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Larynx Definition

Larynx Definition

What is larynx? Talking about the larynx definition, it is structure lying just at the top of trachea. It plays a significant role in the production of vocal sounds. The larynx is also responsible for the protection of windpipe against the entry of food particles.

Owing to its great contribution to phonation, it is also known as voice box or sound apparatus. The voice box contains vocal cords.

In human adults, it lies at the level of third to sixth vertebrae of the cervical region. But in newborn babies, it is at a higher position. That is, here you will find it at the point of second to third vertebrae. As you can see in the larynx pictures,

Larynx covers the tracheal opening through a flexible flap, i.e. epiglottis. The epiglottis sits on the aperture like a lid. To learn more about larynx definition and function, just go through the rest of the article.

Parts of Larynx

After learning the larynx definition, you need to proceed to its parts. The larynx cartilage makes up the structure of the sound apparatus. There are nine laryngeal cartilages in the skeleton of this body part. Out of nine cartilages, six appear in the form of pairs. While the other three remain single. The unpaired cartilages are cricoids, thyroid and epiglottis.

On the other hand, the cuneiform, corniculate and arytenoids are three paired ones. However, talking of the interior of sound apparatus, you can distinguish it into three divisions, viz. subglottis, glottis and supraglottis.

Meanwhile, there are also a number of intrinsic and extrinsic muscles that are present in the region. These muscular structures facilitate the functioning of the organ in various ways. For example, the intrinsic cricothyroid muscles help in the stretching and elongation of the vocal folds.

Different types of sensory and motor nerves innervate various muscular structures of larynx. They include vagus, superior laryngeal and recurrent laryngeal nerves. The vocal folds of voice box are of two types, i.e. false and true.

Here the former do not contain muscle and have nothing to do with the production of sound. But they play their role in the resonance. The true mucosal folds, on the other hand, do have skeletal muscle and play an active role in phonation.

Wednesday

Heart Definition

Heart Definition – What Is Heart?

A simple answer to "What is heart and the heart functions" is that it is the main organ of your body's circulatory system, pumping blood throughout the body. According to the heart definition, you can call it a muscular pump which contracts at regular intervals in order to squeeze the blood through it into the blood vessels.

As you can see in the human heart diagram, there are four chambers in this tireless pumping organ. All the chambers work in coordination for the successful execution of different heart functions. The right chambers contain unclean or the deoxygenated blood. On the other hand, the left chambers contain clean or the oxygenated blood. Just look at the different parts of heart to get a better understanding of the heart functions.

How Heart Works?

In order to understand how the heart works, it is important to know about its main parts. There are four chambers in the heart; the top chambers are atria while the chambers below them are ventricles. As many as four valves control the flow of blood into and out of the heart.

A double-walled membrane, the pericardium, separates the right and left chambers, preventing oxygen-rich blood from mixing up with the one without oxygen. So, the heart functions go smoothly.

Deoxygenated blood enters the right atrium. The valve present between the right atrium and the right ventricle is the tricuspid valve. It opens to let the blood flow into the right ventricle. The valve then closes to prevent the backward flow of blood.

This deoxygenated blood enters the pulmonary artery and moves to the lungs to replenish its oxygen content. This oxygen-rich blood them comes back to the heart through the pulmonary vein. The right atrium receives this oxygenated blood.

The mitral valve between the right atrium and the right ventricle opens to let the blood flow into the right ventricle. It then closes to prevent the backward flow of blood. Finally, there is pumping of the blood into the aorta from where it is distributed to the rest of the body through the arteries. So, you can say that main function of the heart is to supply all the body cells with oxygen and nutrients through the circulation of blood.