Transcript The Respiratory System

The Respiratory System
• System Evolution
• Major Parts of the
Respiratory System
• Functions of the
Respiratory System
The Evolution of the Respiratory
System
• Early creatures did not have a “respiratory
system” but rather exchanged gasses through
their skin. (Still true today as with planarians,
hydra, and some amphibians) These animals
usually have very large surface areas to
maximize respiration.
• More Advanced and Evolved animals have
developed systems that include lungs, trachea,
bronchial tubes and other tissue structures that
help with respiration
Simple to Complex Respiratory
Systems
Breathing
• Diaphragm and Intercostal Muscles
– Separate the Thoracic Cavity from the Pelvic
and Abdominal cavities.
– Diaphragm also expands and contracts
leading to intake and expulsion of air from the
lungs.
Breathing Cont.
• Diaphragm contracts chest cavity
expands pressure goes down air goes
into lungs
• Diaphragm relaxes chest cavity gets
smaller pressure goes up  air goes out
of lungs
Moving Air
• Nose- filters bacteria and dirt through tiny hairs and cilia
• Pharynx-Throat
– Mouth and nose come together
• Larynx- Voicebox
– Vocal Chords (ligaments that vibrate when air goes past)
– Adam’s Apple (larynx swells during puberty)
• Trachea-Windpipe goes to lungs
– Made of cartliage
– Cilia line the inside and make mucous
– Epiglottis- flap of tissue that closes over trachea when you
swallow
Lungs
• Location of Gas Exchange
• Trachea to the Bronchi to Bronchioles to
Alveoli
– Alveoli are tiny air sacs in lungs
How Blood Gets O2 Happy
• Deoxygenated blood flows into the heart
form vena cava
– Right atrium and ventricle
• Then into the Pulmonary Artery
– Goes to lungs
– Gets oxygen
– Returns through pulmonary veins
• Goes to heart
– Left atrium and ventricle
– Rest of body
Diseases of the Mighty Lungs!
• Pneumonia
– Infection of the lungs where the lungs fill with pus and fluid;
(Sometimes the fluid becomes thicker, more like peanut butter
than liquid.)
– Most forms caused by either a bacterium or a virus that infects
the lungs.
– AIDS patients (With weakened immune systems) are subject to
a very rare form (Rare in non-AIDS patients) caused by the
protozoan Pneumocystis carinii.
– Affected parts of the lungs become non-functional as they fill with
fluid.
– In some advanced cases, people must wear masks to avoid
spraying pus and mucus on people around them.
Lung Cancer
Normal
Cancer
• Lung Cancer follows related steps:
– Thickening and Callusing of cells lining the
bronchi. (Cells callus whenever cells are
exposed to irritants.)
– Loss of Cilia in air way = now impossible to
filter dust and dirt from settling in the lungs.
– A tumor begins to develop.
– The tumor then grows until the bronchus is
blocked, cutting off air supply to the affected
lung.
– Then, the lung collapses and and the
secretions in the lung spaces become
infected and pneumonia or localized areas
or pus result.