Neuroanatomy US Medical PG Flashcards - Medical Study Cards
Master Neuroanatomy with OnCourse flashcards. These spaced repetition flashcards are designed for medical students preparing for NEET PG, USMLE Step 1, USMLE Step 2, MBBS exams, and other medical licensing examinations.
Neuroanatomy Flashcard Deck - 10 Cards
Flashcard 91: What is the primary output and function of the Globus Pallidus Externus (GPe) in the basal ganglia indirect pathway?
Answer: Inhibits the Subthalamic Nucleus (STN) via GABAergic projections (part of the Indirect Pathway).
Extra: The GPe receives inhibitory input from the Striatum (Putamen/Caudate) and sends inhibitory output to the STN. It is a key component of the Indirect Pathway of the Basal Ganglia.
Flashcard 92: What are the main pathways of the basal ganglia?
Answer: direct, indirect
Flashcard 93: What structures comprise the lentiform nucleus (of the basal ganglia)?
Answer: putamen, globus pallidus
Flashcard 94: What structures comprise the striatum (of the basal ganglia)?
Answer: caudate, putamen
Flashcard 95: What is the defining anatomical feature of Arnold-Chiari malformation type I?
Answer: Congenital herniation of cerebellar tonsils through the foramen magnum (lower than 5 mm) into the spinal canal.
Extra: Associated with syringomyelia and often asymptomatic until adulthood. Presents with headaches (worsened by Valsalva) and cerebellar symptoms.
Note: Type II (classic Chiari) involves herniation of cerebellar vermis and tonsils plus medulla through foramen magnum with myelomeningocele.
Flashcard 96: What is the defining feature of spina bifida with meningocele?
Answer: Failure of bony spinal canal closure with herniation of meninges but NO neural tissue.
Extra: - Presentation: Newborn with a fluid-filled sac protruding from the lower spine.
- Pathophysiology: Herniation of meninges (dura and arachnoid) through a vertebral defect; the spinal cord remains in the canal.
- Association: Maternal folate deficiency during pregnancy.
- Management: Surgical repair.
Flashcard 97: What is the underlying defect in Spina Bifida Occulta?
Answer: Failure of bony spinal canal closure (no herniation) :: definition
Extra: Presentation: Newborn with tuft of hair or dimple in lower spine.
Etiology: Failure of caudal neuropore closure, associated with maternal folate deficiency.
Management: Surgery usually not necessary.
Dura is intact. Normal AFP.
Flashcard 98: Where is the suprachiasmatic nucleus (SCN) located?
Answer: Anterior hypothalamus
Extra: The suprachiasmatic nucleus (SCN) is located in the anterior hypothalamus, directly above the optic chiasm. It functions as the master pacemaker for circadian rhythms.
Flashcard 99: How many axons can be myelinated by a single Schwann cell?
Answer: one
Flashcard 100: How many axons can be myelinated by a single oligodendroglia?
Answer: multiple (up to 50)
mnemonic: "oligodendro" means "few branches" for a few axons
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