Respiratory System Chapter 37-3

What is Respiration?  Respiration is not just breathing in oxygen  Once oxygen is pulled into the lungs, it is carried to cells via the circulatory system  Once oxygen is at the cells, it is used in Cellular Respiration  Oxygen helps break down sugar to produce ATP (Energy)  Without ATP, our bodies cannot make enough energy to function

What is the respiratory system made of?  The nose and mouth  Breaths air in  The pharynx  The large dead space behind the nose  The larynx  The voice box  The trachea  The largest windpipe that goes down our throat  Bronchi and bronchioles  The smaller branches of the windpipes in your lungs  Alveoli  Tiny grape-like sacs where diffusion of O2 and CO2 happens in your lungs  Diaphragm  Large dome-shaped muscle at the base of the lungs, controls breathing

How does air move in?  When the diaphragm is relaxed, the muscle is dome-shaped  Relaxing this muscle increases pressure on the lungs, forcing the air out  When the diaphragm contracts, it becomes flat  This contraction pulls air into the lungs  Pressure decreases on the lungs allowing them to expand  Even though you can control your breathing, it is still mostly involuntary  Hold your breath and see what happens! Relaxed Diaphragm Contracted Diaphragm

Filtration of the Resp. System  Air first passes through the nose and mouth  These organs warm and filter the air  All of the windpipes in the Respiratory system are lined with tiny hairs, called Cilia and Mucus  Cilia actively sweep out dirt, dust and smoke particles  Mucus keeps the lungs moist from your mouth right down to the alveoli air sacs  DIFFUSION CANNOT HAPPEN IF THE LUNGS ARE DRY!  Mucus also traps dirt, dust and smoke before they damage the lungs Cilia in the Trachea of a Rabbit

The Larynx and Trachea  This is the voice box  In Men, the larynx is larger, creating the Adam’s Apple  The shorter the vocal chords, the deeper the voice and more prominent Adam’s Apple  As air passes through the larynx, the vocal cords vibrate, making a variety of noises  Singing  Screaming  Talking Right: Top-down view Left: Side view Bottom Left: Top of trachea

Inside the lungs: Bronchi- Alveoli  The trachea branches off into two smaller airways, called Bronchi (Bronchus is singular)  Each bronchus branches into smaller and smaller Bronchioles  At the end of every bronchiole is a grape-like cluster of air sacs, called Alveoli  The Alveoli is where gas exchange occurs (Diffusion)  Each Alveoli is wrapped in a net of capillaries Bronchi + BronchiolesAlveoli

Alveoli and Cilia in a Rat lung Cross-section of Alveoli Cilia lining a bronchial tube

Diffusion in Alveoli  As blood passes by the alveoli, it is Deoxygenated (no oxygen in blood)  When there is lots of Oxygen in the alveoli, is flow from high to low concentration into the blood  Carbon dioxide does the opposite, flowing from high to low concentration from the blood to the alveoli

Tobacco and the Resp. Sys.  Tobacco (found in cigarettes, dip, pipe tobacco, etc.) causes MANY health problems  There are over 500 known carcinogens (cancer-causing chemicals) in cigarettes  Most doctors believe at least 90% of lung cancer cases are due to smoking  Diseases cause by smoking include:  Bronchitis, Emphysema, and Lung Cancer

Diseases from Smoking  Bronchitis:  Itis= inflammation, therefore, bronchitis is inflammation of the bronchi  Mucus clogs the airways causing breathing to become difficult  The “Smoker’s cough” is often a result from this  People who suffer from bronchitis often have difficulty doing simple things like climbing stairs

More diseases  Emphysema:  This is a loss of elasticity in the lung tissues  Normally lungs inflate like balloons, but emphysema causes stiff non-elastic scar-tissue from allowing lungs to expand  This is a non-reversible or curable disorder  Lungs lose the ability to diffuse O2 and CO2  Lung Cancer:  180,000 people develop this disease every year, few survive  It spreads very easily making it one of the most difficult cancers to cure  It normally takes a long time to detect it, by the time you know you have it, it may have spread beyond a point that can be cured