ilm1993's version from 2017-07-03 18:56

Type of Neurons

Question Answer
BipolarFound in special senses
UnipolarFound in PNS; have a dorsal horn
MultipolarFound all over the body
Dorsal hornContain unipolar neurons; sensory neurons
Ventral hornmultipolar neurons; motor neurons


Question Answer
Sensory inputmonitoring stimuli; transmits impulses toward CNS
Integrationinterpretation of sensory input; shuttle signals through CNS pathways
motor inputresponse to stimuli ; transmits impulses away from CNS

Central nervous system

Question Answer
What is a part of the CNS?Brain and spinal cord
Visceral afferent fibers carries impulses from visceral organs to the brain
Sensory afferent fiberscarries impulses from skin, skeletal muscles and joints to the brain
Motor efferent divisionCNS to effector organs
NucleusBundle of soma in CNS; GREY MATTER


Question Answer
Peripheral nervous systemPaired spinal and cranial nerves
Somatic nervous systemconscious control of skeletal muscles
Autonomic nervous systemregulates smooth muscle, cardiac muscle and glands
Neuronsexcitable cells that transmit electrical signal

Supporting Cells

Question Answer
Supporting cellscells the surround and wrap neurons
Glial cellsinsulate neurons, guide young neurons, promote health and growth
Astrocytesmost abundant glial cells; on neurons and their synaptic ending. In blood and brain
Microglial cellssmall cells with spiny process; phagocytes
Ependymal cellsline spinal cord and brain; like epithelial cells
Ogliodendrocytewrap CNS nerve fibers ; create myelin sheath. On axon
Schwann cellssurround fibers of PNS; creates myelin sheath ONLY PNS NEUROGLIAL CELL. Contain myelin sheath.
Satellite cellssurround neural cell bodies with ganglia; have ventral horn


Question Answer
Axon Hillock where axons arise
SomaCell body Has no centrioles, has nissl bodies (rough ER)
Neuronslong lived, amitotic, high metabolic rate
Processesaxons and dendrites
Dendriteshort; input regions of the neuron; electrical signals are conveyed as graded potentials
Axonsgenerate and transmit action potentials; secrete neurotransmitters
Myelin sheathwhite matter; protects and increases speed of nerve impulse
Neurilemmaremaining nucleus and cytoplasm in a Schwann cell
Nodes of Ranviersites where axon collaterals can emerge; gaps; Contain Na gated channels
Unmyelinated Axonsschwann cells but no coiling
Axon piliPacked with Na voltage gated channels. When Excited Na will move in


Question Answer
White matterdense collections of myelinated fibers; formed by oligodendrocytes
Grey mattersoma and unmyelinated fibers; Nssl body
Multipolarthree of more processes from cell body
Bipolar2 process (axon and dendrite) from cell body
Unipolarshort, single process from cell body

Electrical current of the body

Question Answer
What does it Reflect?Reflects the flow of ions rather than electrons
There is a potential on either side of membranes whenThe number of ions is different across the membrane

Types of ion channels

Question Answer
Passive, or leakage, channels always open
Chemically gated channels open with binding of a specific neurotransmitter
Voltage-gated channels open and close in response to membrane potential
Mechanically gated channels open and close in response to physical deformation of receptors
Electrochemical gradientthe electrical and chemical gradients taken together

Na –K Gated Channels

Question Answer
Closed when a neurotransmitter is not bound to the extracellular receptorNa+ cannot enter the cell and K+ cannot exit the cell
Open when a neurotransmitter is attached to the receptorNa+ enters the cell and K+ exits the cell
When openions move quickly via electrochemical gradient. Electrical current is created

Voltage-Gated Channels

Question Answer
Closed when the intracellular environment is negativeNa+ cannot enter the cell
Open when the intracellular environment is positiveNa+ can enter the cell

Resting membrane potential

Question Answer
Generated byNa, K, Cl and A-
Inside the cellK and A-
Outside the cellNa and Cl
Are the gates closed or open? closed
Outside isnegative
Inside ispositive

Depolarization phase

Question Answer
What moves in?Na
___ gates are opened; ____ gates are closedNa, K
Theshold? -55 to -50mV

Repolarization phase

Question Answer
_________ gates close Na
____ gates close, voltage-sensitive ___ gates openNa, K
_________ exits the cell and internal negativity of the resting neuron is restoredK
Sodium-Potassium pumprestores ionic distribution


Question Answer
____ gates remain open, causing an excessive efflux of ___Potassium;K
The neuron is ____ to stimulus and depolarization during this timeinsensitive
What makes the neuron go back to resting potential?Na-K ATPase pump

Membrane potential changes

Question Answer
Membrane potential changes are produced bychanges in membrane permeability, alteration of ion concentrations
Types of signalsgraded and action potential
Depolarization the inside of the membrane becomes less negative
Repolarizationthe membrane returns to its resting membrane potential
Hyperpolarization the inside of the membrane becomes more negative than the resting potential
Graded potentialslocals changes in the membrane potential; can initiate action potential
All or nothingaction potentials either happen completely, or not at all
The ___ determines stimulus intensity by the frequencyCNS
Absolute Refractory periodtime from the opening of the Na activation gates until the closing of inactivation gates; depolarization
Relative refractory periodrepolarization and hyperpolization
Rate of impulse is determined byaxon diameter, myelin shealth
Saltatory conductionaction potential is only triggers at the bodes and jump from one node to the next
Saltatory conductions happens in thenodes of ranvier

Action Potential

Question Answer
Amplitude? 100mV
How are they generatedmuscle cells and neurons
Functionneural communication
Action potential in axonnerve impulse


Question Answer
Acetylcholineraseenzyme which break down ACh
ESPSgraded potentials that can initiate an action potential in an axon; uses chemically gated channels
IPSPReduces the postsynaptic neuron’s ability to produce an action potential; more permeable to potassium and chloride ions
Spatial summationpostsynaptic neuron is stimulated by a large number of terminals at the same time
Temporal summationpresynaptic neurons transmit impulses in rapid-fire order