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Chapters 24.1-24.2: Basic Macroeconomic Models
NoteStudied by 32 peoplePhilosophy of Science (IB)
NoteStudied by 79 peopleGroup 18 elements
NoteStudied by 11 peopleFDR & The New Deal
NoteStudied by 17 peopleUnit 4: Learning
NoteStudied by 27 people1.4 Harmony, Texture, Tonality, and Mode
NoteStudied by 20 people
Peripheral Nervous System and Cranial Nerves
- Central Nervous System Layers
- Connective tissues surrounding the CNS serve several functions:
- Mechanical protection
- Nourishment to the nervous system via blood vessels
- Circulation of cerebrospinal fluid (CSF)
- The three layers from outer to inner:
- Dura Mater: Tough outer layer, attached to skull bones. In some areas, forms partitions (dural reflections).
- Arachnoid Mater: Middle layer, contains subarachnoid space filled with CSF.
- Pia Mater: Inner layer directly covering the brain and spinal cord.
- Subarachnoid Space
- True space located between arachnoid and pia mater.
- Contains CSF, essential for brain protection and nourishment.
- CSF is produced by the choroid plexus located in the major ventricles of the brain.
- Cerebrospinal Fluid (CSF) Production and Flow
- CSF originates from blood plasma processed by the choroid plexus.
- Production starts in lateral ventricles -> third ventricle -> fourth ventricle
- Exits the fourth ventricle through:
- Lateral apertures (pair)
- Median aperture (single)
- Flows into the subarachnoid space around CNS.
- Dural Reflections and Sinuses
- The dura mater creates partitions, including:
- Falx Cerebri: Separates the left and right cerebral hemispheres.
- Sinuses formed between the layers of the dura have irregular shapes:
- Superior Sagittal Sinus: Runs anterior to posterior in the sagittal plane.
- Inferior Sagittal Sinus: Slightly lower than the superior sinus.
- Brain Ventricles Overview
- Lateral Ventricles: First two ventricles, connected to the third through the interventricular foramen.
- Third Ventricle: Located between the two halves of the thalamus.
- Fourth Ventricle: Positioned below the cerebellum and contains CSF exit points.
- Arachnoid Granulations
- Extensions of the arachnoid that project into the superior sagittal sinus to drain CSF back into the blood.
- Act as unidirectional valves, allowing waste material from CSF to exit into venous circulation.
- Cranial Nerves Overview
- There are 12 pairs of cranial nerves, categorized by Roman numerals or by specific names.
- Cranial Nerve Naming:
- Often numbered using Roman numerals I to XII.
- Each name typically indicates function or area supplied (e.g., olfactory, optic).
- Specific Cranial Nerves Highlights
- Cranial Nerve I: Olfactory
- Pure sensory nerve for smell.
- Passes through the cribriform plate.
- Cranial Nerve II: Optic
- Pure sensory for vision.
- Passes through optic canal, crosses at optic chiasm.
- Cranial Nerve III: Oculomotor
- Motor nerve controlling most eye movements and pupil constriction.
- Passes through superior orbital fissure.
- Cranial Nerve IV: Trochlear
- Pure motor for one extraocular muscle.
- Also passes through superior orbital fissure.
- Cranial Nerve V: Trigeminal
- Major sensory nerve with three branches:
- V1 (Ophthalmic): Sensory to forehead and upper face.
- V2 (Maxillary): Sensory to mid-face and nasal cavity.
- V3 (Mandibular): Mixed nerve with sensory (lower face, anterior tongue) and motor fibers (muscles of mastication).
- Branches exit through various openings (superior orbital fissure, foramen rotundum, foramen ovale).
- Cranial Nerve VII: Facial
- Mixed nerve for muscles of facial expression, taste (anterior 2/3 of tongue), and parasympathetic control of salivary and lacrimal glands.
- Exits through internal auditory meatus.
- Cranial Nerve VIII: Vestibulocochlear
- Pure sensory for hearing and balance from the inner ear.
- Cranial Nerve IX: Glossopharyngeal
- Mixed nerve for taste (posterior 1/3 of tongue), sensory from the pharynx, and parasympathetic to the parotid gland.
- Cranial Nerve X: Vagus
- Mixed nerve extending beyond the head to thoracic and abdominal organs, controlling parasympathetic functions.
- General Notes
- CSF production is about 500 mL per day, but capacity of the system is roughly 50 mL, leading to continuous cycling of CSF every 8 hours.
- Diseases such as meningitis can compromise CSF circulation and lead to serious complications.
- Understanding cranial nerve pathways, functions, and targets is critical for diagnosing neural conditions.
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Explore Top NotesNoteStudied by 32 peopleNoteStudied by 79 peopleNoteStudied by 11 peopleNoteStudied by 17 peopleNoteStudied by 27 peopleNoteStudied by 20 people
Chapters 24.1-24.2: Basic Macroeconomic Models
NoteStudied by 32 peoplePhilosophy of Science (IB)
NoteStudied by 79 peopleGroup 18 elements
NoteStudied by 11 peopleFDR & The New Deal
NoteStudied by 17 peopleUnit 4: Learning
NoteStudied by 27 people1.4 Harmony, Texture, Tonality, and Mode
NoteStudied by 20 people