Breathing

Mechanics of Breathing

• Breathing is the process of moving air into and from the lungs for gas exchange.
• All aerobic creatures need oxygen for cellular respiration.
• Gas exchange takes place in the alveoli through diffusion.
• The respiratory rate is the number of respiratory cycles per minute.
• Homeostatic mechanisms control the partial pressures of carbon dioxide and oxygen in the arterial blood.
• The diaphragm and intercostal muscles are involved in breathing.
• The diaphragm primarily contributes to the expansion of the chest cavity.
• Accessory muscles of inhalation aid in expanding the rib cage.
• Exhalation involves relaxation of the muscles of inhalation and contraction of abdominal muscles.
• The lungs expand when there is an increase in the volume of the thoracic cavity.

Passage of Air

• The respiratory tract controls inhalation and exhalation.
• Upper airways include the nasal cavities, pharynx, and larynx.
• Inhaled air is warmed and moistened by the nasal mucosa.
• The nasal cavities have narrow passages that expose a large area of nasal mucous membrane to the air.
• Exhaled air from the lungs cools and dries in the cool and dry nose.

Gas Exchange

• Gas exchange occurs in the alveoli of the lungs.
• Oxygen is transported to the cells through the circulatory system.
• Carbon dioxide is a waste product of cellular respiration.
• The partial pressure of carbon dioxide in arterial blood affects pH.
• Hyperventilation and hypoventilation can cause symptoms due to changes in arterial carbon dioxide levels.

Other Functions of Breathing

• Breathing allows for speech, laughter, and emotional expressions.
• Reflexes such as yawning, coughing, and sneezing involve breathing.
• Some animals lose heat through panting.
• Diaphragmatic breathing is also known as abdominal breathing.
• Clavicular breathing may occur during labored breathing or in certain medical conditions.

Effects of Altitude on Breathing

• Breathing at altitude results in decreased atmospheric pressure.
• Alveoli are open to outside air, so lung pressure also decreases with altitude.
• Pressure difference at altitude affects gas exchange in the lungs.
• Effects of high altitude on humans can include altitude sickness and difficulty breathing.
• Atmospheric pressure decreases with height above sea level.

Breathing Mentions

Breathing Data Sources