Reflexes Lab

In this lab, we tested our reflexes using different experiments and actions. Reflexes are rapid involuntary responses to stimuli such as touch and a reflex arc is a pathway to nerve impulses that happens extremely quickly and so does not go to the brain. Reflexes can regulate smooth muscles or stimulate skeletal muscles, it can regulate the heart and glands, digestion, and blood pressure and sweating as well. From this lab I was able to see how quickly the body reacted to different stimuli and how the body reacted as well.This, I could understand at a chemical level through neurons and reflex arcs. The different reflexes in this lab, such as the plantar reflex, also showed how reflexes can show the functionality of our nervous system.

This shows the photopupillary reflex wher the iris contracts and the pupil get smaller due to the bright light.

In the photopupillary reflex, the iris contracts to decrease the size of the pupil so that less light enters the pupil. This can be seen when the eye is exposed to bright light after a period of darkness and the pupil changes size. I was able to witness this in the lab as the pupil decreased. This reflex occurred so that less light would enter the eye because the bright light is a stark contrast to the dark and so the eye needs to be able to adjust.
The patellar reflex is also known as the knee jerk reflex and is when the leg kicks out when the place just below the knee gets hit. Clearly, this reflex can be seen when the leg kicks out and this worked when I hit my lab partner's knee when his legs were crossed. This reflex occurs because the thigh muscle stretches and that sends a message to the spinal cord and so the sense gets sent back out and the reflex occurs.

The blink reflex is when a person blinks when witnessing a stimulus that is moving at a fast speed and it close or nearby to the eyes or face. This can be seen through an experiment where you throw a cotton ball at a person with a see through barrier in front of him/her or suddenly clapping your hands in front of their face. This reflex has evolved due to the need to react to predators quickly and helps the eyes 'defend' themselves against whatever may attack or hurt the organism.
The plantar reflex is a person's foot's reaction to an upward movement on the foot. When I dragged the pen cap up along my lab partner's foot, his toes flexed, showing a normal reaction of the plantar reflex. This reflex occurred because the toes moved closer together showing that there is not nerve damage and that the toes are reacting appropriately. This is also known as the Babinski sign.
In the last reflex, we tested our response times by having one person drop a yardstick and another person catch it as fast as he/she could. Through the distance measured, we could convert that to reaction time. The reaction time decreased significantly by each trial going from 0.35 seconds to nearly zero seconds. However, when the person was texting, the reaction time increased dramatically to over 0.5 seconds. This occurs because the eyes sense the movement and sends the signal and the brain sends a signal to grab the yardstick. This shows just how quick our reflexes and mental processes can be.