PNB 2XB3 - Vestibular and Motor System Questions And Answers Already Graded A+

What are the semicircular canals filled with? - ️️endolymph what is the advantage of having high spontaneous firing rate even in the absence of tilt in the hair cells of the vestibular system? - ️️tilting in the direction opposite to the direction which causes maximal firing rate causes hyperpolarizing the cell in which direction in regards to the striola do the longest stereocilia of the hair cells point to? - ️️in utricle: all cells point towards the striola in saccule: all cells point away from the striola What is the vestibular labyrinth composed of? what are the functions of each? - ️️- utricle and saccule: detect head tilt and linear acceleration - semicircular canals: detect head rotation What are the two otholith organs? - ️️saccule and utricle macula - ️️receptor epithelium, a tissue on top of the utricle and saccule. Macula is an area of the nervous system where there are receptors striola - ️️the midline (a little groove) on the saccule and utricle What causes the transduction in - ️️ the 8th cranial nerve is composed of .... and .... - ️️auditory nerve and vestibular nerve What are the three ways in which the head can rotate in? - ️️Yaw: z axis (saying no) Pitch: y axis (saying yes) Roll: x axis during a rotation, the inertia of the ... causes deflection of the capula - ️️endolymph explain the adaptation that occurs during a rotation - ️️the endolymph catches up with the speed of rotation, and so the capula is no longer deflectedexplain the off response when the rotation stops - ️️the rotation stops, but the endolymph keeps moving due to its inertia, deflecting the capula in the opposite direction, causing the hair cells to hyperpolarize it is where the cell bodies of the axons in the vestibular nerve in a ganglion are - ️️spiral ganglion oculomotor nerve (type of nerve and function) - ️️motor nerve - eye movement, pupillary constriction and accommodation, muscle of upper eyelid abducens nerve (type of nerve and function) - ️️motor nerve - eye movements (abduction or lateral movements) vestibulocochlear (auditory ) nerve (type of nerve and function) - ️️sensory - hearing, sense of balance bilateral loss of VOR on both sides; causes apparent motion of objects and blurring of vision can result when hair cells are destroyed by ototoxic medications such as streptomycin - ️️Oscillopsia dislodged otoconia from utricle enter posterior semicircular canal; causes dizziness in certain head positions. The otoconia has a mass and so exerts a force on the cupula when the head moves - ️️Benign paroxysmal positional vertigo (BPPV) how can BPPV be fixed? - ️️by epley maneuver alcohol enters cupula, creating the illusion of spinning - ️️Positional alcohol nystagmus lesions to premotor area can cause... - ️️apraxia aparaxia - ️️loss of the ability to plan and execute complex voluntary motor tasks what Brodmann's areas of the cortex do primary motor cortex and premotor cortex compromise? - ️️primary motor cortex: area 4 premotor cortex: area 6 and others what are two tracts that make up the primary motor cortex? - ️️corticobullar tract (send axons from the cortex to the spinal cord) and corticospinal tract (send axons to from the cortex to the brain stem) 90% of the corticospinal tract axons - ️️lateral CST (LCST/VCST) decussates in the ... - ️️LCST decussates in the caudal medullawhich CST terminates bilaterally? - ️️VCST do the nerves in the arm or the spinal cord regrow? - ️️the ones in the spinal cord don't, while the ones in the arm do