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48 Cards in this Set
- Front
- Back
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Rostral |
Toward the forehead |
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Caudal |
Toward the spinal cord |
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Major parts of the brain |
Cerebrum, cerebellum, and the brain stem |
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83% of brain volume |
Cerebrum |
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Contains 50% of the neurons |
Cerebellum |
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Longitudinal Fissure |
Separates the two cerebral hemispheres |
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Gyri |
The folds |
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Sulci |
The grooves on the surface |
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Cortex |
Surface layer of gray matter |
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Nuclei |
Deeper masses of gray matter |
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Tracts
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bundle of axons (white matter)
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Orientation of white and gray matter (in the brain)
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Opposite that of the spinal cord
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Nervous system
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develops from ectoderm (embryonic germ tissue)
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3rd Week
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Neural plate become neural groove with neural folds along each side
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4th Week
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Neural folds join to form neural tube
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Lumen of the neural tube
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Develops into the central canal of spinal cord and ventricles of the brain
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Neural Crest
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Def. : Cells along the margin of the neural groove Func. : Develop into sensory and sympathetic neurons and Schwann cells |
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4th Week
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Neural tube exhibits three anterior dilations Three primary vesicles can be distinguished |
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3 Primary Vesicles |
-Forebrain (Prosencephalon) -Midbrain (Mesencephalon) -Hindbrain (Rhombencephalon) |
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-Forebrain
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Prosencephalon
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-Midbrain
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Mesencephalon
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-Hindbrain
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Rhombencephalon
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5th Week
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Subdivision into five secondary vesicles
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5 Secondary vesicles
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Telencephalon Diencephalon Mesencephalon Metencephalon Myencephalon |
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Forebrain divides into
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Telecephalon = becomes the cerebrum Diencephalon = gives rise to the optic vesicles that become the retinas of the eyes |
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Midbrain (remains unchanged)
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Mesencephalon
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Hindbrain divides into the
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Metencephalon = becomes the cerebellum and the pons Myencephalon = becomes the medulla oblongata |
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Meninges of the brain
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Dura Mater Arachnoid Mater Pia Mater |
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Dura Mater
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outermost, tough membrane composed of two layers (Periosteal layer and Meningeal layer) |
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Outer periosteal layer
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contacts the cranial bones
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Formed by dura mater
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Supportive structures Falx cerebri, falx cerebelli, and tentorium cerebelli |
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Arachnoid Mater
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Spider web filamentous layer
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Pia Mater
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A thin vascular layer adherent to the contours of brain
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Ventricles and CNS
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- Lateral ventricles - Third ventricle - Cerebral aqueduct - Fourth ventricle -Central Canal |
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Lateral Ventricles
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found inside cerebral hemispheres
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Third Ventricle
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single vertical space under corpus collosum
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Cerebral Aqueduct
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runs through the midbrain
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Fourth Ventricle
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a small chamber between pons and cerbellum
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Central Canal
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runs down through the spinal cord
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Ventricles
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lined with ependymal cells and contain a choroid plexus of capillaries that produce cerebrospinal fluid
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Cerebrospinal fluid
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a clear liquid fills ventricles and canals and bathes the brain's external surface (in the subarachnoid space)
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The brain produces and absorbs
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about 500 ml/day -Filtration of blood through choroid plexus and modified by ependymal cells -Has more Na+ and Cl- but less K+, Ca+2 and glucose than blood plasma |
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Functions
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- Buoyancy -Protection -Chemical Stability |
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Buoyancy
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floats brain so it's neutrally buoyant
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Protection
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cushions from hitting inside the skull
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Chemical Stability
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rinses away wastes; maintains homeostasis
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Cerebrospinal fluid escapes
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from 4th ventricle at the medial aperture and two lateral apertures to surround the brain in the subarachnoid space
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CSF is absorbed
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by the arachnoid villi then into sinous
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