This presentation describes various aspects of the regulation of tissue oxygenation, including the roles of the circulatory system, respiratory system, and blood, the carrier of oxygen within these components of the cardiorespiratory system. The respiratory system takes oxygen from the atmosphere and transports it by diffusion from the air in the alveoli to the blood flowing through the pulmonary capillaries. The cardiovascular system then moves the oxygenated blood from the heart to the microcirculation of the various organs by convection, where oxygen is released from hemoglobin in the red blood cells and moves to the parenchymal cells of each tissue by diffusion. Oxygen that has diffused into cells is then utilized in the mitochondria to produce adenosine triphosphate (ATP), the energy currency of all cells. The mitochondria are able to produce ATP until the oxygen tension or PO2 on the cell surface falls to a critical level of about 4–5 mm Hg. Thus, in order to meet the energetic needs of cells, it is important to maintain a continuous supply of oxygen to the mitochondria at or above the critical PO2 . In order to accomplish this desired outcome, the cardiorespiratory system, including the blood, must be capable of regulation to ensure survival of all tissues under a wide range of circumstances. The purpose of this presentation is to provide basic information about the operation and regulation of the cardiovascular and respiratory systems, as well as the properties of the blood and parenchymal cells, so that a fundamental understanding of the regulation of tissue oxygenation is achieved.

The human circulatory system is essential for pumping blood throughout a person's body. Without it, humans wouldn't be able to live. This guide explores the main elements of the circulatory system, introduces key parts such as blood vessels and the heart, and examines problems with this system. Complete with fact boxes and intriguing sidebars, accessible language, discussion questions, and descriptive photographs and diagrams, this introduction will appeal to readers of all levels.

Describes the anatomy and functions of the human circulatory system and how it responds to increased activity, the microgravity of space, and other changes.

Presents information about the circulatory system, looking at the heart, blood, and blood vessels that compose it, as well as how they work together to keep the body healthy.

Discusses the parts that make up the human circulatory system, what can go wrong, how to treat those illnesses and diseases, and how to stay healthy.

Addresses the mathematical and numerical modelling of the human cardiovascular system, from patient data to clinical applications.

Discusses what the circulatory system is, how it works, and how it responds to exercise and hemorrhage.