Exploring the anatomy and physiology of ageing. Part 9--The immune system

Several body functions deteriorate with age. The external signs of aging are easily identifiable. For example, the skin becomes dry, less elastic, and thins out, forming wrinkles. The skin of the face begins to appear looser due to a decrease in the levels of elastic and collagen fibers in the connective tissue. Additionally, melanin production in the hair follicle decreases with age, resulting in gray hair. Moreover, the senses of sight and hearing decline, so glasses and hearing aids may...

Aging is a complex biological phenomenon influenced by various processes that affect cellular and systemic functions. Several prominent theories attempt to explain its mechanisms, highlighting cellular limitations, oxidative damage, and hormonal changes as central factors in aging.
Cellular Clock Theory
The cellular clock theory posits that the human lifespan is closely tied to the finite capacity of cells to divide, a phenomenon governed by telomeres, which are protective caps at the ends of...

Immunity is a crucial biological concept about our body's inherent capacity to prevent infections and diseases. A complex network of cells and tissues collectively known as the immune system facilitates this natural defense mechanism. The immune system plays an integral role in maintaining our health and well-being, shielding us from potential health threats.
The immune responses can be categorized into two types: innate and adaptive. Innate immunity comprises nonspecific defenses we are born...

The lymphatic system plays a crucial role in bolstering our immune system. It consists of a network of lymphoid organs, lymph, and lymphatic vessels that provide structural and functional support in safeguarding the body against pathogens such as viruses and bacteria.
The primary lymphoid organs, including the bone marrow and the thymus, serve as the maturation sites for lymphocytes. Secondary lymphoid organs, like the mucosa-associated lymphoid tissue, activate these lymphocytes and serve as...

Overview

Secondary organs, including lymph nodes, the spleen, and mucosa-associated lymphoid tissue (MALT), work harmoniously to protect us from disease and infection.
The spleen is a vital organ in the lymphatic system, nestled in the upper left side of the abdomen. It is composed of two primary regions: the red pulp and the white pulp, each having distinct functions. The red pulp performs a significant role in blood filtration. It efficiently purges the blood of old or damaged red blood cells and...