Neurons Flashcards
Define neurons.
Basic building blocks of the nervous system. Take information from sensory organs to the central nervous system, and from the central nervous system to various effectors.
What does the cell body contain?
Nucleus and organelles
What are dendrites?
Short and branches extension of the neuron that receives impulse and directs them towards the cell body.
Define axon
Thin extensions of the neuron that usually conduct impulses away from the cell body.
What are the components of a neuron?
Cell body, dendrites, axon, myelin sheath.
What are the nodes of ranvier?
Gaps between the myelin sheath that force impulses to travel from node to node.
What is a neurilemma?
A membrane that covers the myelin sheath. It has a protective function and can assist in the regrowth of damaged neurons.
What are axon terminals?
Small knobs on the ends of axons that contain neurotransmitter chemicals, which release when a nerve impulse arrives.
What are the basic types of neurons?
Bipolar, unipolar, multipolar, pyramidal cell.
What is a multipolar neuron?
A motor neuron.
Multiple dendrites and a single axon.
What is a bipolar neuron?
One dendrite and one axon.
Special sensory.
Found in sensory organs, such as the nose, eyes and ears.
What is a unipolar neuron?
A sensory neuron.
Cell body off to one side. One projection carries the impulse towards and then away from the cell body, technically one axon.
What are the distinguishing features of unipolar sensory neurons?
Receptors found at the end of dendrite.
Cell body attached to the side of the axon.
What are the distinguishing features of a motor neuron?
Short dendrite, long axon. Cell body at the end of the neuron.
What is an interneuron?
A neuron which acts as a relay station between the sensory and motor neurons. Found within the central nervous system. Distinguishing features are its’ short axons and dendrites, and the large size of the cell body in proportion to the cell.
