contraction of heart pumps hemolymph (interstitial fluid) through the circulatory vessels into interconnected sinuses surrounding the organs

exchange of gas and chemicals occurs in the sinuses and movement squeezes these to promote circulation

heart pumps blood into large vessels that branch into smaller ones that infiltrate the tissues and organs

blood pressure high enough to provide efficient delivery of oxygen and nutrients in larger animals

connects aqueous environment of the body cells to the organs that exchange gases, absorb nutrients and dispose of wastes

relaxation of the heart draws hemolymph back in the pores, which have valves that close when the heart contracts

blood is confined to vessels and distinct from interstitial fluid; chemical exchange occurs between blood and interstitial fluid and interstitial fluid and body cells

capillaries- infiltrate tissues; the network of capillaries (capillary bed) is where gases and chemicals are exchanged by diffusion between the blood and interstitial fluid around the tissue cells

blood travels thru the body and returns to its starting point in a single circuit

consists of 3 or 4 chambers - 2 atria and 1 ventricle or 2 atria and 2 ventricles

blood enters heart to atrium, then the ventricle where it contracts and forces movement to capillary beds (gills in fish), net diffusion of oxygen in the blood occurs and carbon dioxide leaves the blood. As blood leaves the capillaries, it's converges into a vessel that carryies oxygen rich blood to capillaries throughout the body

1st circuit (pulmonary in humans and pulmocutaneous in amphibians)- right side of heart pumps oxygen poor blood to capillary beds of gas exchange (lungs) tissues where net movement of oxygen occurs in the blood and carbon dioxide out of the blood
2nd circuit (systemic)- left side of heart pumps oxygen rich blood from gas exchange surface to capillary beds in organs and tissues, after diffusion of o2 and co2 the now oxygen poor blood returns to the heart

blood pressure-contraction of heart muscle generates this and exerts force in all directions (down the artery and stretches the walls to dilate is the highest BP); recoil of elastic arterial walls helps maintain BP and hence blood flow

used: as a solvent, in defense, transporting oxygen and other nutrients as well as waste gases, some carbon dioxide, for clotting, regulating osmotic balance and pH buffering

consists of 55% plasma (water, blood electrolytes, plasma proteins like albumin and immunoglobulins) and 45% cellular elements (Platelets, Erythrocytes, Leukocytes: Basophils, Eosinophils, Neutrophils, Lymphocytes, Monocytes)

positive pressure- (amphibians and birds) inflating the lungs with forced air flow or pushing air into the lungs

uptake of oxygen from the environment and discharge of carbon dioxide to the environment

1.)fluid leaked out of capillaries is returned to the blood via the lymphatic system

2.)fluid goes into interstitial fluid and diffuses into lymphatic vessels and now called lymph

3.)lymph circulates in lymphatic system before being draining into large veins of the cardiovascular system at the base of the neck

1.)skin serves as the respiratory organ for sponges, cnidarians, flatworms and some amphibians by facilitating gas exchange between the circulatory system and the environment

2.)gills serve as the respiratory organ for most fish, octopuses, squid, and some mammals (dolphins) by maintaining partial pressure gradients of oxygen and carbon dioxide across the gill and maximized by the exchange of substance or heat between the two fluids (blood and water) flowing in opposite directions

3.)tracheal systems serve as the respiratory organ for most insects by using a network of air tubes throughout the body and enable gas exchange by diffusion at the tips of the air tubes. They do not need a circulatory system due to the short distance air comes in/out (oxygen and carbon dioxide)

4.)lungs serve as the respiratory organ for the majority of mammals and some arachnids by the branching ducts located within (not in direct contact with other organs/tissues so it needs a circulatory system to transport gases) the lungs. Gas exchange occurs at the very end of the ducts via alveoli and diffuses into the capillaries