Sense Organs PDF

**Sense Organs** Are million of receptors distributed widely throughout the skin, mucosa, muscles, tendons and joints and viscera. The **sense organs** are the body **organs** by which humans are able to see, smell, hear, taste, and touch or feel.  Are the specialized **organs** composed of **sen...

**Sense Organs** Are million of receptors distributed widely throughout the skin, mucosa, muscles, tendons and joints and viscera. The **sense organs** are the body **organs** by which humans are able to see, smell, hear, taste, and touch or feel.  Are the specialized **organs** composed of **sensory** neurons, which help us to perceive and respond to our surroundings The five **sense organs** are the eyes (for seeing), nose (for smelling), ears (for hearing), tongue (for tasting), and skin (for touching or feeling). Humans **have** five basic **senses**: touch, sight, hearing, smell and taste. The sensing **organs** associated with each **sense** send information to the brain to help us understand and perceive the world around us. **Eyes** are organs of the visual system. They provide animals with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. **A.Anatomy** - - - - - - - - ​ - - - - - **B. Physiology of Vision** a. Formation of images on the retina is accomplished  by                         1. Refraction (bending) of light rays as they pass through the eye                         2. Accommodation bulging of lens for viewing near objects                         3. Constriction of pupil occurs simultaneously with accommodation and in bright light                        4. Convergence of eyes for near objects so that light rays from the object fall on specific points on the  two retinas; necessary for single binocular vision.          b. Stimulation of retina by light rays producing  photochemical changes in its rods and cones (receptors for optic nerve; dim light causes the breakdown of the chemical rhodopsin which is present in rods, initiating impulse  conduction by rods, bright light causes the breakdown of chemicals in cones; hence, rods are considered  receptors for night vision and cones for day light and color vision)          c. Conduction of impulses to the visual  area in the occipital lobe of cerebral cortex by fibers for optic nerves and tracts Sight, like the other senses is closely related to other parts of our anatomy. The eye is connected to the brain and dependent upon the brain to interpret what we see. How we see depends upon the transfer of light. Light passes through the front of the eye (cornea) to the lens. The cornea and the lens help to focus the light rays onto the back of the eye (retina). The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain. The eye works much the same as a camera. The shutter of a camera can close or open depending upon the amount of light needed to expose the film in the back of the camera. The eye, like the camera shutter, operates in the same way. The iris and the pupil control how much light to let into the back of the eye. When it is very dark, our pupils are very large, letting in more light. The lens of a camera is able to focus on objects far away and up close with the help of mirrors and other mechanical devices. The lens of the eye helps us to focus but sometimes needs some additional help in order to focus clearly. Glasses, contact lenses, and artificial lenses all help us to see more clearly.  **Pathologies/ Disorders**: - - - - **Risk Factors: **Diabetes; Tobacco smoking **Diseases or conditions caused: **Blindness - - **Ear** http://www.specialtycareinstitute.com/files/2016/01/gross-anatomy-of-the-ear-4-638.jpg The outer ear includes: - - - The outer part of the ear collects sound. Sound travels through the auricle and the auditory canal, a short tube that ends at the eardrum. The middle ear includes: - - - - - - The inner ear includes: - - - - **Physiology of hearing** a\. Audible sounds set waves in motion  b\. Sound waves are transmitted through the air to the tympanic  membrane, causing it to vibrate c.. Auditory ossicles transmit sound waves to the fenestra ovalis (oval window) and to the fluid of the inner ear (perilymph)  d. Inner ear fluid transmit sound waves to the receptors (organ of Corti) of cochlear branch of cranial nerve VIII. e\. Cochlear nerves transmit impulses to the auditory areas of the temporal lobes of the cerebrum; hearing results from stimulation of these areas. **Diseases/ Pathology** Cancers of the ear usually occur on the skin of the outer ear. Cancers of the ear can develop inside the ear too, but these are very rare. Otosclerosis is the buildup of spongy or bone-like tissue in the middle ear that prevents the ossicles, namely the stapes in the middle ear, from working properly. The impaired movement and function reduces the sound that actually reaches the ear. Otosclerosis usually results in conductive hearing loss, a hearing loss caused by a problem in the outer or middle ear. Infections of the middle ear are one of the most common reasons for children to see a doctor. Three out of 4 children experience ear infection (otitis media) by the time they are 3 years old. Children are more likely to have ear infections like otitis media that come from bacteria or viruses than adults because of their developing ear anatomy. **Nose**  **Nose**, the prominent structure between the eyes that serves as the entrance to the respiratory tract and contains the olfactory organ. It provides air for respiration, serves the sense of smell, conditions the air by filtering, warming, and moistening it, and cleans itself of foreign debris extracted from inhalations. The **nose** is the body's primary organ of smell and also functions as part of the body's respiratory system. Air comes into the body through the nose. As it passes over the specialized cells of the olfactory system, the brain recognizes and identifies smells. Hairs in the nose clean the air of foreign particles. As air moves through the nasal passages, it is warmed and humidified before it goes into the lungs. - The most common medical condition related to the nose is **nasal congestion**. This can be caused by colds or flu, allergies, or environmental factors, resulting in inflammation of the nasal passages. - Deviated septum - a shifting of the wall that divides the nasal cavity into halves. - Nasal polyps - soft growths that develop on the lining of your nose or sinuses. - Nosebleeds. The body's response to congestion is to convulsively expel air through the nose by a sneeze.Nosebleeds, known medically as epistaxis, are a second common medical issue of the nose. As many as 60 percent of people report nosebleed experiences , with the highest rates found in children under 10 and adults over 50 - Rhinitis - inflammation of the nose and sinuses sometimes caused by allergies. \... - Nasal fractures, also known as a broken nose. Rhinoplasty is a plastic surgery procedure for problems, both medical and aesthetic, with the nose. **Parts of the Nose** A nostril (or naris, plural nares) is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation  The nasal cavity lies just behind the two nostrils and forms the interiors of the nose. The olfactory bulb is a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell. It sends olfactory information to be further processed in the amygdala, the orbitofrontal cortex (OFC) and the hippocampus where it plays a role in emotion, memory and learning The hard palate separates the oral and nasal cavities, The soft palate is composed of muscle and connective tissue, which give it both mobility and support. This palate is very flexible **Gustatory Sense Organ** http://image.slidesharecdn.com/7-140503112208-phpapp01/95/7-the-sense-organs-17-638.jpg?cb=1399119996 - **Vallate papillae: **These large, flat-topped bumps lie just in front of the terminal sulcus, located about two-thirds back on the surface of the tongue. They are surrounded by deep trenches---into which ducts open from fluid-producing glands---and their walls are covered in taste buds. - **Folate papillae: **Though poorly developed in humans, these small folds of the mucosa surface of the tongue are found to the sides. They also have taste receptors located in taste buds. - **Filiform papillae: **Lying in V-shape rows parallel to the terminal sulcus, these bumps are elongated and numerous. They contain nerve endings that are sensitive to touch. Appearing scaly, threadlike, and pinkish-grey in color, they can make the tongues of some animals (such as cats) especially rough. At the tongue's tip, these papillae sit more cross-wise (arranged transversely). - **Fungiform papillae:** Scattered among the filiform papillae are these oddly mushroom-shaped spots that may be pink or red in coloration. They are most commonly found along the tip or sides of the tongue. Many contain receptors for taste within taste buds. General descriptions of the gross parts of the tongue: - **Root:** This is most often defined as the back third of the tongue. It sits low in the mouth and near the throat, and it is relatively fixed in place. It is attached to the hyoid bone and mandible (lower jaw). It is close in proximity to two muscles: the geniohyoid and mylohyoid muscles. - **Body:** The rest of the tongue, notably the forward two-thirds that lie in front of the sulcus. It is extremely mobile and serves multiple functions. - **Apex:** This is the tip of the tongue, a pointed portion most forward in the mouth. It is also extremely mobile. - **Dorsum: **This is the curved upper surface towards the back. It has a V-shaped groove on it called the terminal sulcus. - **Inferior Surface:** Underneath the tongue lies this last feature, important for the ability to visualize veins that allow the rapid absorption of specific medications. - **Burning mouth syndrome** Like it sounds, the symptoms can be unpleasant and causes may be occasionally serious. - **Sleep apnea: **The tongue size and position may increase the risk for sleep apnea due to obstruction of airflow within the throat.^1^ Skin  The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, and cold. Skin has three layers: - The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone. - The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. - The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue. - [Rash](https://www.webmd.com/skin-problems-and-treatments/guide/common-rashes): Nearly any change in the skin's appearance can be called a [rash](https://www.webmd.com/skin-problems-and-treatments/guide/common-rashes). Most rashes are from simple skin irritation; others result from medical conditions. - [Dermatitis](https://www.webmd.com/skin-problems-and-treatments/understanding-dermatitis-basics): A general term for inflammation of the skin. Atopic dermatitis (a type of eczema) is the most common form. - [Eczema](https://www.webmd.com/skin-problems-and-treatments/eczema/understanding-eczema-basics): Skin inflammation ([dermatitis](https://www.webmd.com/skin-problems-and-treatments/contact-dermatitis)) causing an itchy rash. Most often, it's due to an overactive immune system. - [Psoriasis](https://www.webmd.com/skin-problems-and-treatments/psoriasis/psoriasis-topic-overview): An autoimmune condition that can cause a variety of skin rashes. Silver, scaly plaques on the skin are the most common form. - [Dandruff](https://www.webmd.com/skin-problems-and-treatments/understanding-dandruff-basics): A scaly condition of the scalp may be caused by seborrheic dermatitis, psoriasis, or eczema. - [Acne](https://www.webmd.com/skin-problems-and-treatments/acne/acne-vulgaris-topic-overview): The most common skin condition, acne affects over 85% of people at some time in life. - [Cellulitis](https://www.webmd.com/skin-problems-and-treatments/guide/cellulitis): Inflammation of the dermis and subcutaneous tissues, usually due to an infection. A red, warm, often painful skin rash generally results. - [Warts](https://www.webmd.com/skin-problems-and-treatments/understanding-common-warts-basics): A virus infects the skin and causes the skin to grow excessively, creating a wart. Warts may be treated at home with chemicals, duct tape, or freezing, or removed by a physician. - [Melanoma](https://www.webmd.com/melanoma-skin-cancer/melanoma-guide/melanoma-skin-cancer-overview-facts): The most dangerous type of skin cancer, melanoma results from sun damage and other causes. A skin biopsy can identify melanoma. - [Shingles](https://www.webmd.com/skin-problems-and-treatments/shingles/shingles-topic-overview) (herpes zoster): Caused by the chickenpox virus, shingles is a painful rash on one side of the body. A new adult vaccine can prevent shingles in most people. - [Scabies](https://www.webmd.com/skin-problems-and-treatments/understanding-lice-scabies-basics): Tiny mites that burrow into the skin cause scabies. An intensely itchy rash in the webs of fingers, wrists, elbows, and buttocks is typical of scabies. - [Ringworm](https://www.webmd.com/skin-problems-and-treatments/understanding-ringworm-basics): A fungal skin infection (also called tinea). The characteristic rings it creates are not due to worms. Questions: 1. Define Sense Organ. 2. What are the 5 sense organs? 3. Give atleast 1 important function of each organs 4. Give atleast 1 disorder of each sense organs 5. Give atleast 1way to take care of each sense organs.