the thorax: Structure Inspiration Expiration Diaphragm Moves downward and flattens Moves upwards and becomes more domed Ribcage Moves upwards and outwards Moves downwards and inwards. Antagonistics pairs of muscles are needed to cause these movements Inspiration Expiration Volume and Volume inside thorax increases and The volume inside thorax decreases and pressure changes consequently the pressure decreases consequently the pressure increases. Inspiration Expiration Diaphragm The diaphragm contracts so it The diaphragm relaxes so it can be moves downwards and pushes pushed upwards into a more domed the abdomen wall out shape Movement of Abdominal Muscles in the abdomen wall Muscle in the abdomen wall contact the wall muscles relax allowing pressure from pushing the abdominal organs and diaphragm the diaphragm to push it out diaphragm upwards. External External intercostal muscles The external intercostal muscles relax intercostal contract, pulling the ribcage and are pulled back to their elongated Movement of muscles upwards and outwards state. ribcage Internal The internal intercostal muscles The internal intercostal muscles contract intercostal relax and are pulled back into pulling the ribcage inwards and muscles their elongated state downwards.
the thorax: Structure Inspiration Expiration Diaphragm Moves downward and flattens Moves upwards and becomes more domed Ribcage Moves upwards and outwards Moves downwards and inwards. Antagonistics pairs of muscles are needed to cause these movements Inspiration Expiration Volume and pressure changes Volume inside thorax increases and consequently the pressure decreases The volume inside thorax decreases and consequently the pressure increases. Inspiration Expiration Movement of the diaphragm Diaphragm The diaphragm contracts so it moves downwards and pushes the abdomen wall out The diaphragm relaxes so it can be pushed upwards into a more domed shape Abdominal wall muscles Muscles in the abdomen wall relax allowing pressure from the diaphragm to push it out Muscle in the abdomen wall contact pushing the abdominal organs and diaphragm upwards. Movement of ribcage External intercostal muscles External intercostal muscles contract, pulling the ribcage upwards and outwards The external intercostal muscles relax and are pulled back to their elongated state. Internal intercostal muscles The internal intercostal muscles relax and are pulled back into their elongated state The internal intercostal muscles contract pulling the ribcage inwards and downwards.
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