Feb 1, 2011 - Blood

Reminders:

• Histology Projects are due Friday, 2/4 
• Connective Tissue Quiz will be the same day.

Part of the day - Blood
Blood is considered a connective tissue for two basic reasons: (1) embryologically, it has the same origin (mesodermal) as do the other connective tissue types and (2) blood connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes. In circulating blood two different cell types are found: enucleated erythrocytes or red blood cells and nucleated leukocytes or white blood cells. (http://lifesci.rutgers.edu/~babiarz/bloodtx.htm)

 Note - the part of the blood that is missing  (Difficult to do since it is not labeled!) the plasma.

Plasma is the liquid component of blood, in which the red blood cells, white blood cells, and platelets are suspended. It constitutes more than half of the blood's volume and consists mostly of water that contains dissolved salts (electrolytes) and proteins. The major protein in plasma is albumin. Albumin helps keep fluid from leaking out of blood vessels and into tissues, and albumin binds to and carries substances such as hormones and certain drugs. Other proteins in plasma include antibodies (immunoglobulins), which actively defend the body against viruses, bacteria, fungi, and cancer cells, and clotting factors, which control bleeding.

Plasma has other functions. It acts as a reservoir that can either replenish insufficient water or absorb excess water from tissues. When body tissues need additional liquid, water from plasma is the first resource to meet that need. Plasma also prevents blood vessels from collapsing and clogging and helps maintain blood pressure and circulation throughout the body simply by filling blood vessels and flowing through them continuously. Plasma circulation also plays a role in regulating body temperature by carrying heat generated in core body tissues through areas that lose heat more readily, such as the arms, legs, and head.
(http://www.merckmanuals.com/home/sec14/ch169/ch169b.html)

Red Blood Cells get most of the press but it is vital not to ignore the importance of the blood plasma.

Fun Fact - Each square inch of human skin consists of twenty feet of blood vessels.