Respiratory System Lecture Notes PDF

Illustration by Smart-Servier Medical Art By: Dr. Rana Aldahlawi System Respiratory  Function of the Respiratory System Gas...

Illustration by Smart-Servier Medical Art By: Dr. Rana Aldahlawi System Respiratory  Function of the Respiratory System Gas Exchange of Chart Illustration by Smart-Servier Medical Art exchanges gasses takes (oxygen and carbon dioxide) between the blood and the place within external environment the lungs in Passageways the alveoli only site of gas exchange), to the lungs other structures passageways purify, warm, and humidify the incoming air Organs of the Respiratory system  Nose  Pharynx  Larynx  Trachea  Bronchi  Lungs – alveoli  Anatomy of the Nasal Cavity Lateral walls have projections called conchae Increases surface area The nasal cavity is separated from the oral cavity by the palate Anterior hard palate (bone) Posterior soft palate (muscle) The cavity is lined with respiratory mucosa Moistens air Traps incoming foreign particles  Paranasal Sinuses group of four paired Frontal sinuses Illustration by Smart-Servier Medical Art air-filled spaces that (above the eyes) surround the nasal cavity Maxillary sinuses (under the eyes) The sinuses are Ethmoidal sinuses named for the (between the eyes) facial bones in which they are Sphenoidal sinuses located (behind the eyes)  Paranasal Sinuses Function of the sinuses Lighten the skull Act as resonance chambers for speech Produce mucus that drains into the nasal cavity  Pharynx (Throat) Muscular Three regions of The oropharynx passage from the pharynx and nasal cavity to laryngopharynx Nasopharynx – superior region behind larynx are common nasal cavity passageways for Oropharynx – middle region behind mouth air and food Laryngopharynx – inferior region attached to larynx  Larynx (Voice Box) Routes air and food into proper channels Plays a role in speech Made of eight rigid hyaline cartilages and a spoon-shaped flap of elastic cartilage (epiglottis)  Structures of the Larynx Thyroid cartilage Largest hyaline cartilage Protrudes anteriorly (Adam’s apple) Epiglottis Superior opening of the larynx Routes food to the larynx and air toward the trachea Vocal cords (vocal folds) Vibrate with expelled air to create sound (speech) Glottis – opening between vocal cords  Trachea (Windpipe) Connects larynx with bronchi Lined with ciliated mucosa Beat continuously in the opposite direction of incoming air Expel mucus loaded with dust and other debris away from lungs Walls are reinforced with C-shaped hyaline cartilage  Lungs Occupy most of the Each lung is thoracic cavity divided into Apex is near the lobes by fissures clavicle (superior portion) Left lung: Base rests on the two lobes diaphragm (inferior Right lung: portion) three lobes  Coverings of the Lungs Visceral pleura covers the lung surface Parietal pleura lines the walls of the thoracic cavity Pleural fluid fills the area between layers of pleura to allow gliding  Respiratory Tree Divisions Primary Secondary Tertiary Bronchiole Terminal bronchi bronchi bronchi bronchiole end in alveoli  Primary Bronchi Formed by division of the trachea Enters the lung at the hilus (medial depression) Right bronchus is wider, shorter, and straighter than the left  Bronchioles The smallest branches of the bronchi All but the smallest branches have reinforcing cartilage  Respiratory Zone Site of gas exchange Structure of alveoli Alveolar duct Alveolar sac Alveolus  Respiratory Membrane (Air-Blood Barrier) Thin Pulmonary squamous capillaries epithelial cover layer lining external alveolar walls surfaces of alveoli  Events of Respiration Pulmonary ventilation – moving air in and out of the lungs External Internal respiration respiration gas gas exchange exchange between blood between and tissue cells pulmonary in systemic blood and capillaries alveoli  Mechanics of Breathing (Pulmonary Ventilation) Completely mechanical process Depends on volume changes in the thoracic cavity Volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure Two phases Inspiration – flow of air into lung Expiration – air leaving lung  Inspiration Diaphragm and intercostal muscles contract The size of the thoracic cavity increases External air is pulled into the lungs due to an increase in intrapulmonary volume  Expiration Largely a passive process that depends on natural lung elasticity As muscles relax, air is pushed out of the lungs Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage Breathing movements Breathing Movements - Inspiration, Expiration, Mechanism of Breathing - Bing video  Respiration 1. External Respiration Oxygen movement into the blood The alveoli always have more oxygen than the blood Oxygen moves by diffusion towards the area of lower concentration Pulmonary capillary blood gains oxygen Blood leaving the lungs is oxygen- rich and carbon dioxide-poor  External Respiration Carbon dioxide movement out of the blood Blood returning from tissues has higher concentrations of carbon dioxide than air in the alveoli Pulmonary capillary blood gives up carbon dioxide Blood leaving the lungs is oxygen-rich and carbon dioxide-poor Gas exchange in alveoli  2. Internal Respiration CO2 O2 Exchange of An opposite Carbon dioxide Oxygen diffuses gases between reaction to diffuses out of from blood into blood and body what occurs tissue to blood tissue cells in the lungs External Respiration, Gas Transport, and Internal Respiration Summary  Non-respiratory Air Movements Can be caused by reflexes or voluntary actions Cough Laughing Hiccups Yawn sneeze Crying clears lungs of debris  Factors Influencing Respiratory Rate and Depth Physical Chemical factors factors Carbon dioxide levels Oxygen levels Increased body Coughing It is the main regulatory Chemoreceptors in the temperature Volition (conscious chemical for respiration aorta and carotid artery Exercise control) Increased carbon dioxide detect changes in oxygen Talking Emotional factors increases respiration concentration in the blood Changes in carbon Information is sent to the dioxide act directly on medulla oblongata the medulla oblongata  Neural Regulation of Respiration  Neural Regulation of Respiration The Activity of respiratory Medulla Pons Eupnea Hypernia muscles is control rate and appears to Normal Increased transmitted to the depth of smooth out respiratory rate respiratory rate brain by the respiration respiratory rate is 12–15 often due to phrenic and respirations per extra oxygen intercostal nerves minute needs  Respiratory Volumes and Capacities Tidal volume [TV]Normal breathing moves about 500 ml of air with each breath Many factors that affect respiratory capacity Person’s size Gender Age Physical condition Residual volume of air – after exhalation, about 1200 ml of air remains in the lungs  Respiratory Volumes and Capacities Inspiratory reserve volume (IRV) Amount of air that can be taken in forcibly over the tidal volume Usually between 2100 and 3200 ml Expiratory reserve volume (ERV) Amount of air that can be forcibly exhaled Approximately 1200 ml  Respiratory Volumes and Capacities Vital capacity The total amount of exchangeable air Vital capacity = TV + IRV + ERV Dead space volume Air that remains in the conducting zone and never reaches alveoli About 150 ml  Respiratory Volumes and Capacities Functional volume Air that actually reaches the respiratory zone usually about 350 ml Respiratory capacities are measured with a spirometer Spirometer Thank you Any questions? ‫* ﺗم ﺑﺣﻣد ﷲ‬