Histology
, ~
Histology of Lymphoid Organs
Lymphoid Organs:
Lymphoid
·
system is responsible for the immunological defense of the body Lymphoid organs
. are
designed to
gather
& destroy infectious microorganisms & to store lymphocytes .
· Two
categories :
"Primary central Lymphoid organs : responsible for the development of lymphocytes into mature immunocompetent cells
.
~
Fetal liver, prenatal & postnatal bone marrow , a thymus
2 Secondary (peripheral) Lymphoid organs : Responsible for the proper environment in which immunocompetent cells can react with
eachother ,
along with
antigens &other cells to mount an
immunological challenge agains invading antigens or
pathogens .
~
Lymph nodes , spleen, I mucosa associated Lymphoid tissue .
Thymus:
A lymphoid organ located in the mediastemum It is mostly active
central .
during youth.
It is the site of maturation of T dymphocytes & secretes thymic hormones such as thymosin thymopoietin thymulin a
, , ,
thymic humoral factor .
* It differs from other lymphoid organs since it functions strictly in lymphocyte maturation . It also consists of thethymic epithelial cells .
* Cortex of thymus :
Contains
developing
~
thymocytes (T Lymphocytes) Macrophages
, &,
~
Thymic cortical epithelial cells . These cells are linked to eachother by
desmosomes that surround the capillary.
A dual basal
Lamina is present in the space between epithelial cells & capillaries.
~
The thymic endothelial cells , basal Lamina, & endothelial cells form the
functional blood thymus -
barrier. It prevents the contact of
antigenic material
with the
developing
Flymphocytes .
, ~
Histology of Lymphoid Organs
Lymphoid Organs:
Lymphoid
·
system is responsible for the immunological defense of the body Lymphoid organs
. are
designed to
gather
& destroy infectious microorganisms & to store lymphocytes .
· Two
categories :
"Primary central Lymphoid organs : responsible for the development of lymphocytes into mature immunocompetent cells
.
~
Fetal liver, prenatal & postnatal bone marrow , a thymus
2 Secondary (peripheral) Lymphoid organs : Responsible for the proper environment in which immunocompetent cells can react with
eachother ,
along with
antigens &other cells to mount an
immunological challenge agains invading antigens or
pathogens .
~
Lymph nodes , spleen, I mucosa associated Lymphoid tissue .
Thymus:
A lymphoid organ located in the mediastemum It is mostly active
central .
during youth.
It is the site of maturation of T dymphocytes & secretes thymic hormones such as thymosin thymopoietin thymulin a
, , ,
thymic humoral factor .
* It differs from other lymphoid organs since it functions strictly in lymphocyte maturation . It also consists of thethymic epithelial cells .
* Cortex of thymus :
Contains
developing
~
thymocytes (T Lymphocytes) Macrophages
, &,
~
Thymic cortical epithelial cells . These cells are linked to eachother by
desmosomes that surround the capillary.
A dual basal
Lamina is present in the space between epithelial cells & capillaries.
~
The thymic endothelial cells , basal Lamina, & endothelial cells form the
functional blood thymus -
barrier. It prevents the contact of
antigenic material
with the
developing
Flymphocytes .
