Chapter 23- Lymphatic System

Question 1

functions

Answer 1

• produce, maintain, and distribute lymphocytes
• maintain normal blood and interstitial fluid volume
• alternate route for the transport of materials
• -nutrients
• -hormones
• -wastes

Question 2

lymphatic vessels

Answer 2

• network of vessels
• transport fluid called lymph from tissues to the venous system
• range in size
• -small lymphatic capillaries
• -medium lymphatic vessels
• -large lymphatic trunks
• -lymphatic ducts

Question 3

lymphatic vessels pt 2

Answer 3

• are almost always found associated with blood vessels
• location of vessels
• -most tissues
• -absent in: avascular tissue (tendons), CNS

Question 4

what is lymph

Answer 4

• lymph is fluid connective tissue
• it occurs only in lymphatic vessels
• it is derived from:
• -interstitial fluid of tissues
• -lymphocytes
• -macrophages

Question 5

origin of lymph

Answer 5

derived from interstitial fluid

• originates from plasma (interstitial fluid does)
• -water and dissolved materials leak out of capillaries due to diffusion and filtration (27L/day enters interstitial spaces)
• -fluid: lacks proteins, lower 02
• interstitial fluid moves into the lymphatic capillaries and is now known as lymph
• -90% of interstitial fluid is absorbed

Question 6

lymphatic capillaries

Answer 6

• closed ended tubes
• in interstitial spaces
• form networks
• single layer of squamous cells with incomplete basal lamina
• fenestrated

Question 7

lymphatic capillaries differ from blood capillaries

Answer 7

• larger diameter
• thinner walls
• flat and irregular
• have anchoring filaments to keep the passage open
• overlapping endothelial cells

Question 8

formation of lymph

Answer 8

interstitial fluid enters capillaries

• overlapping cells function as one way valves
• moves through fenestrations
• large things such as viruses and debris flow in too
• lymph is filtered plasma, interstitial fluid, and stuff floating around in interstitial fluid, can be cancerous cells, pathogens

Question 9

medium lymphatic vessels

Answer 9

• merging of lymph capillaries
• similar to veins
• -interna
• -media
• -adventitia
• -valves
• merge to form trunks
• travel with arteries of same size

Question 10

lymphatic trunks: naming

Answer 10

named for the region they drain

-ex: lumbar, intestinal, broncomediastinal, subcalvian, jugular

Question 11

lymphatic ducts: draining

Answer 11

• trunks drain into ducts
• two ducts
• -thoracic and right lymphatic
• deliver lymph to venous circulation at subcalvians
• -reintroduced to bloodstream
• -becomes part of plasma and is circulated

Question 12

lymphatic ducts: thoracic duct

Answer 12

• drains lower body; left arm, head and neck
• route:
• -arises form cisterna chyli
• -through diaphragm
• -ascends in front of vertebral column
• -empties into left subclavian vein

Question 13

lymphatic ducts: right lymphatic duct

Answer 13

drains right side of head, neck and right arm

• route:
• -starts in right thorax
• -to the right subclavian vein

Question 14

lymphatic ducts: asymetry

Answer 14

unevenly drain fluid from the body

• thoracic does the majority
• it is much longer and drains the entire inferior half of the body

Question 15

movement of lymph

Answer 15

contain valves

• occur at bulges
• prevent backflow
• -pressure is lower in lymphatics than veins (no heart connection)
• -lymph is moved using similar methods to veins: skeletal muscles, breathing
• if drainage does not occur= lymphedema

Question 16

lymphocytes

Answer 16

• primary cells of the lymphoid system
• allow for specific (or adaptive) immunity
• -multi-faceted immune response to the detection of specific foreign antigens

Question 17

lymphocytes: NK cells

Answer 17

• natural killer cells
• derived directly from bone marrow
• NON-specific immunity
• detect chemical signals other than specific antigens (like all the other leukocytes) and induce apoptosis
• the one lymphocyte that is not cell specific

Question 18

lymphocytes: B-cells

Answer 18

• originate and develop in the bone marrow
• stimulated by an antigen to produce antibodies
• can survive for years as memory cells, and become active once exposed to a similar antigen

Question 19

lymphocytes: B-cells

Answer 19

• originate in the bone marrow but develop in the thymus (t-cells)
• attack cells with antigens indicating viral infection or detrimental mutations
• induce apoptosis
• have memory cells similar to b-cells
• t-cells actually find the antigen themselves and kill it instead of b-cells that produce antibodies

Question 20

lymphoid nodules

Answer 20

• reticular connective tissue dominated by lymphocytes
• MALT
• -mucosa associated lymphoid tissue
• -digestive lymph nodule
• masses of connective tissue attached to organs, not organs themselves

Question 21

MALT

Answer 21

tonsils

• positioned around the pharynx
• remove pathogens that enter via air or food

-

Question 22

three types of tonsils

Answer 22

pharyngeal tonsil
--one nodule in nasopharynx
--aka adenoids
palatine tonsils
--two nodules on the soft palate
lingual tonsils
--two nodules at the base of the tongue

Question 23

aggregated lymphoid nodules

Answer 23

malt

-line mucosa of the small intestine

Question 24

appendix

Answer 24

malt

• blind tube at the beginning of the intestine
• area prone to infection
• -appendicitis
• -intestinal flora enter underlying tissues

Question 25

lymphatic organs

Answer 25

- surrounded by a fibrous connective tissue capsule - include: - -lymph nodes - -thymus - -spleen

Question 26

lymph nodes

Answer 26

- bead shaped - between several afferent and one efferent vessel - hilus: indented region where BV's, nerves, and efferent lymph vessels connect

Question 27

lymph nodes

Answer 27

cortex on outside -capsule has trabeculae that subdivide it -has two regions --outer cortex: consists of aggregated B-cells --inner cortex: t cells enter blood here medulla: -b-cells leave through the efferent vessel lymph will encounter this when traveling through lymph system and the attack on antigens begins

Question 28

lymph nodes: locations

Answer 28

- cervical - axillary - inguinal - pelvic - abdominal - thoracic

Question 29

spleen

Answer 29

- found on left side of stomach - largest lymphatic organ - white pulp - -resembles lymph node - red pulp - -large amounts of RBC - -sinuses, macrophages, T/B cells

Question 30

functions of spleen

Answer 30

- remove old RBCs - store/recycle iron - initiate immune response - blood reservoir - RBC production - major place for interaction between lymph and blood - white pulp encounters pathogens from blood and antibodies will destroy it

Question 31

thymus

Answer 31

- in mediastium - first lymph organ to deveolp - -grows until puberty - -shrinks with age: replacd by fibrous and adipose tissue - 2 lobes with lobules - -cortex: mostly T-cells - -medulla: mostly epithelial cells

Question 32

thymus: t-cells

Answer 32

- cortext produces t-cells - mature and migrate into medulla - enter blood vessels and go into circulation

Question 33

thymus: reticular cells

Answer 33

- produce hormone thymosin | - promote t-cell differentiation