Exam 4 Study GuideChapter 11:Know the parts and functions of the neuronKnow the functions of the nervous system1. Sensory input- information gathered by sensory receptors about internal and external changes2. Integration- processing and interpretation of sensory input3. Motor output- activation of effector organs (muscles and glands) produces a responseBe able to differentiate between the CNS and the PNS1. Central nervous system (CNS) a. Brain and spinal cord of dorsal body cavityb. Integration and control center- Interprets sensory input and dictates motor output 2. Peripheral nervous system (PNS)a. The portion of the nervous system outside the CNSb. Consists mainly of nerves that extend from brain and spinal cord- Spinal nerves to and from spinal cord- Cranial nerves to and from brain Be able to differentiate between the sensory division and the motor division 1. Sensory (afferent) divisiona. Somatic sensory fibers: convey impulses from skin, skeletal muscles, and joints to CNSb. Visceral sensory fibers: convey impulses from visceral organs to CNS2. Motor (efferent) divisiona. Transmits impulses from CNS to effector organs- Muscles and glandsb. Two divisions - Somatic nervous system - Autonomic nervous systemKnow the difference between somatic nervous system and the autonomic nervous system1. Somatic nervous systema. Somatic motor nerve fibers conduct impulses from CNS to skeletal muscleb. Voluntary nervous system - Conscious control of skeletal muscles2. Autonomic nervous systema. Consists of visceral motor nerve fibers b. Regulates smooth muscle, cardiac muscle, and glands c. Involuntary nervous system d. Two functional subdivisions- Sympathetic - Parasympathetic - Work in opposition of each otherBe able to match each type of neuroglia with its functionA. Neuroglia of the CNS1. Astrocytesa. Most abundant, versatile, and highly branched of glial cellsb. Cling to neurons, synaptic endings, and capillariesc. Support and brace neuronsd. Play role in exchanges between capillaries and neuronse. Guide migration of young neurons f. Respond to nerve impulses and neurotransmitters g. Influence neuronal functioningh. Participate in information processing in brain2. Microglial cells a. Small, ovoid cells with thorny processes that touch and monitor neuronsb. Migrate toward injured neuronsc. Can transform to phagocytize microorganisms and neuronal debris3. Ependymal cells a. Range in shape from squamous to columnarb. May be ciliated- Cilia beat to circulate CSFc. Line the central cavities of the brain and spinal columnd. Form permeable barrier between CSF in cavities and tissue fluid bathing CNS cells4. Oligodendrocytesa. Branched cellsb. Processes wrap CNS nerve fibers, forming insulating myelin sheaths in thicker nervefibersB. Neuroglia of PNS1. Satellite cellsa. Surround neuron cell bodies in PNSb. Function similar to astrocytes of CNS2. Schwann cells (neurolemmocytes)a. Surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers- Similar function to oligodendrocytesb. Vital to regeneration of damaged peripheral nerve fibersBe able to differentiate and give examples of unipolar, bipolar and multipolar neurons1. Multipolar: three or more processes (1 axon, others dendrites)a. Most common and major neuron type in CNS2. Bipolar: two processes (1 axon, one dendrite)a. Rare (ex: retina and olfactory mucosa)3. Unipolar: one T-like process (2 axons)a. Also called pseudounipolarb. Peripheral (distal) process: associated with sensory receptorc. Proximal (central) process: enters CNSBe able to define sensor neurons, motor neurons and interneurons1. Sensory a. Transmit impulses from sensory receptors toward CNSb. Almost all are unipolarc. Cell bodies are located in ganglia in PNS2. Motora. Carry impulses from CNS to effectors b. Multipolar c. Most cell bodies are located in CNS (except dome autonomic neurons)3. Interneuronsa. Also called associations neurons b. Lie between motor and sensory neurons c. Shuttle signals through CNS pathwaysd. Most are entirely within CNSe. 99% of body’s neurons are interneuronsBe able to define voltage, charge, current and resistance1. Voltage: a measure of potential energy generated by separated charge a. Measured between two points in volts or millivoltsb. Called potential difference or potential- Charge difference across plasma membrane results in potentialc. Greater charge difference between points = higher voltage2. Current: flow of electrical charge (ions)between two points a. Can be used to do workb. Flow is dependent on voltage and resistance3. Resistance: hinderance to charge flow a. Insulator: substance with high electrical resistance b. Conductor: substance with low electrical resistanceKnow the difference between all types of channels discussed sodium vs potassium channels1. Leakage (nongated) channels, which are always open2. Gated channels, in which part of the protein changes shape to open/close the channela. Chemically gated (lingland- gated) channels - Open only with binding of a specific chemical (ex: neurotransmitter)b. Voltage- gated channels- Open and close in response to changes in membrane potentialc. Mechanically gated channels - Open and close in response to physical deformation of receptors, as in sensory receptorsBe able to define resting membrane potential and know the resting membrane potential of a neuron 1. Resting membrane potential of a resting neuron is approximately 70mVa. The cytoplasmic side of membrane is negatively charged relative to the outsideb. The actual voltage difference varies from 40mV to 90mVc. The membrane is said to be polarized2. Generating a resting membrane potential depends on (1) differences in K+ and Na+ concentrations inside and outside cells, and (2) differences in permeability of the plasmamembrane to these ions.Be able to describe polarization, depolarization and repolarization1. Repolarization: membrane returns to resting membrane potential2. Depolarization: decrease in membrane potential(moves toward zero and above)Know the steps in generating an action potential1. Resting state2. Depolarization: Na+ channels open3. Repolarization: Na+ channels are inactivating, and K+ channels open4. Hyperpolarization: some K+ channels remain open, and Na+ channels resetWhat does the “All or None” principal state?1. An action potential either happens completely, or doesn’t happen at allKnow all synapses discussed in class1. Chemical Synapsesa. Most common type of synapseb. Specialized