The Central Nervous System Chapter 9, part A The Central Nervous System
About this Chapter Emergent properties of the nervous system Anatomy and functions of the CNS Divisions of the brain and what each controls Integration of complex pathways for behavior Language, memory and others
Evolution of the Nervous System Nerve net – jellyfish Simple brain & nerve cord – flatworm Brain & nerve cord with ganglia – earthworm Increasing forebrain – fish, bird & human Olfactory – fish Complex behavior – birds Reasoning & cognition – humans
Evolution of the Nervous System Figure 9-1: Evolution of the nervous system
Embryonic Development of Nervous System Neural plate to neural tube Neural crest–PNS Anterior forms brain Forebrain Midbrain Hindbrain Hollow ventricles Spinal cord Figure 9-2: The embryonic nervous system develops into a hollow tube
Embryonic Development of Nervous System Figure 9-3 a-c: The neural tube specializes into the six major regions of the nervous system.
Central Nervous System: Overview Brain Spinal cord Figure 9-4a: ANATOMY SUMMARY: The Central Nervous System
Protecting the Brain Hair, skin, cranium Venous sinus blood Meninges Drua mater Arachnoid membrane Pia mater Cerebrospinal fluid Figure 9-4b, c: ANATOMY SUMMARY: The Central Nervous System
Cerebrospinal Fluid From coracoid plexus Fills ventricles & subarachnoid Fluid pillow floats brain Exchange transport From blood To brain tissue
Cerebrospinal Fluid Figure 9-5: ANATOMY SUMMARY: Cerebrospinal Fluid
Blood Brain Barrier Extensive capillaries & sinuses Tight junctions: limit permeability Astrocyte foot processes: secrete paracrines Protects brain: hormones & circulating chemicals Many glucose transporters Figure 9-6: The blood-brain barrier
Spinal Cord Regions Cervical Thoracic Lumbar Sacral Figure 9-4a: ANATOMY SUMMARY: The Central Nervous System
Spinal Cord Organization Gray matter: mostly cell bodies Dendrites & terminals Spinal reflex integrating center White matter Bundles of myelinated axons Ascending tracts – sensory Descending tracts – motor Dorsal roots Ventral roots
Spinal Cord Organization Figure 9-7: Specialization in the spinal cord
Brain Overview Trillion interneurons fill the brain Up to 200,000 synapses each Brain divisions Cerebrum Diencephalons Midbrain Cerebellum Pons Medulla oblongata
Brain Overview Figure 9-9b, c: ANATOMY SUMMARY: The Brain
Brain Stem Overview: Midbrain, Pons & Medulla Many cranial nerves enter Pyramids – nerve tracts crossover Midbrain – eye movement control Pons – breathing, signal relay Medulla – involuntary functions Examples: Blood pressure, vomiting Reticular formation: Network in brain stem Arousal, sleep, pain, & muscle tone
Brain Stem Overview: Midbrain, Pons & Medulla Figure 9-9d: ANATOMY SUMMARY: The Brain
Cranial Nerves Table 9-1: The Cranial Nerves