Tag: breathing and respiration

The cricoid cartilage is a ring of hyaline cartilage located at the inferior aspect of the larynx and is the only complete ring of cartilage around the trachea. It has the shape of a signet ring, with a broad portion posterior to the airway (lamina of cricoid cartilage) and a narrower portion circling anteriorly (arch of cricoid cartilage). 

During exercise, your lungs and respiratory system must provide more oxygen to the blood.  You will breathe harder and faster because: Respiratory muscles are stimulated by sympathetic nerves in order to increase the rate of breathing. If the exercise is intense, breathing rates may increase from a typical resting rate of 15 breaths per minute up to 40 – 50 breaths per minute. Hence, during heavy exercise, the breathing rate can increase up to 25 times.

• Normally the inspired air constitutes about 20.84% of oxygen whereas the expired air constitutes about 15.7% of oxygen. And even if one holds his or her breath, it is not possible to breathe out air totally without oxygen.

• The eustachian tube is a canal that connects the middle ear to the nasopharynx. It controls the pressure within the middle ear, making it equal to the air pressure outside the body. No one can breathe out air through eustachian tubes by closing both the nose and the mouth.

• Yes, one can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.

• The lungs cannot be made fully empty by forcefully breathing out all air from them. Residual volume is always present in the lungs, even after the maximum forceful expiration effort. It is about 1500 ml of the air.

The laryngeal prominence (commonly referred to as Adam's apple), a feature of the human neck, is the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx. The structure of the laryngeal prominence forms a bump under the skin. It is larger in adult men, in whom it is usually clearly visible and palpable. In women, the bump is much less visible and is hardly perceived on the upper edge of the thyroid cartilage. The laryngeal prominence is related to the deepening of the voice.

The larynx is known as voice box or sound producing organ. A pair of membranous folds called vocal cords, stretch across the laryngeal cavity. In normal condition, the vocal cords lie apart so that the glottis remains widely open to allow free passage of respiratory air. For sound production, vocal cords come close together, they vibrate when air rushes out through glottis and produce voice.