lecture 2 Retiuculo.ppt
- 1. 1 Human Physiology KAAF University College RES Dr Joseph Somuah Akuamoah Senior lecturer
- 2. 2 The Reticuloendothelial system (RES) Contents • Kupffer cells of the liver • The Spleen • Microglia of the brain • Alveolar macrophages • Bone marrow lymph nodes • Macrophages in the intestine and other tissues
- 3. 3 Importance of RES • The RES is a heterogenous population of phagocytic cells that play an important role in the clearance of particles and soluble substances in the circulation and tissues:- part of the immune system. • The main components of the RES includes Kupffer cells of the liver, microglia of the brain, alveolar macrophages, bone marrow lymph nodes, macrophages in the intestines and other tissues.
- 4. 4 What are Macrophages? • Macrophages are a type of white blood cells that play an important role in the human immune system. • They carry various functions including engulfing and digesting microorganisms. • They clear out debris and dead cells and stimulate other cells involved in immune function. • They develop in the bone marrow from cells known as monocytes and circulate in the blood. • Mushrooms & amino acids increase macrophages. • Macrophages have a long life span, ranging from months to years. • Macrophage deficiency leads to risk of infections
- 5. 5 The RES in the liver The RES in the liver includes: 1.Kupffer cells:- (macrophages in the liver). They constitute 80-90% of them. 2. Fat storing cells and 3. Pit cells 4. Endothelial cells
- 6. 6 The Spleen • The spleen is a component of the RES. • The splenic phagocytes include reticular cells, free macrophages of the red pulp and modified reticular cells of the ellipsoids. • The spleen helps keep harmful microorganisms out of the blood stream • The spleen also removes unhealthy, old and misshapen red blood cells from circulation • The spleen can become swollen after an infection or injury. It can also become enlarged from diseases like cirrhosis, leukemia or rheumatoid arthritis.
- 7. 7 Microglia of the brain • Microglial cells are the most prominent immune cells of the central nervous system (CNS) and are the first to respond when something goes wrong in the brain. • Microglia are broadly distributed throughout the brain and the spinal cord. • Microglia are involved in the pathogenesis of diseases such as Parkinson’s, multiple sclerosis, AIDS, etc.
- 8. 8 Alveolar macrophages • These are the most abundant innate immune cells in the lung parenchyma, located on the luminal surface of the alveolar space. • They are the first to encounter incoming pathogens and pollutants • They help to orchestrate the initiation and resolution of the immune response in the lung. • They secrete cytokines (interleukins and tumor necrosis factor)
- 9. 9 Bone marrow- lymphatic system • Lymphocytes (a type of white blood cells) are the main cells that make up lymphoid tissue (a major part of the immune system). • The lymphocytes are made in the bone marrow. • Lymphoma (a type of blood cancer, also called cancer of lymphatic system) can affect the bone marrow, where blood cells are made. • This will affect the ability to make new blood cells, leading to complications such as infection: a shortage of white blood cells (neutropenia), heightens the risk of infection.
- 10. 10 MACROPHAGES IN THE INTESTINES • Intestinal macrophages play a key role in the gut immune system and the regulation of gastrointestinal physiology (gut motility and secretion). • They are able to keep the gut from chronic inflammation despite constantly facing foreign antigens from food and water. • About 40% of the dry matter in stool is composed of bacteria, many of which are still alive. • It is normal to see a moderate to heavy growth of both Gram negative and Gram positive bacteria in a healthy, normal stool specimen.
- 11. 11 MACROPHAGES IN THE SKIN/OTHERS • When infection begins in a subcutaneous tissue and local inflammation ensues, local tissue macrophages form, attack and destroy the infectious agents. • Infectious agents such as bacteria can be absorbed through the capillaries into the blood. These agents enter the lymph and flow to the lymph nodes where they are trapped by the tissue macrophages.
- 12. 12 WHITE BLOOD CELLS (LEUKOCYTES) • The leukocytes (white blood cells) are the mobile units of the body’s protective system. They are formed from the bone marrow or lymph tissue (normal is 4.0 X 109 /L– 11.0 X109/L) 1. Neutrophils about 62%; seen in acute/severe inflammation. 2. Eosinophils form about 2.3%; seen in parasitic infections 3. Basophils form about 0.4%; some allergic reactions 4. Granulocytes and Monocytes in the tissues swell to become tissue macrophages. They form 5.3% 5. Lymphocytes form 30%, produced from lymph tissue 6. Plasma cells produced from the lymph tissue. • In addition there are large number of platelets, which are another type of cell similar to the white blood cell. The main function is to activate the blood clotting mechanism.
- 13. 13 DISORDERS OF WHITE BLOOD CELLS • In leukopenia the bone marrow produces very few white blood cells. This leaves the body unprotected against many bacteria and other infectious agents. • Uncontrolled production of white blood cells from cancer causes leukemia. • Leukemia types are lymphocytic leukemias. These are from cancer of the lymphoid cells and • Myelogenous leukemia. From cancerous production of young myelogenous cells in the bone marrow. Types are neutrophilic leukemia, eosinophilic leukemia, basophilic leukemia or monocytic leukemia