H11 - Lymphoid Tissue

Question 1

what is the innate immune system?

Answer 1

retains the phagocytic system in the form of monocytes/macrophages

Question 2

what is immune system hat is bases on the presence of trillions of lymphocytes?

Answer 2

adaptive imune system

Question 3

what is the major role in the adaptive immune system?

Answer 3

destruction

- if this is not controlled the body may attack itself resulting in an autoimmune disease

Question 4

what are the primary lymphoid organs?

Answer 4

bone marrow and thymus

- sites of lymphocyte production and maturation

Question 5

what are the secondary lymphoid organs ?

Answer 5

spleen, lymph nodes and nodules

- lymphocytes migrate and aggregate in large numbers

Question 6

what are the three types of lymphocytes?

Answer 6

B cells - produce antibodies

T cells - participate in cellular immunity

NK (natural killer) cells- kill virus infected cells and some tumour cells

Question 7

what are the three types of T cells?

Answer 7

helper T cells
cytotoxic T cells
suppressor T cells

Question 8

what is the purpose of Cluster designation molecules?

Answer 8

identifying cells of the immune system

Question 9

what is the development and fate of B cells ?

Answer 9

produced from stem cells in the bone marrow and remain here to continue their development until they pass in bloodstream to secondary lymphoid organs

Question 10

what is the development and fate of t cells

Answer 10

produced from stem cells in the bone marrow, migrate in the bloodstream to the thymus to mature (most are eliminated) and return back to bloodstream where they are transported to secondary lymphoid organs

Question 11

what is the structure if the thymus ?

Answer 11

it has two lobes subdivided by septa, they each have an outer cortex that is highly cellular and a less cellular inner medulla

Question 12

what happens to T cells as they enter the thymus ?

Answer 12

• enter the cortex and begin proliferation, maturation and selection processes, those that fail undergo apoptosis and by phagocytosed by macrophages
• those which enter the medulla interact with epithelioreticular cells and are presented as self antigens, successful cells then enter the blood stream

Question 13

what do the system of lymphatic vessels and associated lymph nodes provide ?

Answer 13

• drainage of lymph into vascular system
• surveillance of tissue for signs of antigens from foreign invaders
• delivery of absorbed fats from the small intestine into vascular system

Question 14

what are the features of lymph vessels?

Answer 14

thin walled, lined by endothelium and anchored to the tissue by filaments

Question 15

what are the features of lymph nodes?

Answer 15

• encapsulated, highly organised structures interposed along larger lymph vessels
• tend to be found in clusters in areas such as neck, axillae and groin

Question 16

what is the region of actively dividing B cells in lymph node?

Answer 16

germinal center

Question 17

what is the region od resting B cells in lymph node ?

Answer 17

mantle zone

Question 18

what type of lymph cells are found i the paracortical region

Answer 18

T cells

Question 19

what does the medulla of the lymph node contain ?

Answer 19

• medullary cords
• medullary sinuses
• plasma cells
• macrophages

Question 20

B cells progress through developmental stages to become what?

Answer 20

plasma cells

Question 21

what are aggregations of lymph tissue associated with the GI tract?

Answer 21

GALT

Question 22

what is MALT?

Answer 22

mucosa-associated lymphatic tissue

Question 23

what are the aggregations of lymphoid tissue are found associated with the mucosa of the small intestine?

Answer 23

payer’s patch

Question 24

what are the functions of the spleen?

Answer 24

• produce immune response against blood-bourne viruses
• removal of particulate matter and aged blood cells
• production of blood cells during fetal life

Question 25

what make up the white pulp in the spleen?

Answer 25

T or B cells

Question 26

what makes up the red pulp in the spleen?

Answer 26

blood filled capillaries and sinuses

Question 27

how do you know when red blood cells have reached the end of their life span?

Answer 27

red blood cells passing through the organ must leave the capillaries, pass through the parenchyma, and find their way back into venous sinuses through small spaces. Old RBC cannot deform and are unable to pass through the small spaces