Exam 4 Study Guide Chapter 11 Know the parts and functions of the neuron Know the functions of the nervous system 1 Sensory input information gathered by sensory receptors about internal and external changes 2 Integration processing and interpretation of sensory input 3 Motor output activation of effector organs muscles and glands produces a response Be able to differentiate between the CNS and the PNS 1 Central nervous system CNS a Brain and spinal cord of dorsal body cavity b 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 CNS b 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 division a Somatic sensory fibers convey impulses from skin skeletal muscles and joints to CNS b Visceral sensory fibers convey impulses from visceral organs to CNS 2 Motor efferent division a Transmits impulses from CNS to effector organs Muscles and glands b Two divisions Somatic nervous system Autonomic nervous system Know the difference between somatic nervous system and the autonomic nervous system 1 Somatic nervous system a Somatic motor nerve fibers conduct impulses from CNS to skeletal muscle b Voluntary nervous system Conscious control of skeletal muscles 2 Autonomic nervous system a 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 other Be able to match each type of neuroglia with its function A Neuroglia of the CNS 1 Astrocytes a Most abundant versatile and highly branched of glial cells b Cling to neurons synaptic endings and capillaries c Support and brace neurons d Play role in exchanges between capillaries and neurons e Guide migration of young neurons f Respond to nerve impulses and neurotransmitters g Influence neuronal functioning h Participate in information processing in brain 2 Microglial cells a Small ovoid cells with thorny processes that touch and monitor neurons b Migrate toward injured neurons c Can transform to phagocytize microorganisms and neuronal debris 3 Ependymal cells a Range in shape from squamous to columnar b May be ciliated Cilia beat to circulate CSF c Line the central cavities of the brain and spinal column d Form permeable barrier between CSF in cavities and tissue fluid bathing CNS cells 4 Oligodendrocytes a Branched cells b Processes wrap CNS nerve fibers forming insulating myelin sheaths in thicker nerve fibers B Neuroglia of PNS 1 Satellite cells a Surround neuron cell bodies in PNS b Function similar to astrocytes of CNS 2 Schwann cells neurolemmocytes a Surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers Similar function to oligodendrocytes b Vital to regeneration of damaged peripheral nerve fibers Be able to differentiate and give examples of unipolar bipolar and multipolar neurons 1 Multipolar three or more processes 1 axon others dendrites a Most common and major neuron type in CNS 2 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 pseudounipolar b Peripheral distal process associated with sensory receptor c Proximal central process enters CNS Be able to define sensor neurons motor neurons and interneurons 1 Sensory a Transmit impulses from sensory receptors toward CNS b Almost all are unipolar c Cell bodies are located in ganglia in PNS 2 Motor a Carry impulses from CNS to effectors b Multipolar c Most cell bodies are located in CNS except dome autonomic neurons 3 Interneurons a Also called associations neurons b Lie between motor and sensory neurons c Shuttle signals through CNS pathways d Most are entirely within CNS e 99 of body s neurons are interneurons Be able to define voltage charge current and resistance 1 Voltage a measure of potential energy generated by separated charge a Measured between two points in volts or millivolts b Called potential difference or potential Charge difference across plasma membrane results in potential c Greater charge difference between points higher voltage 2 Current flow of electrical charge ions between two points a Can be used to do work b Flow is dependent on voltage and resistance 3 Resistance hinderance to charge flow a Insulator substance with high electrical resistance b Conductor substance with low electrical resistance Know the difference between all types of channels discussed sodium vs potassium channels 1 Leakage nongated channels which are always open 2 Gated channels in which part of the protein changes shape to open close the channel a 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 potential c Mechanically gated channels Open and close in response to physical deformation of receptors as in sensory receptors Be 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 70mV a The cytoplasmic side of membrane is negatively charged relative to the outside b The actual voltage difference varies from 40mV to 90mV c The membrane is said to be polarized 2 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 plasma membrane to these ions Be able to describe polarization depolarization and repolarization 1 Repolarization membrane returns to resting membrane potential 2 Depolarization decrease in membrane potential moves toward zero and above Know the steps in generating an action potential 1 2 3 4 Resting state Depolarization Na channels open Repolarization Na channels are inactivating and K channels open Hyperpolarization some K channels remain open and Na channels reset What does the All or None principal state 1 An action potential either happens completely or doesn t happen at all Know all synapses discussed in class 1 Chemical Synapses a Most common type of synapse b Specialized for release and reception of chemical neurotransmitters c Typically composed of two parts Axon terminal of presynaptic neuron contains