Description: Thin, transparent outer layer of the heart wall. It is also called as Visceral layer of the serous pericardium. Composed of mesothelium and delicate connective tissue.
Function: Prevent excess expansion or movement of the heart
Location: Outer layer. In the zebrafish heart, the epicardium is a serous, nonmuscular membrane that surrounds the heart and is found close to the compact myocardium.
Description: Middle layer. A cardiac muscle tissue and makes up about 95% of the heart. It is striated like skeletal muscle. cardiac muscle is involuntary.
Function: Initiates contraction driving the cardiac cycle
Description: A little cone-shaped organ around the size of a fist. It measures approximately 12 cm (5 in.) long, 9 cm (3.5 in.) wide at its widest point, and 6 cm (2.5 in.) thick, with an average mass of 250 g (8 oz) in adult females and 300 g (10 oz) in adult males.
Function: The circulatory system pumps blood throughout the body, giving oxygen and nutrition to the tissues while eliminating carbon dioxide and other toxins.
Location: The heart rests on the diaphragm. Located within the mediastinum, the medial cavity of the thorax. It is flanked laterally by the lungs, posterior by the vertebral column, and anteriorly by the sternum.
Description: The right atrium’s muscular walls are significantly thinner than those of the ventricles, and the auricle is a wrinkled flap shaped like a floppy dog ear. The auricle is hollow and spreads outward from the anterior surface of the right atrium to enhance the interior capacity.
Function: The right atrium receives and pumps oxygen-depleted blood from the body to the right ventricle.
Location: It is located in the upper right corner of the heart superior to the right ventricle.
Description: The right ventricle is triangular and extends from the right atrium’s tricuspid valve to the heart’s apex. The atrium’s wall is thickest at the apex and thins towards the base.
Function: The right ventricle is responsible for pumping oxygen-depleted blood to the lungs.
Location: It is found below the right atrium and opposite the left ventricle in the bottom right part of the heart.
Description: The heart’s left ventricle is the thickest chamber. The left ventricle is longer and has thicker walls than the right ventricle, and it has a conical shape with an anteriorly protruding apex.
Function: The left ventricle is responsible for delivering oxygen-rich blood to the body.
Location: It is located in the bottom left portion of the heart below the left atrium, separated by the mitral valve.
Structure of three layers of the heart
Epicardium
Description: Thin, transparent outer layer of the heart wall. It is also called as Visceral layer of the serous pericardium. Composed of mesothelium and delicate connective tissue.
Function: Prevent excess expansion or movement of the heart
Location: Outer layer. In the zebrafish heart, the epicardium is a serous, nonmuscular membrane that surrounds the heart and is found close to the compact myocardium.
Myocardium
Description: Middle layer. A cardiac muscle tissue and makes up about 95% of the heart. It is striated like skeletal muscle. cardiac muscle is involuntary.
Function: Initiates contraction driving the cardiac cycle
Location: Middle layer of the heart.
Endocardium
Description: Inner layer. It is a thin layer of endothelium overlying a thin of connective tissue
Function: lines the cavities and valves.
Location: The endocardium is the innermost layer of the heart
Four chambers of the heart
Heart
Description: A little cone-shaped organ around the size of a fist. It measures approximately 12 cm (5 in.) long, 9 cm (3.5 in.) wide at its widest point, and 6 cm (2.5 in.) thick, with an average mass of 250 g (8 oz) in adult females and 300 g (10 oz) in adult males.
Function: The circulatory system pumps blood throughout the body, giving oxygen and nutrition to the tissues while eliminating carbon dioxide and other toxins.
Location: The heart rests on the diaphragm. Located within the mediastinum, the medial cavity of the thorax. It is flanked laterally by the lungs, posterior by the vertebral column, and anteriorly by the sternum.
Right Atrium
Description: The right atrium’s muscular walls are significantly thinner than those of the ventricles, and the auricle is a wrinkled flap shaped like a floppy dog ear. The auricle is hollow and spreads outward from the anterior surface of the right atrium to enhance the interior capacity.
Function: The right atrium receives and pumps oxygen-depleted blood from the body to the right ventricle.
Location: It is located in the upper right corner of the heart superior to the right ventricle.
Right Ventricle
Description: The right ventricle is triangular and extends from the right atrium’s tricuspid valve to the heart’s apex. The atrium’s wall is thickest at the apex and thins towards the base.
Function: The right ventricle is responsible for pumping oxygen-depleted blood to the lungs.
Location: It is found below the right atrium and opposite the left ventricle in the bottom right part of the heart.
Left Ventricle
Description: The heart’s left ventricle is the thickest chamber. The left ventricle is longer and has thicker walls than the right ventricle, and it has a conical shape with an anteriorly protruding apex.
Function: The left ventricle is responsible for delivering oxygen-rich blood to the body.
Location: It is located in the bottom left portion of the heart below the left atrium, separated by the mitral valve.
Left Atrium
Description: A unique appendage of the left atrium is a finger-like pouch that extends from the main body of the atrium.
Function: The left atrium receives and pumps oxygen-rich blood from the lungs to the left ventricle.
Location: The cuboidal-shaped left atrium is the most posterior of all the cardiac chambers, located near the base of the heart.