O

Three

?

Two

?

Active form

Monomer

Monomer

Monomer

Homodimer

"The abbreviations are defined in Table 15-11. Modified from Metealf, D., Nicola, N., and Gough, N. M. (1995). Hormones and blood cell production. In "Endocrinology" (L. J. DeGroot et al., eds.) Vol. 3, pp. 2943-2963. W. B. Saunders, Philadelphia, PA.

"The abbreviations are defined in Table 15-11. Modified from Metealf, D., Nicola, N., and Gough, N. M. (1995). Hormones and blood cell production. In "Endocrinology" (L. J. DeGroot et al., eds.) Vol. 3, pp. 2943-2963. W. B. Saunders, Philadelphia, PA.

tion and that can be divided into cellular and vascular events. The vascular events involve initial dilations of the small arterioles, which result in increased local blood flow (mediated by histamines and prostaglandins) and exudation of fluid. The fluid exudate contains protein components of four enzyme cascades: (i) the ki-nin system, (ii) the blood coagulation system, (iii) the complement system, and (iv) the fibrinolytic system (see Figure 15-22). As a consequence of local processing by these enzyme cascades (which results in inflammation; see the following), the products of the infective agents are carried by the lymphatic system to nearby lymph glands so as to initiate an immune response.

The cells associated with the inflammation process are of two classes: (a) those cells normally present in tissues (e.g., tissue macrophages, mast cells, and endothelial cells) and (b) leukocytes derived from blood (e.g., polymorphonuclear cells, also known as granulocytes, which include the neutrophils, eosinophils, and basophils, and the monocytes).

The mast cells, granulocytes, and monocytes-macrophages are all derived from the hematopoietic cell differentiation process (see Figure 15-21). The granulocytes are the first cells to enter a site of inflammation; they first adhere to the vascular endothelial cells, migrate by chemotaxis to the site of the invading pathogen, and then engulf, kill, and digest the invading organism. The monocytes-macrophages arrive at a later stage in the inflammation process; the monocytes further differentiate into macrophages, which then be come activated. The macrophages have many properties; they can aggressively phagocytose (engulf microorganisms) and secrete cytokines, paracrine hormones (NO, prostaglandins), and digestive enzymes. The mast cells are capable of secreting many local paracrine substances, including histamine, leukotrienes, platelet-activing factor, and interleukins; in addition the mast cell membranes have receptors for the IgE class of antibodies.

The immune response is mediated by specialized cells, the B and T lymphocytes, which are also generated by the hematopoiesis cell differentiation system. The B cells are responsible for antibody production (IgG, IgE, IgM, IgA, and IgD). The T cells are responsible for so-called cell-mediated reactions, which include a complex array of responses, including the killing of virally infected cells and the secretion of lymphokines (e.g., INF,,, which activates macrophages), which are complementary to the production of antibodies by the B cells.

Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

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