Tag: mechanism of respiration in animals

Exhalation is a process to breath out.carbon dioxide is a waste product in the body that release out during exhalation, it is also saturated with water vapor.

Carbon dioxide is released in the process of exhalation in large amount.$CO _2$ dissolves in water and can easily and reversibly form compounds such as carbonic acid and bicarbonates. when it is released out, it is saturated with water vapour and this is the reason for water droplets in the mirror.

The diaphragm is a dome-shaped muscular partition that separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity, containing the digestive organs.

Forced deep breathing (hyperventilation) lowers the partial pressure of CO2 in the blood. Since CO2 is the primary chemical stimulus for breathing, low levels lead to a temporary cessation of breathing (apnea) until CO2 levels rise again.

Breathing involves the contraction and relaxation of the diaphragm and the external intercostal muscles, which change the volume of the thoracic cavity and create the pressure gradients necessary for air movement.

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

During breathing, 20% oxygen is taken in and 15% oxygen is exhaled out. Movement of diaphragm is very important during breathing process. Ribs will also move in and out with the diaphragm. It is not possible to breathe by moving the diaphragm along without moving ribs. Even after forceful exhalation, lungs are never fully emptied. Residual volume, that is minimum amount of air in lungs always remain at all times. Eustachian tube connects middle ear cavity with nasopharynx and hence, one can breathe out air through it by closing both nose and mouth.

A)Nasal chamber opens into nasopharynx which is a portion of pharynx – True because It also connects the nasal system of air chambers and the upper end of the trachea. The opening of the mouth into the pharynx is the oropharynx, and the nasal opening is the nasopharynx. The eustachian tube from the middle ear opens into the pharynx on each side.

B)Larynx produces sound during inspiration as well as expiration – True, because, the larynx commonly called the voice box, is an organ in the top of the neck of tetrapods involved in breathing, producing sound. They have skeletal muscle, cartilage of the upper larynx collapses inward during inhalation, causing airway obstruction, results in the creation of sounds.

C)During swallowing, gullet can be covered by a thin elastic cartilaginous flap called Epiglottis – false, because, the epiglottis is a flap in the throat that keeps food from entering the windpipe and the lungs. The flap is made of elastic cartilage covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally.

D) The trachea is get divided at the level of 6th thoracic vertebra into right and left primary bronchi – False, because The trachea, commonly called the windpipe, is the main airway to the lungs It divides into the right and left bronchi at the level of the fifth thoracic vertebra, channeling air to the right or left lung.

E)The branching network of bronchi, bronchioles, and alveoli comprise the lungs – True.

So, the correct option is ‘2’.

During inhalation, the diaphragm contracts, thus enlarging the thoracic cavity. This reduces intra-thoracic pressure: enlarging the cavity creates suction that draws air into the lungs. When the diaphragm relaxes, air is exhaled by elastic recoil of the lung and the tissues lining the thoracic cavity in conjunction with the abdominal muscles, which act as an antagonist, paired with the diaphragm's contraction.

An average adult breathes approximately 12 to 16 times per minute at rest. Over 24 hours, this equates to roughly 17,000 to 23,000 breaths, with 22,000 being a commonly cited average estimate.