Anatomy and Physiology Exam 41. List the structures and functions of the nose, nasal cavity, and paranasal sinuses. These structures are known as the upper respiratory tract since they are the first structures that the air will pass through (pharynx is also part of). The purpose of the nose is to filter the air and moisten it. The air we breathe has many pollutes and bacteria, and the hair in the nose filters it all out. By the time it reaches the pharynx, the nose has cleansed it to an extent and moistened it. For the anatomy, the nose contains three protrusions called the nasal conchae. These have opening that drain certain secretions into the nose. 2. Describe the structures of the pharynx, larynx, and trachea. All the structures that work to just carry the air to the alveolar in the lungs (where the gas exchange occurs) are known as the conducting zone, meaning everything we are talking about is in the conducting zone right now.The pharynx is the next path that the air takes after passing through the nose. Air and food both go down the pharynx and the tonsils are also housed here. The pharynx is divided into the naso-, oro-, and laryngo sections. The naso- section is the uppermost section that is connected to the nasal cavity, and this is where the tonsils are housed. We also have auditory tubes that travel to the ear cavity for hearing. Then we reach theoropharynx. This is just another passage; just to note that the main palatine tonsils arehere (these are just the main tonsils). Finally we reach the laryngopharynx. This is wherethere is a split in the passage for either food or air. Food will enter the esophagus and air will continue into the larynx. So the pharynx has both food and air and at the end of the laryngo-, it will split. The “door” that keeps food out of the larynx is called the epiglottis and it is closed during swallowing, so the food can only enter the esophagus. Now the air is in the lower respiratory tract. So it’s all simply paths for the air to travel. The larynx is the major organ for sound production. It connects the laryngo- to the trachea. So voice is simply air vibrating across the vocal ligaments (so just like sound is produced by guitar strings, by vibration)—nothing fancy to know the mechanism; just know that the glottis is medial to the vocal chords and speech is produced with the alternate closing and opening of the glottis. Pitch is affected via the length of those vocal chords and the loudness of the sound is determined by the amount of force that the movement of the air causes.The trachea is a flexible tube connecting the larynx to the bronchioles. It is very short and it ends at the primary bronchi. 3. Explain the structure of the lungs and the vascular and neural networks that supply them. The lungs are two structures position superior to the heart. The bronchi arise from the trachea and once the air arrives here, it is moist and free of most contaminates. That was the job of all those different passages that the air took to get here. As the air travelsdown the bronchi, the bronchi get smaller and smaller till we reach the aveoli. As theyget smaller, they change from the primary bronchi to the secondary bronchi to the tertiary bronchi. At the bronchi is actually where coughing is initiated at an area called the carina.There are a right and left lung, and the right lobe has three lobes and the left has two. The reason for this is because the heart is positioned around the left lung, so can’t reallyreplace the heart. This means that the bronchi must have split to deliver the air to both lungs, and indeed it did right after the trachea. The secondary bronchi deliver the air to the right and left lung, and then it splits into the tertiary bronchi. So the bronchi continue to split into the respiratory then they form bronchioles as they progressively get smaller. Finally after a shit ton of bronchioles we reach the terminal bronchioles. Now we enter the respiratory zone starting with the respiratory bronchioles. Then we reach the alveolar ducts, which contain sacs of alveolar. This is where the gas exchange occurs. Blood is brought to the lung via the pulmonary artery as explained in my last guide, and just like the heart, the lungs get their own blood supply from the bronchial arteries. Remember that the pulmonary arteries bring the deoxygenated blood to the lungs so it can pick up the oxygen, so the lungs don’t get to use it for nourishment. The alveoli duct, the sac, and the alveoli make up the pulmonary lobule, which is just a fancy word for the functional part of the lung. Since they are the functioning part, they have to have some form of vessels are these are a lymphatic vessels, an arteriole, and a terminal bronchi.The alveoli have certain cells for gas exchange called the type 1 alveolar cells, so this obviously are essential cells. Other essential cells they have are the type 2 cells, which secrete surfactant. This lowers the surface tension in the alveoli to prevent them from collapsing. There are also macrophages to digest any bacteria as needed. 4. Discuss the relationship of the pleurae to the lungs and thoracic wall, and their functional importance. The pleurae are a cavity that covers the lungs and the thoracic wall, and just like the heart with its visceral and partial layer, it has the same anatomy: Two layers and fluid between them to minimize friction with breathing. Breathing is made possible by pressure changes and this cavity creates these changes. So like the heart, the visceral layer lines the lungs and the partial is outer to the visceral. 5. Define intrapulmonary and intrapleural pressure. Breathing is made possible via pressure changes from the atmospheric pressure compared to the pressure in the lungs or the transpulmonary pressure. We describe negative and positive pressure relative to the atmosphere, which is at 760 mmHg. So the transpulmonary pressure is either less than of greater than 760 mmHg. (and 760 is described as0)There are two pressures that create the transpulmonary pressure, and these are the intrapulmonary (Ppul) and the intrapleural (Pip). The Ppul is the pressure in the alveoli and the Pip is the pressure in the pleural cavity (usually -4). When we inhale, the diagram will contract.This will cause it to enlarge, because of its shape. Enlarging it will increase its volume, which willDECREASE the Ppul (whenever you increase volume, pressure will decrease). So this decrease
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