Question | Answer |
Axon | Neuron has only one, Impulse generator and conductor; Transmits impulses away from the cell body
Multiple branches at end of axon, Terminal branches end in knobs called axon terminals (also called end bulbs or boutons) |
Dendrites | Extensive branching from the cell body;Transmit electrical signals toward the cell body; Function as receptive sites for receiving signals from other neurons |
Types of Neurons-Structural classification | number of dendrites
Unipolar
Bipolar
Multipolar |
Types of Neurons-Functional classification | Sensory
Integrating
Motor |
Neurons structure | Soma:cell body, contains typical cell structures
CNS collection of neuron cell bodies=nucleus; PNS=ganglion |
Functions of the NS | Ovrall is control and communication, achieved through
Monitoring internal/ external stimuli
Processing and interpreting stimuli;Responding to stimuli to maintain homeostasis |
Organization of the NS | CNS, Structures:Brain; Spinal cord
Functions:Integration of incoming stimuli |
Organization of the NS (con't) | PNS; Struct: Cranial nerves,Spinal nerves
Funct:Transduce and direct incoming stimuli to CNS (afferent pathway); Innervate muscles and glands to produce effect (efferent pathway) |
Peripheral Divisions | Somatic:Afferent pathway from external stimuli/
Efferent pathway to skeletal muscles
Visceral:Afferent pathway from internal stimuli
/Efferent pathway to smooth muscle, cardiac muscle, and glands |
Nervous Tissue | consists of branching neurons (nerve cells) and support cells (glia).
is capable of initiating and conducting electrical signals |
Neuron-Characteristics | Longevity:can live/ function for a lifetime; Mostly amitotic:fetal neurons lose their ability to undergo mitosis; neural stem cells are an exception; High metabolic rate:require abundant oxygen and glucose |
Glia | Neuroglia
Glial cells have branching processes and a central cell body
Outnumber neurons 10 to 1
Make up half the mass of the brain
Can divide throughout life |
CNS support cells
Oligodendrocytes | Form myelin in CNS |
PNS support cells
Schwann cells | surround axons in the PNS
Form myelin sheath around axons of the PNS |
Myelin | insulates the axon and ensures the integrity of the neuron’s electrical signal; an outgrowth of the glial cells that produce it;mostly fat with some proteins |
Synaptic-Chemical | Neurons connected by physical space
Electrical activity in pre-synaptic neuron produces chemical exocytosis that acts on post-synptic neuron. |
Spinal Cord Anatomy-Gray Matter | gray color; surrounds hollow central cavities of the CNS; forms H-shaped region in SC; Dorsal half has cell bodies of interneurons;Ventral half has cell bodies of motor neurons; Primarily has of neuronal cell bodies, dendrites, unmyelinated axons |
Spinal Cord Anatomy-White Matter | Lies external to the gray matter of the CNS; Composed of myelinated axons; Consists of axons passing between specific regions of the CNS
Tracts are bundles of axons traveling to similar destinations |