QuestionSBA
QuestionChoice
This is incorrect as group Ia afferent fibres are involved in carrying signals from the muscle spindle fibres to the spinal cord.
10003013
c
Muscle spindle fibres &rarr; sensory IIa fibres &rarr; dorsal root ganglion &rarr; anterior horn of spinal cord &rarr; alpha-motor neuron &rarr; quadriceps muscle &rarr; contraction
QuestionChoice
This is incorrect as the alpha-motor neuron fibres carry signals to the quadriceps muscle for contraction. Hamstrings are also involved in the patellar reflex, as there is reciprocal inhibition which causes relaxation of the hamstrings, allowing quadriceps to contract freely.
10003014
d
Muscle spindle fibres &rarr; sensory Ia fibres &rarr; dorsal root ganglion &rarr; anterior horn of spinal cord &rarr; alpha-motor neuron &rarr; hamstring muscles &rarr; contraction
QuestionChoice
This is incorrect as there is no interneuron involved in the transmission of the stretch reflex. It is a monosynaptic reflex and the afferent Ia fibres directly synapse on the efferent alpha-motor neurons.
10003015
e
Muscle spindle fibres &rarr; sensory Ia fibres &rarr; dorsal root ganglion &rarr; anterior horn of spinal cord &rarr; interneuron &rarr; alpha-motor neuron &rarr; quadriceps muscles &rarr; contraction
QuestionChoice
Muscle spindle fibres are involved in detecting the stretch of muscles and causing reflex contraction. This pathway is known as the stretch reflex, which is elicited when the tendon hammer strikes the patellar tendon. Muscle spindle fibres detect the stretch and send afferent signals via the group Ia fibres. These synapse on the alpha-motor neurons in the anterior horn of the spinal cord directly. The alpha-motor neuron then sends efferent signals to quadriceps muscle to flex, resulting in the involuntary knee jerk.
10003011
a
Muscle spindle fibres -> sensory Ia fibres -> dorsal root ganglion -> anterior horn of spinal cord -> alpha-motor neuron -> quadriceps muscle -> contraction
QuestionChoice
Golgi tendon organs are involved in detecting excess stretch in muscles and causing a reflex relaxation. This pathway is known as the golgi tendon reflex. It occurs when muscles are under excess tension for a long time, for example when weight lifting.
10003012
b
Golgi tendon organ &rarr; sensory Ib fibres &rarr; dorsal root ganglion &rarr; anterior horn of spinal cord &rarr; alpha-motor neuron &rarr; quadriceps muscle &rarr; relaxation
Concept
Chapter
2693
4103
Properties of golgi tendon organs and muscle spindles
Topic
152
Neuroscience
13149
A GP is testing the patellar reflexes of 4year old girl with a tendon hammer.

Which of these is the right pathway of signal transmission when eliciting the patellar tendon reflex?
a