Bleeding!

Introduction: Every one of us has blood coursing through our bodies. Most of us don't think about what our blood does during the day or how it helps us. This section is going to go through the functions of blood, some important words to know, different types of blood, and why our blood needs oxygen. (Picture from http://ochealthinfo.com)

Functions
As described in the Mader textbook on page 106, the functions of blood fall into three main categories.

1. Transport: "Blood delivers oxygen from the lungs and nutrients from the digestive tract to the tissues, where an exchange takes place" (Pg 106). In short, blood is what moves our bodies basic needs around the body.

2. Defense: Certain blood cells are in the body to specifically fight diseases. We will discuss the different types of blood cells later.

3. Regulation: Blood helps to regulate body temperature by picking up heat and moving it around the body.

Definitions

*All definitions can be found in the Mader textbook, pages; 107 through 108

Plasma: The liquid where cells and cell fragments are suspended, classified as a liquid tissue.

Plasma Proteins: Most abundant organic molecules in the blood.

Osmotic Pressure: A force that prevents excessive loss of plasma from the capillaries into tissue fluid.

Hemoglobin (Hb): Iron-containing pigment in red blood cells that combines with and transports oxygen (Pg G-9).

Types

Red blood cells are the most common in the body. According to our book, "there are 4-6 million red blood cells per mm of whole blood" (Pg 108). That is a LOT of blood. Red blood cells carry oxygen, help transport carbon dioxide, and are produced in bone marrow.

Below is a picture from http://science.uwe.ac.uk that we saw earlier, depicting red blood cells.
White Blood Cells do not have a nucleus, or hemoglobin. They are see-through unless stained. White blood cells tend to be larger than red blood cells, also. Primarily, the function of these blood cells are to fight infection. The different types of white blood cells, as described in the book on pages 110 through 111 are: Granular leukocytes and agranular leukocytes. Each of these classifications have the multiple different kinds of white blood cells in them.

Here is a picture of white blood cells found at http://www.sciencemuseum.org.uk.



















Last but not least are the platelets. These come from "fragmentation of certain large cells in the red bone marrow" (pg 113). Platelets are involved in clotting.

Here is a picture of activated blood platelets that was found at http://biomed.brown.edu.


Here is a picture I found that I really liked that showed most of the objects in a vein, artery, capillary. (http://cache.eb.com)


I Need Air!

On of the main goals of red blood cells is to carry oxygen. All of our cells need oxygen in order to survive, just like we need it. Cell respiration needs oxygen. Frolich put it best when describing how oxygen gets into blood. He said, in the powerpoint, that oxygen diffuses across tissues of the alveolus, across tissues of a capillary, across red blood cell membranes, and is there held by hemoglobin protein molecules (Slide 15).

Conclusion: There are some of the major items need to be known about blood. There are three different types: red, white, and platelets. Red blood cells carry oxygen that every other cell needs to survive, and hemoglobins not only give red blood cells their color, they hold onto the oxygen. Next up, is immunity, which deals largely with white blood cells.