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Flashcards in Nervous Tissue Deck (27):

What is the long neuronal process that generally conducts impulses away from the soma of the nerve cells?



What are the shorter processes that receive impulses and carry them toward the soma of a neuron?



What term refers to the cellular mechanisms for producing electrical potentials and currents?



How does signal conduction along unmyelinated fibers work?

Unmyelinated fibers have voltage-gated channels along their entire length, and a zone of depolarization excites voltage-gated channels immediately distal to the action potential.


List the events of a single action potential in order

1: Local potential depolarizes membrane;
2: Threshold is reached;
3: Depolarization spike;
4: Repolarization;
5: Hyperpolarization


List the 6 kinds of neuroglia and tell whether they are in the central nervous system or the peripheral nervous system

CNS: Astrocytes, Microglia, Ependymal cells, Oligodendrocytes;
PNS: Satellite Cells, Schwann Cells


What is the location/function of Satellite cells?

In PNS; surround somas of neurons in ganglia, provide electrical insulation, and regulate the chemical environment of neurons


What is the location/function of Schwann cells?

In PNS; form neurilemma around all PNS fibers and myelin around most of them; aid in regeneration of damaged nerve fibers


What is the location/function of Ependymal cells?

In CNS; line cavities of the brain and spinal cord; secrete and circulate CSF


What is the location/function of Microglia?

In CNS; phagocytize microorganisms, foreign matter, and dead nervous tissue


An electrical potential is a form of what type of energy?

Potential energy


What are the three functional classes of neurons?

Interneurons, sensory neurons, motor neurons


What is the function of somatic neurons?

carry impulses to skeletal muscles and from receptors in the skin


What are some characteristics of neurons?

Excitability and conductivity


What are some characteristics of neuroglia

Bind neurons together and provide a support scaffold; protect the neurons and help them function


How does the endocrine system communicate?



How does the nervous system communicate?

sending quick electrical and chemical messages from cell to cell


What are the two subdivisions of the autonomic nervous system, and what are their functions?

Sympathetic: arouse body for action;
Parasympathetic: has a calming effect


What term is used to describe signal conduction along a myelinated axon?

Saltatory - signal passed from soma to first node of ranvier, where it activates a voltage-gated channel and gets boosted to next node, and so on and so forth up to the terminal. appears to "jump" from node to node


List, in order, the basic steps that describe how the nervous system helps maintain homeostasis

1: Information received by sensory receptors and is transmitted to the CNS;
2: Information is processed and an appropriate response is determined;
3: A command is issued to effectors such as muscles or glands


List the order of events involved in transmission at a cholinergic excitatory synapse, starting with a signal reaching the distal end of the presynaptic axon

1: Opening of calcium gates in synaptic knob as nerve signal arrives;
2: Exocytosis of ACh; diffusion across synaptic cleft;
3: Binding of ACh to receptors on postsynaptic neuron;
4: Opening of sodium gates on post-synaptic membrane allowing influx of sodium;
5: Depolarization of postsynaptic plasma membrane


List the order of events initiated in an adrenergic synapse, after norepinephrine binds to its receptor.

1: G protein dissociates from receptor protein;
2: G protein binds to adenylate cyclase;
3: Adenylate cyclase is activated
4: ATP is converted to cAMP by adenylate cyclase
5: cAMP induces multiple effects in the cell


Give the location and function of Substance P

Found in brain, small intestine, and pain-receptor neurons;
mediates pain transmission


Give the location and function of Enkephalins

Various areas of the brain and spinal cord;
Act as analgesics by inhibiting substance P, secretion increases during labor


Give the location and function of beta-endorphin

Found in digestive tract, spinal cord, and many parts of the brain;
Secreted as a hormone by the pituitary; suppresses pain; reduces fatigue; may produce "runner's high"


Give the location and function of Cholecystokinin (CCK)

Cerebral cortex and small intestine;
Suppresses appetite


What are the two subdivisions of the peripheral nervous system and what are their purposes?

1: Somatic motor division - carries signals to the skeletal muscles
2: Visceral motor division (autonomic nervous system) - carries signals to glands, cardiac muscles, and smooth muscle