How the Immune System Works with a Diagram

The Lymphatic System and Lymph Diagram

Human Circulatory System
In the center of each breast is a highly pigmented nipple that releases milk when stimulated. Chemical digestion begins in the mouth with salivary amylase in saliva splitting complex carbohydrates into simple carbohydrates. Deep lymph nodes and vessels of the thorax and abdomen diagrammatic. Normal flora fill almost all of the available ecological niches in the body and produce bacteriocidins, defensins, cationic proteins, and lactoferrin all of which work to destroy other bacteria that compete for their niche in the body. They are soluble proteins secreted by the plasma offspring clones of primed B cells. This page was last edited on 23 April , at Immune warriors are in combat fighting off vicious invaders trying to take over your body.

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All blood cells are manufactured by stem cells, which live mainly in the bone marrow, via a process called hematopoiesis. The stem cells produce hemocytoblasts that differentiate into the precursors for all the different types of blood cells. Hemocytoblasts mature into three types of blood cells: The leukocytes are further subdivided into granulocytes containing large granules in the cytoplasm and agranulocytes without granules.

The agranulocytes are lymphocytes consisting of B cells and T cells and monocytes. Lymphocytes circulate in the blood and lymph systems, and make their home in the lymphoid organs.

All of the major cells in the blood system are illustrated below. There are —10, WBCs per mm 3 and they live days. About 2,, RBCs are produced each second and each lives for about days They migrate to the spleen to die. Once there, that organ scavenges usable proteins from their carcasses. A healthy male has about 5 million RBCs per mm 3 , whereas females have a bit fewer than 5 million. Normal Adult Blood Cell Counts.

Blood type AB means both antigens are present and type O means both antigens are absent. Type A blood has A antigens and type B blood has B antigens. Some of the blood, but not red blood cells RBCs , is pushed through the capillaries into the interstitial fluid. It flows in the lymphatic vessels and bathes tissues and organs in its protective covering. There are no RBCs in lymph and it has a lower protein content than blood. The lymph flows from the interstitial fluid through lymphatic vessels up to either the thoracic duct or right lymph duct, which terminate in the subclavian veins, where lymph is mixed into the blood.

The right lymph duct drains the right sides of the thorax, neck, and head, whereas the thoracic duct drains the rest of the body. Lymph carries lipids and lipid-soluble vitamins absorbed from the gastrointestinal GI tract. Since there is no active pump in the lymph system, there is no back-pressure produced. The lymphatic vessels, like veins, have one-way valves that prevent backflow. Additionally, along these vessels there are small bean-shaped lymph nodes that serve as filters of the lymphatic fluid.

It is in the lymph nodes where antigen is usually presented to the immune system. The human lymphoid system has the following: The innate immunity system is what we are born with and it is nonspecific; all antigens are attacked pretty much equally. It is genetically based and we pass it on to our offspring.

Normal flora are the microbes, mostly bacteria, that live in and on the body with, usually, no harmful effects to us. We have about 10 13 cells in our bodies and 10 14 bacteria, most of which live in the large intestine.

There are 10 3 —10 4 microbes per cm 2 on the skin Staphylococcus aureus , Staph. Various bacteria live in the nose and mouth. Lactobacilli live in the stomach and small intestine. The urogenitary tract is lightly colonized by various bacteria and diphtheroids. After puberty, the vagina is colonized by Lactobacillus aerophilus that ferment glycogen to maintain an acid pH. Normal flora fill almost all of the available ecological niches in the body and produce bacteriocidins, defensins, cationic proteins, and lactoferrin all of which work to destroy other bacteria that compete for their niche in the body.

The resident bacteria can become problematic when they invade spaces in which they were not meant to be. This causes an overgrowth of Clostridium difficile , which results in pseudomembranous colitis, a rather painful condition wherein the inner lining of the intestine cracks and bleeds.

A phagocyte is a cell that attracts by chemotaxis , adheres to, engulfs, and ingests foreign bodies. Promonocytes are made in the bone marrow, after which they are released into the blood and called circulating monocytes , which eventually mature into macrophages meaning "big eaters", see below. Some macrophages are concentrated in the lungs, liver Kupffer cells , lining of the lymph nodes and spleen, brain microglia, kidney mesoangial cells, synovial A cells, and osteoclasts.

They are long-lived, depend on mitochondria for energy, and are best at attacking dead cells and pathogens capable of living within cells. Once a macrophage phagocytizes a cell, it places some of its proteins, called epitopes, on its surface—much like a fighter plane displaying its hits.

These surface markers serve as an alarm to other immune cells that then infer the form of the invader. All cells that do this are called antigen presenting cells APCs. The non-fixed or wandering macrophages roam the blood vessels and can even leave them to go to an infection site where they destroy dead tissue and pathogens. Emigration by squeezing through the capillary walls to the tissue is called diapedesis or extravasation.

The presence of histamines at the infection site attract the cells to their source. Natural killer cells move in the blood and lymph to lyse cause to burst cancer cells and virus-infected body cells. They are large granular lymphocytes that attach to the glycoproteins on the surfaces of infected cells and kill them. Polymorphonuclear neutrophils , also called polys for short, are phagocytes that have no mitochondria and get their energy from stored glycogen. They are nondividing, short-lived half-life of 6—8 hours, 1—4 day lifespan , and have a segmented nucleus.

The neutrophils provide the major defense against pyogenic pus-forming bacteria and are the first on the scene to fight infection. It is formed when the interstitial fluid the fluid which lies in the interstices of all body tissues [1] is collected through lymph capillaries. It is then transported through larger lymphatic vessels to lymph nodes , where it is cleaned by lymphocytes , before emptying ultimately into the right or the left subclavian vein , where it mixes back with the blood.

Since the lymph is derived from the interstitial fluid, its composition continually changes as the blood and the surrounding cells continually exchange substances with the interstitial fluid. It is generally similar to blood plasma , which is the fluid component of blood.

Lymph returns proteins and excess interstitial fluid to the bloodstream. Lymph may pick up bacteria and bring them to lymph nodes , where they are destroyed. Metastatic cancer cells can also be transported via lymph. Lymph also transports fats from the digestive system beginning in the lacteals to the blood via chylomicrons. The word lymph is derived from the name of the ancient Roman deity of fresh water, Lympha.

Lymph has a composition comparable to that of blood plasma , but it may differ slightly. Lymph contains white blood cells. In particular, the lymph that leaves a lymph node is richer in lymphocytes. Likewise, the lymph formed in the human digestive system called chyle is rich in triglycerides fat , and looks milky white because of its lipid content.

Blood supplies nutrients and important metabolites to the cells of a tissue and collects back the waste products they produce, which requires exchange of respective constituents between the blood and tissue cells.

This exchange is not direct, but instead occurs through an intermediary called interstitial fluid , which occupies the spaces between cells. As the blood and the surrounding cells continually add and remove substances from the interstitial fluid, its composition continually changes. Water and solutes can pass between the interstitial fluid and blood via diffusion across gaps in capillary walls called intercellular clefts ; thus, the blood and interstitial fluid are in dynamic equilibrium with each other.

However, as it flows through the lymph nodes it comes in contact with blood, and tends to accumulate more cells particularly, lymphocytes and proteins.

The red blood cells get their name from an important component called hemoglobin, which give the red blood cells their red color and also act as oxygen carriers.

The red blood cells are circular, biconcave and flattened along with the ability to alter shapes so as to enable them to squeeze through the tiny capillaries. The do not have the cell nucleus as well as most organelles. A low red blood cell count is considered as harmful for the body, due to the fact that they act as suppliers of oxygen to different parts of the body.

The normal red blood cell count in adult men ranges from 4. It is important to know that the number may differ as per the recommendations of the testing lab as well as the age of the person who is getting tested. Low red blood cell count can be diagnosed by a blood test at a laboratory.

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