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69 Cards in this Set
- Front
- Back
Nervous System |
Includes ALL neural tissue in body, contains neurons and neuroglia, Organs: brain, spinal cord, and sensory receptors of sense organs, nerves connect nervous system with other systems. |
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Neurons |
Cells that send and receive signals |
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Neuroglia |
glial cells, cells that support and protect neurons |
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Anatomical Divison of Nervous System |
Central Nervous System and Peripheral Nervous System |
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CNS |
Consist of spinal cord and brain, contains neural and connective tissues, and blood vessels, process and coordinates sensory data from inside to outside, and motor commands control activities of peripheral organs. Also deals with intelligence, memory, learning, and emotion |
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PNS |
Includes all neural tissue outside of CNS, delivers sensory info to CNS, carries motor commands to peripheral tissues and systems |
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Nerves |
(Peripheral nerves) bundles of axons with connective tissues and blood vessels, carry sensory info and motor commands in PNS. Cranial nerves and Spinal nerves |
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Cranial and Spinal Nerves |
Attach to spinal cord |
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Divisions of PNS |
Afferent and Efferent Division |
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Afferent division |
Carries sensory info from PNS sensory receptors to CNS |
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Efferent division |
Carries motor command from CNS to PNS muscles and glands |
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Afferent division receptors |
Detect changes or respond to stimuli, neurons and specialized cells, complex sensory organs |
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Afferent division effectors |
respond to efferent signals, cells and organs |
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Efferent divison |
Somatic Nervous System and Autonomic Nervous System |
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Somatic Nervous System |
controls voluntary and involuntary reflexes, skeletal muscle contractions |
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Autonomic Nervous System |
controls subconscious actions, contractions of smooth muscle and cardiac muscle, and glandular secretions |
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Sympathetic Divison |
stimulating effect |
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Parasympathetic Division |
relaxing effect |
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Neurons |
The basic functional unit of nervous system |
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Neuron Structure |
multipolar neuron, common in CNS, cell body (soma), short, branched dendrites, long, single axon |
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Cell Body |
Large nucleus and nucleolus, perikaryon (cytoplasm), mitochondria, RER and ribosomes, cytoskeleton, nissl bodies |
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Cytoskeleton |
nuerofilaments and meurotubules in place of microfilaments and microtubules; neurofibrils: bundles of neurofilaments that provide support for dendrites and axon |
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Nissl Bodies |
Dense areas of RER and ribosomes, make neural tissue appear gray (gray matter) |
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Dendrites |
highly branched |
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Dendrite spines |
many fine processes, receive info from other neurons, 80-90% of neuron surface area |
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Axon |
long, carries electrical signal (action potential) to target, structure is critical to function |
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Structure of Axon |
Axoplasm, Axolemma, Axon Hillock, Initial Segment, Collaterals, Telodendria, Axon Terminals |
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Axoplasm |
Cytoplasm of axon, contains neurofibrils, neurotubulesm enzymes, organelles |
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Axolemma |
specialized cell membrane, covers the axoplasm |
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Axon Hillock |
thick section of cell body, attached to initial segment |
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Initial Segment |
attaches to axon hillock |
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Collaterals |
branches of a single axon |
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Telodendria |
fine extensions of distal axon |
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Axon terminals |
tips of telodendria |
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Synapse |
where neuron communicates with another cell |
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Presynaptic cell |
neuron that sends message |
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Postsynaptic cell |
cell that receives message |
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Synaptic Cleft |
small gap that separates presynaptic membrane and postsynaptic membrane |
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Synaptic terminal |
expanded area of axon of presynaptic neuron, contains synaptic vesicles of neurotransmitters |
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Neurotransmitters |
are chemical messengers, released at presynaptic membrane, affect receptors of postsynaptic membrane, broken down by enzymes, reassembled at axon terminal |
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Axoplasmic transport |
Neurotubules within the axon, transport raw materials, between cell body and axon terminal, powered by mitochondria, kinesin, and dynein |
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Anaxonic neurons |
found in brain and sense organs, small, all cell processes look alike |
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Bipolar neurons |
found in special sensory organs (sight, smell, hearing), small, one dendrite, one axon |
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Unipolar neuron |
found in sensory neurons in PNS, also called psuedounipolar neurons, have very long axons, fused dendrites and axon, cell body to one side |
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Multipolar neuron |
common in CNS, include all skeletal muscle motor neurons, very long axons, multiple dendrites, one axon |
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Sensory Neurons |
Afferent neurons of PNS, monitor internal environment (visceral s.n.), monitor effects of external environment (somatic s. n.) Unipolar, cell bodies grouped in sensory ganglia, processes (afferent fibers) extend from sensory receptors to CNS |
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Motor neurons |
efferent neurons of PNS, carry instructions from CNS to peripheral effectors (via efferent fibers, axons) |
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Interneurons |
association neurons, located in brain, spinal cord, and autonomic ganglia, between sensory and motor neurons, distribution of sensory info, coordination of motor activity, memory, planning, learning |
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3 types of Sensory Receptors |
Interoceptors, Exteroceptors, Proprioceptors |
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Interoceptors |
monitor internal systems, internal senses |
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Exteroceptors |
External senses, distance senses |
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Proprioceptors |
Monitor position and movement |
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Efferent Axons |
signals fromCNS motor neurons to visceral effectors pass synapses at autonomic ganglia dividing axons into: preganglionic fibers and postganglionic fibers |
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Neuroglia |
half the volume of the nervous system |
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4 types of Neuroglia in CNS |
Ependymal cells, Astrocytes, Oligodendrocytes, Microglia |
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Ependymal Cells |
highly branched processes, contact neuroglia directly, form epithelium called ependymal, line central canal of spinal cord and ventricles of brain, secrete cerebrospinal fluid (CSF), have cilia or microvilli that circulate CSF, monitor CSF, contain stem cells for repair |
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Astrocytes |
large cell bodies with many processes, maintain blood-brain barrier, create 3-dimensional framework for CNS, repair damaged neural tissue, guide neuron development, control interstitial environment |
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Oligodendrocytes |
smaller cell bodies with fewer processes, Myelination: increases speed of action potential, myelin insulates myelinated axons, makes nerves appear white Nodes and Internodes: internodes- myelinated segment of axon, nodes- gaps between internodes, where axons may branch |
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White Matter |
regions of CNS with many myelinated nerves |
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Gray Matter |
unmyelinated areas of CNS |
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Microglia |
smallest and least numerous neuroglia with many fine-branched processes, migrate through neural tissue, clean up cellular debris, waste products, and pathogens |
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3 types of Neuroglia in PNS |
Ganglia, Satellite Cells, Schwann Cells |
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Ganglia |
masses of neuron cell bodies, surrounded by neuroglia, found in PNS |
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Satellite cells |
also called amphicytes, surround ganglia, regulate environment around neuron |
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Schwann Cells |
also called neurilemma cells, form myelin sheath around peripheral axons, 1 schwann cell sheaths one segment of axon, many schwann cells sheath entire axon |
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Neurons Perform: |
all communication, info processing, and control functions of nervous system |
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Neuroglia Preserve: |
physical and biochemical structure of neural tissue |
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Neuroglia is essential to: |
survival and function of neurons |
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Neural Response to Injuries |
Wallerian Degeneration: axon distal to injury degenerates; Schwann cells: form path for new growth, wrap new axon in myelin |