The Respiratory System PDF

# The Respiratory System ## Role of Respiratory - Oxygen Intake and delivery - Regulation of Blood pH - Vocalization - Smell ## Organs of the Respiratory - Nose - Nasal Cavity - Oral Cavity - Pharynx - Larynx - Trachea - Bronchi - Lungs-alveoli ## Function Anatomy of the Respiration Sys...

# The Respiratory System ## Role of Respiratory - Oxygen Intake and delivery - Regulation of Blood pH - Vocalization - Smell ## Organs of the Respiratory - Nose - Nasal Cavity - Oral Cavity - Pharynx - Larynx - Trachea - Bronchi - Lungs-alveoli ## Function Anatomy of the Respiration System ### Nose and Pharynx #### The Nose - Button or hooked in shape. - The only externally visible part of the respiratory system. #### Nostrils - During breathing, air enters the nose by passing through the nostrils or nares. #### Nasal Cavity - It consists the interior of the nose and divided by a midline nasal septum. - The olfactory receptors for the sense of smell are located in the mucosa in the slitlike superior part of the nasal cavity. #### Conchae - The lateral walls of the nasal cavity are uneven, owing to three mucosa-covered projections, or lobes. - Increase the surface area of the mucosa exposed to the air. #### Palate - Nasal cavity is separated from the oral cavity below by a partition called palate. - Hard palate- Supported by the bone. - Soft palate- The unsupported posterior part. ### The Pharynx - Is a muscular passageway about 13 cm (5 inches) long that vaguely resemble a short length of red garden hose. - It is continuous with the nasal cavity anteriorly via the posterior nasal aperture. - The pharynx has three regions: - Nasopharynx - Oropharynx - Laryngopharynx ### Larynx and Trachea #### Larynx (Voice Box) - Routes air and food into proper channels; plays a role in speech. - Located inferior to the pharynx, composed of: - Eight rigid hyaline cartilages - Epiglottis: Spoon-shaped elastic cartilage acting as a “guardian of the airway”. - Thyroid cartilage - Largest cartilage, also called the Adam’s Apple #### Epiglottis Function - Allows air passage during regular breathing. - Covers the larynx during swallowing to route food into the esophagus. - Triggers a cough reflex if foreign substances enter the larynx. #### Vocal Chords - Part of the mucous membrane; vibrate with expelled air to produce sound. - The glottis: Slit-like passage between the vocal cords. Is also responsible for producing sounds. #### Trachea (Windpipe) - Length: 10-12 cm (about 4 inches) extending to the fifth thoracic vertebra. - Lined with a ciliated mucosa and are surrounded by goblet cells. #### Structure - Reinforced by C-shaped hyaline cartilage rings dual purposes: - Open part: Faces the esophagus, allowing expansion during swallowing. - Solid part: Keeps the trachea open during pressure changes in breathing. #### Trachealis Muscle - Completes the posterior wall of trachea, adjacent to the esophagus. - Regulates tracheal diameter for airflow control. ## Lungs - The lungs are large organs located in the thoracic cavity, excluding the mediastinum, which contains the heart, blood vessels, bronchi, and other organs. ### Apex and Base - The narrow superior portion of the lung, called the “apex”, is beneath the clavicle, while the broader lower portion, the “base”, rests on the diaphragm. - The “left lung” has two lobes, and the "right lung” has three, separated by fissures. ### Pleural Membranes - Each lung is covered by the "visceral pleura" - Thoracic cavity walls are lined by the “parietal pleura" ### Pleural Fluid - This fluid reduces friction, enabling smooth movement of the lungs against the thoracic wall during breathing. ### Pleural Space - The space between the pleural layers is more potential than actual one. ### The Bronchial Tree - Main bronchi divide into smaller branches, ending in bronchioles with cartilage for support. ### Respiratory Zone Structures & Respiratory Membrane - Alveoli are tiny air sacs where gas exchange happens with surrounding capillaries. - Oxygen diffuses from alveoli into blood, while CO2 moves from blood to alveoli. - Lungs are soft, spongy, and elastic, allowing them to stretch and recoil. Weigh only about 2 1/2 pounds. - Macrophages clean debris in alveoli, and surfactant prevents collapse of alveolar walls. ## Respiratory Physiology ### Pulmonary- Ventilation - Air must move into and out of the lungs so that the gases in the alveoli of the lungs are continuously refreshed. - This process of pulmonary ventilation is commonly called "breathing". ### External Respiration - Gas exchange (oxygen loading and carbon dioxide unloading) between the pulmonary blood and alveoli must take place. - Remember that in external respiration, gas exchanges are being made between the blood and the body exterior. ### Respiratory Gas Transport - Oxygen and carbon dioxide must be transported to and from the lungs and tissue cells of the body via the bloodstream. ### Internal Respiration - At systemic capillaries, gas exchange occurs between the blood and cells inside the body. This time, oxygen is unloaded from blood and CO2 is loaded. ## Mechanics of Breathing ### Breathing - Also known as pulmonary ventilation. - Is a mechanical process that depends on volume changes occurring in the thoracic cavity. - Keep this rule in mind about the mechanics of breathing: "Volume changes lead to pressure changes, which lead to the flow of gases to equalize the pressure.” ### 2 Phases of Breathing - **Inspiration; inhalation** - When air is flowing into the lungs. - **Expiration; exhalation** - When air is leaving the lungs. ### During Inspiration - When the inspiratory muscles, the diaphragm and external intercostals, contract, the size of the thoracic cavity increases. - Important muscle: diaphragm and external intercostal muscles ### During Expiration - As the inspiratory muscles relax and resume their initial resting length, the rib cage descends, the diaphragm relaxes superiorly, and the lungs recoil. Thus, both the thoracic and intrapulmonary volumes decrease. - Important muscle: abdominal and internal intercostal muscles ### During Expiration (Continuation) - Normally, expiration (breathing out) is a passive process, driven by the natural recoil of the lungs and diaphragm. However, in certain respiratory conditions like asthma, chronic bronchitis, or pneumonia, the airways become narrowed or blocked due to spasms, mucus, or fluid buildup. This makes it harder to exhale air out of the lungs. - When this happens, forced expiration becomes necessary to expel the air. Forced expiration involves the activation of additional muscles: 1. **Internal intercostal muscles:** These muscles, located between the ribs, contract to pull the rib cage downward, helping to push air out of the lungs. 2. **Abdominal muscles:** These muscles contract to squeeze the abdominal organs upward against the diaphragm. This action helps push air out by forcing the diaphragm upwards, reducing the space in the lungs and aiding in the expulsion of air. ## Respiratory Volumes and Capacity - **Tidal Volume (TV)** - This is the amount of air you breathe in and out during normal, relaxed breathing. - It’s about 500 ml. - As a rule, a person is capable inhaling much more air than is taken in during a tidal breath. - **Inspiratory Reserve Volume (IRV)** - This is the extra amount of air you can breathe in “after a normal breath” if you inhale as deeply as you can. - It’s about 3,100 ml. - **Expiratory Reserve Volume (ERV)** - Similarly, after a normal expiration, more air can be exhaled. - The amount of air that can be forcibly exhaled beyond tidal expiration, is approximately 1,200 ml. - **Residual Volume (RV)** - Even after the most strenuous expiration, there’s still some air in the lungs that cannot voluntarily be expelled. - This is about 1,200 ml. - **Vital Capacity (VC)** - The vital capacity is the sum of the tidal volume plus the inspiratory and expiratory reserve volumes. - The total amount of exchangeable air (around 4,800 ml in healthy young men and 3,100 ml in healthy young women. - **Dead Space Volume** - Note that some of the air that enters the respiratory tract remains in the “conducting zone passageways” and never reaches the alveoli to participate in gas exchange. - The air that doesn't help with the gas exchange is about 150 ml. - **Functional Volume** - This is the air that actually gets into the lungs and is used for gas exchange. - It’s about 350 ml during a normal breath. - **Spirometer** - Respiratory Capacities are measured with a spirometer. - Spirometer testing is useful for evaluationg losses in respiratory function and in following the course of some respiratory disesases. ## Non Respiratory Air Movements and Respiratory Sounds ### Nonrespiratory Air Movements - A result of reflex activity, some may be produced voluntarily #### Cough - Mechanism: - Deep breath, closing glottis - Forcing air superiorly from lungs against glottis. - Glottis opens suddenly, a blast of air pushes upward. - Result: Clears the lower respiratory passageways #### Sneeze - Mechanism: - Similar to a cough, except (expelled) air is directed through Nasal Cavities instead of the Oral Cavity. - The uvula becomes depressed and closes oral cavity off from pharynx, routing air through nasal cavities. - Result: Clears upper respiratory passages. #### Crying - Inspiration followed by release of air in a number of short expirations - An emotionally induced mechanism #### Laughing - Same as crying in terms of the air movements produced. - An emotionally induced response. #### Hiccups - Mechanism: - Sudden inspirations resulting from spasms of diaphragm - Initiated by irritation of diaphragm or phrenic nerves - Results: Sound occurs when inspired air hits vocal folds of closed glottis. #### Yawn - Mechanism: - Very deep inspiration, taken by jaws wide open - Ventilates all alveoli ### Respiratory Sounds - As air flows into and out of the respiratory tree, it produces two recognizable sounds that can be picked up with a stethscope #### Bronchial Sounds - Produced by air rushing through the large respiratory passageways (trachea and bronchi) #### Breathing Sounds - Occur as air fills the alveoli, soft murmurs that resemble a muffled breeze. ## Homeostatic Imbalance - Diseased respiratory tissue, muscus, or pus can produce abnormal sounds such as: ### Abnormal Sounds - Crackle (bubbling sounds) - Wheezing (a whistling sound) - Rales ### Rales - Produced by the presence of mucus or exudate in the lung passages or by thickening of the bronchial walls. ## External and Internal Respiration, and gas transport ### External Respiration - Refers to the gas exchange between the alveoli in the lungs and the blood in pulmonary capillaries. - This process involves two main gases: - Oxygen (O2) - Carbon dioxide (CO2) - Governed by diffusion laws: substances move from areas of higher to lower concentration. - Supplies oxygen to the blood for systemic distribution. - Removes carbon dioxide from the blood to be exhaled. - Maintains the oxygen and carbon dioxide balance in the body. ### How External Respiration Operates 1. **Oxygen Exchange** - Oxygen concentration is higher in alveoli than in the blood. - Oxygen diffuses: From alveolar air through respiratory membrane into oxygen-poor blood of pulmonary capillaries - Oxygen binds to hemoglobin, turning dark red blood into bright red. 2. **Carbon Dioxide Exchange** - Carbon dioxide concentration is higher in pulmonary capillaries than in alveoli. - CO2 diffuses: From the blood through respiratory membrane into alveoli. - CO2 is expelled from the body during exhalation. 3. **Resulting Blood Composition** - Blood leaving the lungs: - Rich in oxygen - Poor in carbon dioxide - Prepared for systemic distribution by the heart. ### Factors in External Respiration - Alveolar Oxygen Levels: Higher than blood oxygen levels. - Pulmonary Capillary Carbon Dioxide Levels: Higher than alveolar CO2 levels - Diffusion Gradients: - Oxygen and carbon dioxide move along concentration gradients. - Ensures efficient gas exchange. ### External and Internal Respiration Gas Exchanges - A diagram showing how the exchange of CO2 and O2 take place. ### Gas Transport in the Blood - Refers to the mechanisms by which oxygen (O2) and carbon dioxide (CO2) are carried in the blood. - Involves red blood cells (RBCs), hemoglobin, and plasma. ### Oxygen Transport 1.**Main Transport Mechanism** - 98% of oxygen binds to hemoglobin in RBCs to form oxyhemoglobin (HbO2). - 2% is dissolved in plasma. 2. **Oxygen Release** - Oxyhemoglobin releases oxygen into tissues where oxygen levels are low. ### Carbon Dioxide Transport 1. **Bicarbonate Ion Formation** - Majority of CO2 is carried as bicarbonate ions (HCO3¯) in plasma. - CO2 combines with water in RBCs forms carbonic acid (H2CO3). - Carbonic acid splits into bicarbonate ions and hydrogen ions, aided by carbonic anhydrase enzyme. - Bicarbonate ions diffuse into plasma for transport. 2. **Hemoglobin Binding** - 20-30% of CO2 binds to hemoglobin at a separate site from oxygen, forming carbaminohemoglobin. 3. **Release in Lungs** - Bicarbonate ions re-enter RBCs and combine with hydrogen ions form carbonic acid. - Carbonic acid breaks down into water and CO2. - CO2 diffuses from blood into alveoli exhaled. ### Role in pH Regulation - **Bicarbonate Buffer System:** - Bicarbonate ions act as buffers to minimize pH changes. - Ensures blood pH stays within 7.35-7.45 for homeostasis. ### Gas Transport in the Blood - A diagram showing how the exchange of CO2 and O2 take place in the lungs and body tissues. ### Internal Respiration - Refers to the gas exchange between blood in systemic capillaries and the body’s tissue cells. - Opposite of external respiration: - Oxygen leaves the blood and enters tissues. - Carbon dioxide enters the blood from tissues. - Supplies oxygen to tissue cells for energy production (cellular respiration). - Removes carbon dioxide, a byproduct of metabolism, from tissues. - Helps maintain blood pH balance through carbon dioxide transport mechanisms. ### How Internal Respiration Operates 1. **Oxygen Exchange** - Oxygen detaches from hemoglobin in red blood cells (RBCs). - Diffuses out of blood into oxygen-poor tissues. 2. **Carbon Dioxide Exchange** - Carbon dioxide diffuses: From CO2-rich tissues into blood. - Inside RBCs: - CO2 combines with water forms carbonic acid (H2CO3) - Carbonic acid breaks into bicarbonate ions (HCO3-) and hydrogen ions (H+), aided by by carbonic anhydrase enzyme. - Bicarbonate ions diffuse into plasma for transport. 3. **Resulting Blood Composition** - Venous blood leaving tissues: - Poor in oxygen - Rich in carbon dioxide ### Factors in Internal Respiration - **Oxygen Release:** - Triggered by low oxygen concentration in tissues. - **Carbon Dioxide Transport:** - Majority as bicarbonate ions in plasma. - Enabled by carbonic anhydrase enzyme in RBCs. - **Blood Changes:** - Systemic venous blood becomes oxygen-depleted and CO2-enriched. ## Control of Respiration ### Neural Regulation: Setting the Basic Rhythm - **Respiratory muscles:** - Diaphragm - external intercostals - **Phrenic nerves & intercostals nerves** - **Neural centers that control respiratory rhythm and depth:** - Medulla oblongata - Pons ### Neural Regulation: Setting the Basic Rhythm - **Medulla Oblongata:** - **Ventral respiratory group (VRG)** - Inspiratory neurons stimulate the diaphragm & external intercostals via phrenic and intercostal nerves, during quiet breathing. - Expiratory neurons stop the stimulation of the diaphragm and external intercostals, allowing passive exhalation to occur. - Eupnea, normal quiet breathing rate of 12 to 15 respirations /minute. - **Dorsal respiratory group (DRG)** - Integrates sensory information from chemoreceptors and peripheral stretch receptors. - DRG communicates this information to the VRG to help modify breathing rhythm. - **Pons:** - Communicates with the VRG - Help to smooth the transitions between inhalation & exhalation during activities such as singing, sleeping and exercising. ### Neural Regulation: Setting the Basic Rhythm - Bronchioles and Alveoli have stretch receptors that respond to extreme overinflation by initiating protective reflexes. - In the case of overinflation, the vagus nerves send impulses from the stretch receptors to the medulla ### Hyperpnea - When we exercise, we breathe more vigorously and deeply because the brain centers send more impulses to the respiratory muscles. - After strenuous exercise, expiration becomes active, and the abdominal muscles and any other muscles capable of depressing the ribs are used to aid expiration. ### Neural Control of Repiration - A diagram showing how the body uses nerves to control breathing. ### Nonneural Factors Influencing Respiratory Rate and Depth - Physical Factors - Volition (Conscious Control) - Emotional Factors - Chemical Factors ### Nonneural Factors Influencing Respiratory Rate and Depth - **Physical Factors** - Talking - Coughing - Exercising - Increased body temperature ### Nonneural Factors Influencing Respiratory Rate and Depth - **Volition (Conscious Control)** - Voluntary control of breathing - Respiratory centers will simply ignore messages from the cortex when the oxygen supply in the blood is getting low or blood pH is falling. ### Nonneural Factors Influencing Respiratory Rate and Depth - **Emotional Factors** - Emotions also modify the rate and depth of breathing. - All of these result from reflexes initiated by emotional stimuli acting through centers in the hypothalamus. ### Nonneural Factors Influencing Respiratory Rate and Depth - **Chemical Factors** - Increased level of carbon dioxide & decreased blood pH - Increase in the carbon dioxide level can cause a decreased blood pH - A low blood pH could also result from metabolic activities independent of breathing. - When oxygen levels are low, these same chemoreceptors are also able to detect high carbon dioxide levels. - A decrease in the oxygen level becomes an important stimulus only when the level is dangerously low. ## Development Aspect of the Respiratory System ### Development of a Fetus and Newborn - In the fetus, the lungs are filled eith fluid, and all the respiratory excha made by the placenta. - At birth, the fluid-filled pathway is drained, and the respiratory passage with air. The alveoli inflate and begin to functikn in gas exhcange ### Surfactant - A fatty molecule made by the cuboidal alveolar cells - Gas exchange depends on this nonfunctional and functional respiration - Lowers the surface tension of the film of water lining each alveolar sac alveoli does not collapse between each breath ### Normal Respiration Rates - Newborn Infants = 40-80 respiration per min - Infants= 30 respiration per minute - At 5 yrs old= 25 respiration per minute - Adults= 12-18 respiration per minute ## Respiratory Disorders and All Homeostatic Imbalances ### Homeostatic Imbalances & Respiratory Disorders - A diagram showing a number of different respiratory disorders. ### Homeostatic Imbalances 13.1: Cleft Palate - **Definition:** - Failure of the bones forming the palate to fuse medially. - This may result in breathing difficulty as well as problems with oral cavity functions, such as nursing and speaking. ### Cleft Lip and Palate - A diagram showing the different types of cleft lip and palate. ### Homeostatic Imbalances 13.2 - **Rhinitis** - Inflammation of the nasal mucosa. - The excessive mucus produced results in nasal congestion and postnasal drip. - Caused by cold viruses and various allergens. - **Sinusitis** - Sinus inflammation. - When the passageways connecting the sinuses to the nasal cavity are blocked with mucus or infectious matter, the air in the sinus cavity is absorbed. ### Homeostatic Imbalances 13.3: Tonsilitis - It is the inflammation of the pharyngeal tonsils. - It caused by bacterial infection. - It forces the person to breathe through the mouth. ### Homeostatic Imbalances 13.4: Choking - It is also called foreign body airway obstruction, in which the trachea or airway passage is blocked in which prevents the oxygen to properly enter the body. - There are two types of obstruction which are the anatomical and mechanical obstruction ### Abdominal Thrust, Backslaps, Chest Thrust - A diagram showing how to perform abdominal thrusts, backslaps, and chest thrusts. ### Homeostatic Imbalances 13.5: Smoking Destroys Cilia - Smoking inhibits and ultimately destroys the cilia. - Without these cilia, coughing is the only means of preventing mucus from accumulating in the lungs. ### Homeostatic Imablances 13.6: Pleurisy - Inflammation of the pleurae. - **Insuffiecient Pleural Fluid** - The pleural surfaces becomes dry and rough, which results in friction and stabbing pain with each breath. - **Excess Pleural Fluid** - Due to the excess amount of fluids, it may exert pressure on the lungs which hinders breathing movement. ### Homeostatic Imblances 13.7 - **Atelectasis** - Also called as lung collapse. - This phenomenon occurs when air enters the pleural space through a chest wound, but it may also result from a rupture in the visceral pleura. - **Pneumothorax** - The presence of air in the intrapleural space, which disrupt the fluid bond between the pleurae ### Homeostatic Imbalances 13.8 - **Abnormal Breathing Sounds** - These are sounds created by the respiratory system that is out of the ordinary in wich may have been caused by diseased respiratory tissue, mucus or pus. - **Crackling** - A bubbling, popping or snapping sound, this indicates that there might be fluids in the lungs' small airways - **Wheezing** - A whistling sound which occurs when your breathing tubes in your lungs are narrowed - **Rales** - Are abnormal bronchial sounds produced byt the presence of mucus or exudate in the lung passages or by thickening of the branchial walls. ### Homeostatic Imbalance 13.9 - **Hypoxia** - Inadequate oxygen delivery to body tissues. - **Symptoms:** - Bluish skin and mucosae (cyanosis) in light-skinned individuals. - Cyanosis visible in mucosae and nailbeds in dark-skinned individuals. - **Causes:** - Anemia. - Pulmonary diseases. - Blocked or impaired blood circulation. ### Homeostatic Imbalance 13.9 - **Carbon Monoxide (CO) Poisoning** - A type of hypoxia caused by carbon monoxide binding to hemoglobin, preventing oxygen transport. - **Causes:** - Inhalation of carbon monoxide, often from fires. - **Symptoms:** - Confusion. - Throbbing headache. - Cherry red skin (rare), resembling a healthy "blush." - No cyanosis or respiratory distress. ### Homeostatic Imbalance 13.9 - **(Continuation...)** - **Danger:** - Odorless and colorless gas, making it difficult to detect. - **Treatment for Carbon Monoxide Poisoning** - Administer 100% oxygen to displace carbon monoxide from hemoglobin. - Continuous oxygen therapy until CO is cleared from the body. ### Homeostatic Imbalance 13.10 - **Suppression of the Medullary Centers** - **Causes:** - Overdose of sleeping pills, morphine or alcohol - **Effects:** - Breathing cessation or worst death ### Homeostatic Imbalance 13.11 - **Breathing Stimulus** - In people who reatin carbon dioxide, such as people with emphysema, chronic bronchitis, or other chronic lung diseases, the brain no longer recognizes an increased level as important. In such cases, a dropping oxygen level becomes the respiratory stimulus ### Homeostatic Imbalance 13.12 - **Hyperventilation** - Occurs when a person's breathing is faster and more shallow than normal. When this happens, the body does not take in enough oxygen to meet its demands. - A person experiencing hyperventilation may feel dizzy and faint. ### Homeostatic Imbalances 13.13: Respiratory Disorders - **Chronic Obstructive Pulmonary Diseases** - Major cause of death and disability in the US and has common features like; patients almost has history of smoking, dyspnea, coughing and frequent pulmonary infections, and they are mostly hypoxic - **Chronic Bronchitis** - The mucosa of the lower respiratory passages becomes severely inflamed and produces excessive mucus - **Emphysema** - The walls of some alveoli are destroyed, causing the remaining alveoli to enlarge. The lungs also may also lose its elasticity in this disorder ### Homeostatic Imbalances 13.13: Respiratory Disorders - **Lung Cancer** - Cancer that forms in tissues of the lung, usually in the cells that line the air passages. It is the leading cause of cancer death in both men and women. - **Adenocarcinoma** - Originates as solitary nodules in the peripheral lung are and develops from the bronchial glands and alveolar cells - **Squamous Cell Carcinoma** - Arise in the epithelium of the larger bronchi and tends to form masses that hollow out the bleed - **Small Cell Carcinoma** - Contains lymphocyte-like cells that originate in the main bronchi and grow aggressively in small grapelike clusters within the mediastinum ### Homeostatic Imbalances 13.14 - **Infant Respiratory Distress Syndrome** - Caused by the inadequate surfactant production (mostly due to infants being born to diabetic mothers - Happens to premature infants born before week 28 - Accounts for over 20,000 newborn deaths a year - **Cystic Fibrosis** - It is a genetic disorder caused by a defective gene that makes the body produce abnormally thick and sticky fluid, called mucus - Strikes in 1 out of 2,400 births, and everyday two children die of it ### Homeostatic Imbalance 13.15 - **Sudden Infant Death Syndrome (SIDS)** - Also called crib death - Apparently healthy infants stop breathing and die in their sleep - Believed to be a problem in with the neural control of respiration, most casess occurs in infants placed on their tummy to sleep ### Thank You for Listening! - An image of a person riding a bicycle and a person jumping for joy.