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Lina Le Period 6 Respiratory System - Coggle Diagram
Lina Le Period 6 Respiratory System
Major Functions of the Respiratory System
Dispose of carbon dioxide, which is a waste product of cellular repiration
Olfaction
Supply the body with oxygen for cellular respiration
Speech
Upper Respiratory Structures and Functions
Paranasal
General Description
Mucosa-lined, air-filled cavities in cranial bones surrounding nasal cavity
Function
Lighten skull; may also warm, moisten, and filter incoming air
Pharynx
General Description
Passageway connecting nasal cavity to larynx and oral cavity to esophagus. Three subdivisions: nasopharynx, oropharynx, and laryngopharynx
Houses tonsils( lymphoid tissue masses involved in protection against pathogens)
Function
Passageway for air and food
Facilitates exposure of immune system to inhaled antigens
Nose (external nose and nasal cavity)
General Description
Jutting external portion is supported by bone and cartilage. Internal nasal cavity is divided by midline nasal septum and lined with mucosa
Roof of nasal cavity contains olfactory epithelium
Function
Receptors for sense of smell
Produces mucus; filters, warms, and moistens incoming air; resonance chamber for speech
Lower Respiratory Structures and Functions
Trachea
General Description
Flexible tube running from larynx and dividing inferiorly into two main bronchi. Walls contain c-shaped cartilages that are incomplete posteriorly where connected by trachealis
Function
Air passageways; cleans, warms and moistens incoming air
Bronchial tree
General Description
Consists of right and left main bronchi, which subdivide within the lungs to form lobar and segmental bronchi and bronchioles. Bronchiolar walls lack cartilage but contain complete layer of smooth muscle. Constriction of this muscle impedes expiration
Function
Air passageways connecting trachea with alveoli; cleans, warms, and moistens incoming air
Larynx( sometimes apart of the upper respiratory, depends on textbook)
General Description
Connects pharynx to trachea. Has framework of cartilage and dense connective tissue. Opening(glottis) can be closed by epiglottis or vocal folds
Houses vocal folds(true vocal cords)
Function
Air passageway; prevents food from entering lower respiratory tract
Voice production
Alveoli
General Description
Microscopic chambers at termini of bronchial tree. Walls of simple squamous epithelium overlie thin basement membrane. External surfaces are intimately associated with pulmonary capillaries
Special alveolar cells produce sufactant
Function
Surfactant reduces surface tension; helps prevent lung collapse
Main sites of gas exchange
Lungs
General Description
Paired compose organs that flank mediastinum in thorax. Composed primarily of alveoli and respiratory passageways. Stroma is elastic connective tissue, allowing lungs to recoil passively during expiration
Function
Houses respiratory passages smaller than the main bronchi
Pleurae
General Description
Serous membranes. Parietal pleura lines thoracic cavity; visceral pleura covers external lung surfaces
Function
Produce lubricating fluid and compartmentalize lungs
Layers of the Pleurae
Pleurae: thin, double-layered serosal membrane that divides thoracic cavity into two pleural compartments and mediastinum
Visceral pleura: membrane on external lung surface
Pleural fluid fills slitlike pleural cavity between two pleurae
Provides lubrication and surface tension that assists in expansion and recoil of lungs
Parietal pleura: membrane on thoracic wall, superior face of diaphragm, around heart, and between lungs
Compare and Contrast the Mechanism of Inspiration and Expiration
Inspiration: gases flow into lungs
Principal
External intercostals interchondral part of internal intercostals
Diaphragm (dome descends, thus increasing vertical dimension of thoracic cavity; also elevates lower ribss)
Accessory
Scalenes Group ( elevate upper ribs)
Pectoralis minor
Sternocleidomastoid (elevates sternum)
Expiration: gases exit lungs
Quiet Breathing
Expiration results from passive, elastic recoil of the lungs, dib cage and diaphragm
Active Breathing
Internal intercostals, except interchondral part (pull ribs down)
Abdominals (pull ribs down, compress abdominal contents thus pushing diaphragm up)
Quadratus lumborum (pulls ribs down)
Volume and Pressure relationships in Thoracic Cavity
Volume
Inspiratory reserve volume (IRV): amount of air that can be inspired forcibly beyond the tidal volume (2100–3200 ml)
Expiratory reserve volume (ERV): amount of air that can be forcibly expelled from lungs (1000–1200 ml)
Residual volume (RV): amount of air that always remains in lungs
Needed to keep alveoli open
Tidal volume (TV): amount of air moved into and out of lung with each breath
Averages ~ 500ml
Boyle's Law: relationship between pressure and volume of a gas
Gases always fill the container they are in
Pressure and volume have an inverse relationship
P1V1 = P2V2
Pressure
Intrapulmonary pressure
Pressure in alveoli
Fluctuates with breathing
Always eventually equalizes with atmospheric pressure
Transpulmonary pressure
Pressure keeps lung spaces open
Keeps lungs from collapsing
Atmospheric pressure
Pressure exerted by air surrounding the body
760 mm Hg at sea level = 1 atmosphere
Intrapleural pressure
Pressure in pleural cavity
Fluctuates with breathing
Always a negative pressure
Two inward forces promote lung collapse
Lungs' natural tendency to recoil
Because of elasticity, lungs always try to assume smallest size
Surface tension of alveolar fluid
Surface tension pulls on alveoli to try to reduce alveolar size
One outward force tends to enlarge lungs
Elasticity of chest wall pulls thorax outward
Negative Pip is affected by these opposing forces but is maintained by strong adhesive force between parietal and visceral pleurae
Respiratory Volumes and Capacities
Respiratory Volumes
Tidal volume (TV): amount of air moved into and out of lung with each breath
Averages ~ 500ml
Inspiratory reserve volume (IRV): amount of air that can be inspired forcibly beyond the tidal volume (2100–3200 ml)
Expiratory reserve volume (ERV): amount of air that can be forcibly expelled from lungs (1000–1200 ml)
Residual volume (RV): amount of air that always remains in lungs
Needed to keep alveoli open
Respiratory Capacities
Inspiratory capacity (IC): sum of TV + IRV
Functional residual capacity (FRC): sum of RV + ERV
Vital capacity (VC): sum of TV + IRV + ERV
Total lung capacity (TLC): sum of all lung volumes (TV + IRV+ ERV + RV)
Internal v. External Respiration
External respiration: diffusion of gases between blood and lungs
Partial pressure gradients and gas solubilities
Steep partial pressure gradient for O2 exists between blood and lungs
Alveolar PO2 = 104 mm Hg
Drives oxygen flow into blood
Equilibrium is reached across respiratory membrane in ~0.25 seconds, but it takes red blood cell ~0.75 seconds to travel from start to end of pulmonary capillary
Ensures adequate oxygenation even if blood flow increases 3×
Venous blood PO2 = 40 mm Hg
External respiration (pulmonary gas exchange) involves the exchange of O2 and CO2 across respiratory membranes
Internal respiration: diffusion of gases between blood and tissues
Disorders of the Respiratory System
Tonsillitis
Results in air not properly moistened, warmed or filtered before entering the lungs
When they are chronically enlarged, both speech and sleep may be disturbed
Infected and swollen tonsils can block air passage in nasopharynx, making it necessary to breathe through the mouth
Pleurisy: inflammation of pleurae that often results from pneumonia
Other fluids that may accumulate in pleural cavity
Blood filtrate: watery fluid that oozes from lung capillaries when left-sided heart failure occurs
Blood: leaked from damaged blood vessels
Pleurae may produce excessive amounts of fluid, which may exert pressure on lungs, hindering breathing
Inflamed pleurae become rough, resulting in friction and stabbing pain with each breath
Pleural effusion: fluid accumulation in pleural cavity
Atelectasis: lung collapse due to
Plugged bronchioles, which cause collapse of alveoli, or
pneumothorax, air in pleural cavity
Treated by removing air with chest tubes
When pleurae heal, lung reinflates
Can occur from either wound in parietal pleura or rupture of visceral pleura