Chapter 12.2- Neurons Flashcards
What are the parts of the neuron
– Cell body (soma)
* Large nucleus and nucleolus
* Perikaryon (cytoplasm)
* Mitochondria (produce energy)
* RER and ribosomes (synthesize proteins)
Dendrites
– Short and highly branched processes extending from cell body
▪ Axon
– Single, long cytoplasmic process
– Propagates electrical signals (action potentials)
– Axoplasm
* Cytoplasm of axon
what are the structural classifications of neurons
Anaxonic neurons
* Small
* All cell processes look similar
* Found in brain and special sense organ
Bipolar neurons
* Small and rare
* One dendrite and one axon
* Found in special sense organs (sight, smell,
hearing)
– Unipolar neurons (pseudounipolar neurons)
* Axon and dendrites are fused
* Cell body to one side
* Most sensory neurons of PNS
Multipolar neurons
* Have one long axon and two or more dendrites
* Common in the CNS
* All motor neurons that control skeletal muscles
What are the functional classifications of neurons
– Sensory neurons
– Motor neurons
– Interneurons
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Describe the sensory neuron
A sensory neuron is an unipolar afferent neuron that extends from the sensory receptors to the CNS.
What are the types of sensory receptors
– Interoceptors
* Monitor internal systems (e.g., digestive, urinary)
* Internal senses (stretch, deep pressure, pain)
– Exteroceptors
* Monitor external environment (e.g., temperature)
* Complex senses (e.g., sight, smell, hearing)
– Proprioceptors
* Monitor the position and movement of skeletal muscles and joints
Describe motor neurons.
Motor neurons are multipolar neurons that are a part of the efferent division which sends instructions from the CNS to the somatic motor neurons of the SNS and the visceral motor neurons of ANS.
The autonomic ganglia divides axons into
Preganglionic fibers
* Postganglionic fibers
Describe the interneuron
It is located between sensory and motor neurons. it helps with the distribution of sensory information and coordination of motor activity.
