Question

caw and label these parts in the knee-jerk (postural al reflex. Next to eat help you, here is a colors so that the AND the specific name (such as quadriceps femoris) hould include in your diagram of this reflex. Bes drawing can be read clearly. Any structures not designat Jerk (postural) reflex. Next to each part, write the general (such as effect ps femoris) for each part. To help you, here is a list of all terms that you s reflex. Be sure to color the items in the designated colors so that the res not designated to a color can be drawn in black Quadriceps femoris (pink) Femur (yellow) Patella (yellow) Sensory neuron (blue) Excited motor neuron (green) Inhibitory interneuron Hammer Dorsal root ganglion Hamstrings (pink) Tibia (yellow) Patellar tendon (blue) Cell body of sensory neuron (blue) Inhibited motor neuron (red) Muscle spindle Spinal cord Ventral root

Answer 1

Reflex reaction sensory neuron dorsal root ganglion spinal cord gray matter cell body of sensory neuron white matter motor neurons stretch receptor reflex hammer patellar tendon biceps femoris muscle (flexor) quadriceps femoris muscle (extensor) interneuron cell bodies of motor neurons © 2013 Encyclopædia Britannica, Inc.

THE PATELLAR TENDON (KNEE JERK) REFLEX The patellar tendon k e jerk) reflexlustrates a monosynaptic stretch reflex and reciprocal inhibition of the antagonistic muscle integrating Afferent path: Action potential travels through sansory neuron Receptor Muscle spindle stretches and fires Sensory neuron Synapses in Spinal cord Stimulus Tap to tendon stretches muscle Erent path Somatic motor neuron Effector 1: Quadriceps munci E rent path 2: Interneuron Inhibiting somatic motor neuron Response: Ouadriceps contracts wwinging lower leg forward Elector 2 Hamstring Response Haming stays read owing extension o g reciproca t ion Fig. 13.6

Interneuron Cell body of sensory neuron Afferent impulses from stretch receptor to spinal cord Motor neuron serving quadriceps Motor neuron serving antagonist muscle group (hamstrings) 2 Efferent impulses to alpha (a) motor neurons cause contraction of the stretched muscle that resists/reverses the stretch Initial stimulus: muscle stretch Spinal cord (L2-L4) Patella Muscle spindle Quadriceps (extensors) Muscle- spindle Patellar- ligament Hamstrings (flexors) 3 Efferent impulses to antagonist muscles are damped (reciprocal inhibition) Key: + Excitatory synapse - Inhibitory synapse (a) Copyright © 2004 Pearson Education, Inc.publishing as Beniamin Cummings

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display Muscle spindle Afferent nerve liber . Motor nerve fiber to quadriceps Tap on patollar ligament excites nerve endings of muscle spindle in quadriceps femoris Motor nerve fiber to hamstrings 2 Stretch signals travel to spinal cord via afferent nerve fiber and posterior root. (3) Allerent neuron excitos motor neuron in spinal cord. 4) EMrent signals in motor nerve fiber stimulate quadriceps to contract, producing knee jerk. Excitatory effect Inhibitory effect (5) Al same time, a branch of the afferent nerve fiber stimulates inhibitory motor neuron in spinal cord. That neuron inhibits motor neuron that supplies hamstring muscles Hamstring contraction is inhibited so hamstrings (knee flexors) do not antagonize quadriceps knee extensor).
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