Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
15 Cards in this Set
- Front
- Back
|
Vestibular system |
-balance, maintenance of the head in an upright position -adjustment of eye movements to compensate for head movements spatial orientation -coordinating movements |
|
|
2 components of vestibular system |
-vestibular sacs -semicircular canals |
|
|
Semicircular canals |
-respond to angular acceleration -changes in rotation of the head -receptors respond maximally to sudden turning movements in one specific plane(sagittal, coronal, and horizontal) |
|
|
Vestibular sacs |
-responds to the force of gravity -inform the brain about the head's orientation, linear acceleration |
|
|
Ampulla |
-enlargement that contains the sensory receptors -hair cells similar to those in cochlea -cupula -semicircular canals |
|
|
Cupula |
-cilia embedded with gelatinous mass -rotation of the head cause the fluid in the semicircular canals to move in the opposite direction which pushes against the cupula -triggers receptor potentials in the hair cells |
|
|
2 vestibular sacs in cochlea |
-utricle -saccule |
|
|
Anatomy of vestibular sacs |
-contain a patch of receptive tissue -hair cells -cilia is embedded with an overlaying gelatinous mass -contains otoconia |
|
|
Otoconia |
-crystals of calcium carbonate -weight of the crystals case the gelatinous mass to shift in position as the orientation of the head changes -movement produces a force on the cilia of the receptive hair cells |
|
|
Head straighy |
-crystals push down and stimulation is minimal |
|
|
Head titled |
-crystals move and stimulate hair cells |
|
|
Projection areas |
-the vestibular nuclei on either sides of the brain stem exchange signals regarding movement and body postion -the signals are sent down the following projection pathways in cerebellum:thalamus, spinal cord, reticular formation, cranial nerves(3,4,6) |
|
|
Thalamus |
-allow head and body motor control -conscious of body postion |
|
|
Spinal cord |
quick reflex reactions to libes and trunk to regain balance |
|
|
Reticular formation(brainstem) |
-new posture the body has taken on and how to adjust circulation and breathing due to body position |
