Question

Using a flow diagram to show cause and effect, explain how contraction of the diaphragm produces inspiration.

Short answer

During inspiration, the diaphragm contracts and moves downwards, causing an increase in the volume of the thoracic cavity and a decrease in pressure within it. Consequently, the pressure inside the lungs decreases, leading to air being drawn into the lungs due to the pressure difference between the lungs and atmospheric air. The flow diagram should show the following steps: 1) Diaphragm contracts, 2) Thoracic cavity volume increases, 3) Pressure in the thoracic cavity decreases, 4) Lung pressure decreases, and 5) Air flows into the lungs.

Step-by-step solution

Identify the main components involved in the process

Before creating the flow diagram for inspiration, we need to identify the main components that are involved in the process. These components include the diaphragm muscle, the thoracic cavity, and the lungs.

Describe the diaphragm

The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. It is positioned below the lungs and plays a crucial role in the process of breathing.

Explain the role of diaphragm in inspiration

During inspiration, the diaphragm contracts and moves downwards. This causes an increase in the volume of the thoracic cavity and a decrease in the pressure within it. The pressure inside the lungs also decreases. This difference in pressure between the lungs and the atmospheric air causes air to be drawn into the lungs.

Construct the flow diagram

Now that we have outlined the steps involved in inspiration, we can construct the flow diagram to show cause and effect: 1. Diaphragm contracts: The diaphragm muscle contracts and moves downwards. 2. Thoracic cavity volume increases: As the diaphragm moves down, the volume of the thoracic cavity increases. 3. Pressure in the thoracic cavity decreases: The increase in volume leads to a decrease in pressure within the thoracic cavity. 4. Lung pressure decreases: The decrease in thoracic cavity pressure also causes the pressure inside the lungs to decrease. 5. Air flows into the lungs: Due to the pressure difference between the lungs and the atmospheric air, air flows into the lungs. Remember, the flow diagram should visually represent these steps, with arrows indicating the direction of the process and the cause and effect relationships between the steps.

Summarize the process

In summary, the contraction of the diaphragm leads to inspiration as it increases the volume of the thoracic cavity, which subsequently decreases the pressure in the thoracic cavity and the lungs. This pressure difference causes air to be drawn into the lungs due to the lower pressure inside the lungs. The flow diagram effectively demonstrates the cause and effect relationship between the contraction of the diaphragm and inspiration.