Ch.19 - The Lymphatic System

Question 1

Three parts of lymphatic system

Answer 1

network of lymphatic vessels (lymphatics), lymph, lymph nodes

Question 2

lymph

Answer 2

fluid in vessels

Question 3

lymph nodes

Answer 3

cleanse lymph

Question 4

lymphoid organs and tissues

Answer 4

provide structural basis of immune system by housing phagocytic cells and lymphocytes

Question 5

lymphoid structures

Answer 5

spleen, thymus, tonsils, lymph nodes

Question 6

lymphatic system

Answer 6

returns interstitial fluid and plasma proteins back to blood

Question 7

lymphatic vessels

Answer 7

elaborate network of drainage vessels

Question 8

once interstitial fluid enters lymphatics, it is called…

Answer 8

lymph

Question 9

lymphatic capillaries

Answer 9

blind-ended vessels that weave between tissue cells and blood capillaries

Question 10

How are lymphatic capillaries different from blood capillaries?

Answer 10

more permeable; can take up larger molecules and particles that blood can’t

Question 11

Increased permeability of lymphatic capillaries is caused by two specialized structures

Answer 11

endothelial cells overlap loosely to form one-way minivalves; MVs anchored by collagen filaments to matrix

Question 12

lacteals

Answer 12

specialized lymph capillaries present in intestinal mucosa; absorb digested fat and deliver fatty lymph (chyle) to the blood

Question 13

lymphatic trunks

Answer 13

formed by union of largest collectin vessels, drain large areas of body

Question 14

Regions lymphatic trunks drain:

Answer 14

lumbar, bronchomediatinal, subclavian, jugular trunks, intestinal trunk

Question 15

right lymphatic duct

Answer 15

drains right upper arm and right side of head and thorax

Question 16

thoracic duct

Answer 16

drains rest of body

Question 17

lymphangitis

Answer 17

condition in which lymphatic vessels appear as painful red lines under skin; caused by inflammation of larger lymphatic vessels that contain vaso vasorum

Question 18

lymphedema

Answer 18

severed localized edema; caused by anything that prevents normal return of lmph to blood

Question 19

immune system cells

Answer 19

lymphocytes

Question 20

two types of lymphocytes

Answer 20

T cells; B cells

Question 21

T cells & B cells

Answer 21

protect against antigens

Question 22

T cells

Answer 22

manage immune response

Question 23

B cells

Answer 23

produce plasma cells which secrete antibodies

Question 24

other lymphoid immune cells

Answer 24

macrophages and dendritic cells

Question 25

macrophages

Answer 25

phagocytize foreign substances and help activate T cells

Question 26

dendritic cells

Answer 26

capture antigens and deliver them to lymph nodes

Question 27

reticular cells

Answer 27

produce reticular fibers called stroma

Question 28

main functions of lymphoid tissue

Answer 28

houses and provides proliferation sites for lymphocytes; offers surveillance vantage points for lymphocytes and macrophages as they filter through lymph

Question 29

two types of lymphoid tissues

Answer 29

diffuse lymphoid tissue, lymphoid follicles (nodules)

Question 30

diffuse lymphoid tissue

Answer 30

loose arrangement of lymphoid cells and some reticular fibers

Question 31

lymphoid follicles (nodules)

Answer 31

solid, spherical bodies consisting of tightly packed lymphoid cells and reticular fibers

Question 32

lymphoid organs are groups into two functional categories

Answer 32

primary and secondary

Question 33

primary lymphoid organs

Answer 33

areas where T and B cells mature - red bone marrow and thymus

Question 34

T and B cells originate in ___ ___, but only __ cells mature there; __ cells mature in thymus

Answer 34

bone marrow, B, T

Question 35

Secondary lymphoid organs

Answer 35

areas where mature lymphocytes first encounter their antigen and become activated

Question 36

what are the secondary lymphoid organs?

Answer 36

nodes, spleen, MALT (mucosa-associated lymphoid tissue), and diffuse lymphoid tissues

Question 37

lymph nodes

Answer 37

principal secondary organs or body

Question 38

Where are most lymph nodes found?

Answer 38

embedded deep in connective tissue in clusters along lymphatic vessels

Question 39

Two main functions of lymph nodes

Answer 39

cleanse the lymph; immune system activation

Question 40

lymph nodes are surrounded by

Answer 40

external fibrous capsule

Question 41

capsule fibers extend inward as ___ that divide node into compartments

Answer 41

trabecule

Question 42

two histologically distinct regions of node

Answer 42

cortex, medulla

Question 43

lymph enters convex side of node via

Answer 43

afferent lymphatic vessels

Question 44

lymph travels through large ___ ___ and then into smaller sinuses found throughout cortex and medulla

Answer 44

subscapsular sinus

Question 45

buboes

Answer 45

inflamed, swollen, tender lymph nodes that result when nodes are overwhelmed by what they are trying to destroy

Question 46

largest lymphoid organ

Answer 46

spleen

Question 47

the spleen is served by ___ ___ and __, which enter and exit at the ___

Answer 47

splenic artery, vein, hilum

Question 48

Spleen Functions

Answer 48

site of lymphocyte proliferation and immune surveillance and response; cleanses blood of aged blood cells and platelets, macrophages remove debris

Question 49

The spleen consists of two components

Answer 49

white pulp and red pulp

Question 50

white pulp

Answer 50

site where immune function occurs; contains mostly lymphocytes on reticular fibers

Question 51

where are white pulp clusters found?

Answer 51

around central arteries; appear as islands of white in a sea of red pulp

Question 52

red pulp

Answer 52

site where old blood cells and bloodborne pathogens are destroyed

Question 53

red pulp is composed of

Answer 53

splenic cords (reticular tissue) that separate blood-filled splenic sinusoids (venous sinuses)

Question 54

In children younger than 12 years, what happens if their spleen is removed?

Answer 54

spleen will regenerate if a small part is left

Question 55

Mucosa-associated lymphoid tissue (MALT)

Answer 55

lymphoid tissues in mucous membranes throughout body; protects from pathogens trying to enter body

Question 56

Where are the largest collections of MALT found?

Answer 56

tonsils, Peyer's patches, appendix

Question 57

palatine tonsils

Answer 57

at posterior end of oral cavity; largest tonsils and most often infected

Question 58

lingual tonsil

Answer 58

lumpy collection of follicles at base of tongue

Question 59

pharyngeal tonsil

Answer 59

also called adenoids; located in posterior wall of nasopharynx

Question 60

tubal tonsils

Answer 60

surrounded openings of auditory tubes into pharynx

Question 61

tonsils function

Answer 61

gather and remove pathogens in food or air

Question 62

tonsilar crypts

Answer 62

overlying epithelium invaginates; bacteria or particulate matter enters crypts, where they are trapped and destroyed

Question 63

Peyer's patches

Answer 63

clusters of lymphoid follicles in wall of distal portion of small intestine; also called aggregated lymphoid nodules

Question 64

Peyer's patches function

Answer 64

destroy bacteria, preventing them from breaching intestinal wall; generate "memory" lymphocytes

Question 65

appendix

Answer 65

offshoot of first part of large intestine; contains a large number of lymphoid follicles

Question 66

appendix functions

Answer 66

destroy bacteria, preventing them from breaching intestinal wall; generate "memory" lymphocytes

Question 67

thymus

Answer 67

bilobed lymphoid organ found in inferior neck; extends into mediastinum and partially overlies heart

Question 68

thymus function

Answer 68

functions as lymphoid organ where T cells mature

Question 69

Stops growing during adolescence, then gradually atrophies

Answer 69

thymus

Question 70

Thymus differs from other lymphoid organs in important ways

Answer 70

has no follicles bc it lacks B cells; doesn't directly fight antigens

Question 71

blood thymus barrier

Answer 71

keeps immature T lymphocytes isolated from any antigens to prevent premature activation

Question 72

stroma

Answer 72

made up of epithelial cells, not reticular fibers; provide environment in which T lymphocytes become immunicompetent