How does a human hear? When an object makes a noise, it sends vibrations (better
known as sound waves) speeding through the air. These vibrations are then funneled into
your ear canal by your outer ear. As the vibrations move into your middle ear, they hit
your eardrum and cause it to vibrate as well. This sets off a chain reaction of vibrations.
Your eardrum, which is smaller and thinner than the nail on your pinky finger, vibrates
the three smallest bones in your body: first, the hammer, then the anvil, and finally, the
stirrup. The stirrup passes the vibrations into a coiled tube in the inner ear called the
cochlea. The fluid-filled cochlea contains thousands of hair-like nerve endings called
cilia. When the stirrup causes the fluid in the cochlea to vibrate, the cilia move. The cilia
change the vibrations into messages that are sent to the brain via the auditory nerve. The
auditory nerve carries messages from 25,000 receptors in your ear to your brain. Your
brain then makes sense of the messages and tells you what sounds you are hearing.
While you are sitting in the meadow, you might hear a calm breeze,some bees
buzzing around and maybe some birds chirping. The wind rustles through grass and
creates sound waves. Your ears collect these sound waves and causes your eardrum to
also vibrate. The eardrum the makes your hammer, anvil, and stirrup. The stirrups
The Essay on Sound Waves Travel In Different Material
... the vibration of hammer.Stirrup (Stapes) – Similar to hammer and anvil, stirrup is a tiny bone in the middle ear. Eventually, it also vibrates ... a protective organ for the eardrum. It collects and guides sound waves into the middle ear. The outer ear consists of the following two ...
vibrations move the liquid in your inner ear and the cilia translate those vibrations into
something the brain can understand. The brain processes the messages and realizes that
you are hearing a calm breeze. The same thing would happen if you heard a bee buzzing
around, except the different sound waves that it makes would cause the ear to process a
message that would tell the brain that it is hearing a bee. Likewise for the birds, unless of
course its a bird you have never heard before, but we will assume you have. Since we
have experienced these sensations before, its like the noise comes in, its processed and
matched up to see if we have ever heard anything like it before. Its sort of like pulling
open a filing cabinet and looking for something.
What happens if we have never heard a sound before. Lets say while you were in
the meadow and you heard some hideous shrieking noise. You think to yourself, “What’s
that?” You would probably have to use your other senses to establish exactly what was
making the noise, but after that your mind knows what that particular sound represents.
Using the filing cabinet analogy again, it would be just like adding another folder.
How does our body feel? Our body feels by getting messages from receptors in
our skin. But its not the same for all sensations. For touch and pressure, the skin receptors
get pressed on the transmit a signal to the medulla and the thalamus, then it goes to the
sensory cortex into the parietal lobe of the brain then the brain translates it into a concept
that it can understand. By the characteristics in the signal the brain can tell the difference
between a feather in our palm to being tackled by a lineman. If the sensation is a heat, or
lack there of, is passed directly to the thalamus and then to the reticular formation. My
theory on why it does that is that a change in outside temperature could change our inner-
body temperature, thus unbalancing our homeostasis. But no matter whether its pressure
or temperature, if the sensation is painful our body reacts completely differently. If there
is an instance of pain the brain tells the body to do something to stop it, fast.
While we are laying in the meadow on a mid-June day our skin senses are very
The Essay on Touch Senses Receptors Body Skin
The skin contains numerous sensory receptors which receive information from the outside environment. The sensory receptors of the skin are concerned with at least five different senses: pain, heat, cold, touch, and pressure. The five are usually grouped together as the single sense of touch in the classification of the five senses of the whole human body. The sensory receptors vary greatly in ...
busy. Since it is sunny and in June, I am assuming that it is warm if not hot. Our skin
feels the suns rays burning our delicate skin. It picks up a warmer feeling than when we
were in our car with the AC on. It sends a signal to the brain, via the thalamus to the
reticular formation, that it warm out here. Not only that but you are laying on the ground.
By laying on the ground you are putting pressure on your backside. Your skin can feel the
difference, the side of you facing up is not feeling this pressure. Let’s also say you are
laying down on a rock, a sharp squarish rock. The rock is applying a pressure to your
back also, but is applying more pressure to a smaller area which creates the sensation of
pain. When your brain feels pain it normally would tell your muscles the roll over or sit
up and remove the rock from where you were laying, unless of course you are too lazy
and just deal with the pain. You are also laying in grass, so some of your skin is exposed
to it.This might cause irritation or itchiness. This might cause your brain to want to
scratch.
How does our body know where were are, if we are moving or not? How does it
know which way is up and down? We know this because our two types vestibular senses.
The first is our sense of body rotation. This is monitored by the semicircular canals. Like
the inner-ears cochlea the canals are filled with a fluid which depending on the movement
of the head bends hair bundles that in turn trigger hair cells to send a message to the brain
and the brain interprets the message as at what speed and direction is the body turning.
The second of the vestibular senses is the gravitation and movement of the body. This is
calculated by the vestibular sacs, located between the semicircular canals and the cochlea.
Each sac is filled with fluid and millions of crystals. When your body moves up, down,
left or right the crystals move hair bundles which also trigger messages to the brain. But
even when the body is not moving the gravitational force pulls some of the crystals down
The Essay on Animal Senses vs Human Senses
Through research I discovered that there are animals that have senses that by far exceed our five human senses. One of the animals would be the bat that we spoke about in class. Bats avoid obstacles and nab insects on the wing by emitting ultrasonic squeaks and interpreting the echo the sound waves make after bouncing off objects in the environment. This is called “echolocation,” but ...
giving you a sense of where your head is located relative to the rest of your body. No
mater which of the two types of the vestibular senses are used the ultimate destination
inside the brain is unknown.
While you are laying down your vestibular systems are always checking to see
how your body is moving, but remains mostly still. If you are laying down the crystals in
your vestibular sacs are being pulled towards the back of your head, therefore telling your
brain that down is on your back side and that you are looking up. The semicircular canals
are telling your brain that your body is not spinning or rotating in any fashion.
With all these senses our brain can see, hear, smell, etcetera, but it does not just
“hear” a bird. It hears a noise and interprets it as a bird, this is perception. Perception is
what our brain does to all the information it receives form all our senses. That is a lot of
information. Think about as if you were at a store and you heard a noise that your brain
perceives to be a horse. Is it really a horse, probably not. It could just be some guy who is
good at making animal noises. Now what if you were at a comedy club and you heard the
same noise, but you also saw the comic producing the noise. Your brain would perceive
that it was indeed a horse noise, but the man was making it. This just shows that the more
senses involved in helping the brain to perceive a situation usually increases the chances
that a assumption is correct. So by your brain seeing light, hearing a breeze, feeling
pressure and heat, smelling things it perceives that you are laying in a meadow on a bright
sunny mid-June day.
