Biology 10, LPC
RESPIRATION
Chapter 35

I-Introduction
II-Anatomy of Breathing
III-Ventilation
IV-Gas Exchange

I-INTRODUCTION

Food and O2 into body and then into ciruculatory system. Food residues, water, salts, wastes and CO2 out.

Function of the respiratory system is to deliver O2 to blood and remove CO2.

C6H12O6 + O2 <--------> CO2 + H2O + Energy

Respiratory system includes the lungs, several passageways leading from outside to the lungs, and the muscles that move air into & out of lungs.

II-ANATOMY OF BREATHING

A. Nose-air warmed, moistened, filtered. Sinuses produce mucous, act as resonators.

B. Pharynx = throat-leads to respiratory passages & esophagus. Divides air & food passages. Auditory tubes enter here.

C. Larynx-Passageway between pharynx & rest of respiratory tract. Leads to sound for speaking & singing.
Epiglottis-flap of cartilage that folds down over opening to larynx during swallowing & reopens.

D. Trachea-windpipe-open tube between larynx & top of lungs where it divides -> 2 branches.

E. Bronchus-trachea branches several times

F. Lungs-made of alveoli. Red blood cells go through capillaries.

III-VENTILATION

A. Inspiration-air enters lungs-requires energy

B. Quiet Expiration-depends on elastic recoil of lungs & costal cartilage & relaxation of muscles-passive-no energy required

C. Forced expiration during strenuous exercise-abdominal muscles contract forcibly, pressing the viscera against the passive diaphragm & depressing rib cage to further reduce lung volume

IV-GAS EXCHANGE
Via pressure gradients.

A. O2 exchange between air and blood & between blood and tissues

1. Higher O2 pressure in lung than red blood cells-> O2 binding. Lower O2 pressure in tissues than red blood cells, so O2 -> tissues. Gases diffuse down conentration gradient.

B. CO2 exchange between tissues and blood & between blood and air

1. CO2 produced in tissues & diffuses into blood
2. Blood goes to lungs where CO2 pressure low
3. CO2 diffuses into lungs & is expelled during breathing.