HSC Niche

Question 1

A part of the bone marrow is called the HSC Niche: what does it contain?

Answer 1

Hematopoietic stem cells and progenitor cells (distinct) region of bone marrow referred to HSC Niche

Question 2

Functions of the HSC Niche

Answer 2

contributes to the control of HSC quiescence, proliferation, self-renewal, and differentiation

Question 3

Of what does the HSC Niche “consist” ?

Answer 3

a network of vessels, nerve fibers, bone remodeling cells, and subpopulations of hematopoietic cells

this is a complex three dimensional architecture

Question 4

Thymus

Dark blue staining area
Light Blue staining area
Corpuscle recognition
“dark dots” around corpuscle

Answer 4

dark blue region = cortex
light blue staining region = medulla
Hassall’s corpuscle
Thymocytes = small developing T cells

Question 5

Thymus position and growth

Answer 5

in front of the adam’s apple

peak growth for cortex, medulla
10-15 years of age

fat/connective tissue is the opposite, it increases over the adult’s whole life

Question 6

Spleen morphology

Answer 6

Leaf life structure: a central arteriole surrounded by T lymphocytes (T cell zone: peirarteriolar lymphoid sheath “PALs”) with diverging arterioles called “follicular arterioles” leading to bilateral arterioles connecting the proximal and distal ends of the central arteriole

T cell surrounds central arteriole

Follicular arteriole and marginal sinus surrounded by B cells (lymphoid follicles with a germinal center)

—central artery–>

—> follicular arteriole —> marginal artery —> central artery

—> trabecular artery

Question 7

Periarteriolar lymphoid sheath (PALs)

Answer 7

regions of T cell density surrounding central artery

Question 8

PALs and germinal center of lymphoid follicle

Answer 8

germinal center of lymphoid follicle = aggregates of B lymphocytes surrounding follicular arterioles

PALs are pariarteriolar lymphoid follicles surrounding central artery (aggregates of T lymphocytes)

Question 9

Morphology of a LN:

Answer 9

later