Neurophysiology Flashcards
Pain of visceral origin that follows the dermatome rule?
Referred pain
Increased in what motor neuron activity increases the sensitivity of the muscle spindle?
Gamma - motor neuron activity
An exaggerated form of the Golgi tendon reflex?
Clasp-knife Reflex
Autonomic receptor blocked by hexamethonium at the ganglia but not at the neuromuscular junction?
Cholinergic nicotinic receptors
Blocks Nicotinic receptors only in the ganglia and not in the NMJ?
Hexamethonium
True or False.
Nicotinic receptors are present in both ganglia and NMJ?
True
66/M with chronic hypertension treated with prazosin. Mechanism of action of the drug?
Inhibition of a-1 receptors on vascular smooth muscle leading to vasodilation of cutaneous and splanchnic vascular beds , decreased TPR and decreased BP.
Parasympathetic muscarinic receptor effect on the eyes?
Miosis - contraction of the circular muscle of the iris
Unique feature of C fibers compared to other types?
Have the slowest conduction velocity of any nerve fiber type.
Compared with the cones of the retina , the rods are more sensitive to?
Low intensity light
The apex of the organ of Corti responds to which frequency?
The apex responds better to low frequencies than the base does.
Origin of sympathetic preganglionic neurons?
Originates in the Thoracolumbar Spinal cord
The apex of the organ corti responds to which frequency?
The apex responds better to low frequencies than the base does
Autonomic receptors that mediates increased in heart rate?
Adrenergic B-1 Receptors
Total blindness of the left eye. Structure damaged?
Left optic nerve
Reflex responsible for monosynaptic excitation of ipsilateral homonymous muscle
Stretch reflex ( myotactic)
Cells in the visual cortex that responds best to moving bar of light?
Complex Cells
-respond to moving bars or edges with correct orientation.
Cell in the visual cortex respond to stationary bars?
Simple cells
Cell in the visual cortex respond to lines, curves, and angles?
Hypercomplex cells
Drug/ Drug class contraindicated in a child with history of asthma?
Propranolon ( Beta 2- antagonist)
Will cause further bronchoconstriction from an already increased resistance in asthma.
Stimulatory adrenergic receptor that forms IP3 and an increase in intracellular Ca?
Alpha 1 receptor
The excessive muscle tone produced in decerebrate rigidity can be reversed by ?
Cutting the dorsal roots blocks the reflexes since decerebrate rigidity is caused by increased reflex muscle spindle activity.
Body part with the largest representation on the primary motor cortex?
Fingers
Autonomic receptor that mediates secretion of epinephrine by the adrenal medulla?
Cholinergic nicotinic receptors
Blindness in the temporal field of the left eye and nasal field on the right eye. What structure is damaged?
Right optic tract ( homonymous contralateral hemianopia )
A dancer spins to the left and eyes snap quickly to the left. This fast eye movement is called?
Nystagmus
Occurs in same direction as the rotation.
A dancer spins to the left and eyes snap quickly to the right. This fast eye movement is called?
Postrotatory Nystagmus
Autonomic drug that stimulates adenylate cyclase?
Choices:
atropine , clonidine, curare, norepinephrine, phentolamine, or propranolol.
Norepinephrine
among the autonomic drugs only B1 and B2 act by stimulating adenylate cyclase.
Atropine - Muscarinic cholinergic antagonist
Clonidine- alpha 2 agonist
Curare- Nicotinic cholinergic antagonist
Phentolamine - alpha 1 antagonist
Propranolol- B1 & B2 antagonist
Activates transducing in photoreception?
Metarhodopsin II
Activates transducing
Effects of pathogens in producing fever?
Increase Interleukin 1
- Increase prostaglandins
- Increase in set point temperature
- Shivering
- Vasoconstriction of blood vessels
True or False.
Olfactory receptor cells are considered neurons.
True, and the only neurons that regenerate.
Effect of chorda tympani lesion.
Impaired taste function
Produces maximum excitation of the hair cells in the right horizontal semicircular canal?
Rotating the head to the right
In Disdiadokinesia , what organ or structure is affected?
Cerebellum
Autonomic receptor activated by low concentrations of epinephrine causing vasodilation .
Adrenergic Bata-2 receptors
Complete transection of the spinal cord at the level of T1 would most likely result in ?
Temporary loss of stretch reflex below the lesion.
Transection of spinal cord causes spinal shock and loss of all reflexes below the level of the lesion.
Definition of sensory receptor potentials?
Are graded in size depending on stimulus intensity.
May bring the membrane potential of the receptor cell either toward (depolarization) or away (hyperpolarization)
Tru or False.
Receptor potentials are not action potentials.
True
Blindness in the temporal fields of the left and right eyes. What structure is damaged?
Optic chiasm ( bitemporal hemianopia)
Primary function is to coordinate rate, range, force, and direction of movement?
Cerebellum
Reflex responsible for polysynaptic excitation of contralateral extensors?
Flexor withdrawal reflex
Function of nuclear bag fibers?
They detect dynamic changes in muscle length.
Function of Nuclear chain?
Detect static changes.
Muscle stretch leads to a direct increase in firing rate of this type of nerve?
Group Ia fibers
42 / F with Pheochromocytoma treated with phenoxybenzamine. What is the moa of the drug?
Decrease IP3 / Ca 2+ , phenoxybenzamine is an a-1 antagonist , thus decreasing IP3 / Ca2+
Effect of atropine on AV node conduction velocity.
Increased AV node conduction velocity.
Muscarinic receptors decreases AV Node conduction, thus muscarinic antagonists agents such as atropine , will increase AV node conduction velocity.
What waves in the EEG in a person with closed eyes but awake?
Alpha waves
Nerve affected in claw hand?
Ulnar Nerve
Nerve affected in wrist drop?
Radial Nerve
Nerve affected in ape hand/ Hand of benediction?
Median Nerve
Parkinsons:
Mechanism ?
Location in the brain ?
NT affected ?
Mechanism: degeneration of dopaminergic neurons
Location: Substantia nigra pars compacta
NT affected: Dopamine
Heteronymous bitemporal hemianposia?
Optic chiasm
Innervated by alpha- motoneurons, for voluntary muscle contraction?
Choices: Intrafusal or Extrafusal
Extrafusal