Lymphatics (ex.III)

Question 1

What are the 3 primary lymphatic organs and what cells do they develop?

Answer 1

• Bone Marrow - B cells
• Bursa of fabricius - B cells
• Thymus - T cells

Question 2

What are the 3 secondary lymphatic organs?

Answer 2

• lymph nodes (filters lymph)
• spleen (filters blood)
• mucosal associated lymphoid tissue

Question 3

The function of the lymphatic system is to protect the body against ________ and help in removal and disposal of ________.

Answer 3

protect against pathogenic organisms

remove degenerating cells

Question 4

What are the antigen presenting cells?

Answer 4

dendritic cells, macrophages, B cells

Question 5

Where can fixed macrophages be found?

Answer 5

• sinudoids of liver
• sinusoids of spleen
• sinusoids of lymph nodes
• reticulum of bone marrow
• thymus

Question 6

Where can free macrophages be found?

Answer 6

• blood (monocytes)
• lung
• serous cavities

(build up of fluid attracts macrophages)

Question 7

Which cells of the lymphatic system usually produce cytokines that create an environment conducive for cell development? They also have a background structural function.

Answer 7

stromal cells

reticular cells

Question 8

What types of cells are present in a nodule of the Cloacal Bursa?

Answer 8

• lymphocytes
• B-cells
• macrophages (to take up apoptotic cells)

Question 9

Where in the body is the source of pluripotent stem cells(B and T cells)?

Answer 9

bone marrow

B cells mature in bone marrow
T cells migrate to thymus to mature

Question 10

The thymus is surrounded by a connective tissue ____ which sends in ____ that divide the organ into lobules.

Answer 10

capsule

septae

Question 11

Where in the thymus does positive selection occur?

“good” lymphocytes are chose to further develop to T cells

Answer 11

cortex

Question 12

Where are Tingible body macrophages found and what is their purpose?

Answer 12

thymus

they phagocytose and eliminate dead or apoptotic T cells

Question 13

Where in the thymus does negative selection occur?

“bad” lymphocytes are broken down

Answer 13

medulla

Question 14

What are large central calcified or degenerated cells surrounded by concentric circles of keratinized cells called?

Answer 14

thymic/Hassall’s corpuscles

these are unique to the thymus and more obvious in the medulla

Question 15

Where do arteries enter the thymus?

Answer 15

corticomedullary junction within the septa

the arteries branch into a capillary network in the cortex

Question 16

Mature T cells leave the thymus via the _____ at the ___ junction and enter the blood to travel to secondary lymphatic tissues.

Answer 16

postcapillary venules

corticomedullary junction

Question 17

What is the only lymphatic organ with both afferent and efferent lymph vessels as well as sinuses containing lymph?

Answer 17

lymph node

Question 18

Where do arteries enter and veins leave the lymph node?

Answer 18

hilus

Question 19

Where do afferent lymphatics enter the lymph node?

Where do efferent lymphatics leave the lymph node?

Answer 19

afferent: multiple sinuses along the capsule
efferent: hilus

Question 20

In lymph nodes ____ extends from the capsule into the cortex and medulla providing structural support.

Answer 20

trabeculae

Question 21

What 3 cell types are supported by the lymph node stroma?

Answer 21

lymphocytes
macrophages (antigen presentation)
plasma cells

Question 22

____ are specialized vessels located in the paracortex that can only infiltrate lymphocytes in the lymph nodes.

Answer 22

high endothelial venules (HEV)

Question 23

What path does lymph travel in filtration through lymph nodes starting with the afferent vessel ending with the efferent vessel?

Answer 23

afferent -> marginal (sudcapsular) sinuses -> corticle (trabecular) sinses -> medullary sinuses -> efferent

Question 24

What type of lymph node follicle is activated? Why has it become activate?

Answer 24

secondary follicle

antigens have been presented

Question 25

Secondary follicle of lymph nodes can be identified by their outer ___ zone and inner ___ center.

Answer 25

marginal zone

germinal center

Question 26

The ____ is the area between follicles in the cortex of lymph nodes.

Answer 26

parafollicular area (aka paracortex)

prominent blood vessels can be found here

Question 27

What are follicular dendritic cells responsible for?

Answer 27

antigen presentation inside follicle of lymph nodes

This leads to the development of specified T and B cells that are sent out of the lymph node.

Question 28

Lymph enters back into the blood stream via the ____.

Answer 28

thoracic duct

Question 29

____ occurs when the thoracic duct is ruptured.

Answer 29

Chylothorax

the thorax is filled with a milk fluid called chyle

Question 30

What secondary lymphatic organ recovers and stores iron?

Answer 30

spleen

Question 31

What can be stored in the spleen?

What species does not have a storage type spleen?

Answer 31

iron, RBCs, and platelets

feline

Question 32

Central arterioles, periarteriolar lymphoid sheaths and follicles can be found in the ___ of the spleen.

Answer 32

white pulp

Question 33

Blood vessels of the spleen have a discontinuous basement membrane to allow blood to filter through. RBCs along with hemosiderin pigment can be seen in the ___ of the spleen.

Answer 33

red pulp

Question 34

Aggregated lymphatic nodules of the small intestine are also know as:

Answer 34

Peyer’s patch

Question 35

What are the blind ended lymphatic capillaries within intestinal villi of the small intestine?

Answer 35

lacteals

Question 36

____ from the chyme are absorbedand ener the lacteals to become part of the chyle.

Answer 36

micelles

are converted to chylomicrons

Question 37

list the only areas of the body where lymph vessels cannot be found

Answer 37

• eye
• cartilage
• bone/bone marrow
• spleen
• CNS

Question 38

Lymph flows in one direction, from the ___ to the ___

Answer 38

periphery to the heart