Class Notes (806,856)
Canada (492,490)
Physiology (634)
PSL300H1 (220)
Lecture 15

Lecture 15

5 Pages
Unlock Document

University of Toronto St. George
Doug Mac Kay

15 ReflexesOctober 15 2007ReflexesBasic element of motor controlbending back of a sensory stimulus within the CNS to produce a motor responseperform a specific taskoften a feedback loop regulating force position of limbs contraction etcReflex LoopStretch reflexStimuluspassive stretch of a muscle by applied load or contraction of antagonist muscleopassive because the force is external to the muscleResponseactive contraction of muscle negative feedbackoeg patellar tendon reflexfastest and very sensitive due to muscle spindle afferents large afferents group 1a and monosynaptic connection to motoneurons direct connectionno interneuronal processingStretch reflex functionEssential for stabilizing postureoreflex strongest in postural musclesstretches are very minutelatencies of about 25 ms for forearm muscles 37 ms for ankle extensorsolatencytime between the delivery of the stimulus and the onset of the motor response olonger conduction distance longer latencyparallel multisynaptic paths through spinal cord goes through interneurons and a transcortical path signals carried back down spinal cord to motor neuronsduring movement reflex suppressedoget rid of posture whenever you want to moveGolgi tendon reflex GTOStimulusactive tensioncontraction in muscleResponserelaxation or reduction of tension negative feedbackGTO afferents Ib synapse on interneurons in intermediate zone of spinal cord no direct connectionIbinterneurons inhibit amotoneurons of same muscleGolgi tendon reflex propertiesPrevents movementosuppressed when net motion is desiredComplementary to stretch reflex to stabilize postureotheyre just operating in the opposite directionsin certain conditions reflex output is reversed positive feedback instead of negative because of connections to interneurons1
More Less

Related notes for PSL300H1

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.