Practical 4 Review Sheet Dr Opoku Spring 2014 Lab 10 Nervous System Divisions 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 neurons o CNS astrocytes oligodendrocytes microglia and ependymal cells o PNS Schwann cells and satellite cells Cell body clusters and location Nuclei neuron cell bodies in the CNS Ganglia neuron cell bodies found outside the CNS Axon bundles location Tract neuron fibers running through the CNS Nerve neuron fibers running through the PNS Supporting cells their functions Pg 210 figure 14 1 CNS o Microglia act as phagocytes defensive cells o Oligodendrocytes myelinate the cytoplasmic extensions of neurons o Astrocytes most abundant CNS neuroglia plays a role in capillary neuron exchanges and control the chemical environment around neurons o Ependymal cells ciliated columnar cells that beat to create unidirectional that circulates CSF PNS o Schwann cells myelinate the cytoplasmic extensions of neurons o Satellite cells myelinate the neuron cell body Neuron parts their function Pg 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 Axon terminal synaptic knobs at the end of an axon that form synapses junctions with may branch into collaterals neurons or effector cells Axon hillock the beginning point of the axon in between the cell body and axon where the axon 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 Nissl chromatophilic bodies an elaborate type of rough endoplasmic reticulum involved transport function in the metabolic activities of the cell 1 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 neurons Structural classification of neurons Pg 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 CNS Structure of a nerve tract coverings Pg 216 figure 14 8a Nerve tract covered by epineurium Fascicle covered by perineurium Axon covered by endoneurium Blood vessels Brain parts Pg 227 figure 16 2 pg 230 figure 16 4 Cerebrum Longitudinal Fissure divides the cerebral cortex into two left and right hemispheres Corpus Callosum the major commissure that connects the Septum pellucidum separates the lateral ventricles of the Central Sulcus divides the frontal lobe from the parietal two hemispheres cerebral hemispheres lobe 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 cortex 2 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 control Diencephalon 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 epithalamus Brainstem 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 prominences o Cerebral aqueduct located dorsal to the pons and ventral to the cerebellum o 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 cord Cerebellum Pg 232 figure 16 6 Arbor Vitae the treelike branching of the cerebellar white matter Vermis midline lobe of the cerebellum All cranial nerves Pg 235 figure 16 9 CNI Olfactory o Axons of olfactory neurons run from the nasal mucosa through the ethmoid bone to synapse with olfactory bulbs o Function is purely sensory carries afferent impulses associated with sense of smell CNII Optic o 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 cortex o Function is purely sensory carries afferent impulses associated with vision CNIII Oculomotor o Fibers emerge from dorsal midbrain and courses ventrally to enter the orbit and exit skull via superior orbital fissure o Function is primarily motor
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