Lab 10: Cardiovascular System I – Blood and the Heart
Lab 10: Cardiovascular System I – Blood and the Heart
Blood tissue and the Heart
Learning Objectives
When you are prepared for the Test on Week 10 Learning Objectives in Week 11, you will be able to:
- Differentiate between red blood cells, white blood cells, and platelets in appearance and general functions.
- Differentiate between white blood cell types in terms of appearance, proportion in a healthy individual, and how they are used to diagnose various health conditions.
- Identify structures of the heart and their functions.
- Identify major blood vessels going in and out of the heart and coronary blood vessels.
- Describe the pathway of blood through the heart and associated blood vessels, and state whether the blood is oxygenated or deoxygenated at any point in that pathway.
The cellular elements are referred to as the formed elements and include red blood cells (RBCs), white blood cells (WBCs), and platelets. The extracellular matrix, called plasma, makes blood unique among connective tissues because it is fluid. This fluid, which is mostly water, perpetually suspends the formed elements and enables them to circulate throughout the body within the cardiovascular system.In the laboratory, blood samples are often centrifuged in order to separate the components of blood from one another (Figure 10.1). Erythrocytes are the heaviest elements in blood and settle at the very bottom of the tube. Above the erythrocyte layer we see the buffy coat, a pale, thin layer of leukocytes and platelets, which together make up less than 1% of the sample of whole blood. Above the buffy coat is the blood plasma, normally a pale, straw-colored fluid, which constitutes the remainder of the sample.
In normal blood, about 45 percent of a sample is erythrocytes, which is referred to as the hematocrit. The hematocrit of any one sample can vary significantly, however, about 36–50 percent, according to gender and other factors. Not counting the buffy coat, which makes up less than 1% of the blood, we can estimate the mean plasma percentage to be the percent of blood that is not erythrocytes: approximately 55% (Table 10.1).
| COMPONENT AND % OF BLOOD | SUBCOMPONENT AND % OF COMPONENT | TYPE AND % (WHERE APPROPRIATE) | SITE OF PRODUCTION | MAJOR FUNCTION(S) |
| Plasma
46 – 63% of blood |
Water; 92% of plasma | Fluid | Absorbed by intestinal tract or produced by metabolism | Transport medium |
| Plasma proteins; 7% of plasma | Albumin; 54 – 60% of plasma proteins | Liver | Maintain osmotic concentration, transport lipid molecules | |
| Globulins; 35 – 38% of plasma proteins | Alpha globulins – liver | Transport, maintain osmotic concentration | ||
| Beta globulins – liver | Transport, maintain osmotic concentration | |||
| Gamma globulins (immunoglobulins) – plasma cells | Immune responses | |||
| Fibrinogen 4 – 7 percent | Liver | Blood clotting in hemostasis | ||
| Regulatory proteins; <1% of plasma | Hormones and enzymes | Various sources | Regulate various body funct