CIRCULATION AND CARDIOVASCULAR SYSTEMS TRANSPORT IN INVERTEBRATES

LEARNING OBJECTIVES  The student is able to use representations or models to analyze quantitatively and qualitatively the effects of disruptions to dynamic homeostasis in biological systems.  The student is able to design a plan for collecting data to support the scientific claim that the timing and coordinator of physiological events involve regulation.

ACADEMIC VOCABULARY Circulatory system Open circulatory system Closed circulatory system Cardiovascular system Heart Vessels Arteries Arterioles Capillaries Venules Veins Valves Cardiac cycle Systole Diastole

WHY DO ANIMALS NEED A CIRCULATORY SYSTEM?

The metabolic needs of the cells of many small animals are met by direct exchange of materials with the external medium. The metabolic needs of the cells of larger animals are met by a circulatory system that transports nutrients, respiratory gases, and metabolic wastes throughout the body.

WHAT IS AN OPEN CIRCULATORY SYSTEM AND CLOSED CIRCULATORY SYSTEM?

OPEN CIRCULATORY SYSTEMS Extracellular fluid leaves vessels and percolates through tissues.

CLOSED CIRCULATORY SYSTEMS The blood is contained in a systems of vessels. Closed circulatory systems have several advantages, including the ability to selectively direct blood, hormones, and nutrients to specific tissues.

HOW HAS THE VERTEBRATE CIRCULATORY SYSTEM EVOLVED?

HOW HAS THE VERTEBRATE CIRCULATORY SYSTEMS EVOLVED The circulatory systems of vertebrates consist of a heart and a closed system of vessels containing blood that is separate from the interstitial fluid. Arteries and arterioles carry blood from the heart; capillaries are the site of exchange between blood and interstitial fluid; venules and veins carry blood back to the heart.

HOW HAS THE VERTEBRATE CIRCULATORY SYSTEMS EVOLVED? The vertebrate heart evolved from two chambers in fish to three in amphibians and reptiles and four in crocodilians, mammals, and birds. This evolutionary progression has led to an increasing separation of blood that flows to the gas exchange organs and blood that flows to the rest of the body.

HOW HAS THE VERTEBRATE CIRCULATORY SYSTEMS EVOLVED? The simplest (two- chambered heart) has an atrium that receives blood from the body, and a ventricle that pumps blood out of the heart. An aorta distributes blood to arteries.

HOW HAS THE VERTEBRATE CIRCULATORY SYSTEMS EVOLVED? In birds and mammals, blood circulates through two circuits: the pulmonary which transports blood between the heart and lungs, and the systemic, which transports oxygen-rich blood between the heart and tissues

HOW HAS THE VERTEBRATE CIRCULATORY SYSTEMS EVOLVED?

HOW DOES THE MAMMALIAN HEART FUNCTION? The human heart has four chambers. Valves in the heart prevent the backflow of blood. The cardiac cycle has two phases: systole, in which the ventricles contract; and diastole, in which the ventricles relax. The sequential heart sounds (“lub-dub”) are made by the closing of the heart valves.

CIRCULATION AND CARDIOVASCULAR SYSTEMS