Reflexes

Question 1

Reflex

Answer 1

sudden, autonomic, involuntary response to a stimulus

-spinal reflex or cranial reflex depending on where integration takes place

Question 2

Classification types
Processing site
complexity of circuit
response
development

Answer 2

• spinal vs cranial
• monosynaptic vs polysynaptic
• somatic vs visceral
• innate vs acquired

Question 3

Reflex arc

Answer 3

• sensory receptor
• sensory neuron
• integrating center
• motor neuron
• effector

Question 4

Stretch reflex

Answer 4

• regulates muscle length
• stimulus = muscle stretch
• receptor = muscle spindle
• sensory neuron = synapses with motor neuron in anterior gray horn
• integration: monosynaptic (agonist) and polysynaptic (antagonist)
• motor neuron = alpha exits through ventral root
• effector = skeletal muscle–> contraction of agonist and relaxation of antagonist

Question 5

Muscle spindles

Answer 5

• interspersed among muscle fibers parallel
• measure stretching
• intrafusal muscle fibers = special inside fibers and gamma motor neurons
• extrafusal muscle fibers = surround muscle fibers suppplied by alpha motor nerons

Question 6

Tendon Reflex

Answer 6

• polysynaptic
• control muscle tension by causing musle relaxation when tension is great
• sensory receptors = golgi tendon organs
• tension –> tendon organ stiumulation –> nerve impulse –> spinal cord –> motor neuron causes muscle relaxation

Question 7

Tendon organs

Answer 7

• at junction of tendon and muscle
• protect tendons and muscles from excess tension
• thin capsule of connective tissue that encloses a few tendon fascicles

Question 8

Flexor reflex

Answer 8

• withdrawal reflex
• polysynaptic
• ipsilateral
• step on tack –> nerve impulse–> activate interneuron –> activate motor neuron –> muscle contraction –> withdrawal of leg

Question 9

Crossed Extensor Reflex

Answer 9

• polysynaptic
• contralateral
• contraction of muscles that extend joints in opposite limb in response to painful stimulus
• Step on tack–> nerve impulse –> activation of several interneurons –> activate motor neurons –> muscle contraction causing flexion of the leg steppin on tack and extension of opposite leg