Chapter 23- Lymphatic System Flashcards Preview

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Flashcards in Chapter 23- Lymphatic System Deck (33)
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1

functions

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

2

lymphatic vessels

-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

3

lymphatic vessels pt 2

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

4

what is lymph

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

5

origin of lymph

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

6

lymphatic capillaries

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

7

lymphatic capillaries differ from blood capillaries

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

8

formation of lymph

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

9

medium lymphatic vessels

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

10

lymphatic trunks: naming

named for the region they drain
-ex: lumbar, intestinal, broncomediastinal, subcalvian, jugular

11

lymphatic ducts: draining

-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

12

lymphatic ducts: thoracic duct

-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

13

lymphatic ducts: right lymphatic duct

drains right side of head, neck and right arm
-route:
--starts in right thorax
--to the right subclavian vein

14

lymphatic ducts: asymetry

unevenly drain fluid from the body
-thoracic does the majority
-it is much longer and drains the entire inferior half of the body

15

movement of lymph

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

16

lymphocytes

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

17

lymphocytes: NK cells

-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

18

lymphocytes: B-cells

-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

19

lymphocytes: B-cells

-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

20

lymphoid nodules

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

21

MALT

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

-

22

three types of tonsils

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

23

aggregated lymphoid nodules

malt
-line mucosa of the small intestine

24

appendix

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

25

lymphatic organs

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

26

lymph nodes

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

27

lymph nodes

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

28

lymph nodes: locations

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

29

spleen

-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

30

functions of spleen

-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

31

thymus

-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

32

thymus: t-cells

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

33

thymus: reticular cells

-produce hormone thymosin
-promote t-cell differentiation