nervous system Flashcards
function of the nervous system
controls the body by communicating with the various parts
- foundation of our conscious experience, personality and behaviour
2 divisions of the nervous system
CNS-brain/spinal cord
peripheral nervous system-cranial and spinal nerves. afferent(sensory) and efferent (motor)
sensory division subunits
visceral sensory division: internal environment-carries info from the organs of the thoracic and abdominal cavity
somatic sensory division: external environment-receptors in skin. position/movement: muscles, bones and joints
motor division
-visceral motor division: autonomic nervous system. involuntary. sympathetic and parasympathetic
- somatic motor division- voluntary: carries signals to skeletal muscles
2 cells of nervous tissue
neurons and neuroglia
neuroglia of cns and functions
-astrocytes: nutrient/repair
- oligodendrocytes: myelinate neurons
- microglia: macrophages
- ependymal cells: specialized epithelial cells
neuroglia of pns
schwann cells- myelinate neurons
satellite cells- regulate external environment
what is a neuron
basic functional unit of the nervous system
properties of neurons
-excitability (irritability)
- conductivity
- secretion…axon terminals release neurotransmitters
neuron classification-structure and function
- multipolar neurons-away from CNS
- bipolar neurons - special senses
- unipolar neurons- impulses to CNS
afferent (sensory) neurons
from tissues conduct impulses to cns
efferent (motor) neurons
impulses away from CNS to tissues
interneurons
in cns
90% of neurons
connect sensory and motor pathways
nucleus
clusters of cell bodies in CNS (grey matter)
ganglion
cluster of cell bodies in the PNS
tract
bundles of myelinated axons (fibers) in the CNS (white matter)
nerve
bundle pf axon fibers in the pns (often wrapped in connective tissue)
what are nerves classified by
identified based on direction of impulses
mixed nerves
carry both sensory and motor impulses
