Organs of the Immune System: pgs 9-10

Question 1

The lymphatic system is a _____ pressure system, so the lymphatics are very thin walled.

Answer 1

Low pressure

Question 2

What pharyngeal pouches develop to make up the thymus?

Answer 2

3rd and 4th pharyngeal pouches

Question 3

________ are rapidly dividing lymphocytes that populate the cortex of the thymus.

Answer 3

Thymocytes

Question 4

T/F - T cells must mature under the influence of the thymic epithelium in order to cary out cell mediated immunity.

Answer 4

True

Question 5

What is the term used when T cells mature in the thymic epithelium?

Answer 5

Education

Question 6

Approximately how many thymocytes will die without leaving the thymus?

Answer 6

90%

Question 7

The thymic cortex is extremely sensitive to _______________ and underconditions of stress, the thymus shrinks.

Answer 7

corticosteroids

Question 8

Can antigens enter the thymus?

Answer 8

No. No antigens can enter the thymus because the blood vessels entering the thymus have unusually thick basement membranes and there is no lymphatic drainage

Question 9

What are two hormones (of many) that are secreted by the thymus?

Answer 9

Thymosin and thymopoietin

Question 10

What are the primary lymphoid organs?

Answer 10

Bone marrow and thymus

Question 11

What do lymphocytes do in secondary lymphoid organs/tissues?

Answer 11

They function - they ARE NOT made and mature there (only in primary lymphoid organs)

Question 12

What are some secondary lymphoid organs?

Answer 12

Spleen
Lymph Nodes
Peyer’s patches
Others

Question 13

Where do the B cells reside in lymph nodes?

Answer 13

Follicles

Question 14

Where do T cells, macrophages and dendritic cells reside in the lymph node?

Answer 14

Paracortex

Question 15

What is the flow of lymph through the lymph node?

Answer 15

Subcapsular sinus -> B area -> T area

Question 16

What cell is a descendant of a B cell?

Answer 16

Plasma cell

Question 17

What do T helper cells do?

Answer 17

Up regulate and enhance response

Question 18

T/F - both T and B cells circulate?

Answer 18

False - Just T cells circulate, B cells do not.

Question 19

What do Ts cells do?

Answer 19

They shut down an ongoing immune response (energy expensive and damage to own tissues).

Question 20

Where do lymph nodes cluster?

Answer 20

Where the appendages meet the trunk.

Question 21

A “nude” mouse or rat has no ________. In humans its call DiGeorge Syndrome.

Answer 21

Thymus

Question 22

What’s the difference in a neonatal thymectomy and an adult thymectomy?

Answer 22

Neonatal - animal dies of wasting away due to intestinal bacteria and other normal flora

Adult - No immediate consequences, animal seems normal at first, normal Ab due to mature T cells in periphery, animal will die at end though due to loss of T cells over time