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TL Respiratory
Respiratory A&P review (LAG)
Question | Answer |
---|---|
What are the functions of the respiratory system? (GE, D, R, S, M, D) | gas exchange, Delivery of O2 to tissues, Removal of CO2, synthesis of surfactant and other chemicals, metabolism and detoxification of drugs and toxins, defense against infection |
What are the major organs housed in the thorax? | Lungs, mediastinum – heart and major vessels |
What’s unique to the first 7 ribs? | true ribs – attached to sternum and vertebral column |
How do ribs 8-10 attach? | to the rib above |
How do ribs 11&12 attach? | only at the vertebra, no anterior attachment |
What is the name of the spaces between ribs? | intercostals spaces |
What is the name of the angle between the xyphoid process of the sternum and the costal cartilages? | Costal angle |
What muscle is the major muscle of respiration? | the diaphragm |
What does contraction of the diaphragm do? | Contraction of the diaphragm promotes inhalation by flattening the dome shaped muscle downward toward the abdomen causing expansion in the lungs thus a decrease in pressure resulting the rushing in of air |
What does contraction of the external intercostals muscles do? | expand the rib cage anterioposteriorly |
What does contraction of the internal intercostals muscles do? | Accessory muscles for expiration |
What does natural compliance mean when referring to the thorax? | Means it wants to spring outward and expand |
Describe the features of the right lung. | thicker, wider, shorter (liver), 3 lobes- upper, middle, lower, 10 segments |
Describe the features of the left lung. | narrower(mediastinum), longer, 2 lobes – upper, lower, 8 segments |
What’s a lingula? | area between left upper and lower lobes |
What’s an Apex? | the top pointy area of the lung |
What makes up the pleural space? | The two layers of serous membrane surrounding the lungs- visceral pleura and parietal pleura and 5-15mL of fluid to facilitate smooth movement between the layers |
Name the 3 sections of the pharynx. | nasopharynx, oropharynx, laryngopharynx (or hypopharynx) |
Name two structures located in the nasopharynx. | adenoids and openings to Eustachian tubes |
Name two structures in the laryngopharynx. | epiglottis and larynx (voice box) |
Describe the cartilage of the trachea. | 16-20 C shaped with open side to back |
About where do the right and left bronchi divide? | about the second or third intercostals space |
What is the cartilage called where the left and right bronchi devide? | carina |
Define the area included in the term airway. | from the nose to the terminal bronchioles |
What structures make up the upper airway? | nasal cavity, sinuses, mouth, pharynx, and larynx |
Describe the components of atmospheric air. | 21% Oxygen, 78% nitrogen, some other stuff |
List the primary functions of the nasal cavity. | warm/cool, filter, humidify inspired air |
Why is aspirated fluid more likely to go in the right lung? Why is it that ETT displacement more commonly happens in the right bronchus? | the right bronchus is shorter, wider, less bent – straight angle off main bronchus |
Name the descending parts of the tracheobronchial tree. | trachea, main stem bronchi to lobar branches to segmental bronchi to subsegmental bronchi to bronchioles to terminal airways |
What are airways less than 2mm in diameter? | bronchioles |
Define anatomical deadspace. | normal passages for air (airways) where no gas exchange takes place – nose to conducting airways |
Define alveolar deadspace. | Areas in aveoli where gas exchange does not occur |
Define physiologic deadspace. | alveolar dead space + anatomical dead space |
Define mucociliary escalator. | specialized mucous membrane lining the lower respiratory tract; composed of pseudostratified columnar epithelium; lined with cilia that work like an escalator to carry mucous trapped debris to the pharynx for expectoration or swallowing |
Name several substances that inhibit/paralyze the cilia of the lower respiratory tract. | smoke, pollutants, alcohol, anesthesia, high O2, dehydration |
What structure of the respiratory tract marks the transition to the respiratory zone? | the bronchioles |
Name the structures that make up the respiratory zone. | terminal bronchioles, alveolar ducts, alveolar sacs, and alveoi |
Where does gas exchange take place? | in the alveoli |
How many alveoli are there in the adult lung? | about 300 million |
What structures surround the alveoli? | pulmonary capillaries |
What kinds of cells make up the epithelium of the alveoli? | Type I – pneumocytes line most of the alveolar surface, type II pneumocytes produce surfactant, Alveolar macrophages phagocytize bacteria and foreign particles |
What is the function of surfactant? | reduces surface tension and prevents collapse |
Where is the interstitium of the alveoli and what is it made of? | lies between alveoli – made up of capillaries, lymphatic channels, nerves and elastic tissue which gives the lungs their elastic recoil |
What are two properties of the lungs that contribute to their function? | recoil and compliance |
Define recoil. | Ability to return to resting position after stretching |
Define compliance. | Ability to expand |
Explain the connection between recoil and the pathophysiology of emphysema. | Ephysema results in loss of recoil due to alveolar wall breakdown resulting in hyperinflation |
Describe the relationship between compliance and pulmonary fibrosis. | In pulmonary fibrosis connective tissue is replaced with scar tissue resulting in stiff, noncompliant lungs |
Define ventilation. | movement of air in and out of the respiratory tract |
What is required to achieve effective ventilation? | air reaches the alveoli so that gas exchange can take place; requires patent airway; working parts of respiration, thoracic cage, lungs, and muscles must be intact and functioning |
Define respiration, internal and external. | respiration is the exchange of gases; internal - tissue level; external – lungs |
What is required to have effective respiration? | adequate ventilation |
Explain Boyles law. | The pressure gas exerts is inversely related to volume so that when volume goes up (as in expanding thoracic cavity) pressure goes down; When volume goes down (such as in smaller area in the thoracic cavity during expiration) pressure goes up |
How many mmHg is atmospheric pressure? | 760 mmHg |
Discuss the relationship of atmospheric pressure to intrathoracic/intraplueral pressure. | intrathoracic/intrapleural pressure is always slightly below atmospheric pressure |
Describe how the receptors that regulate ventilation in the Medulla work. | Medulla/respiratory center has receptors sensitive to CO2 and H+ ions with arterial CO2 being the main stimulus for increased ventilation/decreased O2 is a lesser stimulus for increased ventilation |
Describe how the peripheral chemoreceptors located in the carotid and aortic bodies work to control ventilation. | they are sensitive to decreased O2 mainly but also increased CO2 and decreased PH. |
What pressure activates the carotid and aortic bodies? | PO2 below the normal of 100mmHg, but maximal response to PO2 below 50-60mmHg |
Name the receptors in the lung that help regulate ventilation. | Pulmonary stretch receptors, Irritant receptors, J receptors |
What is the function of Pulmonary stretch receptors? | prevent overinflation -say we’ve just had a nice stretch, that’s enough now,make more surfactant – Hering-Breuer Reflex |
What is the function of Irritant receptors. | Create urge to cough |
What do J receptors do? | increase respiratory rate (and possibly involved in the subjective feeling of dyspnea) in response to barotrauma like pneumonia, pulmonary embolism, pulmonary edema |
What type of movement facilitates the exchange of O2 for Co2 in the alveoli? | Diffusion |
Define diffusion. | the movement of substances from a place of higher concentration to lower concentration |
Explain why O2 moves from the alveoli to the pulmonary capillary bed and why CO2 moves out. | Alveolar pressure of O2 is about 100mmHg, Venous pressure is about 40mmHg |
Define ventilation/perfusion matching. | ventilation is the air being carried to the aveoli and perfusion adequate flow of blood to pick up oxygen; matching means That the amount of oxygen delivered is the amount that the body needs and the blood is able to pick it up and deliver it. |
What happens if we have ventilation but lack perfusion? | No gas exchange |
What is dead space? | where no gas exchange takes place |
Give some examples of condition that increase the amount of dead space. | Emphysema and pulmonary embolism |
Give some examples of conditions in which the blood flow to the aveoli is adequate but ventilation is inadequate. | pneumonia, atelectasis, ARDs |
Give 2 ways that O2 is delivered by the blood. | 3% is dissolved and 97% is bound to Hgb |
What does pulse oximetry tell us about? | O2 bound to Hgb |
How is CO2 carried in the blood? | 70% in bicarbonate, 20% in doxygenated Hgb- carbaminohemoglobin, 10% dissolved – this value is what PCO2 measures in ABGs |
What percentage of energy is used by a healthy person for breathing at rest? With exercise? | 5%; up to 30% with exercise |
Name two factors that affect the work of breathing. | airway resistance (narrowed airways) and compliance (stretchiness) |
Give 5 local manifestation of respiratory dysfunction. | cough- lasting longer than 2-3 wks may = pulmonary disease; excessive nasal secretions; expectoration of sputum; Pain – pleuritic, intercostals, generalized; Dyspnea |
What are some outward signs of dyspnea? (raLB, AM, FN, T, AE, G, C) | rapid, audible, labored breathing; accessory muscles; flared nostrils; tachycardia; anxious expression; gasping; cyanosis |
What’s the difference between hypoxia and hypoxemia? | hypoxemia means decreased PaO2; Hypoxia means inadequate tissue oxygenation |
Give 6 possible causes of hypoxemia/hypoxia. (VP, HA, IO, A, AH, CI) | ventilation/perfusion mismatch (most common); High altitude; not enough O2 in inspired air; anemia; abnormal Hgb; Circulatory impairment like hypotension or low cardiac output |
What values provide the most reliable indication of hypoxemia? | ABGs |
What are the early signs of hypoxia? | (think Sympathetic nervous system) tachycardia, dilated pupils, tachypnea, irritability, unexplained apprehension |
What are the later signs of hypoxia? | combativeness, retractions, cyanosis, hypotension, HA and decreased LOC |
When does hypoxemia become the main respiratory stimulus? | in situations where CO2 retention and resulting acidosis are long standing such as in COPD |
How does lack of oxygen result in acidosis? | anaerobic metabolism results in lactic acid |
Define hypercapnia/hypercarbia. | increased CO2 in arterial blood |
What causes hypercapnia/hypercarbia? | Inadequate alveolar ventilation such as occurs in respiratory depressioin, pneumonia, pulmonary edema, and obstructive lung disease |
Describe how excess CO2 leads to excess hydrogen or acidosis. | CO2 and Water combine in the blood to form H2CO3 in greater than normal amounts(carbonic acid – weak acid) which dissociates into Hydrogen and bicarbonate |
What is the normal balance/ratio between bicarbonate HCO3 and carbonic acid H2CO3? | bicarbonate 20: carbonic acid 1 |
What signs are associated with acidosis resulting from increased CO2? | tachycardia, hypertension, dizziness, HA, Mental cloudiness, LOC if severe |
Define respiratory failure. | Oxygenation and/or ventilation not working adequately |
Briefly define the pathophysiology of respiratory failure. | inability to supply the body with adequate oxygen (Oxygenation failure) and rid it of CO2 (ventilatory failure) |
What PaO2 and PaCO2 levels define respiratory failure? | PaO2 < 50 mmHg; PaCO2 > 50mmHg and pH < 7.25 |
What are the two classifications of respiratory failure? | acute or chronic |
Name some causes of Ventilatory failure (alveolar hypoventilation). | upper airway obstruction, Depression of respiratory center (medulla); Problem with transmission of nerve impulse from respiratory center to muscles of respiration; Mechanical abnormailities of the chest wall or lung; Smokers (COPD) |
What are some potential causes of depression of the respiratory center (medulla)? (O A H C) | O.D., anesthesia, Head trauma, CVA |
Give some examples of conditions that would interfere with impulse transmission from the respiratory center to the muscles of respiration. | Lesion at the cervical level of the spinal cord; nerve or neuromuscular disorders like polio, Guillain-Barre, Myasthenia Gravis |
Define Guillain-Barre. | serious disorder that occurs when the body's defense (immune) system mistakenly attacks part of the nervous system. This leads to nerve inflammation that causes muscle weakness; often starts with a minor infection like a lung/GI infection. |
Define Myasthenia Gravis. | chronic progressive disease characterized by chronic fatigue and muscular weakness (especially in the face and neck); caused by a deficiency of acetylcholine at the neuromuscular junctions. |
Give some examples of mechanical abnormalities of the chest wall or lung. | Pleural effusion, pneumothorax, hemothorax, flail chest |
What are some causes of oxygenation failure? | ventilation perfusion mismatch |
Name some conditions that would lead to ventilation/perfusion mismatch. | Pneumonia, ARDS, atelectasis, Severe Pulmonary edema, pulmonary embolism |
What should be done in the case of respiratory failure? | Provide O2, Ventilation or both; diagnose the underlying disorder |