L13 Vestibular System Flashcards
Basic Structure of the Vestibular System
_______________ LABYRINTH is defined by the space in the bones (Filled with _____________)
________________ LABYRINTH (within the Osseus Labyrinth) is filled w/ _______________
OSSEUS LABYRINTH is defined by the space in the bones (Filled with PERILYMPH)
MEMBRANOUS LABYRINTH (within the Osseus Labyrinth) is filled w/ ENDOLYMPH (high potassium) => more excitable (Higher resting membrane potential))
_____________________ is a cone-shaped structure, covered in receptor cells called “hair cells”. Covering this structure is a gelatinous mass called the _____________.
Crista Ampullaris is a cone-shaped structure, covered in receptor cells called “hair cells”. Covering this structure is a gelatinous mass called the Cupula.
3 ___________ associated w/ SEMICIRCULAR CANALS
2 ________ associated w/ OTOLITHIC ORGANS
3 Cristae associated with SEMICIRCULAR CANALS
2 Maculae in the UTRICLE and SACCULE
Vestibular Pathways? (3)
Primary Sensory Pathway: Projection to Cortex via Thalamus => conscious perception of vestibular sense
Vestibulospinal Reflexes: Changes in the activity of body muscles induced by movements of the head in space aimed at stabilizing posture
Vestibulo-Occular Reflexes: ensures that images remain fixated on the retina even though the head is moving
Anterior Semicircular Canal controls the ________________and_______________ Muscles
Anterior Semicircular Canal controls the Superior Rectus and Inferior Oblique Muscles
Horizontal Semicircular Canal controls the ______________ and _______________ Muscles
Horizontal Semicircular Canal controls the Medial Rectus and Lateral Rectus Muscles
Posterior Semicircular Canal controls the_______________ and _______________ Muscles
Posterior Semicircular Canal controls the Inferior Rectus and Superior Oblique
Describe the Vestibulo-Occular Reflex
How to test the Vestibulo-Occular Reflex?
Vestibulocerebellar Reflexes bypass __________________=> direct projection to the Cerebellum.
Output from Cerebellum returns to ______________________ => modifies _________________ and ____________________
Vestibulocerebellar Reflexes bypass Vestibular Nucleus=> direct projection to the Cerebellum
Output from cerebellum returns to Vestibular Nuclei => modifies EYE MOVEMENT and VESTIBULOSPINAL Reflexes
Superior Vestibular Nuclei: Receive inputs from ______________________ => _______________________________
Superior/Medial Vestibular Nuclei: Receive inputs from Semicircular Canals => Medial Longitudinal Fasciculus
Medial Vestibular Nuclei: Receive inputs from ______________________ => _______________________________
Superior/Medial Vestibular Nuclei: Receive inputs from Semicircular Canals => Medial Longitudinal Fasciculus
Lateral Vestibular Nuclei: Receive Receives input from ______________________ => ______________________
Lateral Vestibular Nucleus: Receives input from Otoliths (Saccule/Utricle) => Projects mainly to Lateral Vestibulospinal Tract
Inferior (Descending) Vestibular Nucleus: Receives input from __________=> _______________________________________________
Inferior (Descending) Vestibular Nucleus: Receives input from Otoliths (Saccule/Utricle) =>
- Cerebellum
- Reticular Formation
- Spinal Cord
- CONTRLATERAL Vestibular Nuclei
Input/Pathway/Role of Lateral Vestibular Nuclei?
Input/Role/Pathway of Medial/Superior Vestibular Nuclei?
Which vestibular nucleus plays an important role in the maintenance of posture?
Lateral Vestibular Nucleus=> Neurons travel through **Lateral Vestibulospinal Tract down to the Horn of the VENTRRAL Spinal Cord => Synapses ANITI-GRAVITY Motor Neurons => Helps body stay upright
Projections from the Lateral Vestibular Nucleus?
Second Order Neurons travel through Lateral Vestibulospinal Tract down to the Horn of the VENTRRAL Spinal Cord => Synapses ANITI-GRAVITY Motor Neurons => Helps body stay upright
Input of Lateral Vestibular Nuceli?
Receives input from Utricle and Semicircular Canals
Input of Medial/Superior Vestibular Nuceli?
Receives input primarily from Semicircular Canals
Where does the Medial Longitudinal Fasciculus (MLF) Begin and what role does it serve?
- MLF begins in the MEDIAL VESTIBULAR NUCLEUS and connects it to the cranial nerve nuclei that control eye movement (CN VI, IV, III)
- MLF continues inferiorly as the vestibulospinal tract connecting to motor nuceli. At each level it connects the motor nuclei of one side with the one on the opposite that controls synergistic muscles
Which nuclei are responsible for mediating reflex movements of the neck that stabilize the positon of the head in space?
Medial and Superior Vestibular Nuclei =>
- Medial Longitudinal Fasciculus (MLF)
- Medial Vestibulospinal Tract
Which Nuceli are involved in controlling the Vestibulo-Occular Reflexes?
Semicircular Cannals => Medial and Superior Vestibular Nuclei via the Medial Longitudinal Fasciculus (MLF) =>
- Abducens Ncuelsu (CN VI)
- Trochlear Nucleus (CN IV)
- Occulomotor Nuclei (CN III)
In the ____________________ Canals movement of the cupula TOWARDS the Ampula => Excitation
In the HORIZONTAL Canals movement of the cupula TOWARDS the Ampula => Excitation
In the ______________________Cannals Movement AWAY From the Ampulla is excitatory
In the ANTERIOR/POSTERIOR Cannals Movement AWAY From the Ampulla is excitatory
Hair cells are oriented _______________ from the Striola in the Saccule
Hair cells are oriented AWAY from the Striola in the Saccule
Hair cells are oriented ______________ the Striola in the Utricle
Hair cells are oriented TOWARDS the Striola in the Utricle
The ____________ is sensitive to Horizontal Acceleration
The UTRICLE is sensitive to Horizontal Acceleration
The ____________ is sensitive to Verticle Acceleration
The SACCULE is sensitive to Verticle Acceleration
_________________ is the sensory area within the utricle and saccule containing the hair cells
MACULA is the sensory area within the utricle and saccule containing the hair cells
Tips of the Cillia in otolith organs project into the _________________, covered in crystal of calcium carbonate (________________) which add weight and inertia
Tips of the Cillia in otolith organs project into the Otolythic Membrane, covered in crystal of calcium carbonate (Otoconia) which add weight and inertia
Each semicircular duct has a swelling called the _____________ near its junction with the ___________
Each semicircular duct has a swelling called the Ampula near its junction with the Utricle
The Ampulla has a structure called the _____________ which consists of hair cells embedded in a gelatinous mass called the ______________
The Ampulla has a structure called the Crista which consists of hair cells embedded in a gelatinous mass called the Cupula
The _____________ moves in response to the intertial flow of endolymph in the Semicircular Canals. Endolymph flows _________________ rotation of the canal
The Cupula moves in response to the inertial flow of endolymph in the Semicircular Canals. Endolymph flows OPPOSITE rotation of the canal
