Term
What structures are contained in the corpus callosum, and what do they do?
Where is the corpus callosum? |
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Definition
Basal ganglia (control of movement)
amygdala (regulation of emotion, stress, and appetite)
hippocampus (memory formation and learning)
Lies deep in the longitudinal fissure and interconnects the cerebral hemispheres |
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Term
What structures are in the diencephalon, and what do they do?
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Definition
Thalamus--transmits sensory
Hypothalamus--master neurohormone organ |
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Term
What forms the brain stem?
What else is contained in the brainstem?
What is in the pons? |
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Definition
The midbrain pons and medulla form the brainstem.
Also contains the reticular activating system (alertness and consciousness).
The pons contain ascending and descending fiber tracts and the nuclei of the trigeminal nerve and facial nerve. |
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Term
What forms the spinal cord?
What control centers are located here?
What cranial nerve nuclei are here? |
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Definition
The medulla extends from the pons to the foramen magnum where it becomes the spinal cord.
It has ascending and descending fiber tracts and contains the respiratory and cardiovascular control centers.
Cranial nerves VIII-XII |
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Term
| What does the cerebellum help with? |
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Definition
| Equilibrium, muscle tone regulation, and the coordination of voluntary muscle activity. |
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Term
What happens with over-stimulation of a nerve? When is this helpful?
Why does this happen? |
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Definition
Fatigue
Seizure--most cease due to this
After a while, there is a washout of neurotransmitters. Also, the ion concentrations in the post synaptic membrane become so imbalanced that the impulse c/n be propagated. |
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Term
What role does alkalosis play in neuron excitability?
Acidosis?
What about hypoxia? |
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Definition
Alkalosis greatly increases excitability--lowers the seizure threshold.
Acidosis decreases excitability--increasing the seizure threshold.
Reduces neuron excitability--this explains why a loss of oxygen will cause unconsciousness in 3-7 seconds. |
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Term
What cranial nerves innervate the dura matter?
What are the other meninges, and what are the spaces? |
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Definition
Olfactory
Optic
Oculomotor
Trigeminal
Arachnoid mater (thin, avascular)
Pia mater (thin, avascular)
Between the dura mater and arachnoid mater is the subdural space (potential), and the subarachnoid space is between the arachnoid and pia mater. Contains CSF. |
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Term
| Where do the preganglionic neurons of the sympathetic nervous system originate? |
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Definition
| Intermediolateral gray horn of the spinal cord between T1 and L2(3). Thoracolumbar division. |
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Term
| How many neurons are in the autonomic pathways? |
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Definition
| 2--a preganglionic and post ganglionic fiber. |
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Term
| Describe the preganglionic fiber in the SNS. |
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Definition
| Short, myelinated. Releases acetylcholine at the junction which attaches to nicotinic receptors. |
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Term
| Describe the post ganglionic fiber in the SNS. |
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Definition
| Long, unmyelinated. Synapses with efferent organ. Secretes norepinephrine which attaches to alpha and beta receptors. |
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Term
| What happens when the sympathetic preganglionic fibers exit the spinal cord? |
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Definition
| The exit via the anterior ventral root and transfer through the white ramus communicans, then enter the sympathetic chain. They may ascend, descend, or synapse at the level which they were generated. |
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Term
| How is the adrenal medulla stimulated? |
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Definition
| By preganglionic sympathetic fibers, which release acetylcholine to the adrenal medulla--no post ganglionic fibers. |
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Term
| What's different about sweat glands? |
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Definition
| Produced by sympathetic stimulation. As always, the preganglion is short and the post ganglion is long, BUT both secrete acetylcholine!!! The post ganglion secretes acetylcholine with binds with muscarinic receptors, stimulating sweat glands. |
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Term
| Where does the parasympathetic system arise from? |
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Definition
| Cranial nerves II, VII, IX, and X, and S2-S5. Craniosacral division. |
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Term
| Describe the pre and post ganglionic fibers in the parasympathetic system. |
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Definition
Pre ganglionic is LONG and myelinated. Acetylcholine is released and attaches to nicotinic receptors.
Post ganglionic is SHORT and unmyelinated, releases ACETYLCHOLINE which attaches to muscarinic receptors on the organ. |
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Term
| What is the para and sympathetic response of the iris? |
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Definition
Para = constrict
Symp = dilate |
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Term
| What part of the brain controls the autonomic nervous system? |
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Definition
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Term
The anterior and medial regions of the hypothalamus control what division of the ANS?
What about the posterior and lateral? |
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Definition
Parasympathetic
Sympathetic |
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Term
What mediates the "fight or flight" response to emotional situations?
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Definition
| The connection of the limbic system to the hypothalamus |
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Term
| Does the hypothalamus exert direct or indirect control over the ANS? |
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Definition
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Term
| What allows our response to fear? |
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Definition
| Relationship between the hypothalamus and the amygdala and periaquaductal gray |
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Term
How many spinal nerves are there?
Cranial? |
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Definition
31 pairs that connect with the spinal cord and innervate most areas of the body.
12 pairs. |
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Term
| What is the function of the astrocyte? |
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Definition
| Maintain the ion balance around neurons and control the exchange of materials between blood vessels and neurons. |
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Term
| What is the function of the oligodendrocytes? |
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Definition
| Wrap cytoplasmic processes around neurons to create an insulating barrier called a myelin sheath. |
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Term
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Definition
| Neuroglial cells that are phagocytic macrophages that provide a protective function by engulfing micrroorganisms and cellular debris |
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Term
| What do the ependymal cells do? |
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Definition
| Line the fluid-filled cavities of the brain and spinal cord. |
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Term
What is the basal ganglia?
What are some of the functions associated with it? |
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Definition
A collection of nuclei found of both sides of the thalamus, which is interconnected with the cerebral cortex, thalamus, brainstem and cerebellum.
Motor control, emotion, cognition, and learning. |
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Term
| What are some of the sub-divisions of the basal ganglia? |
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Definition
| Putnum, caudate nucleus, pallidus, subthalmic nucleus, substantia nigra. |
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Term
In Parkinson's, where does the disorder occur?
What neurotransmitter is released, and what is the role? |
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Definition
Substantia nigra
Dopamine--inhibitory |
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Term
| What is the extrapyramidal motor system? |
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Definition
| Group of neurons that coordinate the motor movement, involved in complex movements, locomotion, and postural control. |
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Term
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Definition
| substantia nigra, vestibular system, cerebellum and some parts of the sensory cortex. |
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Term
What substance is low in Parkinson's?
What does this lead to?
What is the most important risk factor? |
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Definition
Dopamine
Acetylcholine, the EPS excitatory transmitter, is uninhibited.
Age |
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Term
| What are the symptoms of Parkinson's |
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Definition
Tremors (worsens with rest)
Rigidity (first appears in neck)
Akinesia
Postural instability
Emotional disturbances (insomnia, depression, memory loss, hallucinations, dementia) |
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Term
| What is the treatment for Parkinson's aimed at? |
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Definition
| Either increasing the amount of dopamine in the substantia nigra or inhibiting the acetylcholine. |
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Term
| What 2 substances breakdown dopamine? |
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Definition
| MAO and COMT, so if you can inhibit those, you might improve the symptoms of Parkinsons |
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Term
| Why should Parkinson's patients continue to take their L-dopa before surgery? |
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Definition
| It has a short half-life, and abrupt withdrawal can worsen muscle rigidity and interfere with ventilation |
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Term
| What can be used as an anti-emetic in Parkinson's? Why? |
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Definition
| Zofran can be used. Phenergan, butyophenones, and reglan all have antidopaminergic effects that can exacerbate symptoms. |
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Term
| What type of drugs might be useful in an exacerbation of Parkinson's? |
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Definition
| Anticholinergics or benadryl (good for premedication and sedation + has antiemetic effect) |
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Term
| Why would induction of someone on L-dopa cause hypo or hypertension? |
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Definition
| L-dopa is a pre-curser to catecholamines, so if you just took a dose, you will be hypertensive. However, this can lead to down-regulation of the catecholamine receptors, so when the dose wears off, you not only have fewer catecholamines, but you also have fewer receptors. |
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Term
| What are some other considerations in Parkinson's? |
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Definition
Autonomic instability--use A-line
Use direct acting pressors |
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Term
| What is the dysfunction in huntington's |
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Definition
| Caudate nucleus of the basal ganglia is destroyed or dysfunctional, leading to too little acetylcholine and too much dopamine. |
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Term
How is dopamine moderated in the caudate nucleus?
What happens in huntingtons? |
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Definition
| GABA inhibits dopamine, but GABA is reduced in Huntingtons |
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Term
| Describe the symptoms of huntingtons |
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Definition
Jerking, uncontrolled, random movements
Prior to the movements, patients exhibit mood changes, rage issues. Violent tendencies, egocentric behavior, compulsive behaviors |
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Term
| What type of drugs are helpful in huntingtons? |
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Definition
| Antidopaminergics (Haldol)--helps control movements and address behavior problems. |
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Term
What happens to the airway in Huntingtons?
What drugs have prolonged action, and why? |
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Definition
May lose control of pharyngeal muscles.
Succs, esters (locals) due to reduction in plasma cholinesterase |
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Term
What type of drugs can cause dystonias?
How is GABA thought to be related to spasmotic torticollis? |
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Definition
Antidopaminergic drugs
Thought to be a defect in the production or release of GABA |
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Term
What are some anesthetic implications of spasmotic torticollis?
What if it is caused by drugs? |
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Definition
If patient has chronic neck distortion, can alter vertebral structure and anatomy--may need fiberoptic intubation.
Benadryl 25-50 mg IV can reverse if caused by drugs. |
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Term
What happens in Alzheimers?
Are regionals a good idea for this population? |
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Definition
Progressive loss of grey matter. Progressive impairment of memory, judgement, decision making and emotional lability.
Only if they are cooperative. |
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Term
What is the effect of central acting drugs with alzheimer's patients? what type of dosing is best?
What drugs should be avoided? |
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Definition
Prolonged effects, post op confusion and delerium. Better to use small doses more frequently.
Anticholinergics that cross the BBB (atropine, scopalamine) can cause delerium. Glycopyrolate does not cross the BBB |
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Term
Describe MS
What is an important factor in conduction across demyelinated neurons? |
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Definition
Reversible demyelination at random sites in the brain and spinal cord. Chronic inflammation eventually produces scarring and permanent effects.
Temperature--increases in body temp exacerbate symptoms. As little as 0.5 degree increase may cause complete conduction block! |
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Term
What regionals are okay, and what should be avoided?
Are these patients CV stable or labile?
What about succs? |
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Definition
Spinals can exacerbate the disease, but epidurals and blocks do not.
CV may be unstable d/t autonomic dysfunction.
Succs should be avoided esp. if the pt has paralysis, paresthesia, or is chair or bed bound. |
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Term
What is ALS?
What is usually the cause of death? |
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Definition
Neurodegenerative disease that affects the MOTOR neurons.
Ventilatory failure d/t resp. muscle involvement |
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Term
| What are the big anesthetic implications of ALS? |
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Definition
Respiratory care--may be difficult to wean.
Muscle weakness--do not use succs. Also sensitive to NDMRs.
Avoid regionals. |
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Term
What is Guillain Barre?
What treatment do some people respond to? |
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Definition
Immune reaction against the myelin following viral or GI infection. Also assoc. with HIV and neoplastic disease.
Plasmaphoresis. |
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