A sense is the “physiological capacity” that allows all living organisms to perceive what is around them.
A very clever man called Aristotle decided that humans have five senses that are the most important for humans to survive in their world around them. Without these sense we would probably keep bumping into things or eat food that is poisonous to us! While we have 5 main senses (see below) humans also have other types of sub-senses such as pain, balance and direction. Some scientists say we actually have ten senses - sight, sound, taste, touch, smell, pain, balance, thirst, and hunger and even humor! Sense of humor is our ability to laugh at something we find funny. Many theories exist as to why we might have a sense of humor. Some scientists believe that laughing and humor keeps us healthy, acts as a stress reliever and even is a “Gift from God”. Although, animals don’t have a sense of humor! The main senses that all living organisms have are known as the 5 senses. These senses help them learn about the world around them.
What are the five senses?
Sight: The ability of the brain and eye to detect light, color and distance of objects so we don’t walk into a lamp post. Hearing: The ability of the brain and ear to sense sound waves and vibrations so we don’t step in front of an oncoming bus. Taste: A chemical sense. When we put something in our mouth, this sense allows the tongue (taste buds) and brain to detect one of FOUR receptors. The four taste receptors are, sweet, salty, sour and bitter. Smell: Also known as olfaction, this is a chemical sense. We can recognise a wide variety of smells and odors. Some smells are pleasant and some are not! The ability of the brain and olfactory receptors which are located in the nose are what allow us to smell. Touch: While the other four senses (sight, hearing, smell, and taste) are located in specific parts of the body, your sense of touch is found all over in your skin. The skin is full of nerve endings.
What is a sense organ?
A specialized organ that allows us perceive or sense something. Examples of sense organs are the eye, ear, tongue, nose, or skin, where sensory neurons are concentrated and that functions as a receptor. Also called a sensor. The Eye: allows us to sense light (sight) The Ear: allows us to sense sound (hearing) The Tongue: allows us experience the sense of taste. The Nose: allows us experience sense of smell (olfaction) The Skin: allows us to sense touch. None of these senses would register with us, if we did not have nerve endings.
What are nerve endings?
A nerve is an enclosed, cable-like bundle of peripheral axons. Nerve endings in our ears, tongue, skin, nose or eyes (our sense organs) send signals to our brain via special pathways called nerves. Our brain then interprets what is going on for us (Fire!) and tells us how we should react (Remove your hand!) Our sense organs (and the senses related to them) tell our brain important information about our environment and help keep us stay away from danger or find food and shelter.
What are non–human senses?
While humans have some sub-senses that animals don’t have, some animals have their own special, unusual senses, which humans don’t have. Bats use echolocation to navigate their world. Electroreception is the ability to sense electric fields. Echolocation is a high frequency sound wave that is emitted by the bat. The sound waves travels and bounces off objects located nearby. The bat then measures the time it takes for the echo to return and calculates the direction it came from. Echolocation helps them find their way around in the dark and locate their food.
Interesting Facts:
- You have more pain nerve endings than any other type.
- There are about 100 touch receptors in each of your fingertips.
- You are born with about 10,000 taste buds, but this drops over time to about 5000 by the time you are old.
- Our sense of smell is connected really well to our memory.
- Each time you blink, you shut your eyes for 0.3 seconds, which means your eyes are closed at least 30 minutes a day just from blinking.
- The ear never stops working, even when people are asleep. The ear continues to hear sounds, but the brain shuts them out.
