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 O2 and CO2

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 CO2 ↑, 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