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Download Nervous System: Brain
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Chapter 7: Central Nervous System: The Brain Brain Anatomy Four major regions − cerebral hemispheres − diencephalon − brain stem − cerebellum Brain Anatomy cerebrum is divided into the cerebral hemispheres surface of brain is covered in gray matter called the cerebral cortex surface has ridges and grooves − ridges = gyri − grooves = sulci − deeper grooves = fissures Brain Anatomy lobes named for cranial bones Brain Anatomy Functional areas of the brain have been identified: Prefrontal Cortex Most complicated region, coordinates info from all association areas Important in intellect, planning, reasoning, mood, abstract ideas, judgement, predicting events Phineas Gage Somatic sensory area impulses from sensory receptors in the body are interpreted here pathways are crossed − left side of cortex receives impulses from the right side of the body and vice versa Primary motor area allows us to consciously move muscles axons form major voluntary motor tract − corticospinal or pyramidal tract pathways are crossed L to R Brain Anatomy cell bodies of all these neurons form the gray matter cerebral white matter is fiber tracts − what cells put the white in white matter? corpus callosum connects cerebral hemispheres Brain Ventricles spaces through which CSF circulates Brain Anatomy Diencephalon − − − 1. thalamus 2. hypothalamus 3. epithalamus Brain stem − − − − 4. midbrain 5. pons 6. medulla oblongata 7. reticular formation 8. Cerebellum location & function Protection of CNS bone - skull membranes - meninges watery cushion - cerebrospinal fluid (CSF) Meninges 3 connective tissue membranes − − dura mater - “tough mother” arachnoid mater - “spider” − subarachnoid space – filled with CSF pia mater - “gentle mother” Meninges Meningitis inflammation of the meninges threat to CNS Cerebrospinal Fluid watery “broth” similar to blood plasma continually formed by choroid plexus − capillary clusters in roof of ventricles cushions nervous tissue CSF circulates from lateral vent. to the 3rd vent. through cerebral aqueduct, into 4th vent. central canal of spinal cord most to subarachnoid space through 4th vent. returns to blood via arachnoid villi lumbar (spinal tap) CSF Circulation Blood-brain barrier constant internal environment is essential for brain function least permeable capillaries − − − water glucose essential aa's fats, respiratory gases, fat-soluble molecules − alcohol, nicotine, anesthetics Diencephalon thalamus − relay station for sensory impulses hypothalamus, hypo = “under” − autonomic system center − limbic system − regulates pituitary gland epithalamus, epi = “on top of” − pineal body − choroid plexus knots of capillaries that form the cerebrospinal fluid (CSF) Brain Stem midbrain − pons = “bridge” − fiber tracts medulla oblongata − corpora quadrigeminia nuclei regulate vitals reticular formation − gray matter in brain stem awake/sleep cycles
