Evolution of the Human Immune System

-
Human immune system is an orchestra of various defence mechanisms functioning at different levels, from individual cells to the whole body. Specialised immune mechanisms can be subdivided into innate and adaptive immune systems. Innate immune mechanisms use receptors recognising conserved molecular patterns of pathogens. Adaptive immune system depends on the production of vast repertoires of immune receptors and selective expansion of pathogen‐specific ones. Some basic cellular functions such as ubiquitination and autophagy as well as stress response pathways also contribute to the immune defence. Various immune defence systems work autonomously but in communication with each other. All responses are coordinated at the body level by hormones and other mediators. Layered and redundant structure of the human immune system offers great efficiency in the detection and elimination of pathogens. All immune mechanisms evolve interactively in concordance with human environment and history. 

Comments

Post a Comment

Popular posts from this blog

Cell Reproduction

-
Image
Genetic Control of Protein Synthei s s, Cell Function, and Cell Reproduction    Virtually everyone knows that the genes, located in the nuclei of all cells of the body, control heredity from parents to children, but most people do not realize that these same genes also control day-today function of all the body’s cells. The genes control cell function by determining which substances are synthesized within the cell which structures, which enzymes, which chemicals. The general schema of genetic control : Each gene, which is a nucleic acid called deoxyribonucleic acid (DNA), automatically controls the formation of another nucleic acid, ribonucleic acid (RNA); this RNA then spreads throughout the cell to control the formation of a specific protein. Because there are more than 30,000 different genes in each cell, it is theoretically possible to form a very large number of different cellular proteins. Some of the cellular proteins are structural proteins, which, in associati...
Read more

The Anterior Pituitary and Hypothalamus

-
Image
The anterior pituitary is often referred to as the “master gland” because, together with the hypothalamus, it orchestrates the complex regulatory functions of multiple other endocrine glands. The anterior pituitary gland produces six major hormones: (1) prolactin (PRL), (2) growth hormone (GH), (3) adrenocorticotropin hormone (ACTH), (4) luteinizing hormone (LH), (5) follicle-stimulating hormone (FSH), and (6) thyroid-stimulating hormone (TSH). Pituitary hormones are secreted in a pulsatile manner, reflecting stimulation by an array of specific hypothalamic releasing factors. Each of these pituitary hormones elicits specific responses in peripheral target tissues.  The Disorders of the Anterior  Pituitary and Hypothalamus  Hormonal products of these peripheral glands, in turn, exert feedback control at the level of the hypothalamus and pituitary to modulate pituitary function. Pituitary tumors cause characteristic hormone excess syndromes. Hormone deficiency m...
Read more

Hypothalamic Tumor

-
Image
HYPOTHALAMIC, PITUITARY, AND OTHER SELLAR MASSES PITUITARY TUMORS    Pituitary adenomas are the most common cause of pituitary hormone hypersecretion and hyposecretion syndromes in adults. They account for ~15% of all intracranial neoplasms. At autopsy, up to one-quarter of all pituitary glands harbor an unsuspected microadenoma. Pathogenesis    Pituitary adenomas are benign neoplasms that arise from one of the five anterior pituitary cell types. The clinical and biochemical phenotype of pituitary adenomas depend on the cell type from which they are derived. Thus, tumors arising from lactotrope (PRL), somatotrope (GH), corticotrope (ACTH), thyrotrope (TSH), or gonadotrope (LH, FSH) cells hypersecrete their respective hormones. . Plurihormonal tumors that express combinations of GH, PRL, TSH, ACTH, and the glycoprotein hormone α subunit may be diagnosed by careful immunocytochemistry or may manifest as clinical syndromes that combine features of these hor...
Read more