Tag: respiratory system of human

Inhalation (also known as inspiration) is the flow of air into an organism. It is a vital process for all human life. In humans it is the movement of air from the external environment, through the airways, and into the alveoli. Inhalation begins with the contraction of the muscles attached to the rib cage. This causes an expansion in the chest cavity. Then takes place the onset of contraction of the diaphragm, which results in expansion of the intrapleural space and an increase in negative pressure according to Boyle's Law. This negative pressure generates airflow because of the pressure difference between the atmosphere and alveolus. Air enters, inflating the lung through either the nose or the mouth into the pharynx (throat) and trachea before entering the alveoli. 

External respiration also known as breathing refers to a process of inhaling oxygen from the air into the lungs and expelling carbon dioxide from the lungs to the air. Exchange of gases both in and out of the blood occurs simultaneously. External respiration is a physical process during which oxygen is taken up by capillaries of lung alveoli and carbon dioxide is released from blood. Internal respiration or tissue respiration/cellular respiration refers to a metabolic process in which oxygen is released to tissues or living cells and carbon dioxide is absorbed by the blood. Once inside the cell the oxygen is used for producing energy in the form of ATP or adenosine triphosphate. Therefore, the correct answer is option D.

Chloride shift is a process which occurs in a cardiovascular system and refers to the exchange of bicarbonate (HCO$ _{3-}$) and chloride (Cl-) across the membrane of the red blood cells (RBCs).
Therefore, the correct answer is option C.

Inhaled air contains more oxygen used to create energy and less carbon dioxide. Exhaled air which contains more carbon dioxide produced as a waste product of energy production and less oxygen as it has been used in respiration. Inhaled air contains 21% oxygen, 0.04% CO$ _2$ and 79% N$ _2$. Exhaled air contains 16% oxygen, 4% CO$ _2$ and 79% N$ _2$.

The diaphragm is located below the lungs and is the major muscle of respiration. It is large, dome-shaped muscle that contracts rhythmically and continually. upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. Upon exhalation, the diaphragm relaxes and returns to its dome-like shape, and is forced out of the lungs.
Therefore, the correct answer is option B.

Inhaled air contains more oxygen used to create energy and less carbon dioxide. Exhaled air which contains more carbon dioxide produced as a waste product of energy production and less oxygen as it has been used in respiration. Inhaled air contains 21% oxygen, 0.04% CO$ _2$ and 79% N$ _2$. Exhaled air contains 16% oxygen, 4% CO$ _2$ and 79% N$ _2$. 

Increase in volume of thoracic cavity is seen in case of inspiration. Inspiration results in flattened diaphragm. The volume of thoracic cavity decreases during expiration and the diaphragm relaxes and comes to its original dome shape. 

Component       Inspired air     Expired air

The most important muscles of forced expiration are those of the abdominals. When these muscles contract, intra-abdominal pressure is raised, and the diaphragm is pushed upward. These muscles also contract forcefully during coughing, vomiting, and defecation. The internal intercostal muscles assist active expiration by pulling the ribs downward and inward thus decreasing the thoracic volume.