Exam 3 Nervous System 1 Flashcards
what are the three types of neurons?
bipolar, pseudounipolar, and multipolar
what do bipolar neurons function in?
sensory function; specifically vision and olfactory reception (sight and smell)
what do bipolar neurons look like?
two prominent extensions going off the cell body in opposite directions
what do pseudounipolar neurons look like?
continuous dendrite and axon that bypass the major part of the cell body
what is special about pseudounipolar neurons?
the dendrite can carry an AP (functions like an axon)
what is the dendrite of the pseudounipolar neuron called and why?
peripheral axon; carries sensory information from the peripheral sensory receptors in the body toward the cell body)
what is the axon proper of the pseudounipolar neuron called and why?
central axon; carries sensory information from the dendrite/peripheral axon toward the CNS where it connects to part of the CNS
pseudounipolar neuron cell body
DOES NOT appear to function in integration of incoming sensory signals, unlike motor neurons
what do multipolar neurons look like?
dendrites at the top (multiple coming off the cell body) with one long prominent axon which ends at the terminals
what do multipolar neurons function as?
motor neurons
what are neurons in the CNS called and why?
post-mitotic cells; once they mature, they no longer divide
what is the exception to post-mitotic cells in the CNS?
neurons in the hippocampus; they continually divide in order to form and maintain new memories
what is the function of Schwann cells and Oligodendrocytes?
synthesis myelin, incorporate it into their cell membranes, cell membranes grow, and they envelop the axons of neurons in a concentric circular arrangement
where are Schwann cells found?
Peripheral NS
where are Oligodendrocytes found?
Central NS
what does myelin act as?
an insulator on the axons because it’s nonpolar lipid so there is no Na/K current
what do myelinated cells exhibit?
saltatory conduction
what is the relationship between one Schwann cell and the axon of a neuron that it will myelinate?
1:1
how many axons of different neurons can Oligodendrocytes myelinate?
many
what is the general function of Astrocytes?
regulate the cellular environment and the surrounding environment that neurons exist in
what are the specific functions of Astrocytes?
- connect the capillaries that feed blood to the brain to the neurons
- involved in transporting nutrients from the blood to the neurons
- nourishing function to the neurons of the CNS
what percent accounts for the weight of the brain on the body’s weight? and how much is the brain responsible for metabolism?
brain weight is about 8% of body weight, but is responsible for about 25% of total metabolism
what is the function of Astrocytes and foot processes?
astrocytes surround groups of neurons or individual neurons and help isolate them from other groups of neurons