which are the sensory organs of an organism?what are their functions?
Answers
Eyes obviously allow us to see. But if you break it down, they do more than just that. Using our eyes, we can judge depth, interpret new information, and identify color (the wavelengths of light that reflect off surfaces).
Noses are used to smell scents. They get a sense for what particles are traveling through the air, which can help us identify if dangerous chemicals are nearby. Smell also has the strongest connection to memory; a familiar smell can remind us of things long forgotten.
Ears allow us to hear sound - to detect vibrations in the air particles around us. But the inner ear also helps us maintain balance and regulate sinus pressure. This is especially useful when you change altitude (like, for example, when you are flying in an airplane).
Tongues are used to taste foods, allowing us to figure out if something is going to be useful to our bodies or poisonous. They also allow us to sense hot and cold in food and liquids.
Last of all is the skin, which is responsible for what may be the most important senses in the human body. The skin performs a huge number of functions.
Each sense organ contains different receptors.
General receptors are found throughout the body because they are present in skin, visceral organs (visceral meaning in the abdominal cavity), muscles, and joints.
Special receptors include chemoreceptors (chemical receptors) found in the mouth and nose, photoreceptors (light receptors) found in the eyes, and mechanoreceptors found in the ears.
OOOH, THAT SMELL: OLFACTION
Olfactory cells line the top of your nasal cavity. On one end, olfactory cells have cilia — hair-like attachments — that project into the nasal cavity. On the other end of the cell, are olfactory nerve fibers, which pass through the ethmoid bone and into the olfactory bulb. The olfactory bulb is directly attached to the cerebral cortex of your brain.
As you breathe, anything that is in the air that you take in enters your nasal cavity: hydrogen, oxygen, nitrogen, dust, pollen, chemicals. You don’t “smell” air or dust or pollen, but you can smell chemicals. The olfactory cells are chemoreceptors, which means the olfactory cells have protein receptors that can detect subtle differences in chemicals.
The chemicals bind to the cilia, which generate a nerve impulse that is carried through the olfactory cell, into the olfactory nerve fiber, up to the olfactory bulb and to your brain. Your brain determines what you are smelling. If you are sniffing something that you haven’t experienced before, you need to use another sense, such as taste or sight, to make an imprint in your brain’s memory.
MMM, MMM, GOOD: TASTE
The senses of smell and taste work closely together. If you cannot smell something, you cannot taste it, either. Taste buds on your tongue contain chemoreceptors that work in a similar fashion to the chemoreceptors in the nasal cavity. However, the chemoreceptors in the nose will detect any kind of smell, whereas there are four different types of taste buds, and each detects different types of tastes: sweet, sour, bitter, and salty.
e size of the pupil, which dilates to allow more light into the eye or contracts to allow less light into the eye. The iris and pupil are covered by the cornea.
Behind the pupil is an anterior chamber. Behind the anterior chamber is the lens. The ciliary body contains a small muscle that connects to the lens and the iris. The ciliary muscle changes the shape of the lens to adjust for far or near vision. The lens flattens to see farther away, and it becomes rounded for near vision. The process of changing the shape of the lens is called accommodation. People lose the ability of accommodation as they grow older, prompting the need for glasses.
Behind the lens of the eye is the vitreous body, which is filled with a gelatinous material called vitreous humor. This substance gives shape to the eyeball and also transmits light to the very back of the eyeball, where the retina lies. The retina contains photoreceptors, which detect light.
Two types of sensors detect light:
Rods detect motion. The rods work harder in low light.
Cones detect fine detail and color. The cones work best in bright light. There are three types of cones: one that detects blue, one that detects red, and one that detects green. Color blindness occurs when one type of cone is lacking.
A TOUCHY-FEELY SUBJECT: TOUCH
The skin contains general receptors. These receptors can detect touch, pain, pressure, and temperature. Throughout your skin, you have all four of these receptors interspersed. Skin receptors generate an impulse when activated, which is carried to the spinal cord and then to the brain.