H2 Lymphatic System

Question 1

List major functions of lymphatic system:

Answer 1

1. Drain excess interstitial fluid
2. Provide alternative transportation (hormones, nutrients, waste)
3. Immune response (lymphocytes)

Question 2

Lymphatic vessels begin as networks of ____ capillaries in microcapillary beds.
Lymphatic capillaries form network within _____ tissues

Answer 2

Blind-ended

Loose connective

Question 3

Endothelial tubes lacking continuous basal lamina resulting in high permeability.

Answer 3

Lymphatic Capillaries

Question 4

The lymphatic system has no central pump, but relies on ____ for movement. Lymphatic vessels posses ____ to prevent backflow.

Answer 4

Skeletal muscle compression

Valves

Question 5

B Lymphocytes were first recognized in _____ of birds.

Membrane-bound B-cell receptor is known as _____.

Answer 5

Bursa of Fabricius

Immunoglobulin

Question 6

Activated B cells are known as ____. They secrete non-membrane bound form of immunoglobulins known as ____.

Answer 6

Plasma Cells

Antibodies

Question 7

B cells = ____ immunity

T cells = ____ immunity

NK cells = ____ immunity

Answer 7

Humoral

Cell-mediated

Innate

Question 8

Accumulations of lymphatic tissue found within alimentary canal, respiratory passages, and genitourinary tract. Not surrounded by a connective tissue capsule. Mostly lymphocytes.

Answer 8

Diffuse Lymphatic Tissue

Question 9

Discrete concentrations of lymphocytes contained in meshwork of reticular cells. Found in walls of alimentary canal, respiratory passages, genitourinary tract.

Answer 9

Lymphatic Nodules (follicles)

Question 10

A Lymphatic nodule consisting primarily of small lymphocytes is known as _____.

A lymphatic nodule containing light staining germinal center and outer mantle zone is known as ____.

Answer 10

Primary Nodule

Secondary Nodule

Question 11

A Morphological indication of response to antigen; develops when lymphocytes binds antigen, returns to primary nodule, and proliferates. Light staining; folllicular dendritic cells present.

Answer 11

Germinal Center

Question 12

Darker outer ring of small lymphocytes that encircle the germinal center

Answer 12

Mantle Zone (corona)

Question 13

Lymphatic nodules are disperse randomly by themselves, but aggregations of lymphatic nodules are found in specific locations:

Answer 13

1. Tonsils
2. Peyer’s Patches
3. Vermiform Appendix

Question 14

Located within the ileum of small intestine; consists of numerous aggregations of lymphatic nodules containing T and B lymphocytes.

Answer 14

Peyer’s Patches

Question 15

Accumulations of lymphocytes associated with different mucosal areas

Answer 15

MALT (Mucosa-Associated Lymphatic Tissue)

Question 16

Types of MALTs:

Answer 16

GALT (Gut-Associated Lymphatic Tissue)

BALT (Bronchus-Associated Lymphatic Tissue)

Question 17

Small, bean shaped encapsulated lymphatic organs interposed along pathway of lymphatic vessels. Filter lymph.

Answer 17

Lymph Nodes

Question 18

_____ lymphatic vessels convey lymph towards the node; enter at convex surface of capsule.

____ lymphatic vessels convey lymph away from the node; leave at hilum (concave)

Answer 18

Afferent

Efferent

Question 19

____ = Dense connective tissue surrounding node

____ = Dense connective tissue extending from capsule

____ = Reticulare cells and reticular fibers that form fine supporting meshwork

Answer 19

Capsule

Trabeculae

Reticular Tissue

Question 20

These cells synthesize/secrete reticular fibers (type III collagen) and ground substance. Elongated cytoplasmic process. Supporting role in expressing surface molecules and producing substances that attract T/B cells and dendritic cells.

Answer 20

Reticular Cells

Question 21

Bone marrow-derived antigen presenting cells. Monitor environment for antigens (present to T cells). Localized to T cell-abundant areas.

Answer 21

Dendritic Cells

Question 22

Act as both phagocytes and antigen presenting cells

Answer 22

Macrophages

Question 23

These cells have multiple, thin, hairlike branching cytoplasmic processes that interdigitate between B cells in germinal centers. No APCs, but similar to Macrophages.

Answer 23

Follicular Dendritic Cells (FDCs)

Question 24

_____ of lymph node is divided into cortex and medulla.

Answer 24

Parenchyma

Question 25

Forms outer portion of lymph nodes (except at hilum).

Answer 25

Cortex

Question 26

____ cortex continues germinal centers. Mainly B cells. ____ cortex contains majority of T cells. Medulla contains mainly ____ cells.

Answer 26

Superficial Cortex (nodular cortex) Deep Cortex (paracortex) B

Question 27

The medulla consists of cords of lymphatic tissue (____) that contain lymphocytes, macrophages, dendritic cells, plasma cells and are separated by lymphatic sinuses (____) which converge near hilum to drain into efferent lymphatic vessels.

Answer 27

Medullary cords Medullary Sinuses

Question 28

____ sinus is beneath capsule of lymph node (afferents drain here), it drains into ____ sinuses (extend into cortex along trabeculae) which then drain into ____ sinuses to finally drain into efferent lymph vessels.

Answer 28

Subcapsular (cortical) Trabecular Medullary

Question 29

Lymphocytes conveyed in lymph enter nodes via afferent lymph vessels. However, 90 percent of lymphocytes are conveyed in blood; enter lymph node thru _____ in ____ cortex.

Answer 29

High Endothelial Venules (HEVs) Deep

Question 30

Flow of lymphocytes from blood through lymph node:

Answer 30

HEV -> Deep Cortex -> Superficial Cortex -> Medulla -> Efferent Lymph Vessel

Question 31

Bilobed organ located in superior mediastium, anterior to heart and great vessels.

Answer 31

Thymus

Question 32

Thymus persists as large organ until puberty when _____ is reduce and lymphatic tissue is replaced with ____ tissue.

Answer 32

T cell differentiation and proliferation Adipose

Question 33

Thymus Capsule is made of thin _____ Trabeculae establish domains called ____ -> cortical caps over portions of convoluted and continuous medullary tissue

Answer 33

Connective tissue Thymus Lobules

Question 34

In the Thymus cortex, developing lymphocytes (____) occupy spaces within extensive meshwork of ____ cells.

Answer 34

Thymocytes Epithelioreticular

Question 35

____ cells form the most characteristic feature of the thymus medulla known as ____.

Answer 35

Type VI Epithelioreticular cells Thymic (Hassall's) Corpuscles

Question 36

These cells provide framework for developing T cells. Serve as supporting storma.

Answer 36

Epithelioreticular cells

Question 37

Isolated masses of closely-packed concentrically arranged Type VI epithelioreticular cells with flattened nuclei. Possess keratohyalin granules.

Answer 37

Thymic (Hassall's) Corpuscles

Question 38

Largest lymphatic organ; located in upper left quadrant of abdominal cavity. Filters blood. Enclosed in dense connective tissue capsule from which trabeculae extend into parenchyma.

Answer 38

Spleen

Question 39

Primary role of red pulp of the spleen is ____. It consists of blood-filled sinuses (splenic sinuses) separated by loose meshwork of reticular cells and fibers (splenic cords).

Answer 39

Blood Filtration

Question 40

White pulp consists of ____ tissue, mostly ____. Branches of splenic artery course through and enter white pulp. _____ -> branch of splenic artery initially in central position within white pulp ____ -> aggregates of lymphocytes around artery.

Answer 40

Lymphatic Lymphocytes Central Artery PALS (Periarterial Lymphatic Sheath)

Question 41

Lymphatic nodules displace central artery to ____ position

Answer 41

Eccentric

Question 42

This Sinuses wall has lattice-like structure. Prominent intercellular spaces between endothelial cells (allow blood passage; macrophage processes extend into and monitor)

Answer 42

Splenic Sinuses