What is the largest lymphoid organ?
What type of connective tissue makes up the capsule of the spleen?
dense connective tissue
What type of epithelium makes up the capsule of the spleen?
simple squamous epithelium
What type of cells comprise the white pulp?
thick accumulation of lymphocytes
What pulp of the spleen contains splenic cords?
What type of fibers make up the red pulp of the spleen?
What is found between the splenic cords?
What 3 structures of the body have tonsils?
back of oral cavity
What is GALT?
gut associated lymphoid tissue
What is the function of tonsils?
process antigens coming into the body
What type of epithelium is at the surface of palatine and lingual tonsils?
stratified squamous epithelium
What type of epithelium is found in pharyngeal tonsils?
ciliated pseudostratified columnar epithelium
In which pulp does filtration of erythrocytes occur?
Name 4 hemopoietic functions of the spleen
FORMATION of erythrocytes during fetal life
REMOVAL and destruction of senescent, damaged, and abnormal erythrocytes and platelets
RETRIEVAL of iron from erythrocyte hemoglobin
STORAGE of blood and platelets
Name 4 immune functions of the spleen
antigen presentation by APCs
activation and proliferation of B and T lymphocytes
proliferation of plasma cells, secretion of antibodies in white pulp
production of antibodies against antigens of circulating blood
What type of cells nurture the future thymus?
epithelio-reticular cells (ERCs)
Which cells are derived from the endoderm of the 3rd pharyngeal pouch?
epithelio-reticular cells (ERCs)
Is the cortex or medulla of the thymus more basophilic?
Which ERC separates the cortex from the CT of capsule and trabeculae?
What type of intercellular junctions are found in type 1 ERCs?
Which ERC is found in the midcortex?
Which 2 thymic epithelioreticular cells have desmosomes?
Which ERC isolates the cortex from the medulla?
What type of intercellular junction is found in type 3 ERCs?
What type of circulation is most common in the spleen?
In what region near the central artery are B cells a majority?
In what region near the central artery are T cells a majority?
periarterial lymphatic sheath
What are the 2 components of the red pulp of the spleen?
sinuses filled with blood
splenic cords of reticular fibers
What is the main composition of the white pulp of the spleen?
nodules (Malpighian corpuscles)
What are the 2 components of the Malpighian corpuscles? Name the main cell type found in each.
lymphoid follicles (B lymphocytes)
periarteriolar lymphoid sheaths (T lymphocytes)
What structures are found between the sinusoids of the spleen?
Cords of Billroth
How many cells high are the Cords of Billroth?
In which layer of the thymus are high endothelial venules found? What is their function?
take mature T cells into the blood
Epithelio-reticular cells that become keratinized are known as?
Which ERCs (2) prevent formation of reticulin?
In which ERCs type are Hassal's bodies formed?
Which ERCs are the site for T cell death of the medulla?
What cells destroy unfit thymoblasts?
tingible body macrophage
With age, what happens to the thymic capsule?
replaced by fat
What are the 4 components of the blood thymus-barrier?
basal lamina of ERC
basal lamina of endothelial cells
What is the function of the blood thymus barrier?
sequester the developing T cells from blood borne antigens
Which 2 types of ERCs are connected with collagen type 3?
_____ epithelioreticular cells are located throughout the medulla and are joined by desmosomes.