Left Bundle Branch

Left Bundle Branch The structure indicated is the left bundle branch of the cardiac conducting system. The conduction system of the heart is responsible for the synchronised contraction of the atria and ventricles and is comprised of the following main structures: Sinoatrial node Atrioventricular node Atrioventricular bundle of His Right and left bundle branches Purkinje fibres The electrical activity of the heart begins in the sinoatrial node and travels to the atrioventricular node. From the atrioventricular node the impulses pass down the Bundle of His, whereupon the conducting fibres divide into the right and left bundle branches. The right bundle …

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left bundle branch

Pulmonary Trunk

Pulmonary Trunk The structure indicated is the pulmonary trunk. The pulmonary trunk is one of the great vessels – a term which refers to the major arteries and veins which bring blood to and from the heart. These include: Superior and inferior vena cavae Pulmonary arteries Pulmonary veins Aorta The pulmonary trunk carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation, via the right and left pulmonary arteries. This is the only artery in the adult human body that carries deoxygenated blood. In fetal life, the umbilical arteries also carry deoxygenated blood – this …

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pulmonary trunk

Common Hepatic Artery

Common Hepatic Artery The structure indicated is the common hepatic artery. The common hepatic artery is one of three branches of the celiac trunk and is the first anterior branch that arises from the abdominal aorta. The abdominal aorta consists of anterior, posterior, and lateral branches. There are three anterior branches which supply the foregut, midgut and hindgut structures these are as follows: Celiac trunk – supplies foregut Superior mesenteric artery – supplies midgut Inferior mesenteric artery – supplies hindgut The celiac trunk arises from the abdominal aorta at the level of the upper part of the first lumbar vertebra. …

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common hepatic artery

Blood Capillary

Blood Capillary The diagram illustrates a capillary. Capillaries are the smallest type of blood vessel in the human body. They are responsible for the transfer of oxygen, carbon dioxide, fluids, nutrients, and waste products to and from the body’s tissues. Capillaries form a connection between arterioles and venules. Organ systems that are highly metabolically active have dense capillary networks, such as the muscular system and renal system. Structure: Thin walled one cell layer thick endothelium (simple squamous epithelium). Blood flow sequence heart –> arteries –> arterioles –> capillaries –> venules –> veins –> heart There are three types of blood capillaries: Continuous Fenestrated Sinusoid In …

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