The Respiratory System

Respiratory System Functions Gas exchange: Oxygen enters blood and carbon dioxide leaves Regulation of blood pH: Altered by changing blood carbon dioxide levels Voice production: Movement of air past vocal folds makes sound and speech

Respiratory System Functions Olfaction: Smell occurs when airborne molecules drawn into nasal cavity Protection: Against microorganisms by preventing entry and removing them Temperature regulation: Panting in some animals

Parts of the Nose Nose Only externally visible part of the respiratory system Job is to begin warming, purifying, and humidifying air

Parts of the Nose External Nares (nostrils) Where air enters the nose The openings Nasal Cavity Interior of the nose Has thin-walled blood vessels to begin warming air

Parts of the Nose Nasal Septum Midline dividing nasal cavity into two

Parts of the Nose Respiratory Mucosa Sticky mucous Moistens air and traps bacteria & debris Ciliated cells move mucous back toward throat

Parts of the Nose Conchae Mucosa-covered projections Increase surface area & air turbulence Provide more opportunity for warming & filtration

Parts of the Nose Hard Palate Anterior separation of nasal & oral cavity Supported by bone Soft Palate Posterior separation of nasal & oral cavity

Cleft Palate Palate does not fuse together Can also affect the lip

Parts of the Nose Paranasal Sinuses Openings in skull bones Lighten the skull Resonance chambers for speech Produce mucus

Parts of the Pharynx Pharynx Muscular passageway for food & air “Throat” About 5 inches long Broken into 3 parts

Parts of the Pharynx Internal Nares Opening between nasal cavity and pharynx

Parts of the Pharynx Nasopharynx Oropharynx Laryngopharynx Three divisions of Pharynx Listed from superior to inferior After passing through, air enters larynx, food enters esophagus

Parts of the Pharynx Pharyngeal Tonsils: AKA adenoids High in the nasopharynx Trap bacteria/pathogens Palatine Tonsils In oropharynx, end of soft palate When you get your tonsils out, this is what is removed Lingual Tonsils Base of the tongue

FYI: Tonsilitis Catch too much bacteria; palatine tonsils can’t keep up! EEW.

http://video.about.com/coldflu/Tonsillitis.htm

Larynx AKA Voice Box Routes air and food into proper channels Inferior to pharynx Formed by 8 rigid cartilages and a spoon-shaped flap of elastic cartilage (epiglottis) Thyroid cartilage = Adam’s apple

Epiglottis Cartilage flap of larynx; protector! When not swallowing: Epiglottis flapped up Does not block larynx When you are swallowing: Larynx rises Epiglottis falls Larynx closed off This means that food is directed into esophagus

FYI: If anything other than air tries to enter the larynx, a cough reflex is triggered to get it out and prevent it from going into the lungs!

Vocal Folds Vocal Folds Formed from folds in larynx membrane Vibrate with expelled air Glottis Slit-like passageway between vocal folds

http://video.about.com/coldflu/Laryngitis.htm YouTube - Video Stroboscopy of the Vocal Cords YouTube - Mythbusters - Helium and Sulfur Hexafluoride

Trachea AKA windpipe Has cartilage rings around it to keep it open during pressure changes About 4 inches long Lined with ciliated mucosa to propel mucus (with dust particles & debris) away from the lungs to the throat

Primary Bronchi Two (right & left) Formed by division of trachea Enters the lung, and then breaks off into secondary bronchi

Mediastinum Most central area of the thoracic cavity Includes heart, great blood vessels, bronchi, esophagus, etc. (everything except lungs)

Lungs Site of gas exchange Soft & Spongy, only weigh about 2 ½ pounds Each lung divided into lobes Left: 2 lobes Right: 3 lobes

Parts of Lungs Apex Narrow superior portion By clavicle Base Wide inferior portion Rests on diaphragm Visceral Pleura Covers surface of lung Along with parietal pleura, provides attachment and eliminates friction

Bronchial Tree Bronchioles All of the branching of respiratory passageways in the lungs Divisions include Primary bronchi Secondary bronchi Tertiary bronchi Bronchioli Terminal bronchioli (end in alveoli)

This image is showing the carina – the point where the primary bronchi break off from each other.

Alveoli “Air Sacs” Resemble bunches of grapes Make up bulk of lungs

Respiratory Zone Includes respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli Only places where gas exchange occurs

Walls of Alveoli Made of single, thin layer of squamous epithelial cells Covered with a cobweb of pulmonary capillaries

Respiratory Membrane Made up of alveolar and capillary walls Has air flowing on one side, blood flowing on the other Gas exchange occurs through simple diffusion Oxygen from alveolar air to capillary blood Carbon dioxide leaving blood to air FUN FACT: total surface of alveoli walls is about 50-70 square meters - about the surface of a tennis court!

http://highered. mcgraw-hill http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.html http://video.about.com/asthma/How-Lungs-Function.htm

Steps to Respiration 1. Pulmonary Ventilation (breathing) Air move in and out of lungs so alveoli air is refreshed 2. External Respiration Gas exchange between blood and alveoli air 3. Respiratory Gas Transport Gas transport between lungs and body by bloodstream 4. Internal Respiration (Cellular Respiration!) In body, at capillaries, gas exchange between blood and tissue cells

Respiration Inspiration Expiration Air flowing into lungs (breathe in!) Expiration Air leaving the lungs (breathe out.) Volume changes lead to pressure changes, which lead to the flow of gases to equalize the pressure!

Inspiration Diaphragm and external intercostals contract Diaphragm actually moves DOWN when contracts Thoracic cavity size increases Rib cage lifts Intrapulmonary volume increases Gas molecules spread out due to increased volume! This causes a decrease in pressure, which pulls in more gas.

Inspiration

Expiration Diaphragm and external intercostals relax Internal intercostals and abdominal muscles contract if expiration is forced Thoracic cavity size decrease Rib cage descends Intrapulmonary volume decreases Gas molecules get closer together due to the decrease in volume! This causes a increase in pressure, which forces gas out.

Expiration

Non-Respiratory Air Movements Cough Sneeze Crying – release of air in short breaths Laughing – release of air in short breaths Hiccups Yawn

Lung Development Fetus Birth All respiratory exchange made by placenta Lungs filled with fluid Birth Fluid drained, passageways fill with air Surfacant: fatty molecule that lines each alveolar sac to prevent from collapsing (don’t have enough of this until fetus is 30 weeks) Lungs do not fully inflate for 2 weeks after birth 20 to 40 respirations/min

Lung Development Teens Elderly 12 to 18 respirations/min (rates differ depending on source) Continue to develop alveoli (smoking stops this production!) Elderly Chest wall becomes rigid, lungs lose elasticity, cilia in trachea less effective Vital capacity decreases More at-risk for respiratory tract conditions 18 to 20 respirations/min

Respiratory Conditions Pulmonology – study of diseases of the lungs and respiratory tract Hypoxia – inadequate oxygen delivery to body tissues, causes cyanosis (bluish-tone of skin)

Upper Respiratory Tract Infection Includes things like the common cold, sinusitis, tonsillitis, and laryngitis Symptoms include nasal congestion, cough, running nose, sore throat, fever, facial pressure, and sneezing

http://video.about.com/coldflu/Upper-Respiratory-Infection.htm http://video.about.com/coldflu/Sinusitis.htm

Lung Cancer 1/3 of all cancer deaths in the US Very low survival rate, because usually not caught until very advanced Growth usually occurs in the bronchial tree Problem with smoking… Kills off cilia that cleans & moves mucus out of airway Mucus collects Traps carcinogens from cigarettes

COPD Chronic Obstructive Pulmonary Disease Characterized by limited airflow Symptoms include coughing, wheezing, and shortness of breath (dyspnea) Usually have a history of smoking, but can also be caused by other inhalants (coal, asbestos, air pollution)

COPD Patients retain carbon dioxide, meaning blood becomes slightly acidic Usually results in respiratory failure Two major types (there are other types, but these are the most common)…

Emphysema Characterized by breakdown of elastin in connective tissue of lungs Leads to destruction of alveolar walls Lungs become less elastic, which makes it difficult to exhale

Chronic Bronchitis Characterized by inflammation of the bronchi Mucosa lining of lower respiratory passages become inflamed and produces excess mucus, which leads to blockage Symptoms include persistent coughing with sputum, cyanosis very common

Acute Bronchitis Caused by virus or bacteria Only last days/weeks Symptoms same as chronic bronchitis

http://video.about.com/asthma/Bronchitis.htm

Pneumonia Characterized by: Inflammatory illness of the lungs, alveoli become filled with fluid Varied causes, including bacteria, virus, fungi, chemical, & physical Often diagnosed with chest x-ray

Asthma Characterized by airways constricting due to trigger (exposure to allergens, pollutants, cold air, warm air, moist air, exercise, or emotional stress) Symptoms include wheezing, shortness of breath, chest tightness, and coughing Scientists believe cause is combination of genetics and environment Inhalers act as bronchodilator

Sleep Apnea Characterized by pauses of breathing during sleep 5 or more events, lasting at least 10 seconds each Caused by blockage of the airways due to causes such as decreased muscle tone, increased soft tissue around airway (obesity), and structural features (deviated septum, enlarged tonsils)

Carbon Monoxide Poisoning Competes with oxygen for same binding sites on hemoglobin Binds VERY easily, and so it pushes out oxygen Leading cause of death from fire Victim usually becomes confused, has headache, and blushing of skin

1 in 20 people are unaffected carriers! Cystic Fibrosis Cystic Fibrosis is a recessive genetic disease that effects both the digestive and respiratory system. Abnormally thick mucus gets stuck in many places. Most commonly in the lungs & pancreatic duct Symptoms can include persistent coughing, shortness of breath and frequent upper respiratory infections. 1 in 20 people are unaffected carriers!

Cystic Fibrosis Easily diagnosable with a sweat test Treatment for the GI tract involves taking digestive enzymes before eating. Treatment for the lungs is called CPT, Chest Physiotherapy. A light clapping of the chest, back, and under the arms to loosen mucus in the lungs