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DPT 736 Neuroanatomy > Brainstem > Flashcards

Flashcards in Brainstem Deck (20)
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1

Brainstem

-consists of medulla, pons, and midbrain
-posterior fossa of cranial cavity
-often referred to as the bulb
-contains ascending and descending tracts that pass thru it
-contains tracts that originate in nuclei of brainstem
-brainstem nuclei send and/or receive fibers from 10-12 cranial nerves (III-XII)
-also contains reticular formation

2

External Features

-look at pictures and be able to label

3

Junctions in Brain

-midbrain-diencephalon junction
-pontomesencephalic junction
-pontomedullary junction
-cervicomedullary junction at level of foramen magnum (pyramidal decussation happens here)

4

Midbrain

-dorsal surface: tectum is roof of midbrain made up of superior and inferior colliculi
-ventral surface: cerebral peduncles (in between-interpeduncular fossa)

5

Pons

-dorsal surface: 4th ventricle
-dorsolateral surface: superior, middle, and inferior cerebellar peduncles-connect pons to cerebellum (white tracts)

6

Medulla

-ventral surface: pyramids descend from the pontomedullary junction to pyramidal decussation
-rostral: inferior olivary nuclei-lateral to pyramids
-caudal medulla: posterior columns-fasciculus gracilis, fasciculus cuneatus; posterior column nuclei-nucleus cuneatus, nucleus gracilis

7

Floor of Fourth Ventricle

-extends from pons to rostral half of medulla
-ends at obex (entry to spinal cord's central canal-closed in adults)
-drains into subarachnoid space at foramina of luschka and foramen of magendie
-facial colliculi: abducens (VI) and middle fibers of facial nerve (VII)
-hypoglossal trigone: hypoglossal nucleus (XII)
-vagal trigone: dorsal nucleus of vagus (X)

8

Reticular Formation

-region in brainstem that is involved in multiple tasks such as regulating the sleep-wake cycle and filtering incoming stimuli to discriminate irrelevant background stimuli
-essential for governing some of basic functions of higher organisms and one of the phylogenetically oldest portions of the brain
-motor control
-pain modulation
-sleep and consciousness
-habituation

9

Cranial Nerves Exit Brainstem-Midbrain

-CN III: ventrally from interpeduncular fossa-passes between PCA and superior cerebellar artery
-CN IV: dorsally

10

Cranial Nerves Exit Brainstem-Pons

-CN V: ventrolateral

11

Cranial Nerves Exit Brainstem-Pontomedullar Junction and Rostral Medulla

-CN VI: ventrally at pontomedullary junction
-CN VII, VIII, IX, and X: ventrolaterally (medial to lateral) at pontomedullary junction and rostral medulla

12

Cranial Nerves Exit Brainstem-Cerebellopontine Angle

-region where CN VII, VIII, and IX exit brainstem

13

Cranial Nerves Exit Brainstem-CN XI

-laterally from upper cervical spinal cord

14

Cranial Nerves Exit Brainstem-Medulla

-CN XII ventrally between pyramids and inferior olivary nuclei

15

Sensory and Motor Organization of Cranial Nerves

-have sensor and motor functions
-motor cranial nuclei are more ventral
-sensory cranial nuclei are more dorsal
-three motor columns and three sensory columns of cranial nerve nuclei run through the length of brainstem
-p 500-502

16

Somatic Motor Nuclei

-CN III, IV, XII nuclei remain adjacent to midline and send fibers out near midline
-innervates extraoccular and intrinsic tongue muscles

17

Visceral Motor Nuclei

-two columns
-brachial motor nuclei: functions=muscles of mastication, facial expression, middle ear, pharynx, larynx, SCM, upper trap; trigeminal motor nucleus (CN V), facial nucleus (CN VII), nucleus ambiguous (CN IX, X), spinal accessory nucleus (CN XI)
-parasympathetic nuclei: parasympathetic innervation of head, and thoracoabdominal viscera above splenic flexure; Edgar-Westphal nucleus (CN III), superior (VII), and inferior (IX) salivatory nuclei, dorsal motor nucleus of vagus (CN X)

18

Visceral Sensory Nucleus

-nucleus solitarius (2 parts)
-sleep regulation as well as the following
-rostral nucleus solitarius (gustatory nucleus), taste input from CN VII and IX and X
-caudal cardio-respiratory nucleus: inputs for regulation of cardiac, respiratory, and GI function from CN IX, and X

19

General Somatosensory Nuclei

-aka trigeminal nuclei
-mediates touch, pain, temperature, position, and vibration for the face, sinuses and meninges
-CN V, VII, IX, and X

20

Special Somatic Sensory

-olfaction, vision, hearing, vestibular and taste
-cochlear nuclei and vestibular nuclei from CN VIII