2.2.1. Neural Tissue Flashcards
parts of CNS
brain and spinal cord
parts of PNS
cranial, spinal, and peripheral nerves
afferent neurons function
sensory and receptor neurons. Carry nerve impulse from receptors or sense organs toward CNS
efferent neurons function
motor or effector neurons that carry nerve impulses away from CNS to effectors such as muscles or glands
somatic nervous system function
regulates voluntary body movements
autonomic nervous system
regulates involuntary body movements
sympathetic nervous system
part of autonomic nervous system and stimulates fight or flight response as well as homeostasis
parasympathetic nervous system
part of autonomic nervous system and responsible for rest and digest or regulation of internal organs and glands
Neuron components
- cell body (soma)
- axon (transmit)
- dendrites (receive)
- nerve terminals
astrocyte (astroglia)
star shaped glial cell in CNS that provide mechanical/structural support
oligodendrocyte
type of neuroglia. Function is to support and insulate axons of CNS via myelin sheet
glial cells
non-neural cells that maintain homeostasis, form myelin, and provide support and protection for CNS and PNS
steps of neurotransmission
- depolarization of presynaptic membrane which induces opening of calcium channels
- Influx of calcium into presynaptic neuron causes vesicles in presynaptic neuron to release neurotransmitters into synapse
- Neurotransmitters in synapse bind to receptors in postsynaptic region which causes depolarization in postsynaptic membrane
- membrane retrieval occurs by coated vesicles
gray matter composition
mostly cellular elements: cell bodies of neurons and astroglia with dendrites covered by synapses
white matter composition
mostly axons covered by myelin sheet (oligodendrocytes)
Ectoderm is source for this tissue
- epithelial
2. neural
neuron cell body characteristics
- large nucleus
- light cytoplasm with high transcription rate
- contains nissl bodies (granules of RER)
dendrite characteristics
- multiple per neuron and vary in shape
- receptive surface of neurons and form dendritic spines at the postsynaptic element
- motile
- dendrites are extensions of neuronal perikaryon (bulbous part of the neuron with the nucleus)
axon characteristics
- one per neuron but may branch
- thin (.1 to 25 micron) but long (up to several feet)
- highway for neurons: massive macromolecular and organelle movement (axonal transport)
- contain neurofilaments, microtubules, mitochondria
- do not contain ribosomes or golgi
synapse definition
specialized junction enabling communication between pre and postsynaptic neuron
nerve terminal characteristics
- precede a synapse
- communication is chemical and electrical in nature
- presynaptic nerve terminal contain synaptic vesicles that store and release chemical messenger molecules (neurotransmitters)
types of neurotransmitters
- classical
- peptide
- other