BIO 446L 1st Edition Lecture 12 Outline of Last Lecture I. Joints and Movementa. Diarthrosis and Synarthrosisb. Articular cartilage and intervertebral diskc. Diarthrosisd. Synovial jointsi. Pivotii. Ball and socketiii. Acromioclaviculariv. Hingev. Saddlevi. condyloidOutline of Current Lecture I. Nervous Tissue—Central and Peripheral Nervous Systema. Sensory and motor neuronsb. Central and peripheral nervous systemc. Central nervous systemi. Brainii. Spinal cordiii. Neurons1. Unipolar, bipolar, multipolariv. Synapsesv. Membrane potentialCurrent LectureNervous Tissue- Derived from ectodermo Arises at 3 weeks gestation- Neuron= nerve cell- Glial= support cells in the brain for the nervesThese 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.- Axon= processes extending from cell body- Central nervous system= brain and spinal cordo Nuclei(nerves)= clusters of neuron cell bodieso Tracts= bundles of axons- Peripheral Nervous System= Cranial spinal nerves and gangliao Ganglia= clusters of cell bodies Compare to nuclei of CNSo Nerves= bundles of axons Compare to tracts of CNS- Afferent= sensory (to brain--incoming)- Efferent= motor and autonomic (away from brain—outgoing)- Central Nervous System—brain and spinal cordo Brain has hills and valleys Valleys= sulci Hills= gyrio Lobes of the brain are named according to the skull bone associated Frontal, parietal, occipital, and temporal lobeso Cerebral cortex has many sensory and motor neuronso Anterior and posterior horn= gray matter, in center of spinal cord Dorsal root gangliono Know general locations in the brain of the: Cerebrum and cerebellum—external Midbrain and brain stem (medulla oblongata and pons)—internalo Brain Gray matter on outer edge is the cerebral cortex Gray matter seeping inward is the cell bodies White matter is the tracts Perametal cells= projections up to nuclei on surface of cerebral cortex cellbodies for motor neurons Neutrophil= cell bodies and processes in an interwoven mesh, making up the matrix Meninges= outer layers of the brain- Dura mater= periosteal and mesingeal layer- Arachnoid mater= lacey, blood vessels, cerebral spinal fluid- Subdural space= between dura and arachnoid- Pia mater= like a tight wrap layer around braino Spinal cord Slight space between vertebral bone and dura mater= epi dural space Gray matter in center, white matter surrounding Tracts contain afferent and efferent axons Components of gray and white matter are the same as in the braino Neurons Multipolar neurons= many processes—dendrites and axons- Dendrites= incoming info receivedo lots of synapses on dendrites- Axons= extends out to target organ and branch into many terminals and synapses at organ- Myelin= insulator for axon- Axon hillock= adding machineo Can detect changes in voltage and integrate those changes to initiate an action potential if threshold is reached Bipolar= 2 poles- One dendrite and one axon- Found in the eye Unipolar= sensory (ganglia cell body)- Axon surpasses cell body (peripheral and central process)o Synapses Incoming info received by dendrite and sent to axon hillock Dendritic spine= increases surface area to collect incoming information- Contains actin microfilaments so can grow and spread, add/remove receptors (dynamic) Recall the neuromuscular junction (depolarization with Ca++ and Ach received by ligand gated Na+ channel)o Membrane potential Difference in voltage- Resting is ~-80 mV- Generated by permeability to negative and positive ions Threshold= level of membrane potential difference at which axon hillock will fire an action potential Action potential- Eave of depolarization of entire membrane- Local depolarization—Na+ channels open- Threshold is reached large influx of Na+ depolarization potassium channels open slowly (moving K+ out of cell)
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