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. Diaphragm

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 O 2 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 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. Normal Cancer

Which is the healthy heart??

Arteriosclerosis- oh my!