Respiratory System

Function Obtain oxygen for cellular respiration Remove carbon dioxide Filter and entrap particles from air Control temperature of the air Control water content of the air Produce vocal sounds Participate in smell

Major Organs of the Respiratory System Trachea (windpipe) -Extends downward anterior into right and left bronchi -Has ciliated mucous membrane that filters incoming air and moves entrapped particles into the pharynx Bronchi -Branches off into left and right primary bronchi -Makes up bronchial tree which consists of branched airways leading from trachea to microscopic air sacs in the lungs Bronchioles -Smaller tubes that branch from the tertiary bronchi, which branched from the secondary bronchi Alveoli -Smaller microscopic air sacs within the capillary networks

Upper Respiratory Tract Major Structures Nostrils Nasal Cavity Mouth Pharynx Larynx Inhaled air is moistened, warmed, and cleansed by the tissue that lines the nasal cavity.

Larynx Location Includes: Anterior aspect of the neck Inferior to pharynx Superior to trachea Includes: Cricoid cartilage Thyroid cartilage Epiglottis cartilage

3 Cartilaginous Structures Cricoid cartilage: ring of hyaline Thyroid cartilage (Adam’s apple) Epiglottis guards glottis, prevents food from going into trachea, involved in gag reflex protect vocal folds, changes pitch of voice Provides attachment for muscles involved in opening

Lower Respiratory Tract Major Structures Trachea Bronchi Tertiary Bronchi Bronchioles Alveoli Diaphragm

Lungs Structure 3 lobes in right lung 2 lobes in left lung Pleura Pleura cavity Pleural fluid Diaphragm muscle Air enters each lung through a single bronchi, which branches out into bronchioles, and eventually alveoli

Pleura Double layered serous membrane that surrounds the lungs The pleural cavity is the space within, which the lung has grown Serous membranes secrete serous fluid that keeps the lungs from being irritated when breathing

Diaphragm The diaphragm controls breathing Contracted during inhalation, relaxed during expiration Air flows from high pressure to low pressure When inhaling, air pressure lower on the outside of lungs than the inside lungs When exhaling, air pressure higher on the outside of lungs than the inside of lungs

Steps of Respiration Ventilation: movement of air in/out of lungs External respiration: gas exchange between blood and air in lungs Gas transport in blood between blood and body cells Internal respiration: gas exchange between blood and cells

Respiratory Volume & Capacity Tidal volume: amount of air inhaled and exhaled in a natural breath Expiratory and inspiratory reserve volume: amounts of air possible to inhale or exhale Residual volume: residual air constantly remaining in the lungs Total lung capacity: volume of air contained in lungs at end of a maximal inspiration

Gas Exchange in Alveoli When the partial pressures in the lungs are different than the partial pressures in the capillaries, diffusion occurs O2 diffuses from lungs into alveolar capillaries during inhalation CO2 diffuses into the lungs from the alveolar capillaries during exhalation

How Blood Carries Gases Oxygen and carbon dioxide are carried by hemoglobin in the red blood cells 2 or 4 oxygen can be carried by a single blood cell

Carbon Dioxide Transport Can be carried in solution, bound to hemoglobin, or as bicarbonate ion CO2 + H2O  H2CO3 -Carbon dioxide reacts w/ water to form carbonic acid H2CO3  H + + HCO3- - Resulting carbonic acid dissociates, releasing hydrogen ions and bicarbonate ions H + + HCO3-  H2CO3  CO2 +H2O - Hydrogen ion and bicarbonate ions recombine to form carbonic acid, and carbonic anhydrase breaks down to yield carbon dioxide and water

Lung- Heart Relationship The pulmonary artery start from the heart carrying oxygen depleted blood to the lungs The pulmonary vein returns oxygen rich blood from the lungs to the heart

Respiratory Center in the Brain Although we can control our breath, most respiration is autonomic The respiratory system, located in brainstem, is made up of neurons, widely scattered in medulla oblongata and pons Medulla rhythmicity area contains 2 groups Dorsal: controls basic rhythm of inspiration and emit bursts of impulses that signal the diaphragm and other inspiratory muscles to contract Ventral: during heavy breathing neurons generate impulses that increase inspiratory movements

Factors That Affect Breathing Chemicals, stretching of lung tissues, emotional states, and chemoreceptors Hyperventilation: Diaphragm and chest muscle spasms and/or airways become constricted, causing person to breathe rapidly Asthma: Thickens muscle in bronchial tubes, restricting airways and making it harder to breathe

Lung Cancer Lung cancer results in large parts of the lung becoming inactive Causes: Family history of lung disease or cancer, smoking, being regularly exposed to unsafe chemicals or air Effects: Shortness of breath, dizziness, painful breathing, chronic coughing

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