anatomy exam5

anatomy exam5 - Chapter 16-Nervous Tissue: Controls and...

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Chapter 16—Nervous Tissue: Controls and integrates all body activities within limits that maintain life ; Three basic functions: (1) sensory (sight, smell, sun on your face, hunger); (2) integrated; (3) reactive/motor function (breathing, thinking, heart beat, move arm) Major structures of the nervous system: Brain, cranial nerves, spinal cord, spinal nerves, ganglia, enteric plexuses and sensory receptors Nervous system divisions : Central nervous system (CNS)-consists of the brain and spinal cord; Peripheral nervous system (PNS)-consists of cranial and spinal nerves that contain both sensory and motor fibers, connects CNS to muscles, Subdivisions of the PNS: Somatic (voluntary) nervous system (SNS )—made up of: (a) neurons from cutanious (right under skin) and special sensory receptors that go to the CNS; (b) motor neurons that go to skeleton muscles; Autonomic (involuntary) nervous systems —(a) sensory neurons from our visceral organs (i.e. stomach, gut) that send messages to CNS/brain (b) motor neurons that go to smooth and cardiac muscles, sympathetic speeds heart rate up and parasympathetic slows heart rate down; Enteric nervous system (ENS) —involuntary sensory and motor neurons that work independently of ANS and CNS and go to the G.I. track Neuroglial cell: Half of the volume of the CNS; Smaller cells than neurons; 50X more numerous; Cells can divide-rapid mitosis in tumor formation (gliomas); 4 cell types in CNS-astrocytes, oligodendrocytes, microglia & ependymal; 2 cell types in PNS-Schwann and satellite cells; gliomas causes brain tumors CNS: astorcytes- Star-shaped cells; Form blood-brain barrier by covering blood capillaries; Metabolize neurotransmitters; Regulate K+ balance; Provide structural support CNS: oligodendrocytes- Each forms myelin sheath around more than one axons in CNS; Analogous to Schwann cells of PNS, alike because covers neuron with myelin sheath, most common of 4 types of CNS, analogous (alike, similar too) CNS: microglia- Small cells found near blood vessels; Phagocytic role; Derived from cells that also gave rise to CNS: ependymal cells-Form epithelial membrane lining cerebral cavities & central canal, produces CSF and with cilia transports it, lines ventricles of the brain to push or transport and also produces the CSF (cerebrospinal fluid) PNS: Schwann cell- Cells encircling PNS axons
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PNS: satellite cells- Flat cells surrounding neuronal cell bodies in peripheral ganglia; Support neurons in the PNS ganglia Functional classification of neurons: Sensory (afferent) neurons—transport sensory information from the skin, muscles, joints, and organs to the CNS; Motor (efferent) neurons—sends motor neural impulses to the muscles and glands; Interneurons (association) neurons—90% of neurons in our body, connect the sensory and motor neurons neurons: definition--Functional unit of nervous system; Have capacity to produce action potentials=electrical excitability; Cell body-single nucleus, prominent nucleus, Nissal bodies (chromatophilic substance), neurofilaments-give
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This note was uploaded on 06/25/2008 for the course KIN 2501 taught by Professor Hargroder during the Spring '08 term at LSU.

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anatomy exam5 - Chapter 16-Nervous Tissue: Controls and...

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