In this lesson, we will learn about our kinesthetic and vestibular senses, which are responsible for things like movement and balance. We'll talk about what each of these senses do, and why we need them.
Sense and Movement
How can you tell when you're standing up versus lying down? Is there a difference between movement and motion? These might seem like odd questions, but they're actually getting at some very important ideas about sensation and perception! The fact that we can stand up, balance, and walk is the result of specialized systems in our bodies.
We are all familiar with the five main senses: sight, hearing, taste, touch, and smell. But we also have two additional senses: kinesthetic and vestibular. These senses are important to our movement and balance in different ways. In this lesson, we'll talk about kinesthetic and vestibular senses, what each of them does, and why we need them.
Kinesthetic sense is basically the sense of movement. It's all about how we can sense if our body is moving. It's an awareness of our own body in terms of things such as where our limbs are currently resting. It's also referred to as muscle memory. For example, you can raise your leg without looking at it, and you can continue typing even when you close your eyes. Proprioception is similar, but scientists think this might be related to our awareness or sense of movements, rather than the movements themselves. All of this is based on internal feedback in our body. In other words, it's quite different from something like sight, which relies on external signals from the world.
The entire nervous system, which is an assemblage of nerve cells that transmit signals from our brain and spinal cord to the rest of our body, is responsible for kinesthetic sense. In our muscles, joints, and tendons, we have neurons that respond to things like touch and pressure. These neurons work with other parts of our body to monitor our body's movement.
Kinesthetic sense is what allows us to know things like when we've reached a doorway we're walking toward, or how heavy an object is when we lift it up. Kinesthetic sense is very important to activities like sports. Imagine you're running down a soccer field with the ball in front of you. You wouldn't want to be looking down exclusively at the ball, right? You also need to look up at the goal and at the other players around you. Kinesthetic sense is what makes this possible.
Vestibular sense is our sense of balance. Where kinesthetic sense deals with our actual movements, like lifting a leg or an arm, vestibular sense has more to do with our movement in relation to the external world. Here's an example to illustrate the difference. You can close your eyes, and you'll still be able to complete kinesthetic movements, like lifting your hand to your face. But you can't spin around and around in a circle with your eyes closed without losing your balance. This is why dancers must keep their eyes open and fixed on a stable object in order to complete this movement.
So vestibular sense is all about things in our external world; we need it to keep our balance, or our body's equilibrium. In order to maintain balance, we need input from a few different places, but the major component is the inner ear. Our vestibular system is located in our inner ear, which is filled with tiny hair cells that communicate information about our balance.
Our sense about our body's motion arises in what are called semicircular canals in the inner ear. Inside these canals, there is a fluid that triggers those little hair cells to send information about how our body is rotating in relation to gravity. Have you ever been on a rocky boat and gotten sea sick? This happens because our inner ear senses motion (the rocking of the boat), and the hair cells get overstimulated. This imbalance makes us feel sick.
Vestibular sacs are organs located in our inner ear, which tell us where our head is in relation to our body. So, are we looking up, down, or side to side? These vestibular sacs are in between the semicircular canals and the cochlea, or the part of our ear largely responsible for hearing. The vestibular sacs connect the semicircular canal and the cochlea, and are important to balance.
Without our vestibular system, we would feel dizzy and off-balance all the time and would have trouble doing things like controlling our head's posture.
We encounter the world through our senses. Whether we're talking about seeing, hearing, or smelling, our senses help us understand the world around us. In addition to the five main senses that we're all familiar with, we also have two additional senses: kinesthetic sense and vestibular sense. Without our kinesthetic sense, it would be very difficult to do things like play sports. We wouldn't have much sense about where our arms and legs are, which would make something like playing hockey pretty hard! Without our vestibular sense, we wouldn't really be able to do much of anything because we would constantly be off balance.
Kinesthetic sense is all about how we can tell the position of our limbs. This sense helps us to do things like raise an arm without looking at it. A related sense is proprioception, which is our awareness of our movements based on internal feedback. Kinesthetic sense is what allows us to do things like play sports. It also helps us to understand things like touch or how heavy an object might be.
Vestibular sense has more to do with balance. Our vestibular system is located primarily in our inner ear, and it's what helps us maintain balance. Tiny hair cells inside of our semicircular canals transmit information about our balance. Essentially, our vestibular system works with gravity to keep us from falling over!