The patellar reflex, also known as the knee-jerk reflex, is a simple reflex arc that involves the stretching of the quadriceps muscle in the thigh, leading to the contraction of the muscle and the extension of the lower leg. It is a common lab test used to assess the integrity of the spinal cord and the peripheral nervous system. In this lab report, we will describe the procedure for performing the patellar reflex test, the results obtained, and the interpretation of those results.
To perform the patellar reflex test, the subject is seated with their legs hanging off the edge of a table or bench. The tester stands facing the subject and gently lifts the subject's lower leg by the ankle, allowing the quadriceps muscle to stretch. The tester then strikes the patellar tendon just below the kneecap with a reflex hammer, causing the quadriceps muscle to contract and the lower leg to extend. The reflex response is observed and recorded.
In a normal reflex response, the quadriceps muscle will contract and the lower leg will extend within a fraction of a second after the patellar tendon is struck. The response should be quick and strong, indicating that the reflex arc is functioning properly.
If the reflex response is absent or weak, it may indicate damage to the spinal cord or the peripheral nervous system. This could be due to a variety of factors, such as injury, disease, or neurological disorders. Further testing may be needed to determine the cause of the abnormal reflex response.
It is important to note that the patellar reflex test is just one of many tests that can be used to assess the integrity of the nervous system. Other tests, such as the biceps reflex and the ankle reflex, can also be performed to provide a more comprehensive evaluation of the nervous system.
In conclusion, the patellar reflex test is a simple and effective way to assess the functioning of the spinal cord and the peripheral nervous system. It is a valuable tool for identifying potential problems and guiding further diagnostic and treatment efforts.
lab report methods
The maneuver enhances the reflex through the. Lesions that damage the sensory or motor fibers, or damage to the spinal cord, generally diminish a reflex unless the spinal cord has been completely transected. During this part of the phase, Ca2+ is being pumped back into the sarcoplasmic reticulum, the cross-bridge cycle stopsand the muscle is stretching back to its original length. Camille Martinez Bio 217. The coordination of motor activity in antagonistic muscles may also be studied. Based on our results, the hypothesis is acceptable.
When you tap the patellar tendon, you rapidly stretch themuscle causing the quadriceps and therefore the muscle spindles within the quadriceps to stretch. After all three stages of the experiment were completed, the videos were reviewed for comparison between the baseline reflex and the three changing factors, along with any discrepancies and problematic areas that may have altered the results. Methods We utilized an EKG reading unit with electrodes and a reflex hammer. It is important to note that, even with the simplest of reflexes, there are multiple inhibitory and stimulatory influences that can affect the excitability of the motor neuron. Beyond simple reflexes with integrating centers in the spinal cord, more complex reflexes have integration centers in the brainstem or even in the cerebrum. Double this length for the total length of reflex pathway in meters. Reflex testing is of clinical value.
Each stimulus causes a twitch. The SR then closes its calcium ion channels and the calcium ion pumps return the calcium into the SR. Thus, the reflex is enhanced. Autonomic reflexes are those which are unaware to us and act on visceral organs of the body, whereas somatic reflexes involve skeletal muscle stimulation. Deb Girard, owns a similar company. Our hypothesis correspond to the study done because with higher stimulus input the greater the reflex but our assumption didn't not agree with the result.
A reflex arc refers to the neural pathway that a nerve impulse follows. ACh diffuses across the synaptic cleft and binds to the ACh-gated channels on the motor end plate MEP of the sarcolemma plasma membrane of the muscle fiber. Polysynaptic reflexes are more advanced and complex than monosynaptic reflexes since they involve interneurons. Make a mark with a marker at this spot. Introduction A neural system is needed for many organisms to respond to internal and external stimuli. In the case of the monosynaptic knee-jerk reflex, hitting the patellar tendon with a mallet stretches the intrafusal fibers of the spindles in the quadriceps muscle, leading to contraction.
Anatomically remote muscle contraction facilitates patellar tendon reflex reinforcement while mental activity does not: a within-participants experimental trial. Tap the tendon smartly with the wide end of the reflex hammer a few times to locate a point on the tendon which produces a consistent contraction of the gastrocnemius muscle and a downward movement of the foot plantar flexion. To be more precise, an EMG measures fluctuations in the electrical activity of muscles due to muscle cell action potentials. Click AutoScale on the EMG screen. Print Auditory Response Time Lab Report The purpose of this experiment is to determine the response time for dominant and non-dominant hand for visual stimuli, and using only dominant hand to test auditory and tactile response.
The reinforcement utilized is the Jendrassik Maneuver. Polysynaptic reflexes are more complex, but also more common. Normal EMG recording for a stretch reflex in LabScribe. Anatomically remote muscle contraction facilitates patellar tendon reflex reinforcement while mental activity does not: a within-participants experimental trial. Surface electromyography EMG measures the electrical activity in a muscle by placing recording electrodes on the skin over the muscle. It was hypothesized that when a participant will be asked to switch a task over repeating one, he or she will be significantly slower in reacting.
Introduction For every effect, there is a definite cause. The purpose was to see if there was a noticeable difference when not paying attention to a reflex. Please cite: Haen Whitmer, K. Press the Enter key on the keyboard to mark the recording. For our experiment we stimulated the patellar reflex, with and without reinforcement to measure the relative strength of the impulse. In this lab, we stimulated the patellar reflex with a reflex hammer with reinforcement by hooking our hands together and without reinforcement to gauge the effects of reciprocal inhibition. They involve interneurons, found in the CNS, which further process stimulus and output information.
The Achilles reflex is a monosynaptic stretch reflex similar to the patellar reflex. It's hard to consider this exact result when the subject can control their movement. Skeletal muscles respond to stimuli in response to signals it receives from the nervous system. To describe the effects of resistance and starting length on the initial velocity of shortening. In this lab, two monosynaptic reflexes in a human subject will be studied: the Achilles tendon reflex, and the patellar tendon knee-jerk reflex.
Record on your data table. After you have the reflex time measurements go on to Step 3 below. Tests for simple muscle reflexes, such as the patellar reflex, are basic to any physical exam when motor nerve or spinal damage is suspected. . Interneurons help integrate the information between the motor and sensory neurons. It was requested that both hands be placed one either side of the subjects legs on the lab bench and grasp the edge hard. Firmly strike your pointer finger in a downward motion using the wide end of the reflex hammer.
Unfused Tetanus An unfused tetanus is when the muscle fibers do not completely relax before the next stimulus because they are being stimulated at a fast rate; however there is a partial relaxation of the muscle fibers between the twitches. The patellar reflex is illustrated in Figure 1. Note the relative placement of extrafusal contractile fibers around the spindle. What do reaction times tell you about how these signals are processed? Record a total of ten trials using the same tapping force, noting the plantar flexion of the joint. The contraction of the extrafusal fibers, that is, contraction of the belly of the muscle, releases tension on the intrafusal fibers, decreasing stimulation to neuron. Introduction There are two groups of reflexes in the human body, with two ways to categorize each of them.
