Different kinds of circulation

Circulatory Pathways

There are four circulatory routes in the human body. They move blood to certain organs throughout the body. the following

• Pneumatic circulation
• Systemic circular distance
• The flow of the portal
• The fetal heartbeat

Fetal circulation disappears after delivery. The portal circulation is the divide that joins the systemic circulatory pathways. The pulmonary circulation and the systemic circulation are thus the two main circulatory systems.

The Pulmonary Circulation

The pulmonary circulation transports blood to and from the lungs. In order for gaseous exchanges to occur, it carries blood devoid of oxygen from the right ventricle to the alveoli of the lungs. Low-oxygen blood is pumped into the pulmonary trunk by the right ventricle. After an 8 cm diagonal uphill trek, the right and left pulmonary arteries leave the pulmonary trunk. In contrast, the right pulmonary artery enters the right lung through the left pulmonary artery. The thick networks of pulmonary capillaries that encircle the alveoli were eventually formed when the pulmonary arteries in the lungs divided into numerous smaller arteries and arterioles. The exchange of gases between the blood and the air in the alveoli here enables the blood to gain oxygen and lose carbon dioxide. When gas exchanges occur and the blood's oxygen level rises, the blood turns a bright red color.

After passing through the capillaries, the blood travels through microscopic venules, veins, and finally the pulmonary veins. The pulmonary circuit is finished by the two pulmonary veins found in each lung, which discharge blood into the left atrium. This circuit's function is to replenish the blood's oxygen levels and eliminate carbon dioxide.

The Systemic Circulation

The systemic circulation is the largest circulatory channel. It carries oxygenated blood from the left ventricle to all of the body's tissues. It delivers oxygen, minerals, and other essential components in addition to carrying carbon dioxide and other metabolic wastes.

Oxygen-rich blood from the pulmonary circulation is pumped back into the aorta by the left ventricle. Systemic arteries let blood go from the aorta in a number of different routes. The numerous aortic branches divide further to form the arterioles, which in turn give rise to the delicate capillary network. The deoxygenated blood is then returned to the right atrium by the systemic veins. All of the organ veins below the diaphragm exit through the inferior venacava. The body parts above the diaphragm are drained by the superior venacava. The coronary sinus, superior and inferior vena cava, and vena cava all empty unoxygenated blood into the right atrium.

The Portal Circulation

Materials can be transferred directly from one organ to another thanks to a form of diversion in the venous return system called the portal circulation. It transports blood from the abdominal organs to the liver. The portal system is made up of the veins that drain blood from capillaries in the spleen, stomach, pancreas, and intestine. Instead of emptying their blood directly into the inferior vena cava, they deliver their blood to the liver through a common vein called the hepatic portal vein. This venous network is known as the hepatic portal circulation. The hepatic portal blood is rich in the nutrients received from the digestive organs. As blood reaches the liver, hepatic cells store some blood components and change others to get them ready for systemic circulation. The phagocytic cells of the liver destroy bacteria that have survived the digestive mucosa.

The hepatic portal vein is made up of the superior mesenteric vein and the splenic vein. The superior mesenteric vein removes blood from the small intestine, stomach, pancreas, and a small piece of the large intestine. Through the splenic vein, blood is ejected from the pancreas, stomach, and a portion of the large intestine. When the portal vein penetrates the liver, it divides into progressively smaller branches. Finally, a vast network of sinus-like channels known as sinusoids receives the portal blood. They are expanded capillaries that serve as blood routes in the tissues of the liver, spleen, and other structures. After leaving the sinusoids, blood is finally collected by the hepatic veins, which then empty into the inferior vena cava. The portal vein system supports the ability of the liver cells to function. For instance, the portal system carries the majority of the digestive end products from the small intestine to the liver and circulation. The liver processes, stores, and discharges these nutrients into the bloodstream as required.

The Fetal Circulation

The circulation of blood within a developing fetus is referred to as fetal. The developing fetus exchanges nutrients and waste with its mother through the placenta, a structure that is housed inside the mother's uterus. The umbilical cord is used to attach it to the fetus's umbilicus. There are five ways in which the circulation during pregnancy and the circulation after delivery are different. The additional five vessels are the umbilical arteries, vein, ductus venosus, foramen ovale, and ductus arteriosus.

A pair of umbilical arteries provide the placenta with fetal blood. Fetal blood absorbs oxygen and nutrients from the placenta while expelling CO2 and wastes. Through a single umbilical vein, oxygen-rich blood from the placenta is returned to the mother. The umbilical vein splits into two branches as it ascends to the liver. The branch that connects to the hepatic portal vein and enters the liver only receives a small amount of blood. The ductus venosus, the next branch, which empties into the inferior vena cava, is where the majority of the blood travels. Blood enters the right atrium after mixing with deoxygenated blood in the inferior vena cava.

Some of the blood that enters the right atrium travels to the right ventricle, but the foramen ovale, which is located in the septum between the right and left atria, is where the majority of the fetal blood passes. The foramen ovale allows blood from the right atrium to enter the left atrium and then the systemic circulation. The pulmonary artery is the pathway by which blood enters the right ventricle. Some blood enters the lungs of the fetus. However, a large portion of the blood in the pulmonary artery travels through the ductus arteriosus, a channel that joins the pulmonary artery to the aorta by traveling through the pulmonary circulation. Through the systemic circulation, the blood in the aorta is transported to every area of the developing fetus's body.

Blood entering the internal iliac arteries travels through the umbilical arteries and into the placenta for another exchange. The fetal liver, kidney, and lung are too immature to carry out their intended duties. They are therefore not operating. Several things happen shortly after delivery that change the fetal circulation and develop the neonatal circulation, including the onset of renal, pulmonary, and digestive processes. The blood flow through the entire umbilical vessel is stopped when the umbilical cord is tied. Within one to three hours after birth, these arteries shrink and transform into fibrous ligaments.

Postnatal Circulatory System Changes

• With the first breath, the pulmonary arteries dilate due to increasing alveolar O2 pressure.
• Obstetrical clamping causes umbilical arteries and veins to convert into medial umbilical ligaments and to spontaneously contract.
• The ductus arteriosus contracts and transforms into the ligamentum arteriosum between 10 to 15 hours of birth.
• The foramen ovale closes and changes its name to the fossa ovalis as a result of elevated left atrial pressure and decreased right atrial pressure.
• Additionally, the ductus venosus tightens and develops into the ligamentum venosum.