Reflexes Lab

In this lab, we tested out the photo pupillary reflex, the knee jerk reflex, the blink reflex, and the babe, what's your sign reflex. We then did an activity where we tested our response time to something we see with two trials: one with texting and one without. In the notes, we learned that reflexes are rapid, predictable, and involuntary responses to stimuli. A reflex arc is a pathway to nerve impulses and they do not go to the brain. Reflexes are simply natural reactions we are all born with and they are a sign that your body is healthy. Neurons are highly specialized to transmit messages from one part of the body to another.

Claim Evidence Reasoning

Part 1: Photopupillary Reflex

Claim: When the intensity of the light entering the eye increases, a photopupillary reflex is triggered, and the colliery body of the iris is stimulated to contract. We observed that the pupil decreased in size  and less light entered the eye.

Evidence: In our experiment, I covered my eye with my hands for two minutes and then after, shined a flashlight close to one eye. We observed the pupil and played close attention to the size. We saw that the size of the pupil decreased, and less light entered the eye.

Reasoning: This reflex occurred because the photopupillary reflex is triggered when the intensity of the light entering the eye increases.

Part 2: Knee Jerk Reflex

Claim: The knee jerk reflex is a 2 neuron reflex arc. The reflex goes from sensory neuron to spinal cord to motor neuron to the knee. The knee jerk reflex is also called a monosynaptic reflex because there is only one synapse in the circuit needed to complete the reflex. We observed t hat when Michelle hit my knee at a certain spot near my knee cap, my leg kicked out;

Evidence: In our experiment, Michelle hit my knee at a spot just below the knee cap. On my first try, my leg did not kick out, but after several tries, it finally worked. I think that our problem at first was that we did not hit the right place, but soon figured out our mistake.

Reasoning: The tap below the knee causes the thigh muscle to stretch. Information is then send to the spinal cord. After one synapse in the ventral horn of the spinal cord, the information is sent back out to the muscle.

Part 3: Blind Reflex

Claim: The Blind reflex is the automatic closure of the eyelid when an object is perceived as coming to rapidly to the eye. We observed that I did blink as a cotton ball was thrown at me.

Evidence: I stood behind a see-through barrier and Michelle through a cotton ball at me, and I did the same to her after. We both blinked every time the cotton ball was thrown over, which shows that the blink reflex did work properly for both of us.

Reasoning: People blink typically 15 times per minute, and this reflex really does protect the cornea from dying out and from contact with foreign objects. This reflex response is initiated by sensory stimuli that activate afferent neurons.

Part 4: Babe, what's your sign

Claim: The plantar reflex is used as an important neurological test. It is initiated when the sole of the food is stimulated with a blunt instrument. Our claim is that as a result, our toes did flex and move closer together, which shows that this reflex was functioning properly.

Evidence: In this test, I sat on the table and took my shoes and socks off of one food. Michelle took a pen with a cap on it and firmly grade the pen up the sole of the food from the heel to the base of the big toe. As a result, we observed that the toes flexed and moved closer together.

Reasoning: This response occurred because the plantar reflex was working properly in each of our bodies. This reflex was a response that occurred when the body receives a certain stimuli. However, if there is nerve damage one might show Babinski's sign, where the toes spread apart and upward.

Part 5: How Fast are You?

This activity is designed to measure response time to something that you see. In this test, we took a ruler and helped is near the end with the highest number and let is hang down. We had another person put his or her hand at the bottom of the ruler and have them ready to grab the ruler. We recorded the level at which we each caught the ruler. We had three trials and took the average time (used table to convert the distance to time).
This reaction time experiment required visual information to travel to the brain. Then our brain sent a motor command to the muscles of your arm and hand.
My average time was 0.18 seconds and Michelle's average time was 0.15 seconds.

We repeated the test again, except this time we texted while doing it. We observed that our reaction time was dramatically reduced.

My average time without texting was 0.18 seconds but my average time with texting was 0.42 seconds, which shows that texting did have a huge effect on my time.

Table:

Data while texting

Data without texting

Table: Class Data

This test showed us that texting can severely decrease reaction rate. This therefore shows that texting while driving is very dangerous and it is a huge distraction. This is a major reason so many people die in car accidents. Texting changed the reaction rate.

In this picture, we are doing the "How Fast Are You?" Test