cirulatory system

Open Circulatory System

(ex. Insects and mollusks) - The fluid leaves the vessels and circulates in the body cavity

1. Arteries 2. Aorta 3. Arterioles

1. Large diameter vessels. Carry blood away from the heart to other parts of the body. Usually carry oxygenated blood (except the pulmonary artery). 2. The largest artery. First artery of the systemic circuit. Connects to the left ventricle. 3. smaller branches of arteries that lead to capillaries.

Functions of Circulatory Systems in Vertebrates

1. Nutrient and waste transport. 2. O2 and CO2 transport. 3. Temperature maintenance. 4. Hormone circulation.

1. Systole 2. Diastole

1. contraction phase of the heart. 2. relaxation phase of the heart.

1. Venules 2. Veins

1. vessels which pick up blood from capillaries. 2. large diameter vessels. Carry blood from venules in all parts of the body toward the heart. Usually carry deoxygenated blood (except pulmonary veins).

1.Septum 2. Pericardium

1. wall that separates left and right ventricles 2. double-layer membrane that surrounds the heart.

Capillaries

Smallest diameter vessels. Functional unit of the circulatory system. Oxygen, carbon dioxide, nutrients, wastes, and hormones are exchanged between tissues and the blood here.

Gastrovascular Cavity

The gastrovascular cavity is surrounded by cells that absorb nutrients and pass them to neighboring cells by diffusion

Cardiovascular System

The heart plus all blood vessels. The blood must circulate to every part of the body. So there are blood vessels throughout the body.

Vena cava

The largest veins. The last vein of the systemic circuit. Connects to the right atruim.

Heart

a muscular organ which pumps blood. Located just below the sternum. Four chambers: 2 atria, 2 ventricles. Atria (upper chambers) have thin walls. Ventricles (lower chambers) have thick, muscular walls.

Closed Circulatory System

ex. Vertebrates, including humans) - blood (fluid) never leaves the vessels