The left atrium of the heart is spelled /lɛft ˈeɪtriəm ʌv ðə hɑrt/. In this word, the "l" is pronounced as the voiceless alveolar lateral fricative /ɬ/, the "e" is pronounced as the short mid-front vowel /ɛ/, and the "a" is pronounced as the open mid-back unrounded vowel /æ/. The final "m" is pronounced as the bilabial nasal /m/. The stress is on the first syllable, and the word is spelled according to English phonetic spelling conventions.
The left atrium is an anatomical structure found in the human heart and is one of the four chambers of the heart. It is a thin-walled, muscular chamber located on the left side of the heart. The left atrium receives oxygenated blood from the lungs through the pulmonary veins.
Functionally, the left atrium serves as a reservoir for blood, temporarily storing and collecting it before sending it to the left ventricle. It acts as a holding chamber, ensuring a continuous flow of blood to the body even during the relaxation phase of the heart. It plays a crucial role in maintaining efficient blood circulation by regulating the flow of blood between the atria and ventricles.
The left atrium is separated from the left ventricle by the mitral valve, a two-flapped valve that prevents the backward flow of blood. Once the left atrium is filled, it contracts and forces the blood through the mitral valve into the left ventricle. From there, the left ventricle pumps the oxygenated blood to the rest of the body through the aorta.
The left atrium also plays a part in the regulation of blood pressure and fluid balance. When its walls become stretched due to excessive blood volume, it triggers a response to increase the heart rate, allowing for more efficient pumping of blood.
In summary, the left atrium is an important component of the heart's structure and plays a vital role in the circulation of oxygenated blood throughout the body.