primary and secondary lymphoid organ

1. K.VIMAL RAJ
 Read and develop our knowledge.

2. Lymphoid system
These are specialized organ fight against the pathogen.
 lymphatic system is described in seventeenth century by
Thomas bartholin.
It helps to rid the body toxins and other unwanted materials.
The primary function of lymphoid system is transport the
lymph.
The lymph is fluid like fighting white blood cells against the
pathogen.
It was in two types
primary lymphoid organ
secondary lymphoid organ

3. Primary lymphoid organ:
 It is the site for the generation of WBC(white blood
cells)
 It contain either B-cells or T- cells.
 And antigen can't enter in this site.
 Here the leukocytes(B,T-cells) are differentiated
and matured.
 Decreases in size and strength with age.
 There are mainly two primary lymphoid organ
 bone marrow.
Thymus .

4. Bone marrow
 It is soft and fixable in nature found in bone cavity.
 It is the site for the origin and the development B-
cells
 There are two categories of bone marrow is found
Red marrow
Yellow marrow

5. Bone marrow function
 Bone marrow transplant saves the lives of people
from leukemia, lymphoma and other blood cancer.
 Bone marrow generates platelets to prevent the
blood bleeding.
 It generates the RBC for the purpose of carry the
oxygen molecules.

6. Thymus
It is flat bilobed organ found above the heart.
It has two lobes surrounded by fibrous capsule.
The outer lobe is cortex and the inner one is medulla.
 cortex crowed with actively proliferating small
lymphocytes.
Medulla contain mature lymphocytes(T-cells).

7. Thymus function
It is the major site for T lymphocyte proliferation in the
body.
It role also found in the development of cell mediated
immunity.
Thymus release the thymosin hormone that stimulates
the maturation of T-cells.

8. Secondary lymphoid organ
It is the site for the adaptive immunity response.
It contain both B cells and T cells.
Antigen enter in and stimulates the lymphocytes.
Here the lymphoid cells become functional.
Increases in size with age,
There are some secondary lymphoid organ was
found
Lymph node
Spleen
 MALT
 peyer’s patches.

9. Lymph node
It is small, round or ovoid bodies
The node is differentiated into outer cortex and inner
medulla
In the cortex there is accumulation of lymphocytes,
macrophages and follicular dendritic cells arranged
in primary follicels.
Primary follicels enlarge to form secondary follicels
contain germinal center.
The medulla is the core of the lymph node mainly
processes T –lymphocytes.
The medulla also contain the lymphoid linage cells.

10. Lymph node function
It act as the filter for lymph.
It helps for the proliferation and circulation of T and
B cells.
It rise the immune reaction and fight against the
microbial infection.

11. spleen
It is the largest lymphoid organ.
It found in the left side of the abdominal cavity.
It was ovoid shape and red in colour.
It contain red and white pulp reign that act as filter.
It also contain macrophages.

12. Spleen function
It helps to fight against the certain bacteria.
Platelets and WBC are stored in spleen.
It serve as graveyard.

13. MALT
The MALT means mucosa associated lymphoid
tissues.
It produce the IgA immunoglobulin molecules.
It found the respiratory track.

14. Peyer’s patches
It is the small masses of lymphoid tissue
It found in small intestine.
It play a important role in traping antigen from
pathogen and destroy them.

15. Thank you