Chapter 3) what are the nervous system's functional units Flashcards
Golgi
-The nervous system is composed of a network of interconnected fibers “Nerve Net”
Cajal
-Nervous system is made of discrete cells
-Used the Golgi stain to show that the nervous system was made up of discrete cells thereby supporting the neuron hypothesis
Neuron hypothesis
Neurons are the units of brain function
Basic structure of the cell
-Cell body
-Dendrites, Collect information from other cells
-Axon, carries messages to other neurons
Neurons
-Most behaviors are produced by groups of hundreds or thousands of neurons
-Functional groups of neurons/neural networks connect wide areas of the brain and spinal cord
Dendrites
Gather information from other neurons
Cell body/Soma
-Core region that contains the nucleus (DNA)
-Integrates the information
-Life sustaining support mechanism
Axon
Carries information to be passed on to other cells
Dendritic spine
-Sites of excitatory synapses
-Mediate learning that lasts (habituation, sensitization)
-Structural basis for behavior, memory and individual skills
-Increases dendrites surface area (allows it to receive for input, easier to reach threshold)
-Usually the point of contact with axons of other cells
Axon hillock
-Juncture of the soma and axon
-Where action potential begins
-Must reach threshold before reaching here
Axon collaterals
Branches of an axon
Teleodendria
End branches of an axon
Terminal button/End foot
-Knob at the tip of an axon that conveys information to other neurons
Synapse
-Gap between one neuron and another neuron
-Usually between an end foot/terminal button of an axon and a dendritic spine of another neuron
Sensory neurons
-Afferent
-Carry information from the sensory receptors in or on the body to the spinal cord
-Myelinated axons
-1) Bipolar
-2) Somatosensory dendrite
Interneurons/association neurons
-Associate sensory and motor activity within the CNS
-1) Stellate
-2) Pyramidal cell
-3) Purkinje cell
Motor neuron
-Efferent
-Send signals from the brain and spinal cord to muscles
-Myelinated axons
-Multipolar
-Reside in the lower brainstem and spinal cord and all efferent (outgoing) information must pass through them to reach the muscles
1) Bipolar neurons
Transmit afferent (incoming) sensory information from retina light receptors to the neurons that carry information into the brains visual centers
2) Somatosensory dendrite
Connects directly to its axon so the cell body sits to one side of this long pathway
1) Stellate
-Star shaped cell
-Small
-Many dendrites extend around cell body
2) Pyramidal cell
-Has a long axon
-Pyramid shape body
-Two sets of dendrites
1) Apical
2) Basal
3) Purkinje cell
-Extremely branched dendrites that forms a fan shape
-Dendrites are very dense
5 types of glial cells
1) Ependymal cell
2) Astrocyte
3) Microglial cell
4) Oligodendroglia cell
5) Schwann cell
1) Ependymal cell
-Small, ovoid
-Found in the walls of ventricles
-Make and secret CSF
-Hydrocephalus