Nerve Reflexes Flashcards
Pathways of reflex arc
(River sometimes invade mountain environments)
Receptor
Sensory neuron
Interneuron
Motor neuron
Effector
An often-used model of nerve pathways is the ___.
reflex arc
A ___ are is a way of visualizing the direction of transmission of nerve, signals (action potentials).
reflex arc
Synthesizing the component parts of the reflex arc, we see that a ____ at the receptor results in a reaction by an effector.
stimulus
TRUE or FALSE
In addition, less than one sensory neuron may converge on a single association neuron, or multiple motor neurons may diverge from a single association neuron.
False, more than one sensory neuron
Autonomic reflexes typically involve ___ efferent neurons, whereas somatomotor reflexes involve only ___ efferent neuron.
two, one
Afferent and efferent neurons generally form bundles of parallel fibers called ___ (in the peripheral nervous system [PNS]) or ____ (in the CNS)
nerves, tracts
a classic example of stretch reflex in which the stimulus is stretching of the quadriceps femoris muscles; done when the patellar ligament is tapped.
Function: Measures the posture maintenance and coordination of muscle activity if absent or greatly exaggerated, it may indicate that neurons within the brain or spinal cord is damaged
The patellar reflex, or knee-jerk reflex
(exaggerated response) results from damaged or diseased motor areas in the central nervous system
hyperreflexia
(inhibited response) results from degeneration of nerve pathways, voluntary motor control, and other factors
hyporeflexia
The ___ is a spinal reflex that involves nerves C5 and C6. Have the subject sit with the elbow flexed at approximately 90 degrees and palm facing downward. Put your thumb on the biceps (brachii) tendon at the inside angle of the elbow and press gently. Tap your thumb with a reflex mallet. Flexion of the elbow is the normal response.
biceps reflex
The __ is a spinal reflex that involves nerves C6 and C7. Have the subject lie on a table, with an arm across the abdomen. Supporting the subject’s arm with the elbow flexed at a 90 degree angle, sharply tap the posterior surface of the upper arm just proximal to the olecranon
The lower arm should extend as the triceps brachii muscle reflexively contracts.
triceps reflex
(ankle-jerk reflex) is a spinal reflex that involves nerves S1 and S2, and results in plantar flexion of the foot. Have the subject kneel on a chair, facing away from you, with the toes pointing toward the floor. Tap the middle of the Achilles (calcaneal) tendon with a reflex mallet.
The Achilles reflex
are those that result from the stimulation of cutaneous (skin) receptors.
Cutaneous reflexes
involves cutaneous receptors rather than deep receptors in muscles or tendons. Position the subject’s bare foot with the lateral surface resting on a table or chair.
Demonstrate this reflex by firmly sweeping the handle of the mallet along the lateral region of the sole
In a normal adult, the toes flex. In a Babinski response, the toes extend and move apart. The ___ is normal in infants (up to 18 months) in whom the nerves have not fully myelinated, but the response is abnormal in adults.
The plantar reflex, Babinski response
