somatosensation
Ability to sense touch, pain and temperature
T/F: sensory information detected from one side of the body is perceived by the opposite side of the brain
true
alpha motor neuron
a motor neuron that innervates extrafusal muscle fibers
extrafusal muscle fiber
one of the muscle fibers that are responsible for the force exerted by contraction of a skeletal muscle
the final common path
a term for the spinal cord motoneurons, the ones ultimately responsible for stimulating peripheral muscles to generate behavior
cutaneous sensation
touch, pressure, heat, cold, and pain
free nerve ending
respond to temperature changes and pain
encapsulated receptor
primarily mechanoreceptors that inform about object movement and friction
proprioception
our sense of body position
proprioceptor
low threshold mechanoreceptors that inform the CNS about movement and position by detecting the stretch of the tissue in which they lie
muscle spindle
fusiform structures that run in parallel to extrafusal fibers; conveys information about muscle length and stretch
which muscles have more spindles?
muscles used for precision movements (extraocular eye muscles, fingers/hands)
golgi tendon organ
detects tension
joint receptors
act as limit detectors
gamma motor neuron
innervates intrafusal muscle fibers; causes contraction of the spindle, keeping it taut
what innervates muscle spindles?
One efferent fiber and one or more afferent fibers
type Ia afferent
sensitive to speed and length of stretch; faster
type II afferent
sensitive to length of stretch, not speed; slower
reciprocal inhibition
the simultaneous contraction of one muscle and the relaxation of its antagonist to allow movement to take place
where are GTOs located?
myotendinous junction
how do vibration illusions work?
type Ia spindle afferents are selectively stimulated
visual capture
the tendency for vision to dominate the other senses
ruffini-like receptors (type I)
slowly adapting nerve fibers; signals static joint position, joint movement, direction and speed of movement
paciniform receptors (Type II)
rapidly adapting nerve fibers; signals joint movement (especially velocity)
golgi endings (Type III)
slowly adapting receptors; only found in ligaments (role unknown)
free nerve endings (Type IV)
signals tissue damage; located in fibrous capsule and ligaments
which receptors are found in the fibrous part of the joint capsule?
ruffini-like and paciniform receptors