Chapter 12 Neural TissueDescribes the anatomical and functional divisions of the nervous system.Central Nervous System (CNS)Consists of the spinal cord and brainSpinal cord: The spinal cord is a long, fragile tube-like structure that begins at the end of the brain stem and continues down almost to the bottom of the spine. The spinal cord consists of nerves that carry incoming and outgoing messages between the brain and the rest of the body.Brain: The brain reviews all stimuli – from the internal organs, surface of the body, eyes, ears, nose and mouth. It then reacts to these stimuli by correcting the position of the body, the movement of limbs and the rate at which the internal organs function. The brain can also determine mood and levels of conscious and alertness.Contains neural tissue, connective tissues and blood vesselsThe neural tissue is a specialized tissue with some specialized functions. It is the main component of the nervous system – both the CNS and PNS. This includes the on.AxonsAxoplasmThe axoplasm or cytoplasm of the axon, contains neurofibrils, neurotubules, small vesicle, lysosomes, mitochondria and various enzymes.축삭에서 막으로 둘러싸인 내용물. 세포외액과 같은 정도의 이온 강도와 전도성을 갖지만 이온조성은 세포외액과 전혀 다르다. 즉 세포외액에는 Na＋과 Cl－이 다량 함유되어 있고 K＋은 적지만, 축삭형질에는 K＋이 다량 함유되어 있고 Na＋은 적다. 음이온은 유기 음이온이 중심이며 Cl－는 적다. 또한 Ca2＋의 농도도 대단히 낮다.AxolemmaThe axolemma, the plasma membrane of the axon, surrounds the axoplasm. In the CNS, the axolemma may be exposed to the interstitial fluid.신경축삭을 둘러싸고 있는 7nm가량 두께의 형질막. 이 반투성 막내에서 전위구배를 형성하기 때문에 축삭내측이 외측보다 70mV 정도로 전위가 낮다 (정지전위). 각종 인지질로 구성된 2층막에 섬모양으로 단백질이 분포하여 유동한다. 단백질 중 채널단백질은 나트륨이나 칼륨을 통해 전기적 흥분을 일으킨다 (활동전위).Axon hillock and Initial segmentThe base or initial segment, of the axon in a typical neuron joins the cell body at a thickened region known as the axon hillock.CollateralsAn axon may branch along its length, producing side branches known as collaterals.Telodendria and Axon terminalThe main axon trunk and any collaterals end in a series of fis integration—they distribute sensory information and coordinate motor activity.Three Types of Sensory ReceptorsInteroceptorsInteroceptor monitor the digestive, respiratory, cardiovascular, urinary and reproductive systems and provide sensations of distension, deep pressure and pain.ExteroceptorsExteroceptor provide information about the external environment in the form of touch, temperature or pressure sensations and the more complex senses of taste, smell, sight, equilibrium (balance) and hearing.ProprioceptorsProprioceptors monitor the position and movement of skeletal muscles and joints.Describe the locations and functions of the various types of neuroglia.NeurogliaEpendymal cellsEpendymal cells line the central canal and ventricles, where they form a simple cuboidal to columnar epithelium. Ependymal cells assist in producing and monitoring CSF. In addition, the cilia of the ependymal cells help to circulate CSF in the third ventricle of the brain.AstrocytesAstrocytes are the largene 내외에서 흥분시가 아닌 상태에 존재하는 전위차를 의미한다. 생물은 체내에 다량의 염류가 있는데, 이것이 해리해서 이온을 일으키고 있으므로 생체에 전기가 생기는데, 휴지근 일지하도 전류를 일으킬 조건은 존재하므로, 일반적으로 정지전위가 있다고 한다.정지전위에는 3가지 경우가 있다. 첫째는 막전위인데 세포질 속에 미소전극을 꽂아 넣고, 세포 내외의 전위를 측정할 수 있다. 대형 아메바에서는 밖이 (+)로 95mV, 화살꼴두기의 거대신경에서는 50mV, 개구리의 단일근섬유에서는 100mV이다. 둘째는 개구리의 피부와 같이 생체막을 횡단하는 것인데, 핵막에도 막전위가 있다. 셋째로 동식물의 축에 따라 전위차가 있다.Describe the events involved in the generation and propagation of an action potential.Action PotentialsPropagated changes in transmembrane potentialAffect an entire excitable membraneLink graded potentials at cell body with motor end plate actionsInitiating Action PotentialInitial stimulusA graded depolarization of axon hillock large enough (10 to 15mV) to change resting potential (-70mV) to threshold level of voltage-gated sodium channels (-60 to -55mV)Four Steps in the Generation of Action PotentialsDepolarization to thresholdActivation of Na+ channelsRapid depolarizationNa+ ions rush into cytoplasmInner membrane changes from negative to positto postsynaptic cell, depending on:Amount of neurotransmitter releasedSensitivity of postsynaptic cellTwo Classes of NeurotransmittersExcitatory neurotransmittersCause depolarization of postsynaptic membranesPromote action potentialsInhibitory neurotransmittersCause hyperpolarization of postsynaptic membranesSuppress action potentialsThe Effect of a NeurotransmitterOn a postsynaptic membraneDepending on the receptorNot on the neurotransmitterFor example, acetylcholine (ACh)Usually promotes action potentialsBut inhibit cardiac neuromuscular junctionsCholinergic SynapsesAny synapse that release ACh at:All neuromuscular junctions with skeletal muscle fibersMany synapses in CNSAll neuron-to-neuron synapses in ONSAll neuromuscular and neuroglandular junctions of ANS parasympathetic divisionEvent at a Cholinergic SynapseAction potential arrives, depolarizes synaptic terminalCalcium ions enter synaptic terminal, trigger exocytosis of AChACh binds to receptors, depolarizes postsynaptic membran wm)
Chapter 1 Properties and Overview of Immune ResponsesEffectiveness of Vaccines for Some Common Infectious Disease Table 1.1 This table illustrates the striking decrease in the incidence of selected infectious disease in the United States for which effective vaccines have been developed. Data from Orenstein WA, Hinman AR, Bart KJ, Handler SC: Immunization. In Mandell GL, Bennett JE, Dolin R (eds.): Principles and practices of infectious disease, 4 th ed. New York, 1995, Churchill Livingstone; and Morbidity and Morality Weekly Report 58: 1458-1469, 2010.Innate and Adaptive Immunity Figure 1-1 The mechanisms of innate immunity provide the initial defense against infections. Adaptive immune responses develop later and require the activation of lymphocytes. The kinetics the innate and adaptive immune responses are approximations and may vary in different infections. ILC, innate lymphoid cell; NK, natural killer,Innate and Adaptive Immunity Innate immunity is an immunological subsystem that cells have low levels of S1PR1 because the receptor is internalized after binding S1P in the blood. Therefore, naïve T cells that have recently entered a lymph node cannot sense the S1P concentration gradient between the T cell zone of the node and the lymph in the medullary sinus and efferent lymphatics and these T cells cannot exit the node. After activation of a naïve T cell by hours for naïve T cells or day foe several days and the activated cells also will not leave the node. After several hours for naïve T cells or days for activated and differentiated effector T cells, S1PR1 is re-expressed and these cells can then sense the S1P gradient and exit the node.Migration of B cells Figure 3.8 Naïve B cells enter lymph nodes and mucosal-associated lymphoid tissues through HEV, migrate into follicles, become activated and differentiate into antibody-producing cells, some of which are plasmablasts that enter the circulation and migrate into BM or mucosal tissues, where they fully differens Figure 5.8 The membrane forms of the Ig heavy chains, but not the secreted forms, contain transmembrane regions made up to hydrophobic amino acid residues and cytoplasmic domains that differ significantly among the different isotypes. The cytoplasmic portion of the membrane form the μ chain contains only three residues, whereas the cytoplasmic region of IgG heavy chains ( γ heavy chains) contain 20 to 30 residues.Membrane and secreted forms of Ig heavy chains Figure 5.8 The secreted forms of the antibodies end in C-terminal tail pieces, which also differ among isotypes; μ has a long tail piece (21 residues) that is involved in pentamer formation, whereas IgGs have a short tail piece (3 residues).The generation of monoclonal antibodies Figure 5.9 In this procedure, spleen cells from a mouse that has been immunized with a known antigen or mixture of antigens are fused with an enzyme-deficient partner myeloma cell line, with use of chemicals such as polyethylene glycol that can facilitgen-binding portion of the TCR is formed the V β and V α domains. The ribbon diagram (right) shows the structure of the extracellular portion of a TCR as revealed by x-ray crystallography. The hypervariable segment loops that form the peptide-MHC binding site are at the top.Binding of a TCR to a peptide-MHC complex Figure 7.7A The V domains of a TCR are shown interacting with a human class I MHC molecule, HLA-A2, presenting a viral peptide (in yellow) . A is a front view and B is side view of the x-ray crystal structure of the trimolecular MHC0peptide-TCR complex.Binding of a TCR to a peptide-MHC complex Figure 7.7B The V domains of a TCR are shown interacting with a human class I MHC molecule, HLA-A2, presenting a viral peptide (in yellow) . A is a front view and B is side view of the x-ray crystal structure of the trimolecular MHC0peptide-TCR complex.Components of the TCR complex Figure 7.8 The TCR complex of MHC-restricted T cells consists of the αβ TCR non-covalently linked to the stimulate the expression of more B7 molecules and the secretion of cytokines that activate T cells. Thus, CD40L on the T cells makes the APCs better at promoting and amplifying T cell activation.The mechanism of therapeutic costimulatory blockade Figure 9.7 A fusion protein of the extracellular portion of CTLA-4 and the Fc tail of an IgG molecule is used to bind to and block B7 molecules, thus preventing their interaction with the activating receptor CD28 and inhibiting T cell activation.Changes in surface molecules after T cell activationStructure of IL-2 and its receptor Figure 9.9 The crystal structure of IL-2 and its trimeric receptor shows how the cytokine interact with the three chains of the receptor.Regulation of IL-2 receptor expression Figure 9.10 Resting (naïve) T lymphocytes express the IL-2R βγ c complex, which has a moderate affinity for IL-2. Activation of the T cells by antigen, costimulators and IL-2 itself leads to expression of the IL-2R α chain and increased levelshow}
생리학 Ch.12 Neural Tissue 정리
Cellular and Molecular Immunology Ch1~Ch15 정리
