Circulatory System. Function and Structure of the Circulatory System. Transport of gases, nutrients, wastes, and hormones. Highway system for leukocytes Helps maintain homeostasis by transporting warm blood to extremities Helps stabilize pH and ionic concentrations of body fluids.
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Blood leaves the body tissues via various veins and enters the right atrium of the heart via the vena cava. Through thetricuspid valveto the right ventricle where it is pumped through a semi lunar valve into the pulmonary artery where it is passed to the lungs to be oxygenated.Blood enters the left atrium via thePulmonary veinfrom the lungs. Flows through themitral valveto the left ventricle. Pumped out of the left ventricle through a semi lunar valve into the aorta. Branches through series of arteries to all parts of the body. Then the whole process starts again!!!
In a closed circulatory system, blood is not free in a cavity; it is contained within blood vessels. Valves prevent the backflow of blood within the blood vessels.
This type of circulatory system is found in vertebrates and several invertebrates including annelids, squids and octopuses.
In an open circulatory system, blood is pumped from the heart through blood vessels but then it leaves the blood vessels
Blood flows slowly in an open circulatory system. The animal must move its muscles to move the blood within the spaces.
Arthropods and most mollusks (except cephalopods: nautilus, squid, octopus) have an open circulatory system
Open versus Closed Circulatory System
Amphibians have a three chambered heart: two atria and a single ventricle. Deoxygenated blood and oxygenated blood mix; maximum efficiency is not needed to supply the body’s needs.
Lizards have a muscular septum which partially divides the ventricle.When the ventricle contracts, the opening in the septum closes and the ventricle is momentarily divided into two separate chambers.This prevents mixing of the two bloods.
Four Chambers: Birds, Crocodiles, and MammalsThe septum is complete in the hearts of birds, crocodiles, and mammals providing two separate circulatory systems:
Raynaud’s phenomenon is a condition in which cold temperatures or strong emotions cause blood vessel spasms that block blood flow to the fingers, toes, ears, and nose. Raynaud's phenomenon also occurs without another disease, medication, or cause. This is called primary Raynaud's phenomenon. It most often begins in people younger than age 30. Strong emotions or exposure to the cold causes the fingers, toes, ears, or nose to become white, then turn blue. When blood flow returns, the area becomes red and then later returns to normal color. The attacks may last from minutes to hours.People with primary Raynaud's phenomenon (no other cause or condition) have problems in the same fingers on both sides, but they do not have very much pain.About 5% of the U.S. population has Raynaud’s.
A weakened and bulging area in the aorta, the major blood vessel that feeds blood to the body.Because the aorta is the body's main supplier of blood, a ruptured thoracic aortic aneurysm can cause life-threatening bleeding.Depending on the size and rate at which the thoracic aortic aneurysm is growing, treatment may vary from watchful waiting to emergency surgery. Once a thoracic aortic aneurysm is found, doctors will closely monitor it so that surgery can be planned if it's necessary. Emergency surgery for a ruptured thoracic aortic aneurysm can be risky.