Introduction

Lymphoid tissue covers all of the various tissues that are important in mounting an immune response. This includes discrete organs such as the spleen, thymus and lymph nodes, as well as more diffuse aggregations of lymphocytes. This topic also gives some background information of the properties of immune cells, including the different types of lymphocytes, and their functions. By the time you have finished reading through this topic, you should know about the different ways in which immune responses are elicited, and the ways in which different lymphoid tissues take part in the immune responses.

Objectives

By the time you have finished this topic, you should know:

1. The origin, subsequent development and roles of the two major classes of lymphocyte.
2. The general properties of primary and secondary lymphoid tissues
3. The structure and function of one type of primary lymphoid tissue: the thymus gland.
4. The histological structure of four different types of secondary lymphoid tissue; lymph nodes, tonsils, Mucosa associated lymphoid tissue and the spleen, and how their structure is adapted to their different functions.
5. The involvement of the lymphoid tissues in some common medical conditions.