Label the features of the heart using the hints provided. Crista terminalis Pectinate m. Limbus fossa ovalis Fossa ovalis Opening of inferior vena cava Opening of coronary sinus Reset Zoom < prev=”” 2=”” of=”” 30=”” next=””>
The correct answer and explanation is:
To label the features of the heart with the provided hints, here’s a breakdown of each term:
- Crista Terminalis:
The crista terminalis is a muscular ridge located in the right atrium of the heart. It runs vertically from the superior vena cava to the inferior vena cava, and it separates the smooth-walled portion of the right atrium (the sinus venarum) from the rough, muscular portion (the atrium proper). It plays a role in the conduction system of the heart, particularly in coordinating the atrial contraction. - Pectinate Muscle (Pectinate m.):
The pectinate muscles are a series of parallel ridges in the walls of the atria, particularly in the right atrium. They are located primarily in the anterior portion of the right atrium and are involved in the mechanical function of the heart by aiding in the contraction of the atrial walls during systole. These muscles also contribute to the efficient filling of the ventricles. - Limbus Fossa Ovalis:
The limbus fossa ovalis is the raised border around the fossa ovalis in the interatrial septum. The fossa ovalis itself is a depression that marks the site of the foramen ovale, an opening that was present in fetal circulation. The limbus forms a boundary around the fossa ovalis and is important in distinguishing it during anatomical dissection. - Fossa Ovalis:
The fossa ovalis is a depression located on the interatrial septum, which is the septum separating the left and right atria. This structure is a remnant of the foramen ovale, which is an opening that allowed blood to flow between the atria during fetal life, bypassing the lungs. After birth, the foramen ovale typically closes and the fossa ovalis remains as a shallow indentation. - Opening of Inferior Vena Cava:
The opening of the inferior vena cava is located in the right atrium and serves as the entry point for deoxygenated blood coming from the lower half of the body. The inferior vena cava returns blood from the lower extremities, abdomen, and pelvis to the right atrium, where it is then pumped into the right ventricle and sent to the lungs for oxygenation. - Opening of Coronary Sinus:
The coronary sinus is a large venous structure that collects deoxygenated blood from the heart muscle (myocardium). It opens into the right atrium near the tricuspid valve. This blood is returned to the right atrium after circulating through the myocardium to ensure that the heart muscle receives oxygenated blood and removes waste products.
In conclusion, these features are all located in the right atrium of the heart and are involved in the circulation of blood within the heart and to the rest of the body. Their anatomical arrangement facilitates the proper flow of blood through the heart’s chambers, ensuring efficient circulation.