The conchae and meatuses also conserve water and prevent dehydration of the nasal epithelium by trapping water during exhalation. Conchae serve to increase the surface area of the nasal cavity and to disrupt the flow of air as it enters the nose, causing air to bounce along the epithelium, where it is cleaned and warmed. The inferior conchae are separate bones, whereas the superior and middle conchae are portions of the ethmoid bone. Each lateral wall of the nasal cavity has three bony projections, called the superior, middle, and inferior nasal conchae. The nasal septum is formed anteriorly by a portion of the septal cartilage (the flexible portion you can touch with your fingers) and posteriorly by the perpendicular plate of the ethmoid bone (a cranial bone located just posterior to the nasal bones) and the thin vomer bones (whose name refers to its plough shape). The nares open into the nasal cavity, which is separated into left and right sections by the nasal septum (Figure 3). The alar cartilage consists of the apex of the nose it surrounds the naris. Septal cartilage is flexible hyaline cartilage connected to the nasal bone, forming the dorsum nasi. The nasal bone articulates superiorly with the frontal bone and laterally with the maxillary bones. The nasal bone is one of a pair of bones that lies under the root and bridge of the nose. As a result, when looking at a skull, the nose is missing. While the root and bridge of the nose consist of bone, the protruding portion of the nose is composed of cartilage. Underneath the thin skin of the nose are its skeletal features (see Figure 2, lower illustration). The philtrum is the concave surface that connects the apex of the nose to the upper lip.įigure 2: This illustration shows features of the external nose (top) and skeletal features of the nose (bottom). An ala is a cartilaginous structure that forms the lateral side of each naris (plural = nares), or nostril opening. On either side of the apex, the nostrils are formed by the alae (singular = ala). The dorsum nasi is the length of the nose. The bridge is the part of the nose that connects the root to the rest of the nose. The root is the region of the nose located between the eyebrows. The external nose consists of the surface and skeletal structures that result in the outward appearance of the nose and contribute to its numerous functions (Figure 2). When discussing the nose, it is helpful to divide it into two major sections: the external nose, and the nasal cavity or internal nose. The major entrance and exit for the respiratory system is through the nose. The epithelium of the nasal passages, for example, is essential to sensing odors, and the bronchial epithelium that lines the lungs can metabolize some airborne carcinogens. Several structures within the conducting zone perform other functions as well. The major functions of the conducting zone are to provide a route for incoming and outgoing air, remove debris and pathogens from the incoming air, and warm and humidify the incoming air. Section 14 - Special Senses Toggle Dropdown.Chapter 44 - Development of the Male and Female Reproductive Systems.Chapter 43 - Anatomy and Physiology of the Female Reproductive System.Chapter 42 - Anatomy and Physiology of the Male Reproductive System.Section 13 - Reproductive System Toggle Dropdown.Chapter 40 - Divisions of the Skeletal System.Section 12 - Skeletal System Toggle Dropdown.Chapter 39 - Muscle Fiber Contraction and Relaxation. Section 11- Muscular System Toggle Dropdown.Chapter 35 - An Overview of the Endocrine System.Section 10 - Endocrine System Toggle Dropdown.Chapter 33 - Basic Structure and Function of the Nervous System.Section 9 - Nervous System Toggle Dropdown.Chapter 32 - The Urinary System and Homeostasis.Chapter 31 - Gross Anatomy of the Kidney.Section 8 - Urinary System Toggle Dropdown.Chapter 29 - Organs and Structures of the Respiratory System.Chapter 26 - The Adaptive Immune Response: B-lymphocytes and Antibodies.Chapter 25 - The Adaptive Immune Response: T-lymphocytes and Their Functional Types.Chapter 24 - Barrier Defenses and the Innate Immune Response.Section 6 - Circulatory-Immune System Toggle Dropdown.Chapter 20 - Chemical Digestion and Absorption.
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