Breathing - class-V

Spirometry is the process of recording the changes in the volume and movement of air in and out of the lungs and the instrument used for this purpose is called spirometer or respirometer.

The diaphragm is a characteristic feature of all mammals, used for respiration. Other options like pinna, 7 cervical vertebrae, or scrotal sacs have exceptions among mammals.

• The respiratory tract carries air from the mouth and nose to the lungs.
• In the lungs, the gases oxygen and carbon dioxide are exchanged between the alveoli and the capillaries. 
• Exhaled air contains less oxygen and more carbon dioxide, Hence, The air we breathe out contains more carbon dioxide.

• The diaphragm is a thin skeletal muscle that sits at the base of the chest and separates the abdomen from the chest.
•  It contracts and flattens when you inhale. 
• This creates a vacuum effect that pulls air into the lungs.
•  When you exhale, the diaphragm relaxes and the air is pushed out of lungs. Hence, diaphragm forms the floor of the chest cavity.

• Respiration includes two processes: inhalation and exhalation.
• Inhalation (also known as inspiration) occurs when air or other gases enter the lungs.
•  And exhalation is the process by which the body expels carbon dioxide. Hence, Taking in of carbon dioxide is inhalation is a wrong statement.

Component                        Inspired air         Expired air
  $CO _2$                                    0.04%                   4%
Because carbon dioxide is released at the alveolar surface during the gaseous exchange between blood and alveoli.

Component              Inspired air            Expired air
Nitrogen                      79%                     79.6%

Inspired air contains more oxygen whereas, the expired air contains more of carbon dioxide content as well as water vapours. Air enters with oxygen is diffused with carbon dioxide leading to the exchange of gases.

The act of breathing air into the body the help of lungs is called inhalation. By this process, fresh air enters into the lungs that contain large amount of oxygen.

The act of breathing out air from the lungs is called as Exhalation. By this process, the foul air i.e, (containing ${ CO } _{ 2 }$) is expelled out of the lungs.

The diaphragm is a dome-shaped, muscular and membranous structure that separates the chest and abdominal cavities in mammals. It is the principal muscle of respiration that maintain the volume of air in the chest cavity during breathing.

Humans have lungs to carry out respiration. Lungs are ingrowths of the body wall and correct to the outside by a series of tubes and small openings.

During inspiration, the diaphragm moves down. The contraction of muscle fibers of the diaphragm causes it to become flat and lowered down thereby increasing the volume of the thoracic cavity in anteroposterior axis, in rabbit or lengthwise in man.

Increased CO2 levels in the blood (hypercapnia) are detected by chemoreceptors, which signal the respiratory center to increase the rate and depth of breathing to expel excess CO2.

At rest, metabolic requirements are at their lowest, which is reflected in lower pulse rates, lower breathing rates, and reduced O2 intake and CO2 output.

Frogs and earthworms are classic examples of organisms that utilize cutaneous respiration, meaning they breathe through their moist skin. While frogs also have lungs, their skin is a primary respiratory surface, and earthworms rely entirely on cutaneous respiration.

The rate of breathing in humans is primarily regulated by the concentration of carbon dioxide in the blood. Chemoreceptors detect changes in CO2 levels and pH, signaling the brain to adjust the ventilation rate to maintain homeostasis.

Carbon dioxide is a waste product of the body. It is majorly exhaled out by the body so that it will reduce the competition to gets bind to the haemoglobin with oxygen. It is saturated with water vapours.

• When you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. This increases the space in your chest cavity, into which your lungs expand. The intercostal muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.
• Hence the size of the chest cavity increases during inhalation is a true statement.
• So, the correct answer is 'True'.

During exercise, the muscle cells need more oxygen to sustain their work This results in an increase in breathing and heart rate because both the lungs and the heart work extra to keep up with the ever growing need of oxygen.

• Breathing (or ventilation) is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly by bringing in oxygen and flushing out carbon dioxide.
• The Normal range of breathing rate per minute in an average adult person at rest is 15-18.
• So, the correct answer is '15-18'.

During any physical exercise such as running or cycling the two vital organs of our body heart and lungs come into action since lung try to bring oxygen into the body to provide energy and side by side removing carbon dioxide formed by strenuous physical activity. While the heart pumps oxygen-rich blood to skeletal muscle undergoing physical exercise to meet their metabolic requirements.

Blood that is low in oxygen concentration and high in carbon dioxide. The rate of diffusion of a gas is proportional to its partial pressure within the total gas mixture. The lungs are never completely empty: There is always some air left in the lungs . At high altitudes, Patm decreases but concentration does not change. So, the correct option is "B" (Increases).