Ch. 10 Special Senses: The Nose and Tongue

Human Body Structure and Function

Mrs. Clayton

Special Senses: The Nose

•Our organ of smell – also part of the respiratory system

•Can detect about 10,000 different smells

•Smell accounts for 90% of what we think of as taste

Special Senses: The Nose•When we breathe in, air passes through our nares(nostrils- opening to the nose) • It has two chambers divided by a septum made up of cartilage and bone, and is covered by mucous membranes•Thin hairs lining our nose help to clean the air of foreign particles

Special Senses: The Nose

•As air passes through our nasal sinuses it is warmed before it goes to our lungs

•Air also passes over specialized cells of the olfactory system called the olfactory epithelium

•Here our brain recognizes and identifies the smells

Special Senses: The Nose- Disorders

•Rhinitis- nasal congestion caused by colds, allergies, or environmental factors; results in inflammation of the nasal passages

•Nasal polyps- soft, noncancerous growths in the lining of the nasal passages or sinuses; result from chronic inflammation; medications or surgery

•Deviated septum- a bend in the cartilage structure of the septum; can cause blockage in air flow through one nostril, headaches, loud breathing or snoring; surgical correction

•Epistaxis- nosebleeds

Special Senses: The Nose

•Effects of aging on smell:

•As we age there is a decrease in the amount of olfactory neurons

•This decrease in the sense of smell can cause loss of appetite, and loss of ability to detect warning smells (ex-smoke)

Special Senses: The Tongue

•The tongue is a mass of muscle tissue with structures called papillae

•Located on the papillae are taste buds for sweet, sour, salty, bitter, and umami (a savory taste)

•A single taste bud contains 50-199 taste cells!

Special Senses: The Tongue

•All taste buds can detect all five sensations (umami, sweet, salty, sour, and bitter)

•Four of these help the body meet its nutritional needs

•Umami guides the intake of meat and cheese for proteinneeds

•Sweet guides the intake of sugars for our carbohydrate needs

•Salty guides the intake for necessary minerals

•Sour guides the intake of certain fruits for vitamin C needs

•Bitter protects us by helping detect spoiled foods and poisons

Special Senses: The Tongue

• Before food can be tasted it must first be dissolved in a fluid

• Saliva is produced by our salivary glands and aids in digestion

• There are 3 major salivary glands

• Parotid glands- largest, sit inside each cheek

• Submandibular glands- located along the mandible

• Sublingual glands- located under the tongue

Special Senses: The Tongue-Disorders

• Hairy tongue- white, brown, black discolorations

• Enlargement of the papillae on the tongue resembling hair-like projections

• Associated with heavy tobacco use, mouth breathing, bad oral hygiene, some antibiotic therapy, radiation or debilitation

Special Senses: The Tongue-Disorders

•Geographic tongue-inflammatory condition of the mucous membrane

•Common condition

•Characterized by smooth, red areas lacking papillae which migrate over time

• The cause is unknown, but the condition is completely benign

Special Senses: The Tongue-Disorders

•Fissured tongue- deep grooves on the top of the tongue

•Condition is usually painless, although some complain of associated burning

•Common condition

•Seen more in older adults but can be seen in children

Special Senses: The Tongue-Disorders• Tongue cancer- most

common is squamous cell carcinoma

•Associated pain and sores

•More common in men than women, and is rare under the age of 40

•Most commonly caused from excessive tobacco and alcohol use, HPV, and genetic predisposition