Immune System - National Library of Medicine - PubMed Health. Definition of leukocyte by Medical dictionary. Leukocyte [loo´ko-sīt] a type of bloodcellthatlackshemoglobinand is thereforecolorless.Leukocytesarelarger in sizeandfewer in numberthanerythrocytes; normallythebloodhasabout8000 of themper mm3.
In contrast to erythrocytes,leukocytescanmoveaboutundertheirownpowerwithameboid movement. Bone Marrow and the Immune System. What is bone marrow?
Bone marrow is the spongy tissue inside our bones. All bones in newborn babies have active marrow, which means they are producing new marrow cells. By the time your child reaches young adulthood, the marrow inside the bones of the hands, feet, arms, and legs stop producing new marrow cells. In adults, active marrow is found inside the spine, hip and shoulder bones, ribs, breastbone, and skull. Through the Microscope. (11111 Reads) Table of Contents| Chapter Article List| Printable Version | Printable Chapter [Prev] | [Next] The primary tissues of the immune system are the bone marrow and thymus and these are involved in the creation and maturation of immune cells.
The secondary tissues of the immune system are the spleen, lymphatic system, lymph nodes and MALT. These tissues contain mature immune cells and are the active part of the immune system. The immune system consists of a complex network of organs and tissues, connected by blood and lymphatic vessels, that work together to prevent infection. Adenoids and Tonsils. What are adenoids and tonsils? This leaflet gives a brief overview of problems which may occur with tonsils and adenoids.
There are separate more detailed leaflets on related topics such as tonsillitis, glandular fever and sore throat. Tonsils Tonsils are lumps of soft tissue and are part of the immune system. You have two tonsils, one on either side at the back of the mouth. Tonsils vary in size from person to person. Immune System. The immune system, which is made up of special cells, proteins, tissues, and organs, defends people against germs and microorganisms every day.
In most cases, the immune system does a great job of keeping people healthy and preventing infections. But sometimes problems with the immune system can lead to illness and infection. About the Immune System The immune system is the body's defense against infectious organisms and other invaders.