Reflex Lab Analysis

In this lab, we tested out our reflexes in various experiments. The way we respond to a reflex is through a reflex arc, a pathway to nerve impulses that doesn't go through the brain, increasing the response time by not having to go through to the reception, integration and response pattern. Somatic reflexes are used to stimulate skeletal (voluntary) muscles, and autonomic reflexes regulate smooth muscles (involuntary). Knee- jerk reflexes are a two neuron reflex arc, going from sensory neurons to the spinal cord to the motor neurons in the knee. Withdrawal reflexes (like when you touch something hot) is a 3 neuron reflex arc. A sensory neuron is stimulated, and the action potential goes to the spinal cord, causing the finger to withdraw, and a second impulse is when the brain is stimulated and the person becomes aware of the heat after the stimulus has already been removed.
     The first experiment we did was to test our photo pupillary reflex, where we shone a light into each others eye after covering it for 2 minutes to see the pupil expand and contract when stimulated by light.  When light was shined into the eye, the pupil contracts automatically, demonstrating a autonomic reflex arc. We need to have a photo pupillary reflex so our eyes can adjust to high and low light levels.
     The second experiment was about the knee jerk reflex, a reflex that is often tested at doctor's office by using a hammer to hit the area just below the knee that causes your leg to kick out. There is only one synapse needed to create the reflex response. The sensory receptor that receives the signal is a propioreceptor that causes the thigh muscles to contract. Although it doesn't seem that a kicking reflex would be used very often, espcially today, we use this reflex a lot when it comes to simple tasks like running and walking, and it helps us maintain our balance.
     The next reflex tested was a blink reflex that is used to protect our eyes when we think something is about to hit our face. To test this we had one person stand behind a see through barrier in front of their face and then threw a cotton ball at their face. Nearly everyone blinked when the cotton ball was thrown, and in the cases that they didn't blink it was likely because they were expecting the cotton ball and were consciously keeping their eyes open.
     This test tested the plantar reflex, with one person sitting on a table and the other dragging a pen across the bottom of their feet. When this happened, the other person's toes wiggles and moved closer together. This is a neurological test so if someone had a disease (like Multiple Sclerosis) that damaged the nervous system they would not have this reaction and would instead would have a reaction that showed Babinski's sign where the toes spread apart and upward.
   For the last test we tested our reaction times by seeing how quickly we could catch a ruler that was dropped unannounced, and using the measurements on the ruler to correlate it to our reaction times. Then, to show the effects of texting on reaction time, we texted with one hand while trying to catch the ruler with the other. Our reactions were a lot slower when we were texting, with about a 0.10 second difference between the times, which seems small, but can quickly be amplified when it comes to reacting fast in life and death situations like driving. The data and averages for the class are collected below and displayed in a bar graph (thanks Mr.Orre!). It was really shocking to see how much texting affected our reaction times, but how laxly people still treat texting and driving Whenever I drive to/from school or when I'm picking up my brother from his school I never fail to see at least one person texting while driving. It's easy to think that we can do both things at once and not have a diminished performance in each of them, but our brain can't multitask the way we think it can. The term multitasking by itself is already somewhat of a misnomer, since we can't really do two tasks together, our brain just changes between the two tasks quickly rather than doing both simultaneously.

Reaction Time Graph (Period 2)