Vanders Physiology Flashcards
What 2 sections is the nervous system divided into?
Central nervous system
Peripheral nervous system
What are glial cells?
Non-neuronal cells. Don’t participate directly in electrical communication.
What is the soma of a neuron?
A cell body
What is the function of dendrites?
Receive incoming information from other neurons
They increase the cells surface area
Dendritic spines further increase surface area so further increase amount of info it can receive
In terms of axons, what is a collateral?
What does a greater degree of branching mean?
A branch in the axon
More branching - increases sphere of influence
Where on the axon are the neurotransmitters released from?
Axon terminal
On some neurons…
Bulging areas along the axon called varicosities
Difference between axon insulation in the brain and in the peripheral nervous system?
Both have a myelin sheath
In brain - from oligodendrocytes - one cell, many insulations
In PNS - schwann cells - one cell, one insulation
How are materials moved up and down the axon of neural cells?
Microtubule skeleton running the length of the axon
Motor proteins: kinesins and dyneins
Kinesin mostly transport from cell body towards axon terminals
Dyneins other direction
What are the 3 functional categories of neurons?
Afferent neurons - sensory - convery info towards CNS
Efferent neurons - motor - convey info away from CNS
Interneurons - connect neurons within the CNS
What is the difference about the afferent and efferent cell bodies?
Afferent - cells bodies outside the CNS e.g. dorsal root ganglion
Efferent - cell bodies within the CNS though there are exceptions e.g. enteric nervous system
What proportions of neurons are interneurons? (completely within the CNS, connect 2 neurons together)
99%
What are the characteristics of afferent neurones?
Transmit information into the CNS from receptors at their peripheral endings
Single process from the cell body splits into a long peripheral process (axon) that is in the PNS and a short central process (axon) that enters the CNS
What are the characteristics of efferent neurons?
Transmit information out of the CNS to effector cells, particularly muscles, glands, neurons, and other cells
Cell body with multiple dendrites and a small segment of the axon are in the CNS, most of the axon is in the PNS
What are the characteristics of interneurons?
Functions as integrators and signal changers
Integrate groups of afferent and efferent neurons into reflex circuits
Lie entirely within the CNS
Account for >99% of all neurons
