The Respiratory System PDF

The Respiratory System Objectives Discuss the process of respiration. Understand the functional organizations of the respiratory system. Identify the functions of respiratory system structures. Discuss asthma as an example of a homeostatic imbalance. Identify the compone...

The Respiratory System Objectives Discuss the process of respiration. Understand the functional organizations of the respiratory system. Identify the functions of respiratory system structures. Discuss asthma as an example of a homeostatic imbalance. Identify the components of the respiratory membrane. Understand the physical properties of the lungs. Discuss mechanics of breathing. Discuss modified breathing movements.  Respiration Cellular respiration External and internal respiration  Respiration 1. The exchange of air between the atmosphere and the lungs (Breathing). 2. The exchange of O 2 and CO 2 between the lungs and the blood. 3. The transport of O 2 and CO 2 by the blood. 4. The exchange of gases between blood and the cells.  External Respiration Inspiration (inhalation): the movement of air into the lungs. Breathing Breathing provides humans with methods for expressing emotions. Expiration (exhalation): the How?? movement of air out of the lungs. How do emotions affect your breathing rate? Emotions like fear and anxiety can Ever notice your breath cause shortness of breath. quickening when you’re afraid? This is your body’s fight, flight, or freeze response in action. When you’re relaxed, do you find yourself breathing at a On the other hand, When you’re slower pace? feeling calm, your nervous system is in a relaxed state, and your breath That’s not a coincidence. becomes slower.  How do emotions affect your breathing rate? “When we breathe normally, the body maintains a healthy balance between oxygen and carbon dioxide “However, when we start to feel anxious, we may breathe too much or too little, and this balance gets out of control. When we breathe too much, also known as hyperventilating, less oxygen makes its way to the brain, and we experience many unpleasant sensations, including dizziness, lightheadedness, increased heart rate, tingling sensations, and blurred vision.” Our emotions are closely linked with your physiological (body) state, including heart rate, blood pressure, and how you breathe.  How do emotions affect your breathing rate? Our emotions are closely linked with your physiological (body) state, including heart rate, blood pressure, and how you breathe.  Functional Organization of the Respiratory System Conduct air Participate in gas exchange The Journey of Air through the Respiratory System 1. Nose and Nasal Cavity The nose is a specialized organ at the entrance of the respiratory system. As air passes through the nasal cavity, it is: 1. Warmed by blood in the capillaries. 2. Filtered by nose hairs. 3. Moistened by mucus.  The Journey of Air through the Respiratory System 2.. Pharynx A tube formed by skeletal muscle lined by mucous membrane. Functions of the pharynx: 1. Passageway for air and food. 2. Provides a resonating chamber for speech sounds.  2.. Pharynx The pharynx is divided into three regions: ❑ Nasopharynx ❑ Oropharynx ❑ Laryngopharynx 2.. Pharynx  The Journey of Air through the Respiratory System 3. Larynx (Voice Box) A short passageway that connects the pharynx with the trachea. Functions of the Larynx: 1. Passageway for air. 2. Prevents ingested materials from entering the respiratory tract (epiglottis). 3. Produces sound for speech (vocal cords) ). https://www.youtube.com/watch?v=6PymJS97XdY Upper Airway Major Respiratory Structures The major respiratory structures span the nasal cavity to the diaphragm. The Journey of Air through the Respiratory System 3. Larynx (Voice Box) Sound is produced when vocal folds vibrate. This occurs when air is forced past the vocal cords during an expiration (exhalation). https://www.youtube.com/watch?v=Wrbe5fH888k  Vocal Cords The true vocal cords and vestibular folds of the larynx are viewed inferiorly from the laryngopharynx  The Journey of Air through the Respiratory System 4. Trachea A tube that connects the larynx and the two main bronchi. It is formed by rings of cartilage, which make it relatively strong and resilient.  The Journey of Air through the Respiratory System 4. Trachea The respiratory tract contains goblet cells which produce mucus that traps particles and pathogens in the incoming air. It also contains cilia that constantly move in a sweeping motion upward toward the throat, Cilia moving the mucus and trapped Goblet particles and pathogens away cell from the lungs and toward the outside of the body. The Journey of Air through the Respiratory System 4. Trachea At the point where the trachea divides into right and left main bronchi an internal ridge called the carina. The carina contains receptors that when stimulated causes coughing. The Journey of Air through the Respiratory System 5. Bronchi The trachea divides into a right main bronchus, which goes into the right lung, and a left main bronchus, which goes into the left lung.  6. Bronchioles Bronchi lead into tubes that do not have cartilage in their walls called bronchioles. A smooth muscle layer allows for bronchoconstriction and bronchodilation that change the size of the lumen, regulating the amount of air reaching the alveoli. Respiratory Zone : Bronchioles lead to alveolar sacs in the respiratory zone, where gas exchange occurs.  Structures of the Respiratory Zone (a) The alveolus is responsible for gas exchange. (b) A micrograph shows the alveolar structures within lung tissue.  Asthma Asthma is a chronic disease characterized by inflammation and edema of the airway, and bronchospasms (that is, constriction of the bronchioles), which can inhibit air from entering the lungs. In addition, excessive mucus secretion can occur, which further contributes to airway occlusion  Asthma Cells of the immune system, such as eosinophils and mononuclear cells, may also be involved in infiltrating the walls of the bronchi and bronchioles. Bronchospasms occur periodically and lead to an “asthma attack.” An attack may be triggered by environmental factors such as dust, pollen, pet hair, or dander, changes in the weather, mold, tobacco smoke, and respiratory infections, or by exercise and stress  Asthma Affected person develops sensitivity to an airborne agent, such as pollen, smoke, or dust. This triggers a localized inflammatory response in the bronchi and bronchioles, resulting in bronchoconstriction, swollen submucosa, and increased production of mucus.  Normal and Bronchial Asthma Tissues a) Normal lung tissue does not have the characteristics of lung tissue during (b) an asthma attack, which include thickened mucosa, increased mucus-producing goblet cells, and eosinophil infiltrates Respiratory Membrane The respiratory membrane consists of an alveolar epithelium, a capillary endothelium, and their fused basement membranes. Oxygen diffuses from an alveolus into the blood within the capillary, and carbon dioxide diffuses in the opposite direction.  The Journey of Air through the Respiratory System Alveolar type Icells: ~95% of the alveolar surface. Extremely thin and involved in gas exchange. Respiratory Membrane Alveolar type IIcells: secrete an oily fluid called pulmonary surfactant. The function of surfactant is to prevent the collapse of alveoli. Alveolar macrophage: phagocytic cell. Surfactant and Premature Babies Surfactant and Premature Babies Gross Anatomy of the Lungs  Lungs The right lung has three lobes: superior, middle, and inferior lobes. The left lung has two lobes: superior and inferior lobes.  Physical Properties of the Lungs 1. Compliance: refers to how easy the lungs can expand under pressure. + In order for inspiration to occur, the lungs must be able to expand when stretched; they must have high compliance. 2. Elasticity: the tendency of a structure to return to its initial size after being distended. + For expiration to happen, lungs must get smaller when tension is released: they must have elasticity.  Mechanics of Inspiration and Expiration Two physical principles for air flow into and out of the lungs: 1. Changes in volume result in changes in pressure: As the volume of a container increases, the pressure within the container decreases. The opposite is also true. As the volume of a container decreases, the pressure within the container increases. 2. Air flows from an area of higher pressure to an area of lower pressure: Air flows through the respiratory passages because of pressure differences between the outside of the body and the alveoli inside the body. These pressure differences are produced by changes in thoracic volume.  Mechanics of Inspiration and Expiration Compliance  Mechanics of Inspiration and Expiration Elasticity  Mechanics of Inspiration and Expiration Compliance Low compliance → stiff lung → extra work required to bring in a normal volume of air.  Mechanics of Inspiration and Expiration Pulmonary fibrosis is associated with a decrease in lung compliance. Increased risk of pulmonary fibrosis is observed after severe COVID-19 infection.  Mechanics of Inspiration and Expiration Elasticity Loss of elasticity → alveoli stay expanded→ air trapping in the alveoli.  Smoking and the Lungs Emphysema: a disease of the lungs that usually develops after many years of smoking. Once the tissue in the lung has been destroyed, it cannot regenerate, and thus there is no cure for emphysema. Treatment: 1. Stopping smoking. 2. Using a bronchodilator, 3. Taking oxygen supplementation if necessary. Smoking and the Lungs Modified Breathing Movements Crying: an inhalation followed by many short convulsive exhalations accompanied by characteristic facial expressions and tears. Laughing: the same basic movements as crying!!! but the rhythm of the movements and the facial expressions usually differ from those of crying. Other modified breathing movements include yawning and sighing.