Blood, Heart, and Circulation 407concentration is Na^1. In addition to Na^1 , plasma contains many
other ions, as well as organic molecules such as metabolites, hor-
mones, enzymes, antibodies, and other proteins. The concentra-
tions of some of these plasma constituents are shown in table 13.1.Plasma Proteins
Plasma proteins constitute 7% to 9% of the plasma. The
three types of proteins are albumins, globulins, and fibrinogen.
Albumins account for most (60% to 80%) of the plasma pro-
teins and are the smallest in size. They are produced by the liver
and provide the osmotic pressure needed to draw water from
the surrounding tissue fluid into the capillaries. This action is
needed to maintain blood volume and pressure. Globulins are
grouped into three subtypes: alpha globulins, beta globulins,
and gamma globulins. The alpha and beta globulins are pro-
duced by the liver and function in transporting lipids and fat-
soluble vitamins. Gamma globulins are antibodies produced
by lymphocytes (one of the formed elements found in blood
and lymphoid tissues) and function in immunity. Fibrinogen,
which accounts for only about 4% of the total plasma proteins,
is an important clotting factor produced by the liver. During
the process of clot formation (described later in this section),
fibrinogen is converted into insoluble threads of fibrin. Thus,
the fluid from clotted blood, called serum, does not contain
fibrinogen but is otherwise identical to plasma.Plasma Volume
A number of regulatory mechanisms in the body maintain
homeostasis of the plasma volume. If the body should lose water,
the remaining plasma becomes excessively concentrated—its
osmolality (chapter 6) increases. This is detected by osmorecep-
tors in the hypothalamus, resulting in a sensation of thirst and the
release of antidiuretic hormone (ADH) from the posterior pitu-
itary (chapter 11, section 11.3). This hormone promotes water
retention by the kidneys, which—together with increased intake
of fluids—helps compensate for the dehydration and lowered
blood volume. This regulatory mechanism, together with others
that influence plasma volume, are very important in maintaining
blood pressure (chapter 14, section 14.6).The Formed Elements of Blood
The formed elements of blood include two types of blood
cells: erythrocytes, or red blood cells, and leukocytes, or white
blood cells. Erythrocytes are by far the more numerous of the
two. A cubic millimeter of blood normally contains 5.1 million
to 5.8 million erythrocytes in males and 4.3 million to 5.2 mil-
lion erythrocytes in females. By contrast, the same volume of
blood contains only 5,000 to 9,000 leukocytes.Erythrocytes
Erythrocytes are flattened, biconcave discs about 7 m m in
diameter and 2.2 m m thick. Their unique shape relates to
their function of transporting oxygen; it provides an increasedMeasurement Normal Range
Blood volume 80–85 ml/kg body weight
Blood osmolality 285–295 mOsm
Blood pH 7.38–7.44
Enzymes
Creatine phosphokinase (CPK) Female: 10–79 U/L
Male: 17–148 U/L
Lactic dehydrogenase (LDH) 45–90 U/L
Phosphatase (acid) Female: 0.01–0.56 Sigma U/ml
Male: 0.13–0.63 Sigma U/ml
Hematology Values
Hematocrit Female: 36%–46%
Male: 41%–53%
Hemoglobin Female: 12–16 g/100 ml
Male: 13.5–17.5 g/100 ml
Red blood cell count 4.50–5.90 million/mm^3
White blood cell count 4,500–11,000/mm^3
Hormones
Testosterone Male: 270–1,070 ng/100 ml
Female: 6–86 ng/100 ml
Adrenocorticotrophic hormone
(ACTH)6–76 pg/mlGrowth hormone Children: over 10 ng/ml
Adult male: below 5 ng/ml
Insulin 2–20 μU/ml (fasting)
Ions
Bicarbonate 24–30 mmol/l
Calcium 9.0–10.5 mg/dl
Chloride 98–106 mEq/L
Potassium 3.5–5.0 mEq/L
Sodium 135–145 mEq/L
Organic Molecules (Other)
Cholesterol, desirable under 200 mg/dl
Glucose 75–115 mg/dl (fasting)
Lactic acid 5–15 mg/dl
Protein (total) 5.5–8.0 g/dl
Triglyceride under 160 mg/dl
Urea nitrogen 10–20 mg/dl
Uric acid Male 2.5–8.0 mg/dl
Female 1.5–6.0 mg/dlSource: Excerpted from material appearing in The New England Journal of
Medicine, “Case Records of the Massachusetts General Hospital,” 302:37–38,
314:39–49, 351:1548–1563. 1980, 1986, 2004.
Table 13.1 | Representative Normal
Plasma Values