Lecture 5 Flashcards
What is the purpose of receptors
they tell us about the external environment, our location in space, and whats going on inside our body
What is proprioception
position of body parts
What is exteroception
vision, hearing, smell, touch
What is interoception
internal objects, organs
Percieved sensation is __________ as it relates to stimulus intensity
logarithmic
What side of the spinal cord do sensory neurons come in
dorsal
What is the proprioceptor neuron composed of
body, long t-shaped axon, and sensory ending
Where is the body of the proprioceptor neuron located
in spinal ganglia (dorsal root ganglia)
What type of conduction to proprioceptor neurons do
antidromic
What is the most complex/detailed type of sensory proprioceptor
muscle splindle
Are muscle spindles parallel or perpendicular to extrafusal fibers
parallel
What two types of sensory endings can be found in muscle spindles
primary (Ia)
secondary (II)
Which intrafusal fibers are primary endings found in
all of them
Secondary endings are not seen in ______
dynamic bag fibers
What are the characteristics of the primary sensory endings
really big and fast
How do the secondary sensory endings compare to the primary
they are half the size and speed of the primary
What three components do muscle spindles contain
intrafusal muscle fibers
afferent sensory fiber endings
efferent motor fiber endings
Gamma motor neurons, which are much smaller than alpha motor neurons, innervate what region of the intrafusal fibers
contractile polar
When a gamma motor neuron activates an intrafusal fiber, it will contract, thus increasing its __________
sensitivity to stretch
What are the three types of intrafusal fibers
dynamic bag fibers
static bag fibers
chain fibers
Dynamic bag fibers are innervated by
single primary (Ia) sensory ending dynamic gamma motor neuron
Static bag fibers are innervated by
single primary (Ia) sensory ending a secondary (II) ending static gamma motor neuron
Chain fibers are innervated by
single primary (Ia) sensory ending a secondary (II) ending static gamma motor neuron
What are the primary (Ia) sensory endings sensitive to
muscle length and speed of lengthening
What are the secondary (II) endings sensitvie to
length but not rate
What do gamma motor neurons do
shorten spindles to increase sensitivity to changes in length
What are the two types of small motoneurons (gamma) innervating intrafusal fibers of muscle spindles
dynamic and static
While dynamic gamma motoneurons innervate dynamic bag fibers, what do static motoneurons innervate
static bag and chain fibers
What are gamma motoneurons and what do they innervate
system to modify sensitivity of the spindle endings; innervate intrafusal fibers
Where are golgi tendon organs located
at the muscular tendonous junction
What are golgi tendon organs innervated with
innervated with fast-conducting (Ib) axons of sensory neurons in spinal ganglia (not gamma motor neurons)
What are GTOs sensitive to
changes in force or tension
GTOs are active during what type(s) of muscle actions
all three: concentric, eccentric, and isometric
Muscle force and joint capsule tension have what type of relationship
direct; as one increases the other increases as well
When muscle force and joint capsule tension increase, articular receptors ______ their response
increase
What are articular receptors sensitive to
changes in joint angle and position
What are cutaneous and subcutaneous receptors good for
touch (gripping and holding things)
What receptor measures vertical pressure and are innervated by one axon
merkel disks
Receptors that measure quickly changing pressure and each is innervated by greater than or equal to 2 axons
meissner corpuscles
Receptors that measure deformation of large skin areas and are slowly adapting
ruffini endings
Receptors that measure rapidly changing mechanical deformation such as vibration and are the deepest receptors
pacinian corpuscles
Afferent nerves from what receptors go into the spinal cord through the dorsal roots
peripheral
Where are articular receptors located
in the joint capsule ligament
What are the two primary differences between muscle spindles and GTOs
muscle spindles: 2 sensory neurons, parallel, sensitive to length, gamma motor neuron system
GTO: only have (Ib), in series, sensitive to force
Proprioceptors induce changes in muscle activity that bypass ________
consciousness
What tells us where our arms and legs are and how heavy or light, or rough or soft the objects we handle are
proprioceptors
What kind of system do proprioceptors help to create that the brain uses to plan and execute movements
internal reference (nervous system memory)
