Respiration Mechanics Quiz

Respiration

• Respiration is the exchange of air between the atmosphere and lungs.
• Breathing involves inhalation (inspiration) and exhalation (expiration).
• Air moves from an area of high pressure to an area of low pressure.
• This pressure difference is crucial for breathing to occur.

Mechanics of Breathing

• Breathing relies on the movement of gases from high to low pressure areas.
• For breathing to happen, there must be a difference in air pressure.

Muscles for Breathing

• The diaphragm is a dome-shaped muscle at the base of the thoracic cavity.
• Intercostal muscles, also known as rib muscles, are located between the ribs.

Types of Breathing

• Inhalation (inspiration) happens when air enters the lungs, and exhalation (expiration) is when air leaves the lungs.

Inhalation (Inspiration)

• It's an active process requiring energy.
• Muscle contractions (intercostal and rib muscles) increase the size and volume of the thoracic cavity.
• Diaphragm moves downwards.
• These changes result in decreasing pressure in the lungs, drawing air from higher pressure (atmosphere) to lower pressure inside the lungs.

Exhalation (Expiration)

• Generally a passive process not requiring much energy.
• Intercostal and rib muscles relax, reducing thoracic cavity size; diaphragm moves upwards.
• The pressure in the lungs increases, pushing air from higher pressure (inside lungs) to lower pressure (atmosphere).

External Respiration

• Happens in the lungs.
• Gases (oxygen and carbon dioxide) are exchanged between the air in the alveoli and blood in capillaries.
• Oxygen diffuses from the air to the blood, and carbon dioxide diffuses from the blood to the air.
• Oxygen is only 30% diffused.

Transport of Oxygen

• 99% of oxygen is transported in red blood cells by hemoglobin.
• A smaller amount remains dissolved in the plasma.

Transport of Carbon Dioxide

• Carbon dioxide is transported in the blood by three main methods: 23% by hemoglobin, 7% dissolved in plasma and 70% as bicarbonate ions.
• CO₂ reacts with water to form carbonic acid, which then dissociates into hydrogen ions and bicarbonate ions.

Internal Respiration

• Occurs in body tissues.
• Oxygen diffuses from the blood in capillaries to the body cells.
• Carbon dioxide diffuses from body cells to the blood in capillaries.

Regulation of Breathing

• Chemoreceptors detect changes in blood conditions, like high acid levels (due to CO2).
• The medulla oblongata is a brain stem structure that regulates breathing.
• Breathing rate increases due to high acidity or low oxygen, triggering nerve signals to increase muscle contractions.
• Breathing can be consciously controlled, but the medulla takes over if CO2 levels are too high.

Test your knowledge on the mechanics of respiration, including the processes of inhalation and exhalation, the role of pressure differences, and the muscles involved in breathing. This quiz covers essential concepts related to how we breathe and the physiological factors that enable respiratory function.