Term
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Definition
| complex, highly organized network of billions of neurons and neuroglia, along with supporting blood vessels and connective tissue. |
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Term
| In order of transmission across synapase, from first structure to last: |
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Definition
| Presynaptic end bulb, synaptic cleft, and postsynaptic neuron. |
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Term
| Membrane potential values, from most negative to zero: |
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Definition
| Resting membrane potential, threshold and depolarized membrane potential. |
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Term
| Basic function of the Nervous system |
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Definition
1. Sensory
2. Integration (CNS)
3. Motor (PNS) |
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Definition
| extensive network of neurons found in the walls of organs of digestive tract. Help in digestive |
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Definition
*Integretes, processes and correlates different types of incoming sensory information, and out going motor commends.
*Scource of thoughts, emotions and memories
*most nerve impulses that muscles to contract and glands to secrete, originate in the CNS |
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Term
| Peripheral Nervous system |
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Definition
Includes all nervous tissue outside the CNS
*cranial nerves and their branches
*spinal nerves and their branches
*ganglia
*sensory receptors |
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| Sensory (afferent) division |
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Definition
| madeup of nerve fibers that convey impulses to the CNS from sensory receptors located throughout the body |
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Definition
| sensory fibers conveying impulses from the skin, skeletal muscles and joints |
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Definition
| sensory fibers conveying impulses from the visceral organs to the CNS |
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Definition
Controls skeletal muscle contractions
*consist of the somatic motor neurons from the CNS that conducts impulses to skeletal muscles only *their cells body is located in the CNS
*Since the motor responses can be controlled consciously, the actin of this part of the PNS is VOLUNTARY. |
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Definition
allows automatic regulation of smooth muscle, cardiac muscles and gland secretions- this occurs at the subconscious level
*visceral motor neurons from the CNS that conduct nerve impulses to:
*smooth muscle, cardiac muscle, glands, and adipose tissue.
*since its motor responses are not normally under conscious control, the actin of the ANS is INVOLUNTARY |
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Definition
The brain of the gut.
*Consists of neurons in enteric plexuses that extend the entire length of gastrointestinal tract. |
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Definition
the excitable nerve cells that transmit electrical signals
*similar to muscle cells, neurons also have the property of electrical excitability: the capability to produce action potential or impulses in response to stimuli. |
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Definition
| supporting cells. *Smaller cells that surround and wrap the more delicate neurons |
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Definition
| produce the insulting covering called myelin sheaths in the CNS |
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Term
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Definition
| epithelial layer formed by the ependymal cells: plays a role in the production of cerebral spinal fluid |
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Definition
produce the insulting covering called the myelin sheaths in the PNS.
*Scwann cells shield most PNS axons (myelinated and unmyelinated) from contracting the interstitial fluid. |
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Term
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Definition
| contains a nucleus surrounded by cytoplasm that includes: lysosomes, mitochondria, golgi complex, lipofusion, and Nissl bodies |
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Definition
prominent clusters of rough ER
* They are the reason why gray matter appears gray |
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Term
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Definition
| clusters of cell bodies in the CNS |
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Definition
| cluster of cell bodies that lie along the nerves in the peripheral NS |
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Definition
| bundles of neuron processes in the CNS |
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Term
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Definition
| bundles of neuron processes in the PNS |
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Term
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Definition
armlike processes extend from the cell body of all neurons
*the brain and spinal cord (CNS) contain neuron cell bodies and their processes
*The peripheral NS consists mainly of neuron processes |
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Term
| Two types of neuron processes |
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Definition
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Term
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Definition
The receiving or input portion of a neuron
*These electrical signals are NOT nerve impulses (action potentials) they are short distance signals called GRADED POTENTIALS |
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Definition
propagates nerve impulses toward another neuron, a muscle fiber, or gland
* They GENERATE and TRANSMIT nerve impulses (ACTION POTENTIAL) away from the cell body |
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Definition
| An elevation where the axon joins the cell body (in the case of multipolar neurons) |
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Term
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Definition
the junction of the axon hillock and the initial segment
*the site where most neuronal impulses arise |
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Definition
The plasma membrane surrounding the axoplasm
*in the central NS, the axolemma may be exposed tot he interstitial fluid or it may be covered by the processes of neuroglia |
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Definition
Side branches of the axon
*collaterals allow a single neuron to communicate with many other cells. |
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Term
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Definition
| the axon and its collaterals end by dividing into many fine processes called axon terminals |
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Definition
| the site of communication between two neurons or between a neuron and an effector cell |
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Definition
sends the message
*usually a neuron |
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Definition
receives the message
*a neuron or another cell type
*neuromuscular junction, neuroglandular junction and adipocytes |
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Term
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Definition
| aggregations of myelinated processes in regions of the brain and spinal cord |
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Term
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Definition
| consists of neuronal cells bodies, dendrites, UNMYELINATED AXONS, axon terminals and neuroglia |
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Term
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Definition
| Multiple sclerosis, diphtheria and heavy metal posioning |
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Term
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Definition
Sheath of Schwann
*the outer nucleated cytoplasmic layer of the Schwann cell, which encloses the myelin sheath
*A neurilemma is found only around axon in the PNS
*the neurilemma aids in the repair of injured axons
*a schwann cell can enclose portions of several unmyelinated axon too!! |
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Term
| Regeneration and Repair of Nervous tissue |
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Definition
*the cell body is intact
*the schwann cells are functional
*scar tissue formation does not occur too rapidly (astrocytes produce scar tissue) |
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Definition
| Allows communication over short and LONG distances within the body |
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Definition
| Used for short distance communication only |
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Term
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Definition
| Used for short distance communication only |
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Term
| Leakage channels (Passive) |
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Definition
ALWAYS OPEN
*The plasma membranes have many more K+ leakage channels that Na+ leakage channels |
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Term
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Definition
Open and close in response to a stimulus
*The presence of gated ion channels in the plasma membranes of neurons and muscle fibers gives these cells their property of electrical excitability. |
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Term
| Voltage gated ion channels |
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Definition
*Opens in response to a change in membrane potential (voltage)
*Used in the generation and conduction of action potentials
*FOUND ON THE MEMBRANES OF EXCITABLE CELLS
*Axons of unipolar and multipolar, sarcolemma and T tubules of skeletal muscle fibers and cardiac cells |
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Term
| Ligand gated ion channels (Chemically gated) |
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Definition
*Opens and closes in response to a specific chemical stimulus
*found greatly on dendrites and cell body of neurons |
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Term
| Mechanically gated ion channels |
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Definition
*Opens and closes in response to mechanical stimulation (vibration, pressure, tissue stretching)
*found in auditory receptors in the ears, in receptors that monitor stomach stretching, in touch receptors in the skin. |
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Term
| Change in resting membrane |
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Definition
ALL NEURAL ACTIVITIES START WITH A CHANGE IN THE RESTING MEMBRANE POTENTIAL OF A NEURON.
*Change is produced by anything that changes membrane permeability to any type of ion, and anything that alters ion concentration on the two sides of the membrane. |
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Term
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Definition
reduction in the membrane potential
*the inside of the membrane becomes less negative or more positive than the resting membrane potential |
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Term
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Definition
| The membrane potential becomes more negative or less positive than the resting membrane potential |
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Term
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Definition
step by step depolarization of each adjacent portion of the plasma membrane.
*this type of conduction occurs in muscle fibers and unmyelinated axons |
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Term
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Definition
occurs in myelinated axons (much faster and more efficient)
*at the nodes of ranvier, the myelin sheath is interrupted and the axolemma has a high density of voltage-gated ion channels |
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Term
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Definition
Large diameter fibers and brief refactory periods
*these fibers carry motor commands to skeletal muscles (268 mph) |
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Term
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Definition
| smaller diameter axons and a somewhat longer refractory period (40 mph) |
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Term
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Definition
have the smallest diameter and the longest absolute refractory period (2 mph)
*unmyelinated axon |
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Term
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Definition
| carry information to the CNS about temperature, pain and general touch and pressure and they carry instruction from the CNS to smooth muscle, cardiac and glands |
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Term
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Definition
the delay that occurs between the arrival of the action potential at the synaptic knob and the effect it has on the postsynaptic membrane
*the fewer synapes involved the shorter the total synaptic delay and therefore, the faster teh responses |
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Term
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Definition
| when the neurotransmitter store cannot keep up with demand for the NT, teh synapse will be inactive until more neurotransmitter is available |
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