The Respiratory System
Post on 30-Dec-2015
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The Respiratory System
Inhale … Exhale …
How important is the Respiratory System?
• How long can you hold your breath?
2 different levels
• Cellular, or internal
• Organism level
Why Breath?
• Respiratory System is a group of organs working together to bring about the exchange of oxygen and carbon dioxide with the environment
• Respiratory System consists of:• Nose• Nasal cavity• Pharynx• Larynx• Trachea• Smaller conducting passageways• Lungs
• air is about 21% Oxygen; 78% Nitrogen; 1% Carbon dioxide, water vapor, argon, and other trace gasses (neon, helium, krypton, hydrogen, and ozone are a few)
• Air enters through the nose or mouth
• Into the nasal cavity – warms and moistens air
• Enters pharynx – back of throat – serves as passageway for food and air
• Trachea – windpipe – leads to lungs
• Direct connection to outside – must filter dust, dirt, smoke, bacteria and other contaminants
• When air goes through the mouth, it doesn’t get filtered as much as when it goes through the nose and nasal cavities
• Lined with mucous secretions and hair
• Top of trachea is Larynx
• Made of cartilage (largest is the Adam’s Apple)
• Also known as Voice box
• Inside is two folds of tissue – the vocal cords
Trachea• C – shaped rings
of cartilage
• Protect the trachea
• Make it flexible
• Keep it from collapsing
• Cells that line the trachea • produce mucus • Lined with cilia• Particles are trapped in the mucus and carried to
upper trachea – swept down into digestive system
• Smoke = Sabotage to system• Cilia stop working after a while• When this happens, particles get lodged in the
trachea – SMOKER’S COUGH
• Trachea divides to bronchi
• Bronchi divide into smaller and smaller passageways and lose the cartilage rings to become bronchioles
• Bronchioles divide further and further until they end in small clusters of hollow air sacs – alveoli
• Gas exchange occurs in alveoli
• Mechanics of Breathing
• Inhalation and Exhalation
• Air pulled into the lungs and air pushed out of the lungs
• 10 – 15 X in a minute
• Diaphragm – large flat muscle along bottom of rib cage and Intercostal (between ribs) muscles
Makeup of air we breath
Gas Chemical Symbol
Air Entering
Lungs
Air Leaving Lungs
Oxygen O2 19.97% 16%
Carbon Dioxide
CO2 0.03% 4.00%
Nitrogen N2 80% 80%
3 million alveoli in a healthy lung
• Blood enters capillaries around the alveoli
• Carbon dioxide rich blood enters, Carbon dioxide diffuses out, Oxygen diffuses in – concentrations are unequal across the alveolar membrane of gasses
• Phospholipids and protein produce a “surfactant” to coat the inside of the alveolus
• Keeps it open and makes it easier to exchange gasses
• Hemoglobin – Found in red blood cells – iron containing compound – makes red blood cells red
• Without Hemoglobin, blood would only be able to carry about 2% of the oxygen needed by the body.
• Control of Respiratory System
• Breathing is involuntary
• What makes you breath?
• How does the nervous system control breathing?
• Sensory neurons check levels of gasses in your blood.
• One set in carotid arteries in the neck
• Other set in the aorta
• These are sensitive to levels of gasses in the blood – especially Carbon Dioxide
LUNG CAPACITIES
• Total Lung Volume – about 6 L• Residual Volume – Following a normal
exhalation, what is left (about 2 ½ L)• Tidal Volume – Volume of air inspired or
expired during a normal (at rest) breath (1/2 L per cycle)
• Inspiratory Reserve – additional air that can be breathed after a normal inspiration (4 ½ L)
• Vital Capacity – total volume of breathable air
Problems
• Hypoxia – High CO2 levels in the blood – provides greatest stimulus to breath
• Influenced by oxygen partial pressure, increased gas density, and emotional states
• Asphyxia – existence of both hypoxia (oxygen shortage) and Carbon Dioxide excess
• Suffocation – stoppage of breathing for any cause resulting in asphyxiation
• Strangulation – stoppage of breathing due to obstruction
Asthma
• Restriction of airways due to inflammation• May cause
– Shortness of breath– Wheezing– Coughing
• Can be triggered by– Cold– Allergies – dust, pet hair, smoke, pollen, etc…– Exercise
Asthma
• Medicines include– Long acting to prevent attacks– Short acting during attacks (bronchodilators)
Lung Caner
Emphysema
• COPD – Chronic Obstructive Pulmonary Disease– Lung tissue destroyed –
cannot function fully– Irreversible condition– Steroids and other drugs– May need Oxygen
permanently
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