The Respiratory System Mr. Z’s Cool Science Classes

What is Respiration? Comparison: Breathing and Respiration Are they the same thing?

What is Respiration? Comparison… –Respiration is the exchange of gases that takes place in the alveoli in the lungs or at the cellular level –Breathing is the movement of air into and out of the lungs

Respiration, the Term Cellular Respiration takes place in the mitochondria –Release of energy from the breakdown of food molecules in the presence of oxygen –In most organisms, oxygen is necessary to maximize ATP production Organism Respiration occurs when the blood carries oxygen from the lungs body tissues and carries carbon dioxide in the opposite direction –Process of gas exchange

Human Respiratory System Function: bring about the exchange of oxygen and carbon dioxide between the blood, the air, and tissues THE PARTS ARE: nose, pharynx, larynx, trachea, bronchi, and lungs

Pharynx Tube at back of mouth, throat Passageway for both air and food Air moves from pharynx to trachea (windpipe) A flap of tissue called the epiglottis covers the entrance of the trachea when you swallow

Respiratory Filter System Air passes directly from environment into some of the most delicate tissues in the body Lung tissue maintains health by keeping respiratory system warmed, moistened, and filtered –Examples: Nasal hairs Mucus Cilia

Larynx Contains elastic vocal cords When muscles pull the cords together, the air moving between them causes the cords to vibrate and produce sounds

Bronchi Two large passageways in the chest cavity Each leads to one of the lungs Each bronchus divides into smaller bronchi and bronchioles Surrounded by smooth muscle that helps to support them and enables the autonomic nervous system to regulate the size of the air passageways

Alveoli Bronchioles subdivide until they dead end in millions of tiny air sacs called alveoli Grouped in clusters (grapes) Surrounded by thin-walled capillary networks The real work of the respiratory system takes place here, where blood and air are side by side

Gas Exchange 150 million alveoli in a healthy lung for use in gas exchange!! Provides LOTS of surface area for diffusion of gases –Oxygen diffuses into the blood –Carbon Dioxide in the blood diffuses the opposite direction

Efficiency of Gas Exchange Gas exchange is efficient in that it both maximizes oxygen intake and minimizes the oxygen exhaled The same is true for carbon dioxide, but in the opposite direction

Why is Hemoglobin Important? Oxygen easily dissolves in the blood, so why do we need hemoglobin? Hemoglobin – oxygen-carrying protein Binds to oxygen and increases the oxygen-carrying capacity of blood by more than a factor of 60

Breathing Movement of air into and out of the lungs No muscles attached to the lungs, so what allows the lungs to inflate during oxygen intake?

Breathing The lungs are sealed in two sacs called the pleural membranes inside the chest cavity Diaphragm – large, flat muscle located that the bottom of the chest cavity

Inhaling Breathing in Diaphragm contracts and the rib cage rises Expands the volume of the chest cavity Cavity is sealed; this creates a vacuum inside the cavity Atmospheric pressure does the rest and fills the lungs with air

Exhaling Generally a passive event Rib cage lowers and diaphragm relaxes Pressure in chest cavity becomes greater than atmospheric pressure Air rushes from lungs

Why does this work? Chest cavity is sealed This is why a chest injury is particularly dangerous; it may allow air to leak into the chest cavity and render breathing impossible

Controlling Breathing You can control your breathing Breathing is not entirely voluntary Nervous system will not allow you to have complete control Breathing is controlled by the BRAIN through careful monitoring of carbon dioxide levels

Carbon Dioxide Monitored Breathing Think about a fighter pilot or you on a commercial airliner. What accommodations must be made for being at a higher altitude? Can you see a possible problem from having breathing controlled by carbon dioxide levels?

Tobacco and Respiration The filtration system meant to protect your lungs from toxins will do so for a limited amount of time Smoking tobacco will eventually destroy your lungs

What is in Tobacco? Three most dangerous substances are nicotine, carbon monoxide, and tar Nicotine – stimulant that increases heart rate and blood pressure Carbon monoxide – poisonous gas that blocks the transport of oxygen by hemoglobin in the blood; deprives heart and other organs of oxygen Tar – contains compounds known to cause cancer

Surgeon General’s Warning..

What is in Tobacco? Smoking tobacco brings nicotine and carbon monoxide into the upper respiratory system Paralysis of cilia; smoke laden mucus trapped in airways Lining of respiratory tract swells, reduces airflow to alveoli

Diseases caused by Smoking Smoking reduces life expectancy Smoking can cause such respiratory diseases as chronic bronchitis, emphysema, and lung cancer

Chronic Bronchitis Bronchi become swollen and clogged with mucus Even smoking a moderate number of cigarettes on a regular basis can produce chronic bronchitis

Emphysema Loss of elasticity in lung tissue Makes breathing difficult; cannot receive enough oxygen or get rid of enough carbon dioxide

Lung Cancer Important but preventable cause Deadly cancer that easily spreads, often before detection

Heart Disease Major cause is smoking Smoking constricts blood vessels Blood pressure rises and heart must work harder Causes drop in body temperature

Smoking and the Non-Smoker Tobacco smoke damaging to all who inhale it; not just to the smokers This has led to restrictions on smoking in restaurants and other public places Particularly dangerous to young children whose lungs are still developing; increases risk for asthma