Biology 21 1
Solution:
Ans.The expiration in human beings is due to:
During inspiration or inhalation, the diaphragm contracts and from dome shape it becomes flat and is moved downwards. The intercostal muscles which are present between the ribs contract and is pulled upwards. This thus increases the size of the thoracic cavity. It leads to the decrease in the pressure inside the thoracic cavity. So, the air moves in and fill the lungs.
During expiration or exhalation, the diaphragm becomes dome-shaped and is back to its relaxed position. The intercostal muscles relax. This decreases the volume of the thoracic cavity. The pressure within the thoracic cavity increases and thus the air is moved out of the lungs.
The type of muscles that run between the ribs and help moving the chest cavity are known as intercostal muscles. These muscles mainly help in breathing. There are two types of intercostal muscles – internal and external. Internal intercostal muscles are present on the inside wall of rib cage whereas external intercostal muscles are present on the outer wall of ribcage.
The diaphragm, is a sheet of muscle that extends across the bottom of the rib cage. The diaphragm separates the heart, lungs & ribs from the stomach and the intestine. It performs an important function in respiration. Apart from Diaphragm, intercostal muscles also play a minor role in respiration.
The rib cage gets raised during inhailing and lowered during exhaling by the rhythmic contraction and relaxation of the external and intercostal muscles.
Lungs expand and contract while we inhale and exhale air during breathing. When we breathe in, diaphragm muscle contracts and moves downward. This increases the space in chest and lungs expand into it. These muscles contract to pull your rib cage both upward and outward when we inhale.
Ans.The expiration in human beings is due to:
- Contraction of lungs
- Ribs and their intercostal muscles.
During inspiration or inhalation, the diaphragm contracts and from dome shape it becomes flat and is moved downwards. The intercostal muscles which are present between the ribs contract and is pulled upwards. This thus increases the size of the thoracic cavity. It leads to the decrease in the pressure inside the thoracic cavity. So, the air moves in and fill the lungs.
During expiration or exhalation, the diaphragm becomes dome-shaped and is back to its relaxed position. The intercostal muscles relax. This decreases the volume of the thoracic cavity. The pressure within the thoracic cavity increases and thus the air is moved out of the lungs.
The type of muscles that run between the ribs and help moving the chest cavity are known as intercostal muscles. These muscles mainly help in breathing. There are two types of intercostal muscles – internal and external. Internal intercostal muscles are present on the inside wall of rib cage whereas external intercostal muscles are present on the outer wall of ribcage.
The diaphragm, is a sheet of muscle that extends across the bottom of the rib cage. The diaphragm separates the heart, lungs & ribs from the stomach and the intestine. It performs an important function in respiration. Apart from Diaphragm, intercostal muscles also play a minor role in respiration.
The rib cage gets raised during inhailing and lowered during exhaling by the rhythmic contraction and relaxation of the external and intercostal muscles.
Lungs expand and contract while we inhale and exhale air during breathing. When we breathe in, diaphragm muscle contracts and moves downward. This increases the space in chest and lungs expand into it. These muscles contract to pull your rib cage both upward and outward when we inhale.
These muscles are located beneath the lungs. These are a dome-shaped muscle that works with lungs to allow inhale and exhale air.