Intergumentary organs, Provas de Genética Médica

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THE SKIN,THE NOSE AND

TOUNGUE

COMPILED BYN MDM VALARIESHEYLINE

THE SKIN

 (^) It is the largest organ and has the following roles  (^) protects underlying structures from injury  (^) provides sensory information to the brain.  (^) protecting the body against ultraviolet rays  (^) regulating body temperature,  (^) preventing dehydration. The skin also  (^) acts as a reservoir for food and water.  (^) It also synthesizes vitamin D when exposed to sunlight

Accessory structures of the skin

 (^) The accessory organs of the skin consist of  (^) integumentary glands, (sebaceous and oil glands)  (^) hair  (^) nails.

fingernail

Roles of the nose

• (^) Allows air to enter your body.
• (^) Contributes to how you look and how you sound when you speak.
• (^) Filters and cleans air to remove particles and allergens.
• (^) Provides a sense of smell.
• (^) Warms and moistens air so it can move comfortably into your respiratory system.

Nose anatomy

• Bone-The hard bridge at the top of your nose is made of bone.
• (^) Hair and cilia: Hair and cilia (tiny, hairlike structures) inside your nose trap dirt and particles. Then they move those particles toward your nostrils, where they can be sneezed out or wiped away.
• (^) Lateral walls (outer walls): The outer walls of your nose are made of cartilage and covered in skin. The walls form your nasal cavities and your nostrils.
• (^) Nasal cavities: Your nose has two nasal cavities, hollow spaces where air flows in and out. They are lined with mucous membranes.
• (^) Nerve cells: These cells communicate with your brain to provide a sense of smell.
• (^) Nostrils (nares): These are the openings to the nasal cavities that are on the face.
• (^) Septum: The septum is made of bone and firm cartilage. It runs down the center of your nose and separates the two nasal cavities.
• (^) Sinuses: You have four pairs of sinuses. These air-filled pockets are connected to your nasal cavities. They produce the mucus that keeps your nose moist.

Physiology of smell

 (^) All odorous materials give off volatile(easily evaporated at normal temperatures). molecules, which are carried into the nose with inhaled air and even very low concentrations, when dissolved in mucus, stimulate the olfactory chemoreceptors.  (^) The air entering the nose is warmed, and convection currents carry inspired air to the roof of the nasal cavity. ‘Sniffing’ concentrates volatile molecules in the roof of the nose. This increases the number of olfactory receptors stimulated and thus perception of the smell. The sense of smell may affect the appetite. If the odours are pleasant the appetite may improve and vice versa. When accompanied by the sight of food, an appetising smell increases salivation and stimulates the digestive system (see Ch. 12 ). The sense of smell may create long-lasting memories, especially for distinctive odours, e.g. hospital smells, favourite or least-liked foods.  (^) Inflammation of the nasal mucosa prevents odorous substances from reaching the olfactory area of the nose, causing loss of the sense of smell ( anosmia)

THE TONGUE

 (^) Taste buds primarily cover your tongue.. The taste buds on your tongue are housed inside visible bumps called papillae. There are three types of papillae that contain taste buds:

• (^) Fungiform: Located on the tip of your tongue. They contain approximately 1,600 taste buds.
• (^) Circumvallate: Located on the back of your tongue. They contain approximately 250 taste buds.
• (^) Foliate: Located on the back portion of your tongue, on each side. There are about 20 of these papillae, and they contain several hundred taste buds each.

Taste buds

 Taste buds are tiny sensory organs that allow you to experience taste. They’re located inside the tiny bumps covering your tongue called papillae. TTaste buds detect five basic tastes, including:

1. Sweet : Sweet foods mostly contain some form of sugar (sucrose, glucose, fructose and lactose). They include foods like honey, fruit and ice cream. 2. Salty : Salty foods contain table salt (sodium chloride) or mineral salts, like magnesium or potassium. Think of foods like pretzels, chips and movie theater popcorn. 3. Bitter : Bitter foods may contain ingredients like caffeine or compounds from plants, among others. Bitter is a complex taste regarding whether your taste buds recognize it as “good” or “bad.” For example, some people like bitter foods, like coffee and dark chocolate, while others don’t. 4. Sour : Sour foods, like citrus fruits and vinegar, often contain some form of acid (acetic acid, citric acid, lactic acid). 5. Umami : Umami is a savory, rich or meaty flavor. Many foods that your taste buds register as umami contain a substance called glutamate. Umami foods include tomatoes, asparagus, fish, mushrooms and soy.

Physiology of taste

 (^) Gustation is a chemical sense that, along with olfaction (smell), contributes to our perception of taste. It starts with the activation of receptors by chemical compounds (tastants) dissolved in the saliva. The saliva and papillae on the tongue distribute the tastants and increase their exposure to the taste receptors which are contained in taste buds located on the toungue,they perceive sweet,soiur,salty,bitter and umami tastes and send it to the brain for interpretation