Inhalation
Negative pressure produced by the contraction of certain muscles like the diaphragm muscle and the intercostal muscles.
The movement of the chest that brings air into the lungs is called inhalation, and it is facilitated by the contraction of the diaphragm and intercostal muscles. Exhalation is the process of removing waste gases from the lungs, which is typically a passive process where the diaphragm and intercostal muscles relax.
Rectus abdominis and diaphragm muscles
With the contraction of the diaphragm by spasm the inhaling of air is stopped suddenly the gap in the vocal cords reduce during the contraction of diaphragm which causes a hiccup and the process is repeated
contraction of the diaphragm and the external intercostal muscles, causing the ribcage to expand and the lungs to fill with air. This process creates negative pressure in the thoracic cavity, drawing air into the lungs to facilitate respiration.
During a period of relaxed and average respiration, the muscles associated with inspiration, or the process of inhaling, include the muscles of the diaphragm, the external intercostal muscles, and the interchondral region of the internal intercostal muscles.
Diaphragm
The diaphragm contractions are primarily regulated by the phrenic nerve, which originates from the cervical spine (C3-C5). This nerve controls the contraction and relaxation of the diaphragm muscle, allowing for the process of breathing to occur efficiently.
The skeletal muscles do have the involuntary muscle because they help it in the contraction process.
Inhalation is an active process and exhalation is a passive process
The force behind weathering by thermal expansion and contraction is the repeated heating and cooling of rocks, causing them to expand and contract. This leads to the breaking down of rocks into smaller pieces due to the stress created by the expansion and contraction process.
Breathing out in crocodiles is a passive process. As the muscles used for inhalation relax, the chest cavity naturally decreases in size causing air to be expelled from the lungs. Crocodiles do not have a diaphragm like mammals to actively control their breathing.