- MESENCEPHALON; MIDBRAIN
- upper and shortest part of brainstem
- EXTERNAL FEATURES OR SURFACES
- VENTRAL SURFACE ( अग्र स्तर )
- emerges from cerebral hemispheres joins to form
- crus cerebri of midbrain (
- converges downwards to enter
- pons
- forms posterolateral boundary of
- interpeduncular fossa ( अंतरा डंगाल खात )
- superficial surface ( उपरिस्थ स्तर )
- corrugated by underlying longitudinal fibers
- crosses transversely from above downwards by ( उसके ऊपर से जाते हैं )
- optic tract ( नेत्र पथ )
- taenia pontis
- superior cerebellar artery , posterior cerebral artery
- medial side ( बाजु के दीवार से )
- groove ( खात )
- occulomotor nerve emerges ( नेत्रप्रेरक तंत्रिका निकलती हैं )
- dorsal aspect ( पृष्ठ स्तर से )
- trochlear nerve emerges ( चौथी नेत्रप्रेरक तंत्रिका )
- curls around lateral aspect of cerebral peduncles
- DORSAL SURFACE ( पृष्ठ स्तर )
- shows four rounded elevations called corpora quadrigemina ( उभाड़ )
- separated from each other by
- cruciform sulcus
- vertical limb of sulcus when ( ऊपरी की ओर परिखा में )
- traced above forms a depression ( एक खात )
- lodges pineal body
- traced below becomes continuous with ( नीचे की ओर )
- frenulum veli
- median ridge on dorsal surface of superior medullary velum ( छावनी )
- laterally from colliculi ( पार्श्व ये चतुष्ठकाय से )
- two superior
- superior colliculus
- two inferior
- inferior colliculus
- INTERNAL STRUCTURE ( अंतः संरचना )
- Mid brain divided by coronal plane passing through cerebral aqueduct in to two parts
- anterior part or cerebral peduncle
- parts from dorsal to ventral ( पीछे से आगे )
- tegmentum ( कंचुक )
- substantia nigra ( मलीन पदार्थ )
- curved , crescent shaped
- pigmented band of grey matter
- deeply pigmented nerve cells
- contain melanin ( polymerized form of dopamine )
- synthesize dopamine
- carried through their axons ( nigrostriatal fibers)
- to corpus striatum
- iron
- spiky process project in to crus cerebri
- parts
- dorsal part (pars compacta ) - medium sized cells
- pars reticularis ( ventral part ) - few cells
- intermingled with fibres of crus cerebri
- crus cerebri ( प्रमस्तिष्क टाँग )
- most anterior part
- white matter
- descending tracts ( अवरोही पथ )
- connect cerebral cortex to
- anterior horn cells of spinal cord
- cranial nuclei
- pontine nuclei
- middle 2/3 of crus ( मध्य टाँग )
- corticospinal ( प्रमस्तिष्क - मेरु )
- corticonuclear
- medial 1/6 th of crus मध्य 1/6 टाँग )
- frontopontine (- ललाट )
- lateral 1/6 th of crus ( पार्श्व 1/6 टाँग )
- temporopontine , parietopontine , occipitopontine
- posterior part or tectum
- LEVELS OF SECTION ( कर्तन स्तर )
- transverse section of midbrain at level of superior colliculus
- grey matter
- more centrally
- occulomotor nucleus
- edinger westphal nucleus
- emerging fibres pass through
- medial side of crus cerebri in posterior of interpeduncular fossa
- mesencephalic nucleus of trigeminal nerve
- more peripheral
- nucleus of superior colliculus
- connections
- prectectal nucleus
-
- cigar shaped
- contains iron
- white matter
- ventral tegmental decussation
- arising from red nuclei
- rubrospinal tracts
- dorsal tegmental decussation
- arising from superior colliculus
- tectospinal and tectobulbar tracts
- Transverse section of midbrain at level of inferior colliculus ( निम्न काय )
- grey matter
- white matter ( श्वेत पदार्थ )
- central part of tegmentum
- decussation of superior cerebellar peduncle
- ventral lateral part of tegmentum
- medial to lateral
- medial lemniscus ( मध्य )
- trigeminal lemniscus ( त्रिधारा )
- spinal lemniscus
- lateral lemniscus
- median longitudinal fasciculus
- tectospinal tracts
- rubrospinal tracts
- hi/midbrain.txt
- 2023/06/23 13:14
- brahmantra
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