Respiratory System Chapter 37

Breathing We breathe about 6 liters of air per minute This is about the same as the heart pumps Men breathe about 12/minute Women breathe about 18/minute Infants breathe about 40/minute

Trachea epiglottis vocal cords Bronchi two large branches Bronchioles hundreds of smaller branches Alveoli air sacs site of gas exchange very thin

The lungs have a greater exposure to the environment than any other part of the body – including the skin. The air we breath contains dust, smoke, bacteria, noxious gases, etc … All come in contact with the blood.

The lungs have a large surface area The convoluted surfaces have a surface area of 80m2 This is about ½ the size of a tennis court!

Each alveolus is surrounded by blood so that 02 and C02 can exchange

The airways must be able to remove particles. The body does this in two ways 1. Coughing removes large particles

2. Small particles are carried upward by millions of small hairs called cilia. They vibrate about 1000/minute Mucus moves 1 – 2 cm/minute It takes 30 minutes to be cleared.

Smooth Muscle Helps you breath Diaphragm Smooth Muscle Helps you breath This is an inferior view of the diaphragm. This muscle separates the abdominal cavity from the thoracic cavity. *When it contracts it will cause inspiration.