Golgi tendon apparatus vs hyperreflexia - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
USMLE Articles
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam

Thread Tools Search this Thread Display Modes
Old 11-27-2014
USMLE Forums Scout
Steps History: Not yet
Posts: 30
Threads: 7
Thanked 2 Times in 1 Post
Reputation: 12
Default Golgi tendon apparatus vs hyperreflexia

A 45 yo man with a history of a stroke comes to the physician for physical therapy. Physical examination shows hyperreflexia of the patellar tendon tap. The spasticity reflects loss of inhibitory influences that normally limit responses to afferent signals that convey informatin about muscle length. Which of the following structures within the muscle actively initiate the abnormal brisk patelar reflex arc in this patient?
a. Alpha motor neurons
b. Extrafusal fibers
c. Golgi tendon apparatus
d. Intrafusal fibers
e. Spindle afferents.

Got this one wrong on Kaplan and apparently only 1/3 ppl answered it correctly, so can someone good with neuro plz enlighten me
Reply With Quote Quick reply to this message

Old 11-27-2014
qirkergaard's Avatar
USMLE Forums Veteran
Steps History: Step 1 Only
Posts: 253
Threads: 19
Thanked 129 Times in 98 Posts
Reputation: 139

Both extra- and intra-fusal muscle fibers regulate length and as such in a muscle stretch, this stretch will stimulate Ia afferent fibers which will eventually stimulate the alpha motor neuron --> causing reflex muscle contraction.

I believe what we're interested is in the efferent part of the myotactic reflex as the q states " the spasticity reflects loss of inhibitory influences that limit responses to afferent signals" and that's provided for by the Golgi tendons. Golgi tendons, unlike extra & intra-fusal fibers, regulate tension of the muscle. They provide inhibitory Ib efferent feedback to inhibit the contraction from going haywire.

So you're alpha motor neuros, intra- and extra-fusal muscle fibers, and spindle afferents are all esentially part of the afferent circuit, that work to produce a muscle contraction. To keep the muscle contraction from over-reacting, you need inhibitory efferent feedback to limit the stretch. Just imagine, if you didn't have this inhibitory feedback, you'd end up having hyperreflexia, and the stretch would continue until you get a serious injury.

I recommend you refer to BRS Physio to read in this more detail.

Hope that helps.
Reply With Quote Quick reply to this message
The above post was thanked by:
fatwalletuab (12-01-2014)


Quick Reply

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Where you live. Leave blank if you don't want to tell.


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Achilles tendon tear flygirl5 USMLE Step 1 Forum 4 06-16-2013 04:03 PM
Deep Tendon Reflexes in the CS Exam! chienpolska USMLE Step 2 CS Forum 1 07-12-2012 11:48 PM
Unsteady gait, facial weakness, and hyperreflexia! tyagee USMLE Step 1 Forum 1 03-10-2012 06:15 AM
20 yo with tendon xanthoma Seetal USMLE Step 1 Forum 4 04-24-2010 07:42 PM
Branchial Apparatus Mnemonic jackat1000 USMLE Step 1 Mnemonics 0 03-05-2010 12:23 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)