Describe The Functions Of The Cardiovascular System

Describe The Functions Of The Cardiovascular System – Virtually every cell, tissue, organ, and system in the body is affected by the circulatory system. This includes the generalized and more specialized functions of transporting materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulating body temperature, and helping to maintain acid balance -base. In addition to these shared functions, many systems enjoy a unique relationship with the circulatory system. Figure 1 summarizes these relationships.

As you learn about the vessels of the systemic and pulmonary circuits, notice that many arteries and veins share the same names, run parallel to each other throughout the body, and are very similar on the right and left sides of the body. These pairs of vessels will be traced on one side of the body only. Where differences in branching patterns occur or where the vessels are singular, this will be indicated. For example, you’ll find a pair of femoral arteries and a pair of femoral veins, with one vessel on each side of the body. In contrast, some vessels closer to the midline of the body, such as the aorta, are unique. In addition, some superficial veins, such as the great saphenous vein of the femoral region, have no arterial counterpart. Another phenomenon that can make studying ships difficult is that ship names can change with location. Like a street that changes its name when it passes through an intersection, an artery or vein can change its name when it passes through an anatomical landmark. For example, the left subclavian artery becomes the axillary artery as it passes through the body wall and into the axillary region, and then becomes the brachial artery as it flows from the axillary region ┬Ělar towards the upper part of the arm (or brachi). You will also find examples of anastomoses where two blood vessels that were previously branching are reconnected. Anastomoses are especially common in veins, where they help maintain blood flow even when a vessel is blocked or narrowed, although there are important ones in the arteries that supply the brain.

Describe The Functions Of The Cardiovascular System

Describe The Functions Of The Cardiovascular System

As you read about the circular pathways, you notice that there is an occasional very large artery known as a trunk, a term indicating that the vessel gives rise to several smaller arteries. For example, the celiac trunk gives rise to the left gastric, common hepatic, and splenic arteries.

The Function Of The Heart Ventricles

As you study this section, imagine that you are on a “Voyage of Discovery” similar to the Lewis and Clark Expedition of 1804-1806, which followed rivers and streams through unknown territory, searching for a water route from the Atlantic to the Pacific Ocean. You could imagine being inside a miniature ship, exploring the different branches of the circulatory system. This simple approach has proven effective for many students in mastering these major circulatory patterns. Another approach that works well for many students is to create simple line drawings similar to those provided, labeling each of the major ships. It is beyond the scope of this text to name all the vessels in the body. However, we will try to discuss the main pathways of blood and familiarize you with the main named arteries and veins in the body. Also, note that individual variations in circulation patterns are not uncommon.

We remember that the blood returning from the systemic circuit enters the right atrium (Figure 2) through the superior and inferior vena cava and the coronary sinus, which drains the blood supply from the heart muscle. These ships are described in more detail later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the carbon dioxide from the waste gas has been collected to be carried to the lungs by delete it From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is called the pulmonary circuit.

The only vessel that leaves the right ventricle is the pulmonary trunk. At the base of the pulmonary trunk is the pulmonary semilunar valve, which prevents blood from returning to the right ventricle during ventricular diastole. When the pulmonary trunk reaches the upper surface of the heart, it curves posteriorly and rapidly bifurcates (splits) into two branches, a left and a right pulmonary artery. To avoid confusion between these vessels, it is important to refer to the vessel that leaves the heart as the pulmonary trunk, rather than also calling it the pulmonary artery. The pulmonary arteries in turn branch many times within the lung, forming a series of smaller arteries and arterioles that eventually lead to the pulmonary capillaries. Pulmonary capillaries surround lung structures known as alveoli that are the sites of oxygen and carbon dioxide exchange.

After gas exchange is complete, oxygenated blood flows from the pulmonary capillaries into a series of pulmonary venules that eventually lead to a series of larger pulmonary veins. Four pulmonary veins, two on the left and two on the right, return blood to the left atrium. At this point, the pulmonary circuit is complete. Table 4 defines the main arteries and veins of the pulmonary circuit that are analyzed in the text.

Human Body’s Organ Systems And Their Function

Figure 2. Pulmonary circuit. Blood leaving the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the pulmonary alveoli. Blood returns through the pulmonary veins to the left atrium.

Left and right vessels that form from the pulmonary trunk and lead to smaller arterioles and eventually to the pulmonary capillaries.

Two sets of paired vessels, one pair on each side, that form from the small venules, which leave the pulmonary capillaries to flow into the left atrium.

Describe The Functions Of The Cardiovascular System

Blood relatively high in oxygen concentration returns from the pulmonary circuit to the left atrium through the four pulmonary veins. From the left atrium, blood moves into the left ventricle, which pumps blood into the aorta. The aorta and its branches, the systemic arteries, send blood to virtually every organ in the body (Figure 3).

The Circulatory System For Kids

The aorta is the largest artery in the body (Figure 4). It arises from the left ventricle and finally descends in the abdominal region, where it bifurcates at the level of the fourth lumbar vertebra into the two common iliac arteries. The aorta consists of the ascending aorta, the aortic arch, and the descending aorta, which passes through the diaphragm and a landmark that divides into the upper thoracic and lower abdominal components. Arteries originating in the aorta ultimately distribute blood to virtually every tissue in the body. At the base of the aorta is the semilunar aortic valve that prevents blood from returning to the left ventricle while the heart relaxes. After leaving the heart, the ascending aorta moves in a superior direction for approximately 5 cm and ends at the sternal angle. After this rise, it reverses direction, forming an elegant arch to the left, called the aortic arch. The aortic arch descends towards the lower parts of the body and ends at the level of the intervertebral disc between the fourth and fifth thoracic vertebrae. Beyond this point, the descending aorta continues near the vertebral bodies and passes through an opening in the diaphragm known as the aortic hiatus. Above the diaphragm, the aorta is called the thoracic aorta, and below the diaphragm, it is called the abdominal aorta. The abdominal aorta ends when it bifurcates into the two common iliac arteries at the level of the fourth lumbar vertebra. See Figure 4 for an illustration of the ascending aorta, aortic arch, and initial segment of the descending aorta plus major branches; Table 5 summarizes the structures of the aorta.

Figure 4. Aorta. The aorta has different regions, including the ascending aorta, the aortic arch, and the descending aorta, which includes the thoracic and abdominal regions.

The largest artery in the body, which originates in the left ventricle and descends in the abdominal region, where it bifurcates into the common iliac arteries at the level of the fourth lumbar vertebra; the arteries originating in the aorta distribute blood to virtually every tissue in the body

Initial portion of the aorta, which rises superiorly from the left ventricle for a distance of approximately 5 cm

Understanding The Functional Organization And Circulatory Flow Of The Cardiovascular System

Left graceful arch connecting the ascending aorta with the descending aorta; it ends in the intervertebral disc between the fourth and fifth thoracic vertebrae

Portion of the aorta that continues inferiorly past the end of the aortic arch; subdivided into thoracic aorta and abdominal aorta

The first vessels to branch from the ascending aorta are the paired coronary arteries (see Figure 4), which arise from two of the three sinuses of the ascending aorta just above the semilunar aortic valve. These sinuses contain the aortic baroreceptors and chemoreceptors critical for maintaining cardiac function. The left coronary artery arises from the left posterior aortic sinus. The right coronary artery arises from the anterior aortic sinus. Normally, the right posterior aortic sinus does not give rise to a vessel.

Describe The Functions Of The Cardiovascular System

The coronary arteries encircle the heart, forming

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