Quote of the Day

Thursday, August 6, 2009

The Beating Heart

The Beating Heart 

The cardiovascular system is a key element in transporting and exchanging substances (such as nutrients, wastes, oxygen, and carbon dioxide) between the environment and the cells that function in tissues. Cardio is from the Greek word kardia, meaning heart, and vascular is from the Latin word vasculum, meaning vessel. 

Here we look at the operation of the mammalian heart, using the human heart as an example. It is the heart that provides the motive force to move blood through the circulatory system so that metabolic fuels and waste products can be transported to and from the body tissues. 


The Vascular Highway 

The blood vessels, or vascular system, of the human body form a closed delivery/pickup system that begins and ends with the heart. All the living cells of the body come in contact with blood vessels and, at capillary interfaces, life-sustaining substances move into and out of these microscopic vessels. 

In this module, you will overview blood vessel structure and function, circulatory pathways or circuits, exchanges of fluid and solutes at capillaries, and blood pressure as it relates to the vasculature. As this module points out, a crucial aspect of the vascular system is that it connects the body cells with organs of exchange, like the lungs, liver, small intestine, and kidneys. 


Membrane Structure and Transport 

This BioCoach activity will help you review the structure of membranes and the variety of ways in which materials travel across membranes by active or passive processes. A companion BioCoach activity, Biomembranes II, reviews the dynamic behavior of membranes, as well as the mechanisms by which membranes allow communication between cells and the formation of multicellular tissues.


Membrane Dynamics and Communication 

This BioCoach activity will help you review how regions of membrane pinch inward or bud outward to allow materials to move through cells; how membranes mediate the communication of signals, as in hormones binding to cell surfaces; and how specialized membrane regions bind different cells into tissues.