Immune cells processes

Among vertebrate species, the neuro-endocrine-immime system is responsible for many complex, inter-related physiological processes including neuronal, homeostatic, reproductive and immune functions. There are four main types of hormone polypeptides, eicosanoids, steroids and thyroid hormones. Reflecting the inter-dependency of the neiiro-endocrine and immune systems, hormones, neuropeptides and other neiirotransmitters are known to be produced by some immune cells and play a role in the regulation of the immune system, while endocrine and nervous tissues express receptors for many substances produced by the immune system. The major focus of interest in endocrine disruption has... 

Fig. 14.1. The Thl/Th2 balance is central to the regulation of normal wound repair. Tissue injury results in the initiation of an inflammatory response, mediated by a variety of cells and their by-products. Immune cells are recruited and cross-regulate the Thl/ Th2 balance that occurs in response to the cytokine environment. This balance is in turn cross-regulated by the chemokine/chemokine-receptor expression profile, which functions to amplify the inflammatory process. Cells residing in the injured tissue release profibrotic mediators, which promote fibroblast activation, proliferation, and differentiation to the myofibroblast phenotype. Myofibroblasts produce collagen to repair damaged tissue, which is an event that is favored by the inhibition of MMP activity. The Thl/Th2 balance is central to whether a normal or aberrant wound-repair process is established A Thl environment promotes normal tissue resolution (fibrinolysis), whereas a Th2 environment maintains the progression of fibrotic disease (excessive collagen deposition).

Figure 11.30 Mechanisms of regulation of phospholipase A2. In all these processes described above, it is phospholipase A that carries out the hydrolysis of membrane phospholipid. Cytokines are local hormones produced by immune cells, T-lymphocytes and macrophages (Chapter 17). Other factors relate to shear stress in endothelial cells and those that stimulate release of granules from mast cells. Eicosanoids are present in the granules and they must be re-synthesised after degranulation in the mast cells. Here the enzymes described above must be present in mast cells.

Inflammation is a local and early response of a tissue to a noxious stimulus, such as physical injury or infection. It results in an increase in the number of immune cells in the area of damage or infection which kill pathogens, remove damaged or dead cells and initiate the healing process. The well-known characteristics of inflammation are redness, heat, swelling and pain. Redness is due to increased blood flow to the damaged area caused by vasodilation of small arterioles, which facilitates an increase in the number of immune cells in the damaged area and facilitates provision... 

The stimulus provided by the binding of the antigen and the co-stimulator initiates the proliferation process. The sequence of signalling mechanisms that results is shown in Figure 17.43. The process of proliferation is the process of the cell cycle which is described in Chapter 20. Some of the factors that are important for stimulation of the cell cycle in immune cells are indicated in Figure 17.44. 

There is evidence that stressful conditions decrease the effectiveness of the immune system the loss of a job, a divorce or a bereavement increases the risk of development of cancer. This is due to impairment of the process of immune surveillance carried out by the neutrophils and other immune cells. They kill tumour cells that are migrating from a primary tumour to establish another tumour in a different tissue. The impairment may be due to chronic activation of the sympathetic system, which increases the... 

Figure 21.20 Diagram of a tori q/de in a patient with a tumour. Lactate produced from glucose by tumour cells is converted back to glucose in the liver (gluconeogenesis) and released into the blood for re-uptake by tumour cell, an ATP-reguiring process. Note that muscle, immune cells and red blood cells will also contribute to the cycle (see. Chapter 6 Figure 6.10).

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