What it Means to Breathe

Breathing When we breathe, we are moving gases from the atmosphere into and out of our lungs Ex. Oxygen, Nitrogen, CO2 Made up of Two Processes: Ventilation Respiration

Ventilation Movement of air from the nasal passages down to the alveoli Occurs because of movement of the diaphragm changes the pressure in the lungs Exhale (Expiration) = Relaxing Inhale (Inspiration) = Contraction

Diaphragm Contraction Causes Volume Changes in the Lungs Medulla Oblongata in the brain sends signals to the diaphragm to contract When it contracts it flattens out and creates more room in the chest cavity, so air gets drawn in due to decreased pressure

Breath Rate Breathing rate depends on the level of CO2 in our blood Increased CO2 = increased breath rate Resting breath rate is between 12 and 20 breaths per minute

Lung Capacity The amount of air that the lungs can hold varies with body size and weight Total Lung Capacity (TLC) ~ 6,000mL Tidal Volume (TV) is the amount of air usually inhaled ~500mL More air can be inhaled or exhaled if forced

Respiration Also known as gas exchange Oxygen is added to the blood and carbon dioxide is removed In the lungs it is called external respiration In the rest of your body it is called internal respiration

Gas Exchange Occurs Because of Diffusion

Oxygen and CO2 Transport Once in the blood, O2 attaches to a molecule called hemoglobin for transport, while CO2 combines with water to form bicarbonate ions, which float in the plasma