Term
| Functions of the nervous system |
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Definition
Sensory input- information gathered by sensory receptors about internal and external changes
integration- interpretation of sensory input
motor output- activation of effector organs (muscles and glands ) produce a response |
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Term
| Divisions of the nervous system |
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Definition
Central nervous system CNS- brain and spinal cord integration and command center
peripheral nervous system PNS- paired spinal and cranial nerves carry messages to and from the CNS |
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Term
| Peripheral nervous system PNS- 2 functional divisions |
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Definition
Sensory (afferent) division- somatic afferent fibers- convey pulses from skin skeletal muscles and joints. Visceral afferent fibers convey impulses from visceral organs.
Motor (efferent) division- transmits impulses from the central nervous system to effector organs |
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Term
| Motor division of the peripheral nervous system |
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Definition
Somatic (voluntary) nervous system- conscious control of skeletal muscles
Autonomic (involuntary) nervous system ANS- visceral motor nerve fibers. Regulates smooth muscle cardiac muscle and glands. 2 functional subdivisions sympathetic and parasympathetic |
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Term
| Histology of nervous tissues- 2 principal cell types |
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Definition
| Neurons excitable cells that transmit electrical signals. No route you Beliles house – supporting cells |
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Term
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Definition
| Most abundant, versatile, and highly branched glial cells. Cling to neurons, synaptic endings, and capillaries. Support and brace neurons. Help determine capillary permeability. Guide migration of young neurons. Control the chemical environment. Participate in information processing in the brain. |
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Term
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Definition
| Small ovoid cells with thorny processes. Migrate toward injured neurons. Phagocytize microorganisms and neuronal debris. |
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Term
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Definition
| Range in shape from squamous to columnar. Maybe ciliated – line essential cavities of the brain and spinal column. Separate the CNS interstitial fluid from the cerebrospinal fluid in the cavities |
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Term
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Definition
| Branched cells. Processes wrap CNS nerve fibers, forming insulating myelin sheaths |
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Term
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Definition
| Surround neuron cell bodies in PNS |
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Term
| Schwan cells (neurolemmocytes) |
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Definition
| Surround peripheral nerve fibers and form Myelin sheaths. Vital to regeneration of damaged peripheral nerve fibers |
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Term
| Neurons nerve cells special characteristics |
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Definition
| Long-lived over 100 years or more. Amitotic with few exceptions. High metabolic rate – depends on continuous supply of oxygen and glucose. plasma membrane functions in: electrical signaling cell to cell interactions during development |
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Term
| Cell body (perikaryon or soma) |
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Definition
| Biosynthetic center of a neuron. Spherical nucleus with nucleolus. Well-developed Goldie apparatus. Rough ER called Nissl bodies (chromatophilic substance). Network of neurofibrils neurofilament's cytoskeleton. Ask on Hillach – cone shaped area from which axon arises. Clusters of cell bodies are called nuclei in CMS ganglia in the PNS |
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Term
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Definition
| Dendrites and exons. Bundles of processes are called tracks in the CNS nerves and the PNS. |
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Term
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Definition
| Short, tapering, and diffusely branched. Receptive input region of a neuron. Convey electrical signals towards the cell body as graded potentials |
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Term
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Definition
| One axon arising from the Axon hillock. Long axons nerve fibers. Occasional branches axon collaterals. Numerous terminal branches telodendeia. Numerous knob like axon terminals synaptic knobs or Boutons secretory region of a neuron release neurotransmitters to excite or inhibit other cells |
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Term
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Definition
| Conducting region of a neuron. Generate and transmits nerve impulses action potentials away from the cell body. Molecules and organelles are moved along axons by motor molecules in 2 directions: anterograde – toward axon terminal retrograde retrograde towards the cell body |
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Term
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Definition
| Segmented protein lipoid sheath around most long or large diameter axons. It functions to: protect an electrically insulate the axon. Increase speed of nerve impulse transmission |
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Term
| Myelin sheaths in the PNS |
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Definition
Schwan cells wraps many times around the axon. – Myelin sheath – concentric layers of Schwann cell membrane.
Neurilemma- peripheral bulge of Schwann cell cytoplasm. Nodes of Ranvier – myelin sheath gaps between adjacent Schwan cells sites were axon collaterals can emerge |
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Term
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Definition
| Then nerve fibers are unmyelinated. Slower transmission of impulses. |
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Term
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Definition
| Formed by processes of Oligodendrocytes, not the whole cells. Nodes of Ranvier are present. No Neurilemma. Thinnest fibers are unmyelinated |
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Term
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Definition
| Dense collections of myelinated fibers |
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Term
| Mostly neuron cell bodies and unmylenated fibers |
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Definition
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Term
| 3 types of neurons structural classification |
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Definition
| Multi polar, bipolar, Uni polar. |
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Term
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Definition
| 1 axon and several dendrites. – Most abundant. Motor neurons and interneurons. |
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Term
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Definition
| One axon and one dendrite. Rare |
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Term
| Uni polar (pseudo unipolar) |
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Definition
| Single, short process that has two branches: peripheral process – more distal branch, often associated with sensory receptor. Central process – branch entering the CNS. |
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Term
| Functional classification of neurons three types |
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Definition
| Sensory afferent, motor efferent, interneurons association neurons |
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Term
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Definition
| Transmit impulses from sensory receptors towards the CNS |
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Term
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Definition
| Carry impulses from the CNS to effectors |
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Term
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Definition
| Shuttle signals through CNS pathways most are entirely within the CNS |
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Term
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Definition
| Neurons are highly irritable. Respond to adequate stimulus by generating an action potential or nerve impulse. Impulse is always the same regardless of the stimulus |
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Term
| Principles of electricity |
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Definition
| Opposite charges attract to each other. Energy is required to separate opposite charges across the membrane. Energy is liberated when the charges move toward one another. If opposite charges are separated, the system has potential energy |
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Term
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Definition
| Measure of potential energy generated by separated charge |
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Term
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Definition
| Voltage measured between two points |
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Term
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Definition
| The flow of electrical charge ions between two points |
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Term
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Definition
| Hindrance to charge flow provided by the plasma membrane |
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Term
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Definition
| Substance with high electrical resistance |
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Term
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Definition
| Substance with low electrical resistance |
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Term
| Role of membrane ion channels |
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Definition
| Proteins serve as membrane ion channels. Two main types of ion channels leakage non-gated channels always open and gated channels three types |
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Term
| Three types of gated channels |
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Definition
| Chemically gated like in gated channels – open with binding of specific neurotransmitter. Voltage gated channels – open and close in response to charges in membrane potential. Mechanically gated channels – opening clothes in response to physical D formation of receptors. |
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Term
| When gated channels are open |
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Definition
| Ions diffuse quickly across the membrane along their electrochemical gradients. Along chemical concentration gradient from higher concentration to lower concentration. Along electrical gradients toward opposite. electrical charge. – Ion flow creates electrical current and voltage changes across the membrane |
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Term
| Resting membrane potential is generated by |
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Definition
| Differences in ionic makeup of ICF and ECF. Differential permeability of the plasma membrane |
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Term
| Differences in ionic makeup of resting membrane potential |
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Definition
| ICF has lower concentration of sodium and chloride then ECF. ICF has a higher concentration of potassium and negatively charged proteins then ECF |
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Term
| Differential permeability of membrane and resting membrane potential |
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Definition
| In permeable to a minus. Slightly permeable to sodium through leakage channels 75 times more permeable to potassium more leakage channels. Freely permeable to chloride. |
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Term
| Resting membrane potential |
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Definition
| Negative interior of the cell is due to much greater diffusion of potassium out of the cell then sodium diffusion into the cell. Sodium potassium pump stabilizes the resting membrane potential by maintaining the concentration gradients for sodium and potassium. |
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Term
| Membrane potentials that act as signals |
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Definition
| Membrane potential changes when: concentrations of ions across the membrane change. Permeability of membranes ions changes. Changes in membrane potential our signals used to receive, integrate and send information. |
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