Question 5 Midterm

Question 1

Reflex

Answer 1

Instantaneous response to a stimulus

occurs at spinal cord does not require the brain

Question 2

Monosynaptic reflexes

Answer 2

Single synapse between afferent and efferent neurons

Question 3

Monosynaptic stretch reflex example

Answer 3

Patellar reflex

Question 4

Stretch reflex

Answer 4

Causes muscle contraction in response to increased muscle length

Question 5

Function of patellar reflex

Answer 5

Keep knees from buckling when standing up straight

Question 6

How does the patellar reflex work

Answer 6

1. Patellar ligament is hit. Causes pull on quadriceps tendon which pulls on quadriceps which sets off stretch receptors.
2. The signal travels to spinal cord via a sensory neurons. The distal end of the sensory neuron (only one process because it’s sensory so it has a proximal and distal end ) Travels in afferent direction.
3. The distal axon projection is going to enter the spinal root and then it enters the dorsal root ganglion.
4. The impulse passes the cell body in the dorsal root ganglion and goes into the proximal end of the axon projection. And into the spinal cord via the dorsal root.
5. The neuron biforcates and synapses with an inhibitory interneuron of the hamstrings and a motor neuron of the quadriceps.
6. The inhibitory interneuron is excited and inhibits the movement of the hamstrings. The motor neuron of the quadriceps is activated. Both efferent signals travel down the motor neurons.
7. The result is that the quadriceps contract but the hamstrings relax causing an extension at the knee.