Presentation on theme: "At the center of everything… but separated by layers of membranes."— Presentation transcript:
At the center of everything… but separated by layers of membranes
It’s all about connections… Brain spinal cord via foramen magnum Spinal cord runs through vertebral canal, formed by vertebral foramina
Meninges mater (umm… matter) Dura mater – “durable” tough, dense; protection from impact, friction Arachnoid mater – cushion from impact Subarachnoid space – CSF runs here Pia mater – in the “pits” direct contact Carries blood vessels Forms nerve sheaths Helps form CSF
More on the pia mater Associated with choroid plexus Secretes CSF Combination of blood vessels & neuroglia ○ Remember which kind? Ependymal cells
It’s not all black and white… but it is gray! Gray matter = unmyelinated neuron cell bodies Accumulate lipofuscin Found primarily in cortex (surface of brain) ○ Highly folded/ridged = gyri Increase surface area Small pockets of gray found in interior White matter = myelinated axons, neuroglia Found in brain’s interior In spinal cord, colors are reversed… outside white, inside gray
Concept check! 1. Describe the three layers of the meninges 2. What is the function of the choroid plexus? 3. Describe the locations of gray and white matter in the CNS Why are they those colors?
Three-Pound Marvel: The Brain Billions of neurons, neuroglia Most multipolar (1 axon, many dendrites) Receive many signals, process them Tracts of axons Information conduit other regions of brain, body
Largest, most anterior portion Emotions Memory Motor movement Thought Contain basal nuclei, cerebral cortex
4 pockets of gray matter – relay motor information to spinal cord Permit coordinated, steady body movements
Convoluted gray matter covering brain Large surface area (18 sq ft.)
Cerebral cortex nourished by vessels in arachnoid layer “Barrier” exists between bloodstream and CSF… Which neuroglia create this? Astrocytes! Prevents harmful substances from entering brain (also medications)
Halves of cerebrum divided by longitudinal cerebral fissure Some division of labor… But you use both halves!
Corpus callosum connects left and right hemispheres Contributes to plasticity of brain
Spinal Cord Where does it start from? (picture) Paper towel roll Blanket Model of spine
White matter 15 pairs nerve tracts Ascending tracts ○ Dorsal ○ Sensory to the brain Descending tracts ○ Lateral & ventral ○ Motor info to effectors Extrapyramidal tracts ○ Info from medulla oblongata posture & muscle tone
Gray matter Made of nerve cell bodies reflexes Transfer info to white matter Dorsal horn sensory Ventral horn Motor White matter muscles Intermediate gray matter b/t “wings” Sensory/motor for glands/muscles
Spinal nerves 31 pairs spinal nerves Part of PNS Reflex arcs for respective body regions
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