Question

life sciences/ grade 11
pre - controlled test
question 3
1.1 identify parts e
1.2 which process in the above diagram illustrates exhalation (process 1 or process 2)
1.3 give two reasons from the diagrams to support your answer to question 3.1.2
1.4 briefly describe the mechanism of inhalation in the human body

Explanation:

1.1: Part E is the diaphragm. It is a dome - shaped muscle that plays a key role in breathing.
1.2: Process 1 illustrates exhalation. During exhalation, the diaphragm relaxes and moves upwards, and the rib - cage moves downwards and inwards.
1.3: In Process 1, the diaphragm is shown as dome - shaped (relaxed) and the rib - cage has moved downwards and inwards. These are key indicators of exhalation.
1.4: During inhalation, the diaphragm contracts and moves downwards, increasing the volume of the thoracic cavity. The external intercostal muscles contract, causing the rib - cage to move upwards and outwards. This increases the volume of the lungs, decreasing the air pressure inside the lungs compared to the outside. As a result, air rushes into the lungs.

Answer:

1.1: Diaphragm
1.2: Process 1
1.3: Diaphragm is dome - shaped (relaxed), rib - cage moves downwards and inwards.
1.4: Diaphragm contracts and moves down, external intercostal muscles contract, rib - cage moves up and out, lung volume increases, air pressure inside lungs decreases, air rushes in.