ANIMAL PHYSIOLOGY
GAS EXCHANGE IN HUMANS
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
External intercostal muscles contract moving the ribs up and outwards.
|
|
|
Internal intercostal muscles contract moving the ribs down and inwards.
|
|
|
External intercostal muscles relax moving ribs down and inwards.
|
|
|
Internal intercostal muscles relax moving ribs up and outwards.
|
Detailed explanation-1: -During inhalation, the diaphragm flattens and the ribs move upwards and outwards due to contraction of the intercostal muscles. This increases the volume of the thoracic cavity and the pressure decreases. As the outside pressure is higher, air gushes into the lungs.
Detailed explanation-2: -When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.
Detailed explanation-3: -The intercostal muscles are the muscles between the ribs. During breathing, these muscles normally tighten and pull the rib cage up. Your chest expands and the lungs fill with air. Intercostal retractions are due to reduced air pressure inside your chest.
Detailed explanation-4: -When you inhale: the intercostal muscles contract, pulling the ribcage upwards and outwards. the diaphragm contracts, pulling downwards. volume of the thorax increases and the pressure inside decreases.
Detailed explanation-5: -Contraction of diaphragm takes place and it moves down. This downward movement of the diaphragm causes less intrapulmonary pressure than the atmosphere. Simultaneously, the external intercostal muscles also contract and cause the ribcage to be able to move outward.