The Senses Working Together

 Each of the 5 senses consists of organs with

specialized cellular structures that have receptors for specific

stimuli. These cells have links to the nervous system

and thus to the brain. Sensing is done at primitive

levels in the cells and integrated into sensations in the nervous system. Sight is

probably the most developed sense in humans, followed closely by hearing.

Our sense of smell works… Our sense of smell is part of our chemosensory system, or the chemical senses. Specialized sensory cells, called olfactory sensory neurons, are found in a small patch of tissue high inside the nose. These cells connect directly to the brain. Each olfactory neuron expresses one odor receptor.

Smells reach the olfactory sensory neurons by way of two pathways. The first pathway is through your nostrils. 95% of our nasal cavity is used just to filter air before it gets your lungs.The second pathway is through a channel that connects the roof of the throat region to the nose.

The olfactory epithelium is a layer of olfactory receptor cells. When odor molecules hit the back of our nose, it stucks in a layer of mucus covering the olfactory epithelium, as they dissolved, they bind to the olfactory receptor cells, which fire and send signals through the olfactory track, up to our brain

Our brain has 40,000,000 olfactory receptor neurons, so an odor can trigger many neurons and all those combinations let us detect an smell. Plus our olfactory neurons are always fresh, they`re the only neuron in our body that get`s replace regularly (4-8 WEEKS)

Our sense of taste works…Our tongue contains five types of taste receptors that register sweetness, saltiness, bitterness, sourness and umami (savory or meaty taste). Chemicals interact with receptors to generate signals which are sent to the brain. Processed signals give us certain ideas about the kind of food we are dealing with and allows us to take certain decisions and modify our behavior accordingly.

The receptors for taste, called taste buds, are situated chiefly in the tongue, but they are also located in the roof of the mouth and near the pharynx. At the base of each taste bud there is a nerve that sends the sensations to the brain. The sense of taste functions in coordination with the sense of smell.

Sweetness, usually regarded as a pleasurable sensation, is produced by the presence of sugars and a few other substancesSourness is the taste that detects acidity. The sourness of substances is rated relative to dilute hydrochloric acid, which has a sourness index of 1Saltiness is a taste produced primarily by the presence of sodium ions. Bitterness is the most sensitive of the tastes, and many perceive it as unpleasant, sharp, or disagreeable, but it is sometimes desirable and intentionally added via various bittering agentsUmami is an appetitive taste and is described as a savory or meaty taste. It can be tasted in cheese and soy sauce, and while also found in many other fermented and aged foods, this taste is also present in tomatoes, grains, and beans.

Our sense of hearing works…

Ears play a significant role in human as well as animal life. It is one of the very important sense organs for human and animal system. It’s a complex energy transfer and exchange system that translates the sound waves into mechanical energy, then into fluid energy and finally into electrical energy.

The auricle and ear canal channel sound waves toward the eardrum. The eardrum vibrates in response to the sounds, setting in motion the bones of the middle ear (ossicles). As the third bone moves in and out of the oval window, the vibrations make waves in fluid of the cochlea - not unlike dropping pebbles in a still lake. The membrane inside the cochlea moves as a reply to these vibrations, stimulating the hair-like nerve endings. The nerve endings send the impulse to the brain for understanding.

Our sense of sight works…

The organs of sight or vision are the eyes. These, along with the optic nerves and the brain allow us to see. Light enters the eye, first passing through the transparent front part of the eye called the cornea. The cornea refracts, or bends, the light waves to focus on the pupil. The light then passes through the pupil, which is an opening in the middle of the colored part of the eye, or iris. The iris can open the pupil wider when there is not much light, or make it smaller when the light is strong.

Once through the pupil, the light passes through the lens, which further refracts and inverts the light, and can be changed in shape by muscles in the eye, finally projecting a focused, upside-down image on the retina.The retina, at the back of your eye, contains millions of photoreceptor cells which respond to light. These cells contain protein molecules called opsins. We have two types of opsins - rods and cones. Opsins each can absorb a particle of light, called a photon, and transmit a signal to the cell. Rods detect colors in shades of grey, and can sense movement and shape.

Cones mainly distinguish color. You have three types which detect different wavelengths of light - red, blue or green. Signals from many cones can produce all the colors we see. They only work in bright light, so in dim light colors are harder to see. Once the cells receive the signal from the opsins, it is transmitted to the optic nerve, which is connected to the retina at the back ofyour eye. (There are no photoreceptors where the optic nerve joins the retina, and this is why you have what is known as a "blind spot" in your eye.) The optic nerve sends the signal to your brain, which interprets the image, and turns it back the right way up.

Our sense of touch works…Our skin acts as the protective barrier between our internal body systems and the outside world. Its ability to perceive touch sensations gives our brains a wealth of information about the environment around us, such as temperature, pain, and pressure. Our sense of touch is controlled by a huge network of nerve endings and touch receptors in the skin known as the somatosensory system. Within the somatosensory system, there are four main types of receptors: mechanoreceptors, thermoreceptors, pain receptors, and proprioceptors.  

When your hand touches an object, the mechanoreceptors in the skin are activated, and they start a chain of events by signaling to the nearest neuron that they touched something. This neuron then transmits this message to the next neuron which gets passed on to the spinal cord until the message is sent to the brain. Now the brain can process what your hand touched and send messages back to your hand via this same pathway to let the hand know if the brain wants more information about the object it is touching or if the hand should stop touching it.