Exam 3 ReviewExam 3 ReviewCh. 10- Names and general locations (face, neck, thorax, etc) of muscles shown in figures 10.4 and 10.5Ch. 11 Fundamentals of the NS and the Nervous Tissue - Action potential physiologyo Action potential: when a neuron is adequately stimulated, an electrical impulse is generated and conducted along the length of its axon; this response is called the action potential (nerve impulse), it underlies all functional activities of the NSo Know all of the steps of an action potential Resting state  depolarization  repolarization  hyperpolarization 1- resting (polarized) state: all gated Na+ and K+ channels are closed- No ions move through voltage-gated channels 2- depolarization: Na+ channels open- Is caused by Na+ flowing into the cell 3- repolarization: Na+ channels are inactivating, and K+ channels open- Is caused by K+ flowing out of the cell 4- hyperpolarization: some K+ channels remain open, and Na+ channels reset - Is caused by K+ continuing to leave the cell- Changes in membrane potential: o Depolarization: reduction in membrane potential (inside becomes less negative)o Hyperpolarization: increase in membrane potential (inside becomes more negative)o Repolarizationo Definitions and physiology (ion channels involved, which ions cross membrane, etc)- Divisions and subdivisions of the nervous system (CNS< PNS, motor division, etc)o Names and functions- Excitatory and inhibitory postsynaptic potentialso Excitatory postsynaptic potential: binding of neurotransmitter at excitatory chemical synapses results in local graded potential called EPSPs, caused by opening of channels that allow simultaneous passage of Na+ and K+o Inhibitory postsynaptic potential: neurotransmitter binding to inhibitory chemical synapses results in hyperpolarization’s called IPSPs, caused by theopening of K+ or Cl- channels, they drive the membrane potential farther from the thresholdo Types of summation  Temporal summation: one or more postsynaptic neurons transmit impulses in rapid fire order and bursts of neurotransmitters are released in quick succession Spatial summation: postsynaptic neuron is stimulated simultaneously by a large number of terminals from presynaptic neurons Why summation is necessary (remember threshold)- Necessary because without, nerve impulses would never start - Ganglia and nucleio Ganglia: lie along the nerves in the PNSo Nuclei: clusters of cell bodies in the CNS - Graded potentials vs. action potentialso Graded potentials  Short lived, localized changes in membrane potential that can be either depolarization or hyperpolarization These changes cause current flows that decrease in magnitude with distance  Their magnitude varies directly with stimulus strength The stronger the stimulus, the more voltage changes and the further the current flows  They are triggered by some change (a stimulus) in the neuron’s environment that opens gated ion channels They are given different names, depending on when and where they occur o Short-distance vs. long-distance communicationo Action potentials as all-or-nothing phenomena It either happens completely or not at allo Graded potentials vary depending on the strength of the original stimulus, but action potentials do noto Etc- Neuroglia in central and peripheral nervous systemso The smaller cells that the neurons associate closely with, act as nerve glueo Six types: 4 in the CNS and 2 in the PNS CNS includes- Astrocytes: most abundant and versatile CNS neuroglia o Their numerous radiating processes cling to neurons and their synaptic endings, and cover nearby capillaries,they support and brace the neurons and anchor then to their nutrient supply lines- Microglial cells: defensive cells in the CNSo Have long thorny processes, their processes touch nearby neurons to monitor their health, when they sense that certain neurons are injured or in trouble, they migrate towards the, they transform into a special type of macrophage that phagocytizes- Ependymal cells: line cerebrospinal fluid-filled cavities o They line the central cavities of the brain and spinal cord, where they form a fairly permeable barrier between the cerebrospinal fluid that fills those cavities and the tissue fluid bathing the cells of the CNS- Oligodendrocytes: have processes that form myelin sheath around CNS nerve fiberso Line up along thicker nerve fibers in the CNS and wrap their processes tightly around the fibers, producing an insulated cover called myelin sheath PNS includes- Satellite cells and Schwann cells: which form myelin surrounding the neurons in the PNS - Satellite cells: surround neuron cell bodies located in PNS- Schwann cells: surround all nerve fibers in PNS- Neuron structure and functiono Distinction between sensory, motor, and interneuronso Sensory (afferent) input: conducts impulses from receptors to the CNS Somatic sensory fiber carries impulse from skin  spinal cord Visceral sensory fiber carries impulse from stomach  spinal cord The nervous system uses its millions of sensory receptors to monitor changes occurring in both inside and outside the body.  Carrying towardso Motor (efferent) output: conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands Motor fiber of somatic NS carries impulse from CNS  skeletal muscle Sympathetic motor fiber of ANS carries impulse from CNS  heart Parasympathetic motor fiber of ANS carries impulse from CNS  bladder The nervous system activated effector organs (the muscles and glands) to cause a response called motor output Carrying away  PNS transmits impulses from the CNS to effector organso Interneurons- Neurotransmitterso Excitatory vs. inhibitory Excitatory: some neurotransmitters are excitatory, causing depolarization Inhibitory: some neurotransmitters are inhibitory, causing hyperpolarizationo Direct vs. indirect Direct: neurotransmitters that act directly are those that bind to and open ion channels- Provoke rapid responses in postsynaptic cells by altering membrane potential- Ach and the amino acid neurotransmitters are typically direct acting neurotransmitters Indirect: neurotransmitters that act indirectly promote broader, longer-lasting effects by acting through intracellular second messenger molecules, typically via G protein pathways- Their action is similar to that of many hormones- The biogenic amines, neuropeptides, and dissolved gases are