KIN 3304 1nd Edition Lecture 10 Outline of Last Lecture I Brief Maximal Tension II Creating Maximal Tension 1 III Creating Maximal Tension 2 IV Creating Maximal Tension 3 V Isometric Static Tension Outline of Current Lecture I Neural Tissue II CNS III PNS IV Afferent PNS V Efferent PNS VI Components of Efferent Division VII Astrocytes VIII Controlling Interstitial Environment IX Maintaining BBB X Creates 3D framework for CNS XI Repairs Damaged Neural Tissue XII Oligodendrocytes XIII Myelin Sheath XIV Schwann Cells XV Neurotransmitter XVI Signaling XVII Receptors XVIII Neutral Regeneration Current Lecture These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute I Neural Tissue a 2 Anatomical Division i Central Nervous System 1 Brain and spinal cord ii Peripheral Nervous System 1 All neural tissue outside the CNS II CNS a Brain and Spinal Cord b Integration processing coordinating sensory input motor output c Higher functions as well i Intelligence memory learning emotions III PNS a Provides sensory information to CNS b Carries motor commands from CNS to peripheral tissues and systems c 2 Divisions i Afferent information to CNS visual commands ii Efferent commands to muscle glands actual movement IV Afferent PNS a Begins at receptors that monitors environment b Receptor may be a i Dendrites sensory process of a neuron ii Specialized cell or cluster of cells ex muscle iii Complex sensory organ ex eye V Efferent PNS a Begins inside CNS ends at an effector b Both afferent and efferent divisions have somatic sensory receptors i Sensory receptors are for conscious control voluntary ii Monitor skeletal muscles joints c and visceral sensory receptors i Visceral receptors do not control ex breathing heartbeat ii Monitor internal tissues smooth cardiac muscle glands VI Components of Efferent Division a Somatic Nervous System i Muscles b Autonomic Nervous System i Things you don t control know diagram of the Central Nervous System VII Astrocytes a Messengers that send information to the body b Largest most numerous glial cells c Functions i Control interstitial environment ii Maintain blood brain barrier BBB 1 BBB filters things from coming in and out of brain 2 Drug delivery goes through this caffeine nicotine iii Creates 3D framework for CNS iv Repairs damaged neural tissue v Guides neuronal development VIII Controlling Interstitial Environment a Astrocytes have cytoplasmic processes i Increases SA of cell 1 Allows exchange of ions molecules with extracellular fluid within CNS ii Processes contact neuronal surfaces 1 Isolate neurons from interstitial space within CNS 2 Keeps chemical composition from changing IX Maintaining BBB a Neural tissue must be isolated i Physically and biochemically ii Hormones chemicals in circulation can disrupt endothelial b Cells lining CNS capillaries have very restrictive permeability i Control chemical exchange between blood into fluid c BBB isolates CNS from general circulation X Creates 3D framework for CNS a Astrocytes have microfilaments b Extend across the cell i Reinforcement provides mechanical strength ii Support neurons of brain spinal cord c Ex building the statue of liberty XI Repairs Damaged Neural Tissue a After CNS damage i Astrocytes make structural repairs ii Stabilizes tissue iii Prevents further injury 1 Produce scar tissue at injury site XII Oligodendrocytes a Second set of glial cells found within CNS b Smaller cell bodies fewer shorter processes i Processes tie axon clusters together c Provide myelin sheath in areas of white matter i kangaroo d Maintain cellular organization in gray matter e Many axons completely sheathed via Oligodendrocytes i Near tip of process plasmalemma expands ii Forms flattened pads that wrap the axon 1 Phospholipid bilayer f Membranous coating called sheath i Improves nerve impulse speed XIII Myelin Sheath a Can form along entire length of axon b Large myelinated areas are internodes c Small gaps exist between sheath produced by adjacent oligos i Myelin sheath gaps or nodes of Ranvier ii Loss of myelin loss of conduction as in M S multiple sclerosis XIV Schwann Cells a All peripheral neurons covered by Schwann cells i Also called neurolemmocytes b Can myelinate only about 1mm of an axon i Covering is called neurilemma ii Oligos can myelinate much more iii Functions the same irrespective of source c Unmyelinated axons are enclosed by processes of Schwann cells XV Neurotransmitter a Chemical compound released by 1 neuron to affect the transmembrane potential of another XVI Signaling a Message from point A to point B Know the image of the receptors PNS CNS chart XVII Receptors a Exteroceptors i External environment ii Touch temperature pressure iii Sight smell auditory b Proprioceptors i Position movement of muscles and joints c Interoceptors i Digestive respiratory cardiovascular etc ii Deep pressure and pain taste XVIII Neural Regeneration a Neurons have limited ability to recover i After injury chromatophilic substance disappears ii If no O2 stroke permanent damage iii Cold nerve injury permanent damage b Wallerian degeneration disintegration of an axon and its myelin sheath distal to injury site i Axon deteriorates ii Macrophage phagocytize debris iii Schwann cells form cord around original axon