The Respiratory System

Functions of the Respiratory System

• Gas exchange (O2 and CO2)

• Produce vocal sounds• Sense of smell• Regulation of blood pH

The Respiratory System• Breathing is the muscular or mechanical action

involving inhaling and exhaling. The function is to ventilate the lungs or pump air in and out of the lungs.

O2CO2

The Respiratory System• Respiration is the mechanical action

taking place in the cell to release energy from food.

The Respiratory System• Gas exchange is the

transfer of oxygen molecules into the blood and carbon dioxide out of the blood (in the capillaries of the lungs).

Gas Exchange Surface Characteristics

• Specially constructed to dissolve and exchange CO2 with O2 (abundant supply of capillaries.

• Large surface area for gas exchange

• Moist environment• Membrane in the lungs is

one cell thick

Gas Exchange Surface Characteristics

Out of Body Lungs

Structures of the Respiratory System

• Air enters through nostrils or mouth. In the nostrils, air is warmed and filtered by tiny hairs.

• Nasal and oral cavities join at the pharynx. Epiglottis opens allowing air down the larynx.

Structures of the Respiratory System

• The larynx is also called the voice box. It contains two thin elastic ligaments (vocal cords) and their vibrations cause sound.

• Air moves down trachea (or windpipe) to one of two bronchi, heading to the lungs.

Structures of the Respiratory System

• Bronchi divide to form bronchioles, and air eventually reaches tiny air sacs called alveoli.

Structures of the Respiratory System

• The trachea, bronchi and bronchioles are covered with cilia that sweep any bacteria and debris upwards.

Structures of the Respiratory System

• Gas exchange occurs are the alveoli – O2 moving into the blood, and CO2 moving out.

Inhalation vs. ExhalationInspiration or Inhaling Expiration or Exhaling

Rib Movement Outwards and upwards Downward and inward

Diaphragm shape Flattens, pulled downward

Dome shaped

Volume of chest cavity

Increases Decreases

Change in pressure

Decreases below atmospheric pressure

Increases

Result Air rushes into the lungs to equalize the pressureMuscles contract

Air is pushed out of the lungs until pressure is equalizedMuscle relaxation

Effects of Smoking on the Respiratory System

Bronchitis

Asthma