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 O2

• 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!