The ANS Maintains Homeostasis
by Regulating the Activities of.
Smooth muscle, glands, cardiac muscle
Dual ANS innervation
most body organs receive impulses from
both sympathetic
and
parasympathetic neurons
functioning in opposition to
one
another; if the sympathetic excites
then the
parasympathetic inhibitis
Sensory input for ANS
Introceptors
ANS regulated by which parts of the brain
hypothalamus and medulla
Polarized neurons
Resting state of neurons, there are more negative charges inside than outside. Not transmitting an impulse
Graded potential
Short distance, happens when gated channels produce a local current that dies after a few millimeters Most occur in dendrites & cell bodies, they do not travel down the axon. Can be added together or cancel each other out. Becomes less negatively charged
Depolarizing graded potential
a stimulus that causes a reduction of the
difference in charge
across the membrane (cell becomes less negatively
charged with
respect to the extracellular fluid)
Hyperpolarizing graded potential
causes the cell to be more negatively charged Most graded potentials occur in dendrites & cell bodies, they do not travel
Perception vs sensation
Perception is awareness and interpretation, sensation is awareness of changes only
Integration
process of combining each
piece of incoming information with
other
arriving and previously stored information
parts of sensation
simulation, transduction, generation, translation/integration
First order neurons
the first neuron in a specific tract - from peripheral somatic sensory receptors to spinal cord or brain stem. facial areas transmitted by cranial nerves
Second-order Neurons
Cell bodies reside in dorsal gray
horn or medullary
nuclei
Transmit sensory impulses from
the brain stem where
their axons
decussate (cross over to opposite
side) before
ascending to the
thalamus or to cerebellum
Synapse with
third-order neurons
third order neurons
Cell bodies reside in thalamus
Relay impulses to the
primary
somatosensory area of cerebral
cortex (post central
gyrus on the
same side)
Results in conscious perception
of
the sensation
Proprioceptors
muscles tendons joints and inner ear - body position ( in muscles these ARE muscle spindles)
Interoceptors
BV, organs, muscles and nervous system. Not consciously perceived, signals internal environment
Phantom pain
due to irritation of a nerve ending in the
healing wound surface
of the amputation; AP is carried to
part of brain and projected
back to portion of limb that is no
longer intact
Thermoreceptors
Adapt quickly to sensation, but lowers signal strength as time goes on. free nerve endings
Nociceptor
Fast and slow types of pain, free nerve endings, found in every type of tissue except for the brain