CHAPTER EIGHTEEN BLOOD
Introduction to the Cardiovascular System A. The cardiovascular system includes a fluid, a series of conducting tubes that distribute the fluid throughout the body, and a pump that keeps the fluid in motion. 1. Blood -- the fluid of the cardiovascular system; distributes materials including nutrients, wastes,
2. Blood Vessels -- the conducting tubes that distribute the blood; three primary types of blood vessels are in the human body. a. Arteries -- carry blood away from the heart to the capillaries, typically red on models because they generally carry oxygenated blood. b. Capillaries -- smallest, most abundant type of blood vessel; permits diffusion between the bloodstream and interstitial fluids. c. Veins -- return blood from capillaries to the heart; typically blue on models because they generally carry deoxygenated blood 3. Heart -- the pump that keeps the fluid in motion. B. This chapter focuses on blood while the blood vessels and heart will be detailed in later chapters. 1. Cardiology = the study of the heart 2. Angiology = the study of arteries, veins, and lymph vessels 3. Hematology = the study of blood
18.1 Basic Hematology A. Functions of Blood 1. Transportation of dissolved gases, nutrients, hormones, and metabolic wastes. 2. Defense against toxins and pathogens. 3. Homeostasis: Regulation of the pH, ion composition of interstitial fluids, water content, body temperature. B. Characteristics of Blood 1. Blood is a liquid connective tissue which constitutes approximately 8% of human body mass. 2. Blood is 4-5 times more viscous than water. 3. Blood is somewhat sticky and has a salt concentration of about .85-.90%. 4. Blood temperature is slightly above normal body temperature (100.4'F or 38'C). 5. Blood pH ranges from 7.35 to 7.45 (slightly alkaline). 6. Blood volumes range from 4-6 liters: a. Males have 5-6 liters b. Females have 4-5 liters 7. Whole blood is a heterogeneous mixture of non-living matrix called plasma (46 -- 63%) and three formed elements (37 -- 54%). C. Plasma is the non-living component; it is composed of water and solutes (7% plasma proteins and 1% all other solutes. 1. Water is the primary component of blood plasma (92%). 2. Plasma proteins are in solution rather than forming insoluble fibers like those in other connective tissues (such as the elastin and collagen fibers of areolar tissue, bone, or cartilage). On average, each 100 mL of plasma contains 7.6 grams of protein, almost five times the concentration of interstitial fluids. The large size and globular shapes of most blood proteins usually prevents them from leaving the bloodstream. The liver synthesizes and releases more than 90% of all plasma proteins.
a. Albumins - constitute roughly 60% of the plasma protein and therefore contribute to
for fatty acids and steroid hormones. b. Globulins - account for approximately 35% of the plasma proteins and are important in attacking pathogens (antibodies also known as immunoglobulin) while others are important in transport by binding to ions, hormones, lipids, and other compounds c. Fibrinogens -- clotting protein th