Unit 4 Lecture 31 Flashcards
Define reflex
a rapid automatic response to a stimulus
Define reflex arc
the “wiring” of a particular reflex
Define innate reflex
reflex you are born knowing
Define learned reflex
reflex acquired through experience
What are the components of a reflex arc?
- Sensory receptor
- Sensory neuron
- Integrating center (w/ or w/out interneuron)
- Motor neuron
- Effector
What are the 4 classification of reflexes?
- Monosynaptic vs. polysynaptic
- Somatic vs. Autonomic (visceral)
- Cranial vs. Spinal
- Ipsilateral vs. Contralateral vs. bilateral
Define monosynaptic
no interneuron
- direct connection between sensory and motor neuron
Define polysynaptic
has interneuron between sensory and motor neuron
Define somatic
voluntary
Define autonomic
involuntary
Define cranial reflex
reflex needs to go to the brain to process
Define spinal reflex
Reflex is processes at the spine
Define ipsilateral
reflex happens on same side of body as stimulus
Define contralateral
reflex happens on opposite side of body as stimulus
Define bilateral
reflex happens on both sides of body
What are the pathways of 4 reflex arcs?
- stretch reflex
- Tendon reflex
- Flexor reflex
- Crossed extensor reflex
What is unique about all the pathways of reflex arcs?
All are somatic and spinal
What is the purpose of the stretch reflex?
Preventing injury from over stretching muscle
How does the stretch reflex start?
The stretch is sensed by a muscle spindle
Anatomy of a muscle spindle during a stretch reflex
Muscle spindle made of intrafusal muscle fibers
Efferent nerve fiber connect to the end plate of the extrafusal muscle fiber
What results in the stretch reflex?
contraction of muscle that was stretched
Summary of the stretch reflex
Monosynaptic, ipsilateral, spinal, somatic
What is the purpose of the tendon reflex?
To prevent damage from TENSION build up
How does the tendon reflex start?
Tension is sensed by the Golgi tendon organ
Anatomy of golgi tendon organ
Golgi tendon organ is connected to the sensory nerve fiber on a tendon
What results in the tendon reflex?
Restriction of the muscle that is contracting
Summary of the tendon reflex?
Polysynaptic, ipsilateral, spinal, somatic
What is the purpose of the flexor reflex
To protect body from more injuries
How does the flexor reflex start?
Pain (or threat of pain) is sensed by nociceptors
Define nociceptors
A sensory receptor for painful stimuli
Flexor reflex pathway
- tack stimulates sensory receptors
- sensory excited neuron
- In integrating center, sensory neuron activate OTHER SEGMENTS of spinal cord
- motor neuron excited
- effector (flexor muscle) contracts and withdraws leg
What results in the flexor reflex?
flexion of affected limb
Summary of flexor reflex
Polysynaptic, ipsilateral, spinal, somatic
What is the purpose of the crossed extensor reflex?
To stabilize body position when a painful stimulus results in flexion of opposite limb
*usually paired w/ flexor reflex
How does the crossed extensor reflex start?
Pain is sensed by nociceptors
What results in the crossed extensor reflex?
Extension of the opposite limb
Summary of the crossed extensor reflex
Polysynaptic, contralateral, spinal, somatic
