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Respiratory System

Respiratory System. Honors Anatomy & Physiology. What Physiological problems resulted from wearing a corset?.

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Respiratory System

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  1. Respiratory System Honors Anatomy & Physiology

  2. What Physiological problems resulted from wearing a corset? Corsets were designed to constrict the waist—the tighter the corset the smaller the waist. A successfully corseted young lady might boast of a 12-inch diameter waist! Problem was, the upper part of the corset included the lower part of the rib cage. What was the result of this constant binding? The corset prevented adequate ventilation and caused a permanent deformity of the rib cage…to say nothing of the displaced abdominal organs. The corseted young lovely couldn’t breathe and often fainted. Herein lies the physiologic basis of the swoon and delicate weakness that characterized wealthy young women. They were not weak because of their female X chromosomes; they were merely hypoxic…no oxygen going to the brain. Fortunately, only the wealthiest could make this fashion statement.

  3. 4 Processes of Respiratory Function: supply O2 dispose of CO2 • Pulmonary Ventilation • Breathing – movement of air into/out of lungs • External Ventilation • Oxygen from lungs to blood • CO2 from blood to lungs • Transport of Respiratory Gases • Via cardiovascular system • Internal Respiration • Oxygen from blood to tissue cells • CO2 from tissue cells to blood *Also involved with smell & speech

  4. Respiratory Organs: Nose • Nose • Airway for respiration • Moistens & warms air • Filters & cleans air • Olfactory receptors • Nasal Cavity • Divided by nasal septum • Lined w/vibressae hairs • Olfactory mucosa • Respiratory mucosa – psuedostratified ciliated epithelial tissue (cilia sluggish in cold weather) • Goblet cells- Mucus • water to humidify • Lysozyme • Defensins - antibiotics • Sensory nerves for sneeze reflex • Superficial capillaries warm air • Superior, middle, and inferior conchae • increase surface area • Deflect non-gas particles into mucus

  5. Pharynx (AKA throat) • 5”long • Nasopharynx • Air passageway only • Uvula & soft palate closes off during swallowing • (fails when laughing!) • Pharyngeal tonsil (AKA adenoids) • Oropharynx • Both swallowed food & air pass through • Palantine & lingual tonsils • Laryngopharynx • Stratified squamous epithelium • Food & air passageway (food has priority) • Extends to epiglottis of larnyx & esophagus

  6. Larynx (AKA Voice Box) • 2” attached to hyoid bone • 3 functions: • Provide open airway • Switching mechanism to direct air & food • Voice production • Adams Apple-laryngeal prominence of thyroid cartilage

  7. Voice Production • Pitch determined by length & tension of chords changes • Tenser chords vibrate faster therefore higher pitch • Deep tones produced by a wide glottis • Loudness depends on force of air stream across chords • Quality depends on length of pharynx to amplify & enhance as well as oral, nasal, and sinus cavities • Enunciation depends on muscles of pharynx, tongue, soft palate & lips

  8. Trachea (AKA windpipe) 4”long, ¾” diameter, 3 layers Mucosa - Pseudostratified ciliated epithelium w/goblet cells Submucosa– connective tissue Adventitia - reinforced by C shaped hyaline cartilage, trachealis smooth muscle decreases diameter of trachea when swallowing food or to produce cough to expel air up to 100mph! Smoking destroys cilia…leaving coughing as only mechanism for preventing debris from entering lungs

  9. Bronchi • Conducting Zone • R/L primary bronchi branch off into 20 and 30 bronchi up to 23 orders of branching • Bronchioles (1mm) lead to terminal bronchioles (0.5mm) • Mucous, Cilia & supporting cartilage are sparse • Respiratory Zone • Alveoli- thin walled air sacs • 300 million account for most of lung volume • Simple squamous epithelial tissue • Densly covered w/cobweb of pulmonary capillaries • Gas exchnage occurs by simple diffusion

  10. Lungs & Pleurae • Each lung in its on plural cavity • Visceral & parietal pleura • Pleural fluid fills pleural cavity • Left Lung • superior & inferior lobes • Right Lung • superior, middle & inferior lobes • Pulmonary arteries branch into pulmonary capillaries surrounding the alveoili • Oxygenated blood is carried out of the lungs by pulmonary viens • Lungs innervated w/parasympathetic (constricts & sympathetic (dilates) motor fibers

  11. Mechanics of Breathing • Atmospheric Pressure = 760mmHg • Boyle’s Law – pressure is inversely proportional to volume • Inspiration • Diaphragm & external intercostals contract • Increases volume of thoracic cavity by almost 500mL • Pulmonary pressure decreases about -6mmHg • Forced inspiration utilizes scalenes, sternocleidomastoid, pectoralis minor, & erector spinae muscles • Expiration • As inspiratory muscles relax, lungs recoil & thoracic volume decreases increasing pressure to 761mmHg • Forced expiration utilizes oblique & transverse abdominals, and internal intercostals

  12. Respiratory Volumes & Capacities • Spirometer– measures respiratory capacities • Vital Capacity • Tidal Volume • Normal quiet breathing (500mL ea/breath) • Inspiratory Reserve Volume • Air taken in forcibly (2100-3200mL over TV) • Expiratory Reserve Volume • Air forcibly expelled (1200mL) • Residual Volume • Air remaining in lungs that cannot be expelled (1200mL) • Allows gas exchange between breaths, keeps alveoli inflated • Dead Space Volume • Air remains in “passageways” and never reaches alveoli (150mL)

  13. Transport of Respiratory Gases by blood • Composition of Alveolar Gas • Gas exchange in lungs • Humidification • Gas mixing w/ea breath • Oxygen Transport • HHb + O2⇋HbO2 + H+ • Deoxyhemoglobin⇋ oxyhemoglobin • Each molecule of hemoglobin can bind 4 O2, after 1 binds, changes shape easily picking up other O2 until saturated • Various factors affect O2 affinity for Hb

  14. Carbon Dioxide Transport • 7-10% Dissolved in Plasma • 20% Bound to a.a. of Hemoglobin • 70% as bicarbonate ions • In Plasma: • CO2 + H2O ⇋ H2CO3 (unstable) ⇋ H+ + HCO3- • O2 release from Hb is enhanced by CO2 loading • Carbonic acid-bicarbonate buffer system – resists shifts in blood pH • In Lungs • Diffuses from blood into alveoli

  15. Control of Respiration • Neural Mechanisms • Medulla Oblongata • Inspiratory neurons cycle w/ expiratory neurons • Respiratory rate: 12-15 breaths per minute • Can be supressed by alcohol or morphine • Influencing Factors • Levels of CO2 (most influential), O2, and H+ in blood • Hypothalmus – emotions • Cerebral motor contral (voluntary) – limited • Irratants constrict bronchioles, stimulate couch or sneeze

  16. What is COPD? Chronic Obstructuve Pulmonary Disease Irreversible decrease in the ability to force air out of lungs

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