reflex
comparatively simple automatic response to a stimulus
reflex arc steps
receptor sensory relay integration motor command relay effector
monosynaptic reflexes
faster and integrated into the spinal cord
monosynaptic reflex example
knee jerk
polysynaptic reflex
at least one interneuron involved
somatic reflex
voluntary involving skeletal muscle
autonomic reflex
reflex that involves smooth muscles, glands, or visceral organs
acquired reflexes
reflexes that are learned through experience
exteroceptors
general sensory receptors that monitor external conditions like heat, cold, pain, pressure
interoceptors
sensory receptors that monitor internal conditions
chemoreceptors
monitor blood pH
visceral stretch receptors
monitors distension of visceral organs
proprioceptors
monitor postural info
free nerve endings
dendrites terminate in epidermic/dermis junction and surrounding tissue; detect pain
merkel cells
associated with free nerve endings; detect light touch
meissner's corpuscles
more superficial encapsulated receptors; detect light touch
pacinian corpuscles
deeper encapsulated receptors; detect forceful pressure
proprioception
sense of body movement and position
muscle spindle
monitor muscle position to ensure muscles don't overstretch
intramural fibers
located in extramural skeletal muscle fibers
alpha-motor neurons
innervate contractile region of extramural fibers
gamma-motor neurons
innervate contractile region of intramural fiber
willful muscle contraction
brain-> gamma-motor neurons to contract the intramural fibers, relieving compression of spindle
receptor transducing function
convert stimuli to action potentials
adaptation
desensitization to constant stimuli
sensitive receptor field
smaller, more dense receptor field