Lecture 22 Flashcards
(35 cards)
What is the term for the “Thickened plate of cells running above the notochord”?
Neural Plate: Thickened plate of cells running above the notochord
State the 3 components that form the tripartite brain AND include what those 3 components will contribute to the pentapartite brain. (list things cranial to caudal)
Prosencephalon: Telencephalon and Diencephalon
Mesencephalon: (stays)
Rhombencephalon: Metencephalon and Myencephalon
Which of the pentapartite structures is NOT divided into alar and basal plates, unlike the rest of the structures?
Prosencephalon
What do the Telencephalic vessels become? what about the Optic vesicles?
Telencephalic vessels: Become the cerebral hemispheres
Optic Vessels: become the retina of the eyes (diencephalon)
What is the major derivative of the Myelencephalon? what does this structure become continuous with?
the Medulla Oblongata and it becomes continuous with the spinal cord
Compare gray matter in the spinal cord with gray matter in the mesencephalon
Gray matter in the mesencephalon is organized into discrete nuclei with white matter interspersed among iti
Gray matter in the spinal cord is located centrally and is surrounded by myelinated tracts (white matter)
What sensory function are the vagal lobes associated with?
taste
How many CN’s leave via the brainstem? what are the 3 components of the brain stem?
10 of the 12
- Medulla
- Pons
- Midbrain
Compare the location of the raphe and raphe nuclei as they relate to one another in the upper medulla.
The raphe is a midline structure, and the raphe nuclei are a pair of nuclei that lie just lateral to the raphe
The raphe nuclei serve as the nucleus for which CN?
CN XII (Hypoglossal)
The Lateral _______ tracts undergo an 85% decussation in the ______ ______.
Corticospinal
Pyramidal Decussation
Where, in cranial/caudal terms, is the pyramidal decussation? what is the main role of the lateral corticospinal tracts?
Pyramidal Decussation: at the inferior border of the medulla
Corticospinal tracts: involved in initiating and modulating movement
For the inferior olivary nuclei receive input from where and have it’s axons project to where?
Receive input from most motor areas of the brain (and spinal cord)
Axons project to the contralateral hemisphere via the olivocerebellar tract
What is the reticular formation associated with?
consciousness and arousal
State the CN nuclei that are considered to be medullary nuclei. What other complex is considered to be medullary nuclei?
CN VIII, IX, X, XI, and XII
Vestibular nuclear complex
what are the following and where are they found?
Cardiac Center
Medullary rhythmicity center
Vasomotor center
Center for coordination head movement and swallowing
Vital reflex centers that are located in the medulla
Describe the inhibitory and excitatory roles of the cardiac center in the medulla
Inhibitory via CN X
Excitatory via T1-T5
What are some symptoms of Wallenbergs Syndrome, that are caused by damage/occlusion of the following?
Spinothalamic tract:
Spinal Trigeminal tract/nucleus:
Nucleus ambiguus:
Glossopharyngeal nerve:
Spinothalamic tract: loss of pain/temp sensation on the contralateral side
Spinal Trigeminal tract/nucleus: Loss of pain/temp sensation on the SAME side of the face and nasal oral cavities
Nucleus ambiguus: Difficulty swallowing and a hoarse, weak voice
Glossopharyngeal nerve: Loss of gag reflex on the SAME side and loss of sensation of the SAME side
Describe the path of transverse tracts of the pons. (include what peduncles they pass through)
They travel through the middle cerebellar peduncles and connect the pons to the cerebellum
State the 2 longitudinal tracts that synapse in the pons
Corticopontine: synapse on the pontine nuclei
Corticobulbar tracts: Synaps with the Trigeminal and Facial nerve neurons
Where in the brain are the sleep center and respiratory center found? what 2 centers compose the respiratory center?
In the pons
Respiratory center = Pneumotaxic and Apneustic
In terms of lesions of the lateral half of the pons, describe the symptoms the following will cause.
Trigeminal Nerve:
Medial Lemniscus:
Pontocerebellar fibers:
Trigeminal Nerve: Loss of general sensation of the face on the SAME side
Paralysis of muscles of mastication (with chin deviating to the SAME side as the lesion)
Medial Lemniscus: Loss of position/muscle/joint sense on the opposite side as the lesion
Pontocerebellar fibers: Hypotonia, Coarse intention tremor, and Tendency to fall to the SAME side as the lesion
Bilateral lesions to the ventral pons leave patients quadriplegic and conscious. Occlusion of what artery causes this? what 2 spinal tracts does this disrupt?
Occlusion of the Basilar artery (spares the reticular formation)
Interrupts the corticospinal and corticobulbar tracts
What symptoms occur when there is a bilateral lesion that involves the pons AND the reticular formation?
The pt will be in a COMA
