19-2: Lymphoid organs

Question 1

lymphoid organs

Answer 1

fight infection, provide resistance to disease
aggregates of lymphatic tissue in the body; all made of a type of reticular connective tissue and consist of two main types of cells

Question 2

What two main types of cells make up lymphoid organs?

Answer 2

lymphocytes and macrophages

Question 3

lymphocytes

Answer 3

main warriors of the immune system, arising in red bone marrow. Develop into T cells or B cells

Question 4

T cells

Answer 4

manage immune response; directly attach and destroy foreign cells

Question 5

B cells

Answer 5

develop into plasma cells which in turn secrete antibodies that immobilize the antigen until it can be phagocytized

Question 6

macrophages

Answer 6

large cells that phagocytize foreign substanes and help to activate T cells (initiating the immune response)

Question 7

What are examples of lymphoid organs?

Answer 7

thymus, spleen, tonsils, Peyer’s patches (on intestines), appendix

Question 8

How are lymphoid organs different from lymph nodes?

Answer 8

They do not filter the lymph of debris, pathogens, or foreign cells

Question 9

spleen

Answer 9

largest lymphoid organ, located in LUQ just inferior to diaphragm

Question 10

What are the functions of the spleen?

Answer 10

1. proliferation of lymphocytes during the immune response
2. cleanses blood of old/defective blood cells, debris, foreign matter, bacteria, viruses, and toxins (NOT the lymph)
3. stores breakdown products of RBCs for later reuse
4. site of erythrocyte production in the fetus
5. stores blood platelets

Question 11

splenestomy

Answer 11

removal of the spleen due to a rupture (usually a direct blow, bursting the thin capsule); splenic artery is tied off.

Question 12

Which organs take over the spleen’s functions if it is removed?

Answer 12

liver and bone marrow

Question 13

Thymus

Answer 13

bi-lobed gland in lower neck/upper chest that is most important in childhood

Question 14

Which is the only lymphoid organ that does not directly fight antigens?

Answer 14

Thymus (no B cells)

Question 15

What is the function of the thymus?

Answer 15

T-lymphocyte maturation - produces hormones to enable T-lymphocytes to function against specific pathogens during the immune response

Question 16

The thymus enlarges during __, stops growing in ___, and in old age ___.

Answer 16

childhood; adolescents; begins to atrophy, being almost entirely replaced by fibrous tissue

Question 17

tonsils

Answer 17

form a ring of lymphatic tissue around entrance to the pharynx, where they appear as swellings of the mucosa

Question 18

palatine tonsils

Answer 18

on either side of the posterior end of the oral cavity; largest and most often infected

Question 19

lingual tonsil

Answer 19

lies at base of tongue

Question 20

pharyngeal tonsils

Answer 20

aka adenoids; in the posterior wall of the nasopharynx

Question 21

What is the function of tonsils?

Answer 21

gather and remove many of the pathogens entering teh pharynx in inhaled air or food

Question 22

Mucosa-Associated Lymphatic Tissue

Answer 22

a collection of small lymphoid tissues that protect the body form inhaled or ingested pathogens

Question 23

What are some examples of MALT?

Answer 23

appendix, tonsils, Peyer’s patches - all located in digestive tract
lymph nodes in bronchi