Vestibular and Cerebellum Flashcards
What is the crista ampullaris?
A structure located in the ampulla at the end of the membranous semicircular duct, lined with columnar epithelial cells and involved in the vestibular system.
Contains hair cells and supporting cells that are essential for detecting rotational movements.
What are the two cell types in the neuroepithelium of the vestibular system?
- Hair cells
- Supporting cells
How do vestibular neurons respond to the deflection of the cupula?
They can either be excited or inhibited by the deflection of the cupula.
What is the role of the macula in the vestibular system?
It is responsible for the sensation of static position of the head and linear acceleration or deceleration.
Where do the axons of the CN VIII vestibular division terminate?
- Most in vestibular nuclei
- Some directly to cerebellum via caudal cerebellar peduncle to fastigial nucleus
How many vestibular nuclei are there?
Four: rostral, medial, lateral, and caudal.
What is the function of the lateral vestibulospinal tract?
Facilitatory to ipsilateral motor neurons to extensor muscles and inhibitory to ipsilateral flexor muscles and contralateral extensor muscles.
Which tract arises from the rostral, medial, and caudal nuclei?
Medial vestibulospinal tract.
What is the function of the medial longitudinal fasciculus (MLF) in the brainstem?
Coordinates eye movements by projecting to motor nuclei of cranial nerves VI, IV, and III.
What is the primary neurotransmitter at synapses between granule cells and Purkinje cells?
Glutamate.
What are climbing fibers and their source?
Axons from olivary neurons that enter the cerebellum through the caudal cerebellar peduncle.
What is the role of Purkinje cells in the cerebellum?
They are the only axons that project from the cerebellar cortex and primarily inhibit cerebellar nuclei.
What neurotransmitter is released by Purkinje cells?
GABA.
Which tracts enter the cerebellum through the caudal cerebellar peduncle?
- Spinocerebellar tracts
- Vestibulocerebellar axons
- Climbing fibers from olivary nucleus
What is the primary function of the cerebellum?
Control of motor activity.
What are the three phylogenetic regions of the cerebellum?
- Archicerebellum
- Paleocerebellum
- Neocerebellum
What is the function of the intermediate zone of the cerebellum?
Concerned with adjusting motor tone and posture to regulate skilled movements.
Fill in the blank: The _______ is responsible for regulating skilled movements of the limbs.
Lateral zone.
True or False: The cerebellum contains more neurons than all the remaining brain combined.
True.
What is the role of the fastigial nucleus?
Projects to vestibular nuclei and reticular formation.
What type of fibers are most abundant in the cerebellum?
Mossy fibers.
What neurotransmitter is released at synapses from climbing fibers?
Aspartate.
What is the role of the caudal cerebellar peduncle?
Connects spinal cord and medulla with the cerebellum.
What is the neurotransmitter released by mossy fibers?
Acetylcholine
