Respiratory System Chapter 23

Respiration Overview

The Respiratory System Provides a means of gas exchange between the environment and the body

The Components of the Respiratory System

1. Upper Respiratory Passages: nose/mouth, pharynx (back of the mouth), larynx (voice box), trachea, bronchi & bronchioles Filter, warm & moisten air Trachea & bronchi are lined with cilia that move mucus towards throat 2. Lower Respiratory Passages: alveoli Thin walled sacs where diffusion of O 2 and CO 2 takes place

Inhalation – ribcage expands, diaphragm contracts downward, space in chest cavity ↑, pressure in chest cavity ↓, and air from outside rushes in Exhalation – ribs drop, diaphragm relaxes upward, space in chest cavity ↓, pressure in chest cavity ↑, and air from inside rushes out

Control of Respiration Breathing is usually an involuntary process Controlled by medulla oblongata When levels of CO 2 ↑, it sends nerve signals to contract the intercostals & diaphragm

Common Disorders Cystic Fibrosis – genetic disease, too much respiratory mucus is produced, breathing is difficult Pneumonia – fluids leak into alveoli due to inflammation (typically from an infection), bronchioles swell and constrict Emphysema – shortness of breath due to damage of alveoli, mainly due to smoking Lung cancer – deadliest type of cancer