disc swelling) in the eye
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What could obstruction of the aqueduct of sylvius cause during development?
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Obstruction of aqueduct of Sylvius during development = hydrocephalus
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At what ICP pressures does focal ischemia and global ischemia?
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Focal Ischemia: 25-55 mmHg
Global Ischemia: >55 mmHg |
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What measurement device can measure and drain CSF?
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Ventriculostomy- can measure intracranial pressure and drain CSF
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What measurement device only measures ICP?
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Subdural bolt- only measures intracranial pressure
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What interventions can be done to decrease ICP?
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Increase ventilation (constricts vessels)
Diurectics and osmotics Increase HOB greater than 30 degrees |
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What is Cushing's triad? What does is signal?
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Hypertension, bradycardia, and irregular respiration
Signals severe cerebral ischemia and impending herniation |
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Is Cushing's Triad a late or early sign?
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Cushings triad is a late sign and you are on the way to herniation.
happens if ICP goes over 30 Increased BP, carotid bodies lower heart rate |
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What induction drug do you not want to give with a pt with an increased ICP?
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No ketamine(increase sympathetic drive)
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Cerebral blood flow is supplied by what two arteries?
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2 carotid provide anterior circulation 80% blood flow.
2 vertebral provides posterior circulation 20% of blood flow. Can supply collateral blood flow. |
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What cerebral artery if blocked, cuts off blood flow to spine?
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Vertebral arteries
Also Branches of the vertebrals and the basilar arteries supply spinal cord, brainstem, cerebellum, ear, diencephalon, and occipital and temporal lobes of cerebral hemisperes |
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What is a common place for CVAs?
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Middle cerebral arteries
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What arteries provide communicatiion between the two hemispheres?
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Communicating arteries
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What percent of CO goes to CBF?
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750-850 ml/min ( 15% of CO)
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How much O2 does the body consume?
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Accounts for 25% of body’s O2 consumption
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What is the normal CBF (ml/100g/min)? What are abnormal flows and what are the results?
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Normal: 50ml/100g brain tissue/min
CBF <20-25: cerebral impairment; slowing EEG CBF <15-20: isoelectric EEG CBF <10: irreversible brain damage |
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What is CBF regulated by?
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Regulated by:
Carbon dioxide concentration Hydrogen ions O2 concentration Ph |
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CBF and ______ have a linear relationship.
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CBF has linear relationship with PaCO2 between 20-80 mmHg
1 mmHg PaCO2= 1-2 ml/100g/min CBF |
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How does CO2 affect CBF?
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Carbon dioxide- increases due to increased brain activity OR hypoventilation increases CBF (double the CO2 = double the CBF and vv)
Hyperventilation will decrease PaCO2 and cause vasoconstriction Increased hydrogen ions from increased PaCo2 or increased neuronal activity cause vasodilation and increased CBF |
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How does pH affect CBF?
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Ph decreases due to increase in CO2 or increased brain cell activity
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What is CMRO2?
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Cerebral Metabolic Rate of Oxygen Consumption (CMRO2): Brain utilizes 20% of body’s O2 at rate of 3.5ml of O2 per 100 grams of brain tissue per minute
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How much glucose does the brain use?
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Glucose is the main energy substrate used by the brain at rate of 5mg/100g/min
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CMRO2 has a linear relationship with what?
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CMRO2 has a direct linear relationship with CPP called coupling: as CMRO2 increases (or decreases) CPP increases (or decreases) as well
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What increases oxygen consumption in the brain?
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Hyperthermia and ketamine increase O2 consumption
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What affects CMRO2?
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Coupling
Temperature: for each 1°C there is a corresponding 7-8% decrease in CMRO2; at 20°C an EEG is flat Seizures increase CMRO2 All volatile anesthetic agents, barbiturates and benzodiazepines decrease CMRO2 Volatile anesthetic agents increase CPP disrupting the linear relationship between the two |
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Does decrease in O2 cause an increase or decrease in CBF?
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Oxygen decrease will cause increased CBF; if CBF decreases leading to decreased O2 supply the vessels will vasodilate to restore CBF to near normal
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What is normal cerebral O2 concentration?
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35-40 mmHg
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Cerebral PaO2 <30mmHg does?
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Tissue hypoxia causing vasodilation
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PaO2 <20 mmHg does?
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Brain damage
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MAP has to be what pressure for normal CBF?
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Normal CBF with mean arterial pressure (MAP) of 50 -150mmHg
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If the MAP falls to 40mmHg what happens?
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cerebral ischemia
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What do HTN pts regulate to?
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Hypertensive patients regulate to higher MAP
The curve shifts to the right: MAP 80-180 mmHg Important to consider when administering anesthetic agents that often decrease BP In these patients a MAP <60 mmHg can seriously compromise CBF All of the volatile anesthetic agents increase CBF in a dose dependent manner |
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CBF autoregulates, how does it regulate for high and low pressures?
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Flow is maintained by vasodilation for decreased pressure and vasoconstriction for increased pressure
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If CBF is outside of autoregulation range flow, what happens to flow?
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Outside normal autoregulation range flow increases with increased pressure and decreases with decreased pressure
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What is normal CPP?
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70-100
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What is the formula for CPP?
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MAP- ICP (or CVP); dependent on MAP
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What are the different MAP pressures at which the brain show EEG changes?
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CPP <50 mmHG: slowing of EEG
CPP 25-40 mmHg: flat EEG CPP <25 mmHg: irreversible brain damage |
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What is luxury perfusion? What are some examples?
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Perfusion in excess of metabolic needs.
Examples: Tumor metabolites that cause vasodilatation in surrounding tissues Inhalation anesthetic agents that decrease CMRO2 and increase CBF |
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What is the steal phenomenon?
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Increased PCO2 or volatile anesthetic agents globally “steal” blood flow from ischemic areas of the brain by causing vasodilation in healthy areas of the brain. Ischemic brain tissue, which already has maximally dilated vessels due to released vasodilator substances, loses luxury perfusion benefit due to global shunting of blood flow
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What is the inverse steal or Robin hood phenomenon?
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Decreased PCO2 constricts normal vessels but not necessarily in ischemic areas due to vasomotor paralysis.
This is one rationale for hyperventilating patients with intracranial tumors associated with increased ICP especially when administering volatile anesthetic agents which cause vasodilatation Decreasing CO2 constricts normal tissure and increasing blood flow in ischemic area of the brain |
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What cranial nerves are in the medulla?
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CN 8-12
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What cranial nerves are in the pons?
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CN 5-7
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What cranial nerves are in the midbrain?
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CN 3 and 4
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What is the name of Cranial nerves 1-7 and what is there function?
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I- Olfactory- smell
II- Optic- see III- Oculomotor- move eye; adduction of eye- the medial rectus IV- Trochlear- moves eye V- Trigeminal- chews VI- Abducens- move eye; abduction of eye- lateral rectus VII- Facial- facial muscles, taste, anterior third of tongue |
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What is the name of Cranial nerves 8-12 and what is there function?
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VIII- Acoustic- balance
IX- Glossopharyngeal- taste, posterior 2/3 of tongue, carotid body and carotid sinus afferents X- Vagus- decrease HR, motor control of larynx and pharynx, aortic body afferent XI- Accessory- shoulder and head movements XII- Hypoglossal- motor, moves tongue |
