Apex Flashcards
Name the 12 cranial nerves
Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal
What cranial nerves provide motor control of the eyes? How does each nerve contribute to the eye’s movement
CN III : adducts
CN IV : Rotation
CN VI : abduction
Which cranial nerve resides in the central nervous system? What is the implication of this?
With the exception of the optic nerve (CN II) all of the cranial nerves are part of the peripheral nervous system. This means that the optic nerve is the only cranial nerve surrounded by the dura. Because of this, it is bathed by CSF, if you inject local anesthetic into the optic nerve during regional anesthesia you will have a big problem.
What is tic douloureux? What cranial nerve contributes to this problem?
Tic douloureux (trigeminal neuralgia CN V) causes excruciating neuropathic pain in the face
What is Bell’s palsy? What cranial nerve contributes to this problem?
Bell’s palsy results from injury to the facial nerve (CN VII). This causes ipsilateral facial paralysis.
Describe the path of Alzheimer’s disease
The development of diffuse beta amyloid rich plaques and neurofibrillary tangles in the brain. Consequences of plaque: dysfunctional synaptic transmission, this is most noticeable in nicotinic AcH neurons, and apoptosis.
What class of drug is used to treat Alzheimer’s? How do the interact with Succinylcholine?
Cholinesterase inhibitors are used to restore the concentration of Ach.
Cholinesterase inhibitors increase the duration of action of succinylcholine, clinical significance is debatable.
Describe the patho of Parkinson’s.
Dopaminergic neurons in the basal ganglia are destroyed.
Decreased dopamine and normal Ach means a relative Ach increase.
Suppression of corticospinal motor system and overactivity of extrapyramidal motor system
What drugs increase the risk of extrapyramidal s/sx in the patient with Parkinson’s?
Drugs that antagonize dopamine should be avoided
Describe the organization of the 3 neuron pathway common to the spinal tracts.
The first order neuron link the peripheral nerve to the spinal cord or brainstem.
The second order neuron links the spinal cord or brainstem to a subcortical structure.
The third order neuron links the subcortical structure to the cerebral cortex.
What is the structure and function of the dorsal column
Transmits mechanoreceptive sensations: fine touch, proprioception, vibration, and pressure.
Capable of 2 point touch discrimination- a high degree of localizing the stimulus.
Consists of large, myelinated, rapidly conducting fibers.
Transmits sensory information faster than the anterolateral system.
What bedside exam can assess the integrity of the corticospinal tract? How do you interpret it?
Babinski test.
Normal response: downward motion of all the toes
Upper motor neuron injury: upward extension of the big toe with fanning of the other toes.
Lower motor neuron injury: no response.
Discuss the patho of neurogenic shock.
Impairment of cadioaccelerator fibers (t1-T4) -> unopposed cardiac vagal tone -> bradycardia and reduced inotropy.
Decreased SNS tone -> vasodilation -> venous pooling -> decreased CO and BP.
Impairment of sympathetic pathways from hypothalamus to blood vessels -> inability to vasoconstriction or shiver -> hypothermia.
Hypothermia is the results of the inability of the cutaneous vasculature to vasoconstriction, causing a redistribution of blood flow to the periphery and allowing more heat to escape from the body.
How can you differentiate neurogenic shock from hypovolemic shock?
Neurogenic: bradycardia, HoTN, hypothermia with pink warm extremities from cutaneous vasodilation.
Hypovolemic: tachycardia, HoTN, cool clammy extremities.
Discuss the use of Sux with spinal cord injury.
Should be avoided 24 hours after injury and should not be used for at least 6 months thereafter (some books say 1 year)
