Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ THE COMPOSITION OF BLOOD ++ Blood is composed of cellular elements (i.e., red blood cells, white blood cells, and platelets) suspended in blood plasma. A person who weighs 70 kg has approximately 5 L of blood with about 2 L of cellular elements and 3 L of plasma. Plasma composition. Plasma is the part of the ECF contained within the cardiovascular system. It is approximately 92% water, 7% protein, and 1% small dissolved solutes (e.g., ions, urea, glucose, amino acids, and lipids). Plasma concentrations of ions and small molecules are similar to those in the interstitial fluid, due to the free exchange of water and small solutes across most blood capillaries (Table 3-1). Protein concentration is higher in plasma than interstitial fluid because most capillaries are impermeable to plasma proteins. The protein concentration gradient creates the colloid osmotic (oncotic) pressure gradient that opposes the filtration of plasma out of the capillaries (see Chapter 4). Albumin is the most abundant type of plasma protein and is the greatest contributor to the plasma oncotic pressure (Table 3-2). Hypoalbuminemia has many causes, including nephrotic syndrome, liver failure, and severe malnutrition. Regardless of the cause, hypoalbuminemia can result in anasarca (generalized massive edema). There are three main cell types in circulating blood (Table 3-3): Red blood cells (erythrocytes) are essential for the transport of O2 and CO2 in blood. There are approximately 5 × 1012 red blood cells per liter of blood. Platelets (thrombocytes) are small cellular fragments that play a key role in hemostasis. There are approximately 300 × 109 platelets per liter of blood. White blood cells (leukocytes) are the only fully functional nucleated cells in circulating blood. White cells play a defensive role in destroying infecting organisms and in the removal of damaged tissue. The total white cell count is approximately 5 × 109 cells per liter of blood. ++Table Graphic Jump LocationTable 3-1Normal Plasma CompositionView Table||Download (.pdf) Table 3-1 Normal Plasma Composition Substance Normal Value Normal Range Sodium 140 mM 136–146 mM Potassium 4.5 mM 3.5–5.5 mM Chloride 100 mM 96–106 mM Bicarbonate 24 mM 22–28 mM Calcium* 2.5 mM 2.2–2.8 mM pH (arterial) 7.40 7.35–7.45 PCO2 (arterial) 40 mm Hg 38–42 mm Hg PO2 (arterial) 90 mm Hg 80–100 mm Hg Glucose (fasting) 80 mg/dL 70–99 mg/dL Urea (BUN) 12 mg/dL 9–18 mg/dL Protein 7 g/dL 6–8 g/dL *Approximately 50% is protein bound.BUN, blood urea nitrogen. ++Table Graphic Jump LocationTable 3-2The Major Types of Plasma ProteinsView Table||Download (.pdf) Table 3-2 The Major Types of Plasma Proteins Plasma Protein Major Source Examples and Functions Albumin Liver Main component of plasma oncotic pressure; binding of various substances α-Globulins and β-globulins Liver Examples (there are many) include hormone-binding proteins and the iron carrier protein transferrin Coagulation proteins Liver... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.