A&P 8

Lung Alveolus Structure - Lung Alveoli Anatomy

A magnified view of an alveolar sac About 95% of the alveolar surface consists of simple squamous epithelial type I cells, and the remaining 5% is occupied by type II cells (or septal cells). These large, rounded cells are located between the type I cells and secrete the pulmonary surfactant. The complex of phospholipids and proteins in the surfactant reduces surface tension inside the alveoli, which keeps the alveolar walls from sticking together as they deflate during exhalation. Small openings called alveolar pores perforate the interalveolar wall and allow air to pass between alveoli. They provide alternative routes to and from the alveoli if an obstruction occurs. A network of capillaries and many supportive collagen and elastic fibers are found in the narrow interstitial spaces that separate the alveoli. Numerous macrophages (or dust cells) protect the lungs from damage. click here to see a histological demonstration of the alveoli Macrophages (dust cells) move about the air spaces and between the alveoli, where they remove (engulf) inhaled particles, foreign invaders, and other types of harmful substances.

Glottis - Structure & Function

A mirror positioned above the larynx shows a superior view of the vestibular and vocal folds. The vocal folds and the space between the folds are referred to as the glottis (= glottic opening). Laryngeal muscles can adjust the size of the glottic opening, depending on need. While breathing, The glottis expands (= abducts) into a triangular shaped opening. The glottis expands into a triangular shaped opening The broader opening allows air to more freely enter and leave the trachea and lungs. Air enters and leaves freely. make voice sounds, the laryngeal muscles reduce (= adduct) the size of the glottic opening to a narrow slit. Laryngeal muscles reduce opening

Oxygen-Hemoglobin Dissociation Curve | How pH Affects Oxygen-Hemoglobin Dissociation Curve

Acidic Blood: A low (= acidic) blood plasma pH of 7.2 causes the O2-Hb saturation curve to shift about 15% to the right of normal (= pH 7.4). A low blood plasma pH of 7.2 Alkaline Blood: In contrast, an elevated (= alkaline or basic) blood plasma pH of 7.6 causes the O2-Hb saturation curve to shift about 15% to the left of normal. An elevated blood plasma pH of 7.6 As blood plasma pH decreases (= becomes more acidic), H+ ions increasingly bind to hemoglobin amino acids, which lessens hemoglobin's affinity for O2. This is referred to as the Bohr effect. The situation reverses as plasma pH increase (= becomes more alkaline; basic).

Eustachian Tubes (Auditory Tubes) of the Pharynx

Along the lateral walls of the nasopharynx are the openings to the Eustachian tubes (auditory or pharyngotympanic tubes). Each narrow tube connects the nasopharynx with the middle ear (highlighted in green) structures found inside the air-filled tympanic cavity of the temporal bone. You can open your auditory tubes by moving your mouth and neck muscles, such as yawning. When this occurs, air can flow between the middle ear and the nasopharynx. This process equalizing the pressure on both sides of the eardrum (or tympanic membrane), making it easier for the eardrum to vibrate in response to sound waves.

Bronchiole Wall Anatomy

An enlarged cross-sectional view of a bronchiole reveals the tissue layers that make up the wall. Ciliated simple columnar cells form the epithelial lining in the large bronchioles. In the small bronchioles, the epithelium changes to simple cuboid cells. Goblet cells and seromucous glands become less numerous with each bronchiole division. A ring of smooth muscle fibers surrounds the epithelium. During exhalation, these muscle fibers contract to help force air out of the bronchioles. The resulting compression causes the epithelium to fold. The thin-walled brochioles are attached to the surrounding elastic alveoli. This connection keeps the bronchioles from collapsing during breathing move-ments. Because they are not needed for support, cartilage plates are characteristically absent. The following photomicrograph shows a more realistic depiction of the layers and structures that make up the tracheal wall. [ Epithelial folds/ smooth muscle

Tracheal Wall Composition and Structure - Anatomy of the Tracheal Tube or Windpipe

An expanded view of the trachea and esophagus. Swipe to switch between views. The wall of the trachea is made up of four distinct tissue layers. Along the luminal surface, the trachea is lined by respiratory mucosa (or mucous membrane). Goblet cells in the pseudo-stratified ciliated columnar epithelium produce mucus, which warms, moistens, and removes foreign particles from the air as it flows through the trachea.. trachea Deep to the mucosa is the submucosa. Like the lamina propria, the submucosa is primarily composed of loose (= areolar) connective tissue. Many blood vessels, neurons, and glands are also present. The (seromucous) glands secrete a combination of water and mucus to the luminal surface of the trachea through narrow ducts. The mucus adds to that secreted by the goblet cells. External to the submucosa is a cartilaginous layer containing c-shaped . The open end of the rings are attached by the trachealis muscle. While coughing, these smooth muscle fibers contract. This narrows the tracheal lumen and increases the velocity of airflow, which helps dislodge mucus and foreign particles. Keep learning with these respiratory system quizzes and diagram labelling exercises. The outer layer of the trachea, the adventitia, is a band of loose connective tissue that loosely bind the trachea to the esophagus and other nearby organs. A photo micrograph shows a more realistic depiction of the layers and structures that make up the tracheal wall.

Olfactory Mucosa (Epithelium & lamina Propria)

An introduction to the Olfactory Mucosa: Olfactory mucosa lines the roof of the nasal cavity and superior turbinates (= nasal conchae) and is structurally modified to detect odor-producing chemicals (= odorants). An expanded view of the olfactory mucosa shows more detail about its layered composition. In the epithelium layer are millions of specialized nerve cells referred to as olfactory receptors. The odorant-sensitive tips of the receptors protrude into the nasal cavity from the free surface of the epithelium. Several non-motile cilia extend from each bulbous tip. Along the cilia are many binding sites for odorants. Surrounding the receptors are many elongated supporting cells or sustentacular cells. Olfactory Mucosa (Epithelium & lamina Propria) An introduction to the Olfactory Mucosa: Olfactory mucosa lines the roof of the nasal cavity and superior turbinates (= nasal conchae) and is structurally modified to detect odor-producing chemicals (= odorants). 1 2 PreviousNext An expanded view of the olfactory mucosa shows more detail about its layered composition. 1 2 PreviousNext In the epithelium layer are millions of specialized nerve cells referred to as olfactory receptors. The odorant-sensitive tips of the receptors protrude into the nasal cavity from the free surface of the epithelium. Several non-motile cilia extend from each bulbous tip. Along the cilia are many binding sites for odorants. Surrounding the receptors are many elongated supporting cells or sustentacular cells. Have you been making any of these common anatomy learning mistakes? PreviousNext A thin layer of watery mucus made by the supporting cells and Bowman's (olfactory) glands covers the receptor cilia and microvilli. During inhalation, odorants are drawn into this fluid layer, where they dissolve and then bind to the cilia receptors. Binding of the odorants causes the olfactory receptors to generate electro-chemical impulses (= action potentials). Receptor axons carry the impulses through the holes in the cribiform plate to the olfactory bulbs at the base of the brain.

Respiratory Mucosa (Nasal Mucosa) Physiology

As air passes over the nasal mucosa, it is prepared or conditioned to safely pass deeper into the respiratory system. Air passes over the nasal mucosa. PreviousNext The heat radiated from the blood vessels in the lamina propria warms the air to near body temperature. Simultaneously, the watery mucus secreted from the goblet cells and seromucosal glands humidifies (= adds moisture) the air. It also traps foreign particles and keeps them from entering other parts of the respiratory tract. ucus secreted from the globet cells and seromucosal glands humidify the air. Wave-like beating of the epithelial cilia moves the debris-filled mucus to the throat, where it is usually swallowed. Beating of cilia move debris-filled mucus to the throat.

Oxygen Myoglobin Dissociation Curve

As shown in the animation, an isolated muscle fiber has been placed in a vial of deoxygenated blood. Inside the muscle fiber, each molecule of myoglobin can bind one O2. The O2-Mb bond is reversible, and the direction of the reaction is dependent on the concentration of O2 (partial pressure or pO2) in the surrounding fluids. pO2 Mb + O2 <———->MbO2 Therefore, as more O2 is forced into the vial of blood, the myoglobin becomes increasingly saturated. Myoglobin becomes saturated as o2 is forced into the blood. Therefore, as more O2 is forced into the vial of blood, the myoglobin becomes increasingly saturated. The steep (= hyperbolic) dissociation curve indicates that much lower concentrations of O2 are needed to saturate myoglobin molecules compared with hemoglobin molecules, which have four heme groups.

bronchi and bronchioles

At the inferior end of the trachea, the airway splits into left and right branches known as the primary bronchi. The left and right bronchi run into each lung before branching off into smaller secondary bronchi. The secondary bronchi carry air into the lobes of the lungs—2 in the left lung and 3 in the right lung. The secondary bronchi in turn split into many smaller tertiary bronchi within each lobe. The tertiary bronchi split into many smaller bronchioles that spread throughout the lungs. Each bronchiole further splits into many smaller branches less than a millimeter in diameter called terminal bronchioles. Finally, the millions of tiny terminal bronchioles conduct air to the alveoli of the lungs. As the airway splits into the tree-like branches of the bronchi and bronchioles, the structure of the walls of the airway begins to change. The primary bronchi contain many C-shaped cartilage rings that firmly hold the airway open and give the bronchi a cross-sectional shape like a flattened circle or a letter D. As the bronchi branch into secondary and tertiary bronchi, the cartilage becomes more widely spaced and more smooth muscle and elastin protein is found in the walls. The bronchioles differ from the structure of the bronchi in that they do not contain any cartilage at all. The presence of smooth muscles and elastin allow the smaller bronchi and bronchioles to be more flexible and contractile. The main function of the bronchi and bronchioles is to carry air from the trachea into the lungs. Smooth muscle tissue in their walls helps to regulate airflow into the lungs. When greater volumes of air are required by the body, such as during exercise, the smooth muscle relaxes to dilate the bronchi and bronchioles. The dilated airway provides less resistance to airflow and allows more air to pass into and out of the lungs. The smooth muscle fibers are able to contract during rest to prevent hyperventilation. The bronchi and bronchioles also use the mucus and cilia of their epithelial lining to trap and move dust and other contaminants away from the lungs.

Lungs Anatomy | Shapes and Surfaces of the Lungs

Due to the elevated position of the liver, the right lung is slightly (= 5 cm) shorter than the left lung. The left lung, however, has less volume because some space is taken up by the heart. Each lung is cone-shaped. The concave base rests on the diaphragm and the narrow apex projects under the clavicle. A double-walled, fluid-filled sac called the pleura envelops each lung and aids in the ventilation process. The anterior, lateral, and posterior lung surfaces lie adjacent to the ribs and are thus often referred to as the costal surface. Learn respiratory system anatomy fast and efficiently with quizzes and labeled diagrams. Between the lungs is the mediastinum. This large open space contains the heart, blood vessels, esophagus, nerves, trachea, and primary bronchi. Along the mediastinal surface of each lung is a depression called the hilum (or hilus). This is the region where the major blood vessels, bronchi, and nerves enter and leave the lung. Together, these structures form the root of the lung. A prominent indentation called the cardiac notch is also present along the mediastinal surface of the left lung. This indentation provides room for the apex of the heart.

Pleura (or Pleurae) and Pleural Cavity of the Lungs

Each lung is enveloped in its own double-membrane pleural sac. The inner membrane of the sac adheres to the outer surface of the lung and is called the visceral pleura. The outer membrane is called the parietal pleura and is an extension of the visceral pleura, which doubles back on itself at the hilum (hilus) and runs along the surfaces of the rib cage, diaphragm, and mediastinum. Both pleurae are serous membranes, which secrete a thin layer of watery pleural fluid into the pleural cavity that separates them. An open space does not normally exist in the pleural cavity because the pleural fluid loosely attaches the two membranes. During breathing movements, this slippery seal allows the two membranes to slide past one another. The pleurae also form a barrier that helps protect the lungs from infections that can occur elsewhere in the thoracic cavity.

Oxygen-hemoglobin Dissociation Curve | How CO Affects Oxy-Hemoglobin Saturation

Each of hemoglobin's four heme groups can also bind to carbon monoxide (CO). If this occurs, O2 cannot bind and carbon monoxide poisoning results. As shown in the animation, carbon monoxide association with hemoglobin is directly related to the plasma partial pressure of CO (= pCO).In this simulation, pCO is allowed to increase to from 0.0 - 0.4 mmHg while the pCO2 is maintained at 40 mmHg, which is normal.At pCO = 0.4 mmHg, the hemglobin is almost fully saturated with CO. This pressure is approximately 250 X less than the pO2 needed to fully saturate hemoglobin with O2. Carbon monoxide association with hemoglobin is directly related to the plasma partial pressure of CO (= pCO). These data indicate that heme has a much greater affinity for CO than for O2. Therefore, if an individual breathes in a relatively small amount of CO, it will saturate the hemoglobin and prevent O2 from binding. As a result, O2 cannot be distributed as needed to the body's tissues.

Bronchopulmonary Segments of the Lungs | Lung Segments | Tertiary Bronchi

Each of the five image descriptionlung lobes is divided by connective tissue walls (= septa) into anatomical compartments called image descriptionbronchopulmonary segments. Typically, there are image description10 segments in the right lung and in the left lung. Each segment functions independently and is supplied by its own image descriptiontertiary bronchus (or segmental bronchus) artery, lymph vessels, and autonomic nerves. Thus, if one segment is infected or damaged, others in the same lobe may not be affected. Right Lung Superior lobe Apical (1) Posterior (2) Anterior (3) Middle lobe Lateral (4) Medial (5) Middle lobe Lateral (4) Medial (5) Inferior lobe Superior (6) (on posterior surface) Medial basal (7) Anterior basal (8) Lateral basal (9) Posterior basal (10) 10 Segments shown on the Right Lungs Left Lung Inferior lobe Superior (6) (on posterior surface) Anterio-medial basal (7,8) Lateral basal (9) Posterior basal (10) Superior lobe Apico-posterior (1,2) Anterior (3) Superior lingular (4) Inferior lingular (5)

Pharynx Histology - Epithelial Lining of the Pharynx

Epithelial Lining of the Pharynx (introduction to pharynx histology) The surface of the nasopharynx is covered by the same pseudostratified columnar epithelium that is found in the nasal cavity. Goblet cells in the epithelium secrete mucus, which further cleans, warms, and moistens inhaled air before it moves deeper into the respiratory tract. The other two regions of the pharynx, the oropharynx and laryngopharynx, are lined by nonkeratinizing stratified squamous epithelium. These areas also form part of the digestive tract. When food is swallowed, the multiple cell layers in the stratified epithelium help protect the underlying tissues from damage caused by food moving through the passageway. An Overview of the Epithelial Lining of the Pharynx

external respiration

External respiration is the exchange of gases between the air filling the alveoli and the blood in the capillaries surrounding the walls of the alveoli. Air entering the lungs from the atmosphere has a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than does the blood in the capillaries. The difference in partial pressures causes the gases to diffuse passively along their pressure gradients from high to low pressure through the simple squamous epithelium lining of the alveoli. The net result of external respiration is the movement of oxygen from the air into the blood and the movement of carbon dioxide from the blood into the air. The oxygen can then be transported to the body's tissues while carbon dioxide is released into the atmosphere during exhalation.

Pulmonary Function Tests Using Spirometry

Forced Vital Capacity (FVC or FVC6) and Forced Expiratory Volume in one second (FEV1) are two pulmonary function tests that are routinely used to determine the health of the respiratory airways and lung tissues. To obtain an FVC, a subject first inhales as much air as possible. Forced Vital Capacity The subject then exhales forcibly through a spirometer for a period of at least six (6) seconds, which nearly empties the lungs of air. The FEV1 is the volume of air that can be forcibly exhaled in one second after a maximal inhalation. Forced Expiratory Volume The ratio of FEV1/FVC should be 75% or higher. Reduced values indicate an obstructive lung disease, such asthma, bronchitis, or COPD (chronic obstruc-tive pulmonary disease), which block normal airflow. Reduced values for both the FEV1 and FVC indicates a restrictive lung disease, such as pulmonary fibrosis or emphysema, which prevent the lungs from fully inflating

Bronchioles of the Lungs

From the tertiary bronchi, air is conducted to and from the alveoli (or air sacs) by a series of small, branching tubules called bronchioles The bronchioles branch many times on their way to the alveoli, and each division produces tubules that are progressively smaller in diameter (magnified here for display). A lobular bronchiole (or preterminal bronchiole), conducts air in and out of a pulmonary lobule (or secondary pulmonary lobule). After entering a pulmonary lobule, a lobular bronchiole divides into three or more terminal bronchioles. Swipe to show/ hide labels Terminal bronchioles measure 0.5 - 1 mm (or less) in diameter and have walls made of simple ciliated cuboidal cells, a few smooth muscle cells, and connective tissue. They are too thick for air exchange, so these tubes are considered to be the last of the conducting zone structures. Two or three respiratory bronchioles typically branch from each terminal bronchiole. These thin-walled tubules are the first respiratory zone structures, and they, in turn, give rise to alveolar ducts, alveoli, and alveolar sacs.

Respiratory System Anatomy - Major Zones & Divisions

Functionally, the respiratory system is separated into a conducting zone and respiratory zone. The conducting zone consists of the nose, pharynx, larynx, trachea, bronchi, and bronchioles. These structures form a continuous passageway for air to move in and out of the lungs. The conducting zone. The respiratory zone is found deep inside the lungs and is made up of the respiratory bronchioles, alveolar ducts, and alveoli. These thin-walled structures allow inhaled oxygen (O2) to diffuse into the lung capillaries in exchange for carbon dioxide (CO2). The respiratory zone. 1 2 PreviousNext Anatomically, the same structures are often divided into the upper and lower respiratory tracts. The upper respiratory tract structures are found in the head and neck and consist of the nose, pharynx, and larynx. The upper respiratory tract The lower respiratory tract structures are located in the thorax or chest and include the trachea, bronchi, and lungs (= bronchioles, alveolar ducts, and alveoli). The lower respiratory tract Please note that many authorities include the larynx with the lower respiratory tract structures.

CO2 effect on Oxygen-Hemoglobin Dissociation Curve

How pCO2 Affects Oxy-Hemoglobin Dissociation Curve: The animations show how the concentration of carbon dioxide in the plasma (partial pressure of CO2 or pCO2) affects oxygen-hemoglobin dissociation curve (O2-Hb saturation). As the graphs reveal, high pCO2 has the same effect on the O2-Hb dissociation curve as low plasma pH and low pCO2 has the same effect as high plasma pH (= Bohr effect). High pCO2 High partial pressure of CO2 Low pCO2 Low partial pressure of CO2 High pCO2 lessens hemoglobin's affinity for O2 in two ways. First, carbon dioxide is converted to H+ and bicarbonate ion in red blood cells via the enzyme carbonic anhydrase. The H+ ions bind to hemoglobin amino acids, and the alteration makes it more difficult for O2 to also associate. Secondly, some of the carbon dioxide binds directly to hemoglobin amino acids. This also causes alteration to the hemoglobin that make it more difficult for O2 to bind.

Bronchi Anatomy | Bronchial Wall Anatomy | Bronchus Wall Anatomy

In cross-section, the bronchial wall appears similar to the trachea. Respiratory mucosa (or mucous membrane) lines the luminal surface. Mucus-secreting goblet cells are present in the epithelium. However, they are less numerous than in the trachea. Deep to the mucosa is a layer containing smooth muscle fibers, hyaline cartilage, and scattered seromucous and mucous glands. The cartilage appears as rings in the larger bronchi but changes to irregular-sized plates in the smaller bronchi. As in the trachea, the cartilage helps keep the bronchial wall from collapsing. The smooth muscle fibers are located between the mucosa and cartilage plates and form a nearly complete ring. They are involuntarily controlled and their movement alters the size of the bronchial lumen. The changes in lumen size may increase airflow during normal breathing, protect lungs tissues from foreign particles and irritants, or improve the effectiveness of a cough. A narrow band of adventitia covers the outer bronchial wall, which connects the bronchus to the surrounding lung tissues. Photomicrograph of the bronchial wall: Components: Cartilage plate, mucosa, smooth muscle & lung tissue

Respiratory Membrane and Gas Exchange

In the lungs, gas exchange takes place in the alveolar sacs. Oxygen (O2) diffuses from the alveoli into the capillaries and RBCs. At the same time, carbon dioxide (CO2) in the capillaries diffuses into the alveoli. Swipe to show/ hide labels The bonding of O2 to hemoglobin in the RBCs causes their color to change from purple to red. See the GIF below During the exchange, the gases must rapidly cross the respiratory membrane that separates the alveolar and capillary lumens. Gas Exchange The respiratory membrane is about 0.6 micrometers thick and consists of the alveolar squamous cell, the capillary endothelial cell, and two fused basement membranes (formed by the alveolar and capillary cells).

Oxygen-Hemoglobin Dissociation Curve

In this tutorial, we will discuss how the concentration of oxygen in the blood plasma (partial pressure of O2 or pO2) affects oxygen-hemoglobin (O2-Hb) saturation. As O2 enters the vial of blood, the plasma pO2 increases and more O2 binds with hemoglobin. pO2 Hb + O2 <———->HbO2 The reaction also causes the color of the RBCs in the vial to change from purple to red. The concentration of oxygen in the blood plasma affects oxygen-hemoglobin saturation. As the pO2 approaches 100 torrs (or mmHg), the hemoglobin molecules become nearly fully saturated. Hb + 1 O2 = 25% saturation Hb + 2 O2 = 50% saturation Hb + 3 O2 = 75% saturation Hb + 4 O2 = 100% saturation The O2-Hb relationship is sigmoidal (or s-shaped) and not linear. (see the image below)The upper end of the curve is flatter than the lower end. This indicates that the first three O2 bind to hemoglobin molecules at relatively low pO2 (= 0 - 40 torr). In contrast, adding the 4th O2 to hemoglobin moleculess requires a relatively high pO2 (= 40 - 100 torr).

Respiratory Mucosa (Nasal Mucosa) | Gross & Microscopic Anatomy

Inside the nasal cavity, the surfaces of the turbinate bones (= nasal conchae) and meatuses are lined (see image below) by respiratory mucosa (= nasal mucosa). An expanded view of the respiratory mucosa shows more detail about its layered composition. Along the luminal (nasal) surface is pseudostratified ciliated columnar epithelium. Interspersed among the columnar cells in the epithelium are many flask-shaped goblet cells. The densely packed cells in the epithelium are embedded in a thin, adhesive sheet called the basement membrane. Deep to the basement membrane is a thicker layer of loose connective tissue called the lamina propria. Many blood vessels and seromucosal glands are also present in the lamina propria.

internal respiration

Internal respiration is the exchange of gases between the blood in capillaries and the tissues of the body. Capillary blood has a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than the tissues through which it passes. The difference in partial pressures leads to the diffusion of gases along their pressure gradients from high to low pressure through the endothelium lining of the capillaries. The net result of internal respiration is the diffusion of oxygen into the tissues and the diffusion of carbon dioxide into the blood

Myoglobin Structure and Function

Myoglobin (Mb) is a structurally complex molecule that binds and stores oxygen inside of skeletal and cardiac muscles cells. A large, coiled polypeptide called globin makes up most of the molecule. In a hydrophobic pocket formed by two of the globin's folds is a heme group. The heme consists of an atom of ferrous iron (Fe2+) and a surrounding porphyrin ring (= four nitrogen-containing pyrrole molecules. Find out how you can learn and remember more efficiently using active recall. The iron can reversibly bond with one molecule of oxygen (O2). Two histidine molecules are associated with the heme. On one of the sides of the heme is the proximal histidine, which binds the Fe2+ of the heme to the nearby globin. It helps stabilize the position of the attached heme. The distal histidine, which is not bound to the heme, helps prevent oxidation of Fe2+ to Fe3+. Oxygen does not bind to Fe3+. The distal heme also reduces carbon monoxide's (CO) affinity for heme, which makes it easier for O2 to bond.

Bronchial Tubes Structure, Functions, & Location | Bronchus Anatomy

Near the sternal angle, the trachea bifurcates (or splits), into the right and left primary (1) bronchi. Each bronchus runs freely for a few centimeters, then enters its respective lung. Air flows in and out of each lung through the primary bronchi. After entering a lung, each 1 bronchus divides into secondary (2) bronchi. The secondary bronchi are also known as lobar bronchi because each one directly conducts air to and from one of the lung's five lobes. Within a lobe, tertiary (3) bronchi branch from the secondary bronchi. Each 3 bronchus conducts air to and from a bronchopulmonary segment, which is an anatomical and functional subdivision of a lobe. Have you been making any of these common anatomy learning mistakes? Because they conduct air in and out of the bronchopulmary segments, the tertiary bronchi are known as segmental bronchi.

Supportive Bones and Cartilages of the Nasal Cavity

Posterior to the nose (nose external), is the nasal cavity. This large passage-way is framed and supported by several bones and cartilages. Supporting the arched roof of the cavity are the frontal bone, sphenoid bone, cribriform plate of the ethmoid bone and nasal bones. The lateral walls of the cavity are framed by the bodies of the two maxilla bones. The cavity floor is supported by the palatine process of the maxilla bones and the horizontal plates of the palatine bones. Together, these bones are referred to as the hard palate. A thin vertical plate, the nasal septum, divides the nasal cavity into two chambers (nasal fossae). The septum consists of the vomer bone, perpendicular plate of the ethmoid bone, and septal cartilage.

Vocal Cords (Vocal Folds) & Vestibular Folds of the Larynx

Projecting into the lumen of the larynx are two pairs of soft tissue folds. Each fold image descriptionextends from the back of the thyroid cartilage to the front of the arytenoid cartilage. The inferior set of folds are called the vocal folds or vocal cords (= true vocal folds). A narrow vocal ligament is embedded in each vocal fold. These elongated bands of elastic tissue vibrate to produce voice sounds (= phonation). Unlike the rest of the larynx, the surfaces of the vocal folds are covered by a protective layer of stratified squamous epithelium. Superior to the vocal folds are the vestibular folds (= false folds or ventricular folds). Each vestibular fold is formed by a thick layer of mucous membrane (= respiratory membrane) and a supportive vestibular ligament. The vestibular folds are not directly involved in the process of voice production. Instead, they lubricate the vocal folds with mucous sections and help prevent food from entering the lower respiratory tract organs.

Introduction to Spirometers & Lung Diseases

Pulmonary Diseases: Normal ventilation of the lungs is affected by many types of obstructive and restrictive pulmonary diseases: 1. Obstructive Diseases (obstructions of the trachea, bronchi, and bronchioles). Common causes: a. Asthma - smooth muscle contractions and/or inflammation that causes the respiratory tubes to narrow. Asthma is often triggered by allergens, infections, exercise, cold air, and irritants. b. Bronchitis - inflammation of the respiratory tubes due to infections or airborne irritants (cigarets smoke). c. Bronchiectasis - widening of the respiratory tubes and an inability to clear secreted mucus. The condition is frequently caused by infections (severe pneumonia) and inherited dysfunctions (cystic fibrosis). d. Chronic obstructive pulmonary disease (COPD) - chronic inflammation of the respiratory tubes and/or lung tissues most often caused by chronic bronchitis or emphysema. 2. Restrictive Diseases (inability to expand the lungs). Intrinsic Causes: a. Destruction of the lung tissues (parenchyma) - due to infections (tuberculosis), autoimmune disorders (sarcoidosis), drugs, asbestos, radiation, and cancers. Extrinsic Causes: a. Problems with the tissue layers lining the lungs (pleurae) - due to inflammation (pleurisy) or damage. b. Extrapulmonary problems - due to neurological disorders (spinal cord injury), neuromuscular disorders that affect the breathing muscles (ALS, myasthenia graves) and chest wall deformities (scoliosis, kyphosis). Spirometers: Spirometry is one of the primary Pulmonary Function Tests (PFT) used to check the health of the lungs and respiratory passageways. When a spirometry test is performed, the subject breathes through a mechanical or electronic airflow sensor called a spirometer. The simplest mechanical spirometers are hand-held devices that contain a set of blades arranged like a windmill. The blades rotate during exhalation, which causes a volume indicator to move or digital display to change values. The blades rotate during exhalation which causes the volume indicator to change values. Electronic spirometers have no moving parts and act as transducers. They digitally convert airflow rates and volumes into electronic signals, which can be digitally analyzed and displayed. Electronic spirometer digitally convert airflow rate and volumes into electronic signals. A recording of a subject's airflow is referred to as a spirogram. The vertical axis of a spirogram indicates airflow volume (in liters) and the horizontal axis indicates time (in seconds). Inhalation causes an upward deflection of a scan line and exhalation causes a downward deflection. Airflow rate is determined by combining the information recorded on the vertical and horizontal axes (volume per second). The results of the spirogram are compared with normal values for an individual's height, weight, sex, and age. A reduced rate of airflow indicates a blockage in one or more of the airways (an obstructive disorder), and a reduced volume indicates an inability to fully expand the lungs (a restrictive disorder).

pulmonary ventilation

Pulmonary ventilation is the process of moving air into and out of the lungs to facilitate gas exchange. The respiratory system uses both a negative pressure system and the contraction of muscles to achieve pulmonary ventilation. The negative pressure system of the respiratory system involves the establishment of a negative pressure gradient between the alveoli and the external atmosphere. The pleural membrane seals the lungs and maintains the lungs at a pressure slightly below that of the atmosphere when the lungs are at rest. This results in air following the pressure gradient and passively filling the lungs at rest. As the lungs fill with air, the pressure within the lungs rises until it matches the atmospheric pressure. At this point, more air can be inhaled by the contraction of the diaphragm and the external intercostal muscles, increasing the volume of the thorax and reducing the pressure of the lungs below that of the atmosphere again. To exhale air, the diaphragm and external intercostal muscles relax while the internal intercostal muscles contract to reduce the volume of the thorax and increase the pressure within the thoracic cavity. The pressure gradient is now reversed, resulting in the exhalation of air until the pressures inside the lungs and outside of the body are equal. At this point, the elastic nature of the lungs causes them to recoil back to their resting volume, restoring the negative pressure gradient present during inhalation.

Paranasal Sinuses and Sinusitis

Several open, air-filled chambers called paranasal sinuses (see the image below) are present in the bones surrounding the nasal cavity. Two image descriptionfrontal sinuses are in the bones just above the orbits, and several small image descriptionethmoid air cells (or sinuses) are in the bones between the orbits. Two large image descriptionmaxillary sinuses are in the cheek bones, and and two image descriptionsphenoid sinuses are in the bones at the base of the skull. A thin layer of respiratory mucosa(or nasal mucosa) lines the paranasal sinuses. Mucus produced in the sinuses normally drains out of small apertures (or ostia) and adds to the mucus in the nasal cavity. The open sinuses also help lighten the skull and resonate the voice sounds. Sinusitis most often occurs when infections, allergies, or tissue irritants cause the sinus mucosa to become inflamed. The edematous (= swollen) membranes block the ostia drainageways that lead to the nasal cavity and mucus accumulates in the open sinus chamber. Air trapped in the sinus is absorbed into the bloodstream, creating a negative pressure or vacuum. As the vacuum builds, so does the sense of pain. The vacuum may draw fluids into the sinus from the bloodstream. Bacteria and other microbes often grow in these fluids leading to more edema and inflammation.

muscles of respiration

Surrounding the lungs are sets of muscles that are able to cause air to be inhaled or exhaled from the lungs. The principal muscle of respiration in the human body is the diaphragm, a thin sheet of skeletal muscle that forms the floor of the thorax. When the diaphragm contracts, it moves inferiorly a few inches into the abdominal cavity, expanding the space within the thoracic cavity and pulling air into the lungs. Relaxation of the diaphragm allows air to flow back out the lungs during exhalation. Between the ribs are many small intercostal muscles that assist the diaphragm with expanding and compressing the lungs. These muscles are divided into 2 groups: the internal intercostal muscles and the external intercostal muscles. The internal intercostal muscles are the deeper set of muscles and depress the ribs to compress the thoracic cavity and force air to be exhaled from the lungs. The external intercostals are found superficial to the internal intercostals and function to elevate the ribs, expanding the volume of the thoracic cavity and causing air to be inhaled into the lungs.

transportation of gases

The 2 major respiratory gases, oxygen and carbon dioxide, are transported through the body in the blood. Blood plasma has the ability to transport some dissolved oxygen and carbon dioxide, but most of the gases transported in the blood are bonded to transport molecules. Hemoglobin is an important transport molecule found in red blood cells that carries almost 99% of the oxygen in the blood. Hemoglobin can also carry a small amount of carbon dioxide from the tissues back to the lungs. However, the vast majority of carbon dioxide is carried in the plasma as bicarbonate ion. When the partial pressure of carbon dioxide is high in the tissues, the enzyme carbonic anhydrase catalyzes a reaction between carbon dioxide and water to form carbonic acid. Carbonic acid then dissociates into hydrogen ion and bicarbonate ion. When the partial pressure of carbon dioxide is low in the lungs, the reactions reverse and carbon dioxide is liberated into the lungs to be exhaled.

Lung Volumes and Capacities

The amount of air in the lungs can be subdivided into four (4) volumes and four (4) capacities. Respiratory (lung) volumes: Tidal volume (TV) is the amount of air that can be inhaled and exhaled during one normal (quiet) breathing cycle (about 500 ml for men & women). Tidal Volume Overwhelmed by anatomy? Take an online crash course with videos and quizzes. Inspiratory reserve volume (IRV) is the amount of air that can be forcibly inhaled beyond a tidal inhalation (about 3,000 ml for men & 2,000 ml for women). Inspiratory Reserve Volume Expiratory reserve volume (ERV) is the amount of air that can be forcibly exhaled beyond a tidal exhalation (about 1200 ml for men & 700 ml for women). Expiratory Reserve Volume Residual Volume (RV) (see image below)- the amount of air remaining in the lungs after an ERV (= about 1,200 ml in men & women). Respiratory (lung) capacities (= two or more respiratory volumes added together):1. Inspiratory capacity = TV + IRV.2. Functional reserve capacity = ERV + RV. 3. Vital capacity (see image below) = TV + IRV + ERV. 4. Total lung capacity = RV + VC.

Respiratory System By: Tim Barclay, PhD

The cells of the human body require a constant stream of oxygen to stay alive. The respiratory system provides oxygen to the body's cells while removing carbon dioxide, a waste product that can be lethal if allowed to accumulate. There are 3 major parts of the respiratory system: the airway, the lungs, and the muscles of respiration. The airway, which includes the nose, mouth, pharynx, larynx, trachea, bronchi, and bronchioles, carries air between the lungs and the body's exterior. The lungsact as the functional units of the respiratory system by passing oxygen into the body and carbon dioxide out of the body. Finally, the muscles of respiration, including the diaphragm and intercostal muscles, work together to act as a pump, pushing air into and out of the lungs during breathing.

The Epiglottis of the Larynx

The epiglottis is a leaf-shaped flap of tissues that projects obliquely from the top of the larynx. Its shape and position are supported by a band of elastic cartilage, which attaches to the posterior of the thyroid cartilage by a small ligament. A midsagittal view of the mouth, nasal cavity, and throat shows the location of the epiglottis relative to the tongue and pharynx. During the swallowing process, the extrinsic muscles attached to the larynx move upward. The flexible epiglottis flattens as it strikes the base of the tongue and covers the opening to the larynx. The epiglottis covers the opening to the larynx Food passes into the esophagus instead of entering the larynx. Once the food enters the esophagus, the extrinsic muscles relax, the larynx returns to its original position, and the respiratory passageway reopens.

Intrinsic Muscles of the Larynx

The intrinsic muscles move the arytenoid cartilages and adjust the tension applied to the vocal folds and ligaments. They are called intrinsic muscle because they originate and insert on the larynx. Transverse arytenoid - vocal ligaments adducted or moved together. Intrinsic Muscles of the Larynx Intrinsic Muscles of the Larynx: The intrinsic muscles move the arytenoid cartilages and adjust the tension applied to the vocal folds and ligaments. They are called intrinsic muscle because they originate and insert on the larynx. PreviousNext Transverse arytenoid - vocal ligaments adducted or moved together. Transverse arytenoid Lateral cricoarytenoids - vocal ligaments adducted or moved together. Posterior cricoarytenoids - vocal ligaments abducted or moved apart Vocalis & Thyroarytenoids - length of vocal ligaments reduced or vocal ligaments loosen. Intrinsic Muscles of the Larynx Intrinsic Muscles of the Larynx: The intrinsic muscles move the arytenoid cartilages and adjust the tension applied to the vocal folds and ligaments. They are called intrinsic muscle because they originate and insert on the larynx. 1 2 PreviousNext Transverse arytenoid - vocal ligaments adducted or moved together. Transverse arytenoid Lateral cricoarytenoids - vocal ligaments adducted or moved together. Rapidly and efficiently memorize larynx muscle anatomy with this handy muscle anatomy reference chart for the head and neck. Lateral cricoarytenoids Posterior cricoarytenoids - vocal ligaments abducted or moved apart. Posterior cricoarytenoids Vocalis & Thyroarytenoids - length of vocal ligaments reduced or vocal ligaments loosen. Cricothyroids - the length of vocal ligaments increase or vocal ligaments tighten.

Thyroid and Cricoid Cartilages of the Larynx

The largest laryngeal cartilage is the thyroid cartilage. [ Anterior view/ Lateral view/ Posterior view ] It consists of two plates of hyaline cartilage and that is shaped like a wedge. The plates are separated posteriorly and fused anteriorly. At the top of the fused border, the thyroid cartilage extends anteriorly, forming the laryngeal prominence or "Adam's apple". Superior to the thyroid cartilage is the hyoid bone, which is connected to the larynx by the thyrohyoid membrane. The hyoid bone is u-shaped and primarily serves as an attachment point for the tongue muscles. [ Anterior view/ Lateral view/ Posterior view ] Inferior to the thyroid cartilage is the ring-shaped cricoid cartilage. Like the thyroid cartilage, the cricoid cartilage is composed of hyaline cartilage. The anterior portion of the cricoid cartilage is narrow and referred to as the arch. The broad posterior portion is called the lamina and forms much of the larynx back wall. Superior to the lamina is arytenoid cartilages, which attach to the vocal cords. [ Anterior view/ Lateral view/ Posterior view ] Inferior to the cricoid cartilage is the trachea, which conducts air to and from the lungs. [ Anterior view/ Lateral view/ Posterior view ]

Location and Functions of the Larynx

The larynx is a short (= 1.5 inch) tube that is located in the throat, inferior to the hyoid bone and tongue and anterior to the esophagus. Forming the larynx are nine (9) supportive cartilages, several intrinsic and extrinsic muscles, and a mucous membrane lining. As a primary function, the larynx provides a carefully guarded air passageway (See the GIF below) between the pharynx and the trachea. During the swallowing process, movements of the cartilages close the entrance to the larynx so food and drink cannot enter. The larynx also houses the vocal folds and ligaments that produce the voice sounds.

larynx

The larynx, also known as the voice box, is a short section of the airway that connects the laryngopharynx and the trachea. The larynx is located in the anterior portion of the neck, just inferior to the hyoid bone and superior to the trachea. Several cartilage structures make up the larynx and give it its structure. The epiglottis is one of the cartilage pieces of the larynx and serves as the cover of the larynx during swallowing. Inferior to the epiglottis is the thyroid cartilage, which is often referred to as the Adam's apple as it is most commonly enlarged and visible in adult males. The thyroid holds open the anterior end of the larynx and protects the vocal folds. Inferior to the thyroid cartilage is the ring-shaped cricoid cartilage which holds the larynx open and supports its posterior end. In addition to cartilage, the larynx contains special structures known as vocal folds, which allow the body to produce the sounds of speech and singing. The vocal folds are folds of mucous membrane that vibrate to produce vocal sounds. The tension and vibration speed of the vocal folds can be changed to change the pitch that they produce.

lungs

The lungs are a pair of large, spongy organs found in the thorax lateral to the heart and superior to the diaphragm. Each lung is surrounded by a pleural membrane that provides the lung with space to expand as well as a negative pressure space relative to the body's exterior. The negative pressure allows the lungs to passively fill with air as they relax. The left and right lungs are slightly different in size and shape due to the heart pointing to the left side of the body. The left lung is therefore slightly smaller than the right lung and is made up of 2 lobes while the right lung has 3 lobes. The interior of the lungs is made up of spongy tissues containing many capillaries and around 30 million tiny sacs known as alveoli. The alveoli are cup-shaped structures found at the end of the terminal bronchioles and surrounded by capillaries. The alveoli are lined with thin simple squamous epithelium that allows air entering the alveoli to exchange its gases with the blood passing through the capillaries

Lung Lobes and Fissures

The lungs are anatomically and functionally divided into large subunits called lobes. The slightly larger right lung is divided into the superior lobe, middle lobe, and inferior lobe lobe. Only two lobes are present in the smaller left lung, the superior and inferior. Each lobe receives air from its own secondary bronchus and is separated from its neighbors by fissures (or connective tissue walls). These anatomical partitions help prevent mechanical damage or infectious agents from affecting nearby the lobes. In the right lung, a horizontal fissure separates the superior and middle lobes and an oblique fissure separates the middle and inferior lobes. A second oblique fissure separates the two lobes of the left lung. The lobes and fissures are also present on the mediastinal surface of the lungs.

mouth

The mouth, also known as the oral cavity, is the secondary external opening for the respiratory tract. Most normal breathing takes place through the nasal cavity, but the oral cavity can be used to supplement or replace the nasal cavity's functions when needed. Because the pathway of air entering the body from the mouth is shorter than the pathway for air entering from the nose, the mouth does not warm and moisturize the air entering the lungs as well as the nose performs this function. The mouth also lacks the hairs and sticky mucus that filter air passing through the nasal cavity. The one advantage of breathing through the mouth is that its shorter distance and larger diameter allows more air to quickly enter the body.

nose and nasal cavity

The nose and nasal cavity form the main external opening for the respiratory system and are the first section of the body's airway—the respiratory tract through which air moves. The nose is a structure of the face made of cartilage, bone, muscle, and skin that supports and protects the anterior portion of the nasal cavity. The nasal cavity is a hollow space within the nose and skull that is lined with hairs and mucus membrane. The function of the nasal cavity is to warm, moisturize, and filter air entering the body before it reaches the lungs. Hairs and mucus lining the nasal cavity help to trap dust, mold, pollen and other environmental contaminants before they can reach the inner portions of the body. Air exiting the body through the nose returns moisture and heat to the nasal cavity before being exhaled into the environment.

Nose & Nasal Cavity Structure & Functions:

The nose and nasal cavity make up the first portion of the upper respiratory tract. Their locations and structures are best viewed when the head is shown in sagittal section. The first portion of the respiratory tract is made up of the nose (or external nose) and an open inner chamber called the nasal cavity. Protruding prominently from the face, the nose serves as a vent for air exchange. Two openings called anterior nares (or nostrils; exterior nares) allow air to enter the nose and pass into the nasal cavity. Individually, each opening is referred to as an anterior naris. Inside the nasal cavity, inhaled air is warmed, moistened, and cleaned so it can travel safely into other parts of the respiratory tract. The nasal cavity also contains structures to detect chemical odorants and resonate the voice. After circulating over the nasal cavity structures, air passes into the pharynx through two posterior nares (or choanae; internal nares). Individually, each opening is referred to as a posterior naris

Supportive Cartilages and Bones of the Nose

The nose functions as an air vent and is supported by bone, hyaline cartilage, and dense fibrous connective tissue. Framing the upper half of the nose are the nasal bones and the medial plates of the maxilla bones. The flexible lower half is framed by the lateral, greater alar, and lesser alar cartilages. Partitioning the nasal cavity into left and right nasal fossae (sing. fossa) is the septal cartilage. Dense fibrous connective tissue supports the rounded lateral walls of the nostrils, which are called ala nasi.

Tonsils & Adenoids (Lymphoid Tissue) of the Pharynx

The openings to the pharynx from the nose and mouth are protected by a ring of tonsils and other types of lymphoid tissue (Waldeyer's ring). Along the anterolateral walls of the oropharynx are the palatine tonsils, which are often referred to as "the tonsils". Pathogens such as viruses and bacteria drain into these masses, where they are destroyed by lymphocytes and other types of leukocytes (white blood cells). When these structures become inflamed and sore, the condition is referred to as tonsilitis. Embedded in the posterior wall of the nasopharynx, near the midline, is the pharyngeal tonsil (adenoids). Inflammation of the pharyngeal tonsil can impede airflow through the nasopharynx, causing breathing difficulties and an alteration of the voice (increased nasal tones). Guarding the base of the tongue is the lingual tonsil.

Anatomical Regions of the Pharynx

The pharynx is a four to five inch fibromuscular tube that conducts air from the nasal cavity to the larynx. It is divided into three anatomical regions. Nasopharynx - region posterior to the nasal cavity, from the internal nares (choanae) to soft palate. Oropharynx - region posterior to the root of tongue, from the soft palate to epiglottis (larynx) and hyoid bone. Laryngopharynx- region posterior to behind larynx, from the epiglottis to cricoid cartilage (larynx).

pharynx

The pharynx, also known as the throat, is a muscular funnel that extends from the posterior end of the nasal cavity to the superior end of the esophagus and larynx. The pharynx is divided into 3 regions: the nasopharynx, oropharynx, and laryngopharynx. The nasopharynx is the superior region of the pharynx found in the posterior of the nasal cavity. Inhaled air from the nasal cavity passes into the nasopharynx and descends through the oropharynx, located in the posterior of the oral cavity. Air inhaled through the oral cavity enters the pharynx at the oropharynx. The inhaled air then descends into the laryngopharynx, where it is diverted into the opening of the larynx by the epiglottis. The epiglottis is a flap of elastic cartilage that acts as a switch between the trachea and the esophagus. Because the pharynx is also used to swallow food, the epiglottis ensures that air passes into the trachea by covering the opening to the esophagus. During the process of swallowing, the epiglottis moves to cover the trachea to ensure that food enters the esophagus and to prevent choking.

Lung Alveoli - Location of Alveolar Ducts and Alveolar Sacs

The respiratory bronchioles inside a secondary pulmonary lobule gives rise to two or more alveolar ducts. Protruding from the thin walls of the alveolar ducts and respiratory bronchioles are many cup-shaped alveoli, each measuring about 0.2 - 0.5 mm in diameter. At the distal end of an alveolar duct, the alveoli are arranged into grape-like clusters called alveolar sac. The alveoli share a common opening to the alveolar duct. Alveolar sacs.

Introduction to Lungs Anatomy

The soft, elastic lungs occupy most of the thoracic cavity and are protected from injury by the surrounding the sternum and rib cage. Both right lung and left lung rest on the diaphragm muscle that separates the thoracic and abdominal cavities. A large portion of each lung consists of blood vessels (arteries, veins, & capillaries) and respiratory tubes (bronchi, bronchioles, & alveolar ducts). Most of the lung volume, however, is made of small clusters of alveoli. Each alveolus is a small, thin-walled, cup-shaped sac that protrudes from the smallest air ducts. There are approximately 300 million alveoli in each lung, and they are the regions where gases are exchanged with nearby capillaries.

Trachea (or Windpipe) Location, Anatomy, and Physiology

The trachea (or windpipe) is a 4-5 inch (= 10-12 cm) vertical tube that runs through the neck and chest, just anterior to the esophagus. Many consider the trachea to be the first portion of the lower respiratory tract, which also includes the bronchi, bronchioles, and lungs. The trachea has a wide lumen (= 1 inch or 2.5 cm) and functions to conduct air between the larynx and (primary) bronchi. Embedded in the wall of the are 16 to 20 tracheal rings made of hyaline cartilage. The cartilage rings stiffen the tracheal wall so the lumen stays open during breathing. In back, the rings are incomplete, giving them a characteristic C-shape.

trachea

The trachea, or windpipe, is a 5-inch long tube made of C-shaped hyaline cartilage rings lined with pseudostratified ciliated columnar epithelium. The trachea connects the larynx to the bronchi and allows air to pass through the neck and into the thorax. The rings of cartilage making up the trachea allow it to remain open to air at all times. The open end of the cartilage rings faces posteriorly toward the esophagus, allowing the esophagus to expand into the space occupied by the trachea to accommodate masses of food moving through the esophagus. The main function of the trachea is to provide a clear airway for air to enter and exit the lungs. In addition, the epithelium lining the trachea produces mucus that traps dust and other contaminants and prevents it from reaching the lungs. Cilia on the surface of the epithelial cells move the mucus superiorly toward the pharynx where it can be swallowed and digested in the gastrointestinal tract.

Turbinate Bones (Nasal Conchae)

The turbinates (turbinate bones or nasal conchae) are thin, curved, bony plates that project from the walls of the nasal cavity into the respiratory passageway. There are three (3) turbinates on each side of the nasal cavity, and all are covered by a thick layer of mucous membrane (= respiratory or nasal mucosa): The smaller superior and middle turbinates are downward extensions of the ethmoid bone. The larger inferior turbinates are individual bones that attach to the maxilla bone. Each extends horizontally along the lateral wall of the nasal cavity and adds surface area to the passageway. Grooves (or indentations) called meatuses are found between the curved turbinates. The curved shapes of the turbinates and meatuses are best viewed in coronal section. During inhalation, air is directed (see the image below) over and under the turbinates. The surface mucosa conditions or prepares the air so it can safely travel into the lungs.

Vestibule Region of the Nasal Cavity

The vestibule is the portion of the nasal cavity that lies directly posterior to the external nares (or nostrils). Because it is located near the body surface, the vestibule region is frequently exposed to destructive agents. To compensate, it is lined by the same stratified squamous epithelium that makes up the skin. The multiple layers of cells in this tissue create a barrier that helps protect the vestibule from damage. Embedded in the epithelial lining are large nose hairs, called vibrissae A layer of mucus typically covers the outer surface of the vibrissae. During inhalation, many airborne particles adhere to the mucus-lined vibrissae, which prevents them from passing deeper into the respiratory passageways. Airborne particles adhere to the mucus-lined vibrissae

General Anatomy of the Larynx - Larynx Anatomy

The walls of the larynx are made up of cartilage, ligaments, membranes, muscles, and respiratory mucosa (or mucous membrane). There are nine (9) laryngeal cartilages, three (3) paired and three (3) single single. Together, they form a supportive skeletal framework. Several ligaments and membranes loosely hold the cartilages together. Swipe to explore the ligaments of the larynx Two sets of muscles control larynx movements. Intrinsic muscles regulate the tension and orientation of the vocal ligaments that produce the voice. Superior view/ Lateral view Extrinsic muscles (not shown) adjust the position of the larynx during the swallowing process. General Anatomy of the Larynx - Larynx Anatomy The walls of the larynx are made up of cartilage, ligaments, membranes, muscles, and respiratory mucosa (or mucous membrane). 1 2 3 PreviousNext There are nine (9) laryngeal cartilages, three (3) paired and three (3) single single. Together, they form a supportive skeletal framework. 1 2 3 PreviousNext Several ligaments and membranes loosely hold the cartilages together. Swipe to explore the ligaments of the larynx 1 2 3 PreviousNext Two sets of muscles control larynx movements. Intrinsic muscles regulate the tension and orientation of the vocal ligaments that produce the voice. Superior view/ Lateral view Extrinsic muscles (not shown) adjust the position of the larynx during the swallowing process. Have you tried using flashcards to solidly your knowledge? Find out how you can make your own. Respiratory mucosa (or mucous membrane) covers most of the interior surface of the larynx. It is continuous with the tissues that line the pharynx and serves to further clean, moisten and warm inhaled air.

Small Cartilages of the Larynx - Arytenoid, Corniculate, & Cuneiform Cartilages

Two arytenoid cartilages are located along the upper edge of the cricoid lamina (or back plate). Directly above each pyramidal-shaped arytenoid cartilage is a small, conical corniculate cartilage. The arytenoid cartilages help regulate the movements of the attached vocal ligaments. Several small intrinsic muscles attach to the surfaces of the arytenoid cartilage. The contraction of these muscles causes the length and position of the vocal ligaments to change. Also found in the larynx are two small cuneiform cartilages. These cartilages are embedded in the quadrangular membranes and aryepiglottic folds that loosely connect the arytenoid cartilages to the epiglottis. The cartilages add support to these soft tissues.

homeostatic control of respiration

Under normal resting conditions, the body maintains a quiet breathing rate and depth called eupnea. Eupnea is maintained until the body's demand for oxygen and production of carbon dioxide rises due to greater exertion. Autonomic chemoreceptors in the body monitor the partial pressures of oxygen and carbon dioxide in the blood and send signals to the respiratory center of the brain stem. The respiratory center then adjusts the rate and depth of breathing to return the blood to its normal levels of gas partial pressures.

Secondary Pulmonary Lobules of the Lungs

Walls of connective tissue (or septa) partitioned the bronchopulmonary segments into many polygonal-shaped secondary pulmonary lobules (or pulmonary lobules). The secondary pulmonary lobules measure approximately 1-3 centimeters in diameter and are most anatomically well-defined along the surface of the lungs. A secondary pulmonary lobule typically contains (see the image below) 3-5 terminal bronchioles (the smallest conducting tubules) and many respiratory bronchioles, alveolar ducts, and alveoli (where gases are exchanged with surrounding blood vesse

health issues affecting the respiratory system

When something impairs our ability to exchange carbon dioxide for oxygen, this is obviously a serious problem. Many health problems can cause respiratory problems, from allergies and asthma to pneumonia and lung cancer. The causes of these issues are just as varied—among them, infection (bacterial or viral), environmental exposure (pollution or cigarette smoke, for instance), genetic inheritance or a combination of factors. Sometimes the onset is so gradual, we don't seek medical attention until the condition has advanced. Sometimes, as with the genetic disorder called alpha-1 antitrypsin deficiency (A1AD), symptoms gradually set in and are often under-diagnosed or misdiagnosed. DNA health testing can screen you for genetic risk of A1AD.

Hemoglobin Molecule - Structure & Function

inside each red blood cell are 200-300 million molecules of hemoglobin (Hb) molecules. Hemoglobin is a large molecule composed of two alpha subunits and two beta subunits. Making up each subunit is a large, folded, polypeptide called globin. Between each two of the globin folds, there is a hydrophobic pocket that contains a heme group. Two histidine molecules are associated with each heme group. Structure of Hmoglobin Subunits An expanded view of the Heme group reveals that it consists of an atom of ferrous iron (Fe2+) and a surrounding porphyrin ring (four nitrogen-containing pyrrole molecules). The iron atom can reversibly bind with one molecule of oxygen (O2). Expanded view of the Hemoglobin molecule On one side of the heme group is the proximal histidine, which binds the Fe2+ of the Heme to the nearby globin. It helps stabilize the position of the attached Heme. The distal histidine, which is not bound to the heme, helps prevent oxidation of Fe2+ to Fe3+. Oxygen does not bind to Fe3+. Because it has four subunits, a hemoglobin molecule can reversibly bond with up to four O2 molecules. When not bonded to O2, deoxyhemoglobin stays in a tensed state (or conformation). The first O2 molecule to bond causes the oxyhemoglobin to shift to a relaxed state. This change in shape makes it easier for additional O2 molecules to bind to the other Heme groups, a property called cooperativity.

crash course of the respiratory system

lobe-finned fish 380 million years ago something started breathing air bacteria used to get oxygen through diffusion "when a material automatically flows from where its concentration is HIGH, to where it's LOW" To get bigger, organisms need circulatory system to transport oxygen and a respiratory system to bring in oxygen. gills work inside of water but there was less water respiratory system: Trachea, lungs, ribs, diaphragm cellular respiration needs diffusion and bulk flow of oxygen One of the keys to efficient diffusion of any material is distance. This is why we can't get our materials through diffusion alone. We need bulk flow. (1x10^20 oxygen on the bus). Then it must diffuse through four layers. Respiratory system takes advantage of bulk flow and diffusion Lungs: pump, no contactable muscle tissue diaphragm: a set of muscles that separates your thorax from your abdomen; breath in, muscle contracts external intercostal muscles: contract the muscles so lungs can expand and pull ribs up and out gases go from high pressure to low pressure mucus in nose and sinuses warm and moisten incoming air, so it doesn't dry out those sensitive lung cells that must remain wet. epiglotis covers the larynx and sends stuff we swallow away from our lungs trachea is a vacuum hose so it wont colapse 2 zones: 1. conductive zone: upper part; nose 2. respiratory zone: includes the bronchioles, alveolar ducts and alveoloi, gas exchange bronchioles-alveolar ducts, alveolar sacs alveli: tiny cavity where oxygen molecules disolve and where CO2 exits 700 million alveoli 75 square meters of moist membrane surface area