What are the main histological features of the thymus gland?
What are the main histological features of the thymus gland?
Overview. The thymus is an encapsulated primary lymphoid organ. Histologically, it is divided into subcapsular cortical, cortical and medullary regions within each lobule, created by the intervening connective tissue septae extending from the capsule.
What type of tissue is in the thymus?
The thymus tissue is distinguishable into an outer zone, the cortex, and an inner zone, the medulla. The organ is composed principally of two types of cells, called, respectively, lymphocytes (see lymphocyte) and reticular cells.
What is the structure of thymus?
The thymus consists of two lobes, merged in the middle, surrounded by a capsule that extends with blood vessels into the interior. The lobes consist of an outer cortex rich with cells and an inner less dense medulla.
Why is thymus also called Lymphoepithelial organ?
Once migration is complete the epithelial cells organize into a loose meshwork separated by the developing vasculature. Following the rapid population with lymphocyte precursors from developing hematopoetic tissues (gestational day 11–12 in the mouse), the thymus becomes a lymphoepithelial organ.
What is Trabeculae in thymus?
Intralobular trabeculae extend from the capsule into the cortex. Within the medulla are conspicuous eosinophilic, whorled structures called Hassall’s corpuscles composed of a concentric mass of epithelioreticular cells joined together by many desmosomes. These are diagnostic of the thymus.
What is medulla of thymus?
The medulla of the thymus contains T-lymphocytes and increased numbers of epithelial cells with pale-staining nuclei. The epithelial cells provide structural support to the medulla and negatively select self-reactive T-cells to generate tolerance against self-antigens.
What is Cytoreticulum?
Definition of cytoreticulum 1 : a relatively solid mesh or framework in which the hyaloplasm is suspended according to some theories of protoplasmic structure. 2 : a meshwork of cells and cell processes (as in connective tissues)
What are the four types of histology?
Histology is the the field of study that involves the microscopic examination of tissue appearance, organization, and function. Tissues are organized into four broad categories based on structural and functional similarities. These categories are epithelial, connective, muscle, and nervous.
How do you analyze histology?
Histology is the study of the microscopic anatomy of cells and tissues of organisms. Histological analysis is performed by examining a thin slice (section) of tissue under a light (optical) or electron microscope [47,74,80,104,127].
What are lobes of thymus?
The thymus is divided into 2 main parts – a right lobe and a left lobe. Each lobe is divided into smaller sections called lobules that give the thymus its bumpy appearance. Each lobule is made up of a centre part (called the medulla) and an outer layer (called the cortex).
What is the thymic Epithelioreticulocytes shape?
Epithelial reticular cells, or epithelioreticular cells (ERC), some called thymic epithelial cell (TEC), are a structure in both the cortex and medulla of the thymus. However, histologically, they are more easily identified in the medulla.