Our Basic Senses

Sense is a biological way of perceiving things that are happening outside in the environment or within the body. These are detected by the specialised receptor cells lying in different sense organs and then they are transmitted in the form of nerve impulses which travel to brain and then the body becomes able to respond to the specific stimuli.

So the question arises here, 

What are the different senses that human beings have?

Here we'll see five different senses along with their sense organs that receive or detect them.

1. Touch: This is the first sense with which we are blessed. When the babies come in this world then before opening their eyes, first thing they feel is the gentle touch of their mothers which welcomes them in this world. So the biggest sense organ, skin is supplied with multiple sensors within it to detect changes in pressure, temperature, pain, vibration etc. They are then sent to brain which are processed by sensory cortex there, this is how we experience different forms of touch. Well you are much smarter than your smart touch phones that you are using now.

2. Sight: This sense is also a blessing as we can see the beauty all around us with our eyes. You know that humans are able to see the objects in the presence of light. Light rays when fall on some surface then they are reflected and enter through cornea which is transparent layer at the front of our eye, it bends those light rays and then they pass through pupil and then directed to the lens which bends them and then the images of those objects are formed on our retina which is like a screen. On our retina, two important nerve cells are lying namely rods (sensitive to dim light) and cones (sensitive to bright light). These cells convert the light into nerve impulses which are then taken by optical nerve to the optical lobe of the cerebral cortex. Hence, we are able to see the things as they are.

3. Hearing: Can you hear different sounds in your surrounding? This is another important sense without which we cannot imagine our life. For hearing, the sense organ is the ear. If you look at the structure of your ear then it’s divided into three main parts. First part is outer ear, sound waves enter the auditory canal through pinna (the visible portion of the ear made up of cartilage) then the sound waves strike the tympanic membrane which produces vibrations. These vibrations are then transmitted to middle ear which has got three tiniest bones of the body, they are malleus, incus and stapes which amplify the incoming vibrations sent by the ear drum. They are then caught by the cochlea which is lying in the inner ear, it has got hair cells which turn the vibrations into nerve impulses and they reach the auditory cortex (the part of the temporal lobe) through auditory nerve. This is how we identify and respond to sounds.

4. Smell: Did you ever imagine how do you smell things like sweet smelling flowers, smell of burning or rotting things? I hope your answer will be, nose. You are right! So within the nose, we have the nasal cleft which transmits the signals to brain. In the brain, there are olfactory bulb and fossa which help detect different types of smell in our surrounding.

5. Taste: It’s kind of very delicious sense. Why are you wondering? Of course with the help of this sense we can taste so many delicious foods and stuff. We sense different tastes like sweet, bitter, sour and salty with our tongue. Around 2000 to 4000 taste buds are lying on our tongue which experience different types of tastes. These stimuli are sent to insular cortex which is lying in the brain and this is how you can say that which food is salty, bitter, sweet or sour.