Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7BIO 210 Lab Handout #10 – Nervous SystemCell body – large rounded region of the cell; biosynthetic center of the cell; contains all organelles except centrioles. Nucleus – large, round; found in cell bodyNeurofibrils – cytoskeletal elements of the neuron; Nissl bodies –elaborate rough ER; dark staining bodies; protein synthesisMitochondria –everywhere; synthesize ATPDendrite –short, branching processes close to the cell body; main receptive or input region convey signals toward the cell body; contains all organelles Axon - only 1 per neuron; very long axons are nerve fibers; the conducting component of the neuron; generate nerve impulses;do not have Nissl bodies or GolgiAxon hillock – cone shaped area of the cell body leading to the axonAxon terminal – knoblike distal endings of terminal branchesSecretory component of the neuron; stores neurotransmitters in vesicles Myelin sheath – whitish, fatty covering; on axon protects, electrically insulates nerves; increases speedSchwann Cell – neuroglia that forms myelin sheath in PNSNodes of Ranvier – gaps in the myelin sheath; Schwann cells do not touch each other Dendrites Neurofibrils Axon hillockMitochondria Nissl bodiesNucleus Axon collateralAxon Schwann cellNucleus Myelin sheathNode of RanvierAxon terminalSynaptic end bulb1 of 7Supporting Cells (Neuroglia)Central Nervous System –4 types1. Astrocytes – star shaped; radiating processes cling to neurons and capillaries anchoring them to their nutrient supply; mop up leaked potassium ions and recycle released neurotransmitters; control the chemical environment around neurons2. Microglia – small ovoid cells with long thorny processes to touch and monitor neurons; transform into a macrophage that phagocytizes invading microorganisms or debris from dying neurons; monitor health of neurons3. Ependyma – squamous to columnar, may be ciliated; line central cavities of the brain and spinal cord; form a semipermeable membrane; beating cilia circulates cerebrospinal fluid 4. Oligodendrocyte – forms myelin sheaths in the CNS 2 of 7Peripheral Nervous System1. Schwann cells –form myelin sheaths around larger nerve fibers in the PNS2. Satellite cells – surround neuron cell bodies within gangliaBrainThe brain is generally divided into 4 major regions:1. Cerebrum – most superior portion of the brain; localizes and interprets sensory inputs; controls voluntary and skilled activity; intellectual and emotional processing2. Diencephalon – central core of the brain; surrounded by the cerebrum; relay station to conduct sensory impulses to the cerebrum; relay station for impulses to and from cerebral motor cortex; memory processing; integration center for involuntary nervous system; regulates hormonal output of the pituitary gland; produces oxytocin and antidiuretic hormone3. Brain stem – between the cerebrum and the spinal cord; visual and auditory reflex centers; relays information from the cerebrum to the cerebellum; controls respiration, heart rate, vomiting, coughing, etc.; sensory relay to the cerebellum4. Cerebellum – cauliflower-like; dorsal to the brain stem; processes information from the cerebral cortex and instructs the cerebral motor cortex resulting in proper balance, posture and smooth, coordinated movementsCerebrumDiencephalonBrain StemCerebellumVentricles – cavities within the brain filled with cerebrospinal fluid; continuous with central canal of spinal cord; lined by ependymal cells1. Lateral – two; large C-shaped chambers; deep within the cerebral hemispheres2. Third – narrow; within the diencephalon3. Fourth – dorsal to the brain stem; continuous with the spinal canal; apertures connect to the subarachnoid space surrounding the brain with fluid4. Cerebral aqueduct – canal-like channel that connects the third and fourth ventricles3 of 7Lateral ventricles Third ventricleCerebral aqueduct Fourth ventriclePosterior Brain ExteriorMeninges – 3 layers of connective tissue membranes that cover and protect the brain & spinal cord 1. Dura Mater – outermost, tough & leather, double layer 2. Arachnoid – middle layer; has threadlike spider web projections to the inner layer 3. Pia Mater – innermost; delicate, highly vascular, clings tightly to brain surfaceScalp Periosteal layerMeningeal layerDura materArachnoid materPia materBoneLongitudinal fissure – separates the two cerebral hemispheres; Transverse fissure – separates the cerebrum from the cerebellumGyri – elevated ridges of tissuesSulci – depressed areas between the gyri;Cerebral Cortex – gray matter of the brain; it is located in the gyriCerebrum – 4 LobesFrontalParietalTemporalOccipitalGray matter contains clusters of Neuron Cell Bodies in the cortex4 of 7Longitudinal FissureGyrus Sulcus Cerebral cortexI – Olfactory bulb – sensory for smell II – Optic chiasma – sensory for visionIII – Oculomotor – mixed for eye movementIV – Trochlear – mixed for eye movementV – Trigeminal – mixed for facial expression & chewingVI – Abducens – mixed for eye movementFacial – VIIMixed for taste, facial expressionsVestibulocochlear – VIIISensory for hearing, balanceGlossopharyngeal – IXMixed for taste, swallowingVagus – XMixed for organ sensations, movementsAccessory – XIMixed for head, neck movementXII – Hypoglossal – mixed for tongue movement12 Cranial NervesFrontal Temporal Transverse fissureCerebellum Parietal Occipital3. Hypothalamus – floor of the 3rd ventricle; “under” the thalamus; Pituitary gland – hangs from the the hypothalamus by the infundibulum,Mammillary bodies – bulge exteriorly from the floor of the hypothalamus; posterior to the pituitary glandDiencephalon – 3 parts1. Epithalamus – forms roof of the 3rd ventricleA. Pineal body – usually dark from producing melatonin; posterior to the thalamus2. Thalamus – 2 large lobes of gray matter; lateral walls of 3rd ventricleIntermediate mass – slender stalk of thalamic tissue that connects the 2 lobes; bridges the ventricleCerebrum – 3 deep components1. Corpus callosum – major tract of fibers connecting the two cerebral hemispheres; 2. Septum pellucidum – membrane separating lateral ventricles of the cerebral hemispheres3. Fornix – bandlike fiber tract inferior to septum pellucidumBrain Stem – has 3 parts:1. Midbrain – between the Diencephalon and the Pons; contains the Cerebral aqueduct and