Lymph node
A secondary nodule within the cortex is the site for
Site of proliferation of B lymphocytes following antigen binding. Forms a germinal center by activated lymphocytes
outline w corona
Lymph sinuses are formed by and are filled with
Formed by reticular tissue, filled with lymphocytes and lymph fluid
A peyers patch is considered this type of lymphoid organ and is abundant where
Secondary lymphoid organ, most abundant in wall of ileum
Are tonsils incompletely or completely encapsulated
Incompletely encapsulated
Function of this lymphoid organ
Filter blood
lymphopoiesis, hemopoiesis, storage of blood cells
What occurs in the germinal Center
Activated B lymphocytes come to primary nodule and proliferate
lymphoblasts formed and further divided to plasma cells and memory cells
follicular dendritic cells assists w proliferation of lymphocyte and present antigen to lymphocyte
What artery enters the lymph node through the hills for blood circulation
Nodal artery
Gut associated lymphoid tissue (GALT)
Intercepts antigens entering body orifices
Components of gross divisions of spleen
Red pulp- area filled w blood
white pulp- gray area w lymphocytes
What is the corona of a secondary nodule composed of
Dense accumulation of lymphocytes surrounding germinal center
displaced naive and memory B lymphocytes and T lymphocytes from original primary nodule
transient newly formed memory B lymphocytes and plasma cell
The branches of the nodal artery traverse through medulla in trabeculae and leave trabeculae to enter
The paracortex and cortex
Where is the site where B lymphocytes and T lymphocytes leave circulating blood and enter peyers patch
High endothelial venules
The stroma of the tonsil includes
Capsule, septa, surface epithelium
Stroma of spleen contains
function of each
Capsule, trabeculae, reticular CT
capsule- helps move stored blood into circulation
trabeculae- contribute to internal support of parenchyma
CT- background supporting tissue
The paracortex is known as what zone and what occurs here
Thymus dependent zone
site of proliferation of T lymphocytes
Once the branches reach the paracortex and Cortex what is formed
Capillary bed formed in cortex, capillaries merge to form High endothelial venules
M cells are located where and what is there function
In simple columnar epithelium that line luminal surface above peyers patch
capture antigens in lumen of ileum, antigen presenting cells embedded in basal surface of M cell
The parenchyma of tonsils include
Nodules, diffuse lymphatic tissue
Summary of vascular supply
Splenic artery—> trabecular artery—> central artery—> penicillar arteries—> venous sinuses—> collecting veins—> trabecular veins—> splenic veins
Medullary cords are the site fro congregation of what cells
Plasma cells, lymphocytes, and macrophages
The high endothelial venules drain into
Larger veins, which exit at the hilus
Two distinguishing characteristics of Peyers patch
No capsule, only efferent lymphatic vessels
The nodules contain
the diffues lymphatic tissue contains
Nodules: primary and secondary, B lymphocytes
tissue: around nodules, t lymphocytes, other leukocytes, high endothelial venules
The splenic artery originates from the
Celiac artery