Membrane Lining The Abdominal Cavity

Summary

Read a cursory summary of this topic

human cardiovascular system, organ system that conveys blood through vessels to and from all parts of the body, carrying nutrients and oxygen to tissues and removing carbon dioxide and other wastes. It is a airtight tubular system in which the blood is propelled by a muscular middle. Two circuits, the pulmonary and the systemic, consist of arterial, capillary, and venous components.

The primary function of the heart is to serve as a muscular pump propelling blood into and through vessels to and from all parts of the body. The arteries, which receive this blood at high pressure and velocity and conduct it throughout the body, have thick walls that are composed of elastic gristly tissue and muscle cells. The arterial tree—the branching system of arteries—terminates in short, narrow, muscular vessels called arterioles, from which claret enters simple endothelial tubes (i.e., tubes formed of endothelial, or lining, cells) known as capillaries. These sparse, microscopic capillaries are permeable to vital cellular nutrients and waste products that they receive and distribute. From the capillaries, the blood, now depleted of oxygen and burdened with waste material products, moving more slowly and under depression pressure, enters modest vessels called venules that converge to class veins, ultimately guiding the blood on its way back to the heart.

This article describes the structure and office of the centre and blood vessels, and the technologies that are used to evaluate and monitor the wellness of these key components of the human cardiovascular system. For a discussion of diseases affecting the heart and blood vessels, come across the article cardiovascular illness. For a full treatment of the composition and physiologic function of claret, run into blood, and for more information on diseases of the blood, see blood illness. To learn more about the homo circulatory organization, run across systemic circulation and pulmonary circulation, and for more nearly cardiovascular and circulatory function in other living organisms, meet circulation.

The heart

Description

Shape and location

The adult human heart is normally slightly larger than a clenched fist, with average dimensions of about 13 × 9 × 6 cm (5 × iii.5 × two.5 inches) and weight approximately ten.v ounces (300 grams). It is cone-shaped, with the broad base of operations directed upward and to the right and the apex pointing downwards and to the left. It is located in the chest (thoracic) cavity backside the breastbone (sternum), in front of the windpipe (trachea), the esophagus, and the descending aorta, between the lungs, and above the diaphragm (the muscular partition between the chest and abdominal cavities). Well-nigh 2-thirds of the heart lies to the left of the midline.

Superficial arteries and veins of face and scalp, cardiovascular system, human anatomy, (Netter replacement project - SSC)

Britannica Quiz

The Human Body

Yous may know that the human encephalon is composed of two halves, only what fraction of the human torso is made up of blood? Learn this fact and much more as you test both halves of your heed in this human anatomy quiz.

Pericardium

The heart is suspended in its own bleary sac, the pericardium. The strong outer portion of the sac, or fibrous pericardium, is firmly attached to the diaphragm below, the mediastinal pleura on the side, and the sternum in front. It gradually blends with the coverings of the superior vena cava and the pulmonary (lung) arteries and veins leading to and from the middle. (The infinite between the lungs, the mediastinum, is bordered by the mediastinal pleura, a continuation of the membrane lining the chest. The superior vena cava is the master channel for venous claret from the chest, arms, neck, and head.)

Polish, serous (moisture-exuding) membrane lines the fibrous pericardium, then bends back and covers the heart. The portion of membrane lining the fibrous pericardium is known as the parietal serous layer (parietal pericardium), that covering the centre every bit the visceral serous layer (visceral pericardium or epicardium).

Get a Britannica Premium subscription and proceeds access to exclusive content. Subscribe Now

The two layers of serous membrane are commonly separated by just 10 to 15 ml (0.six to 0.ix cubic inch) of pericardial fluid, which is secreted by the serous membranes. The slight space created past the separation is called the pericardial cavity. The pericardial fluid lubricates the two membranes with every beat of the eye as their surfaces glide over each other. Fluid is filtered into the pericardial space through both the visceral and parietal pericardia.

Chambers of the middle

The center is divided by septa, or partitions, into correct and left halves, and each half is subdivided into ii chambers. The upper chambers, the atria, are separated by a partition known as the interatrial septum; the lower chambers, the ventricles, are separated by the interventricular septum. The atria receive blood from various parts of the body and pass it into the ventricles. The ventricles, in turn, pump claret to the lungs and to the residue of the body.

The correct atrium, or right superior portion of the heart, is a thin-walled chamber receiving claret from all tissues except the lungs. Three veins empty into the right atrium, the superior and junior venae cavae, bringing blood from the upper and lower portions of the body, respectively, and the coronary sinus, draining blood from the centre itself. Blood flows from the correct atrium to the correct ventricle. The right ventricle, the right inferior portion of the heart, is the chamber from which the pulmonary artery carries claret to the lungs.

The left atrium, the left superior portion of the middle, is slightly smaller than the right atrium and has a thicker wall. The left atrium receives the four pulmonary veins, which bring oxygenated blood from the lungs. Blood flows from the left atrium into the left ventricle. The left ventricle, the left inferior portion of the heart, has walls three times equally thick as those of the right ventricle. Blood is forced from this chamber through the aorta to all parts of the body except the lungs.

External surface of the centre

Shallow grooves called the interventricular sulci, containing blood vessels, mark the separation between ventricles on the front and back surfaces of the middle. In that location are ii grooves on the external surface of the center. 1, the atrioventricular groove, is along the line where the right atrium and the right ventricle come across; information technology contains a co-operative of the right coronary artery (the coronary arteries evangelize blood to the middle muscle). The other, the anterior interventricular sulcus, runs along the line between the correct and left ventricles and contains a branch of the left coronary artery.

On the posterior side of the center surface, a groove called the posterior longitudinal sulcus marks the division between the right and left ventricles; it contains another branch of a coronary avenue. A fourth groove, between the left atrium and ventricle, holds the coronary sinus, a channel for venous claret.