Lymphoid System Components

Question 1

Thymus growth pattern?

Answer 1

regress after childhood

Question 2

Thymus reticulum framework - _______ (from _____)

Answer 2

epithelium (from endoderm)

Question 3

What components make the blood-thymus barrier?

Answer 3

(cortical barrier only)

1. continuous capillaries
2. sheathed by epithelial reticular cells

Question 4

_____ are found in the medulla of the thymus, good diagnosis feature for identification of the medulla.

Answer 4

Hassall’s corpuscles

Question 5

_____ = dense irregular connective tissue covered with mesothelium (in thymus)

Answer 5

splenic capsule (thymus)

Question 6

reticular framework of the lymph nodes is derived from ______

Answer 6

mesoderm

Question 7

lymph node cortex contains:
______ - B lymphocytes
______ - T lymphocytes

Answer 7

follicles

perifollicular

Question 8

lymph node medulla contains:

_____ and _____

Answer 8

cords and sinuses

Question 9

_____ - single site for blood entry and exit within lymph nodes

Answer 9

Hilum

Question 10

what differentiates lymph nodes from spleen and thymus?

Answer 10

lymph nodes have both afferent and efferent lymphatic vessels

Question 11

what is a structural characteristic and the role of the subcapsular space of lymph node?

Answer 11

complete endothelium lining on capsule side and incomplete on parenchymal side.
Facilitates lymphocytes from lymph flow of afferent lymphatics to interact with lymphocytes in nodes.

Question 12

_____ ______ allow for filtration of lymph within lymph nodes

Answer 12

reticular fibers

Question 13

______ - sites where blood-borne lymphocytes enter the node.

Answer 13

High endothelial venules (HEV)

Question 14

HEV have more _____ than typical venule endothelium

Answer 14

cuboidal cells

Question 15

______ - selectively endocytose antigens and transport them to the underlying lymphocytes and dendritic cells

Answer 15

M cells

Question 16

primary function of the spleen is to ______

Answer 16

filter blood, NOT lymph

Question 17

spleen has no _____, so it cannot filter the lymph

Answer 17

afferent lymphatics

Question 18

white pulp of spleen contains: ___, ____, ____.

Answer 18

central artery, periarteriolar lymphatic sheath, follicles - b lymphocytes

Question 19

red pulp of spleen contains: ____, _____, _____.

Answer 19

venous sinuses, Billroth’s strands/cords (splenic strands), and marginal zone

Question 20

two circulation options in spleen and both come off the arterioles of the so called _______

Answer 20

penicillar arteries

Question 21

what are the two circulation options in spleen

Answer 21

• closed: circulation typical of that in other organs
• open: no capillary nor venous sinus after the arteriole. the penicillar arteries dump whole blood into the splenic strands in the extravascular regions to stress red blood cells.

Question 22

______ - Picket-fence type endothelial cells of vascular sinus in spleen

Answer 22

Littoral cells

Question 23

penicillary arteries are located in the _______ within the spleen

Answer 23

marginal zone