Respiratory System Comparative Anatomy Tony Serino, Ph.D. Biology Department Misericordia Univ.

Respiration External Respiration Internal Respiration The exchange of gas between the blood and external environment (usually includes ventilation) Internal Respiration The exchange of gas between the blood and the tissues Cellular Respiration Burning of fuel to produce energy within cells Ventilation (Breathing) Movement of air in and out of the lungs

Gills

Counter Current Exchange

Terrestrial Respiratory Organs Divided into: Upper Respiratory Tract Includes: nostrils (nares), nasal cavity, and nasopharynx Lower Respiratory Tract Includes: larynx, trachea, bronchi, and lungs Conducting Air passages include: nares to terminal bronchioles Move air to respiratory membrane Condition the air Moisten, Warm, Clean

Upper Respiratory Tract

Beginning of Lower Respiratory Tract

Larynx

Vocal Cords

Syrinx

Trachea

Trachea (x.s.)

Mucous Membrane (pseudostratified columnar epithelium)

Bronchi Primary bronchi lead to to each lung (left and right) Secondary (lobar) bronchi lead to each lung lobe (3 on right and 2 on left)

Lobes of Right Lung

Lobes of Left Lung

Bronchi Branches Tertiary Bronchi Primary Bronchi Secondary Bronchi Tertiary (segmental) bronchi lead to each lung broncho-pulmonary segment Bronchi continue to divide at least 20 more times.

Bronchioles Air passages less than 1 mm in diameter are bronchioles. The terminal bronchioles are the last of the purely conducting air passages.

Alveoli highly specialized for Gas Exchange Lots of Surface Area Highly vascular Thin walls

Lung Tissue

Alveolus

Pressures affecting Breathing

Pressure changes around lung

Only used during rapid breathing. CO2 plasma provides stimulus for breathing

Simple Sac Septate Parabronchial Alveolar

Parabronchi

Air Flow in Bird Lung