Reflex Sensation
Describe referred pain:
A sensory experience when pain in one area of the body is sensed in another area of the body.
Describe crossed extensor reflex:
Accompanies flexor reflex in weight bearing limbs, particularly important in maintaining balance. Complex spinal reflex consisting of ipsilateral withdrawal reflex and contralateral extensor reflex. Ex: Stepping barefoot on broken glass and your body instantly pulls away while you still keep balance.
What is the importance of reflex testing in a routine physical examination?
Assess the condition of the nervous system. Distorted, exaggerated, or absent reflexes may indicate degeneration or pathology.
Describe Flexor reflex:
Automatic withdrawal from painful stimulus. Ipsilateral and polysynaptic.
What is an autonomic reflex?
Autonomic (or visceral) reflexes are mediated through the autonomic nervous system and we are not usually aware of them. Gag reflex,
Describe stretch reflex:
By sending commands to the motor neurons the brain senses and sets a muscles length. The reaction of teh stretch reflex is trying to keep the muscle at the same length by shortening the muscle. The stretch reflex is important for maintaining muscle tone and adjusting it reflexively. Patellar, (knee jerk). Or Achilles reflex.
Describe golgi tendon reflex:
By sending commands to the motor neurons the brain senses and sets a muscles length. The reaction of the stretch golgi tendon reflex is trying to keep the muscle at the same length by relaxation and lengthening the muscle.
In what reflexes do higher brain centers participate and why?
Corneal Reflex, Gag Reflex, use cranial nerves.
Example Polysynaptic Reflex:
Crossed extensor reflex
What decreases excitatory levels of muscles?
Fatigue
how does increasing the excitatory levels of the spinal cord effect reflexes?
Gets spinal inhibitors out of the way.
What is a contralateral or ipsilateral response?
Ipsilateral, reflex on same side of body. Contralateral, opposite side of body.
What increases excitatory levels of the spinal cord?
Mental distraction
How do differences if receptor density effect the ability to locate a stimulus.
More density leads to more accurate location.
Give example of cord mediated reflex
Patellar reflex,
Define Reflex:
Rapid involuntary response to a stimulus.
Name Five essential components of a Reflex Arc:
Receptor, Sensory Neuron, Integration center, Motor neuron, Effector.
Define Cord mediated Reflex
Reflex that goes through the spinal cord, but does not use higher functions of the brain, ie, Balance
Describe superficial reflex:
Reflexes elicited by gentle cutaneous stimulation, (stroking the skin with a tongue depressor or brush.) Plantar reflex and abdominal reflex.
What is a somatic reflex?
Somatic reflexes involve the stimulation of skeletal muscles by the somatic division of the nervous system. Ex Patellar reflex. Achielles, Corneal,
Describe Monosynaptic reflex:
When a reflex arc consists of only two neurons in an animal (one sensory neuron, and one motor neuron), it is defined as monosynaptic. Monosynaptic refers to the presence of a single chemical synapse. In the case of peripheral muscle reflexes (patellar reflex, achilles reflex), brief stimulation to the muscle spindle results in contraction of the agonist or effector muscle.
Describe the adaption of receptors with regard to action potential production.
When pressure is first applied to the corpuscle, it initiates a volley of impulses in its sensory neuron. However, with continuous pressure, the frequency of action potentials decreases quickly and soon stops. This is the phenomenon of adaptation.
Describe Polysynaptic Reflex:
in polysynaptic reflex pathways, one or more interneurons connect afferent (sensory) and efferent (motor) signals. All but the most simple reflexes are polysynaptic, allowing processing or inhibition of polysynaptic reflexes within the spinal cord.
Describe superficial reflex:
more needed
Reflex arc of the Achilles reflex:
more needed
Reflex arc of the patellar reflex:
more needed
