Practical 4 Review Sheet- Dr. Opoku, Spring 2014Lab 10- Nervous SystemDivisions & their functions- PNS: neural structures outside of the CNS- CNS: brain and spinal cord (dorsal body cavity)Cell groups & their functions- Neurons: basic functional unit of nervous tissue; highly specialized to transmit messages (nerve impulses) from one part of the body to another- Neuroglia (glial cells): supporting cells by protecting neuronso CNS- astrocytes, oligodendrocytes, microglia, and ependymal cellso PNS- Schwann cells and satellite cellsCell body clusters and location- Nuclei: neuron cell bodies in the CNS- Ganglia: neuron cell bodies found outside the CNSAxon bundles & location- Tract: neuron fibers running through the CNS- Nerve: neuron fibers running through the PNSSupporting cells & their functionsPg. 210 figure 14.1- CNS o Microglia: act as phagocytes (defensive cells)o Oligodendrocytes: myelinate the cytoplasmic extensions of neuronso Astrocytes: most abundant CNS neuroglia; plays a role in capillary-neuron exchanges and control the chemical environment around neuronso Ependymal cells: ciliated columnar cells that beat to create unidirectional that circulates CSF- PNS o Schwann cells: myelinate the cytoplasmic extensions of neuronso Satellite cells: myelinate the neuron cell bodyNeuron parts & their functionPg. 211 figure 14.2a- Cell Body: holds the nucleus and other organelles of the neuron- Dendrites: receptive regions of the neuron that bear receptors for neurotransmitters released by other neurons; neurons may have several dendrites- Axon: nerve fibers that generate and conduct nerve impulses; neurons only have one axon (may branch into collaterals)- Axon terminal: synaptic knobs at the end of an axon that form synapses (junctions) with neurons or effector cells- Axon hillock: the beginning point of the axon (in between the cell body and axon); where theaxon hillock narrows to axon diameter is referred to as the initial segment- Myelin Sheath: a protein-lipid wrapping around the axon formed by Schwann cells- Neurofibrils: the cytoskeletal elements of neurons that have a support and intracellular transport function- Nissl (chromatophilic) bodies: an elaborate type of rough endoplasmic reticulum involved in the metabolic activities of the cell1- Schwann cells: cells that wrap around an axon to form the myelin sheath- Nodes of Ranvier: gaps or indentations in the myelin sheaths- Neurilemma: the outermost nucleated cytoplasmic layer of a Schwann cell Functional classification of neurons- Sensory: afferent neurons that carry impulses from sensory receptors in the internal organs, the skin, skeletal muscles, joints, or special sensory organs- Motor: efferent neurons that carry impulses from the CNS to the viscera and/or body muscles and glands- Association (interneurons): contribute to pathways that connect sensory and motor neuronsStructural classification of neuronsPg. 214 figure 14.5a- Unipolar (know location): contain one short process that extends from the cell body; divides into peripheral and central processes; nearly all neurons that conduct impulses toward the CNS are unipolar- Bipolar: contain two processes attached to the cell body (found in eye, ear, and olfactory mucosa)- Multipolar: contain multiple processes attached to the cell body, all classified as dendrites except for a single axon; most neurons in the brain and spinal cord (CNS neurons) and those whose axons carry impulses away from the CNSStructure of a nerve/tract & coveringsPg. 216 figure 14.8a- Nerve/tract covered by epineurium- Fascicle covered by perineurium- Axon covered by endoneurium- Blood vesselsBrain partsPg. 227 figure 16.2, pg. 230 figure 16.4Cerebrum- Longitudinal Fissure: divides the cerebral cortex into twoleft and right hemispheres- Corpus Callosum: the major commissure that connects thetwo hemispheres- Septum pellucidum: separates the lateral ventricles of thecerebral hemispheres- Central Sulcus: divides the frontal lobe from the parietallobe- Frontal lobe: the most anterior lobe of the cerebral cortex- Temporal lobe: the lateral lobes of the cerebral cortex- Insula lobe*: buried deep in the lateral sulcus, covered by portions of the temporal, parietal, and frontal lobes- Occipital lobe: the most posterior lobe of the cerebral cortex- Parietal lobe: the superior lobe of the cerebral cortex located between the frontal and occipital lobes- Parieto-occipital sulcus: on the medial surface of each hemisphere that divides the occipital lobe from the parietal lobe- Precentral gyrus: location of the primary motor cortex2- Postcentral gyrus: location of the primary somatosensory cortex- Lateral Sulcus: separates the temporal lobe from the parietal lobe- Cerebral cortex: the outermost gray matter of the cerebrum; contains the cell bodies of cerebral neurons- White matter: composed of fiber tracts carrying impulses to or from the cortex- Basal nuclei*: subcortical motor nuclei that are involved in regulating voluntary motor controlDiencephalon - Thalamus: consists of two large lobes of gray matter that enclose the third ventricle- Hypothalamus: makes up the floor and the inferolateral walls of the third ventricle- Epithalamus: forms the roof of the third ventricle and is the most dorsal portion of the diencephalon- Pineal gland: a neuroendocrine structure of the epithalamusBrainstem- Pons: located above the medulla oblongata- Midbrain:o Corpora quadrigemina (distinguish superior and inferior): posterior aspect of midbrain Superior colliculi: two superior prominences Inferior colliculi: two smaller inferior prominenceso Cerebral aqueduct: located dorsal to the pons and ventral to the cerebellumo Cerebral peduncles: fiber tracts in the midbrain connecting the pons below with cerebrum above- Medulla oblongata: located between the pons and the beginning of the spinal cordCerebellumPg. 232 figure 16.6- Arbor Vitae: the treelike branching of the cerebellar white matter- Vermis: midline lobe of the cerebellumAll cranial nervesPg. 235 figure 16.9 - CNI. Olfactoryo Axons of olfactory neurons run from the nasal mucosa through the ethmoid bone to synapse with olfactory bulbso Function is purely sensory- carries afferent impulses associated with sense of smell- CNII. Optico Carries sensory impulses from the retina of the eye through optic canal, crosses over in optic chiasm, and proceeds through the thalamus to the visual cortexo Function is purely sensory- carries afferent impulses associated with vision-
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