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Flashcards in Lymphatic System Deck (39):
1

Lymphatic organs
- What are they formed by?
- What do they include?

Formed by lymphatic tissue (makes lymphocytes via lymphocytopoiesis)

Include: lymph nodes, spleen, thymus, tonsils

2

GALT

Gut associated lymphatic tissue

Lymphatic tissue in the gut

3

Lymphocytes made of 2 elements

1. Connective tissue framework
2. Free cells

4

Connective tissue framework

Free cells

Fixed framework: reticular cells and fibers

Free cells:
Mature lymphocytes, lymphocytes in various stages of development, macrophages and plasma cells

5

Macrophages function

Phagocytize foreign substances
Activate T cells

6

Dendritic cells: appearance and function

Spiny-looking
Function is similar to macrophage

7

Reticular cells

Fibroblast-like cells
Make stroma or network
Supports other cells types in lymphoid organs

8

Nodules

Solid, spherical bodies
Tightly packed reticular elements and cells

9

Tonsils

Simplest lymphoid organ

Forms ring of lymphatic tissue around nose and mouth (pharynx)

10

3 Types of tonsils. Which one is referred to as people getting their "tonsils removed?"

Palatine
Lingual
Pharyngeal

Palatine tonsils = tonsils that people get removed

11

Locations of the three tonsils

Palatine:
Both sides of posterior end of oral cavity (back of mouth)

Lingual:
Base of the tongue

Pharyngeal:
Posterior wall of the nasopharynx
(If enlarged, that obstruct nasal openings and are called adenoids)

12

Tonsils

Lymphoid tissue of tonsils have germinal center

Epithelial tissue overlying tonsil masses invaginates - makes blind-ended crypts

Crypts: trap and destroy bacteria and matter

13

Lymph node - Hilus

Indentation on 1 side of node

Blood vessels and lymphatics enter and leave node via hilus

14

Lymph node - cortex

- location
- regions

Under the capsule

Divided into outer and inner region
- outer: B-lymphocyte area
- inner: deep cortex (paracortinal zone);
Thymus dependent area and has T-lymphocytes

15

Lymph node - medulla

- Medullary cords

Inner node

Made by diffuse lymphatic tissue in the form of strands or cords called medullary cords

16

Lymph nodes - sinsuses

Spaces between adjacent cords of lymph tissue OR
Spaces between lymph tissue and connective tissue

17

Sinuses

Channels for lymph flow through node

Crisscrossed by reticular fibers

Lymph gets filtered here by: macrophages that are suspended in the reticular framework

Slow lymph flow --> Ag interact with lymphocytes

18

3 Sinuses - named by location

Subcapsular (marginal sinus)
- between capsule and lymph tissue of outer cortex

Intermediate (cortical, trabecular) sinuses
- btwn connective tissue and lymph tissue of cortex

Medullary sinuses
- between medullary cords

19

Lymphatics - afferent vessels

Lymph nodes are the only organs with afferent

Numerous vessels

Bring lymph to the lymph nodes for filtering

20

Efferent vessels

Few in number

Carry lymph away from the lymph nodes (E= EXIT)

Efferent of one node can become the afferent of another node

21

Pattern of lymph flow through node

Afferent lymphatics > subscapular sinus > cortical sinus > medullary sinus > efferent lymphatic

Lymph only flows in ONE direction bc of the valves in afferent and efferent lymphatics

22

Functions of lymph node

Filter lymph and phagocytosis of particulate matter
Lymphocytopoiesis
Humoral and cellular immune responses of B and T cells

23

Spleen - size and main function

Largest lymphatic organ

Main function = FILTER blood (does not filter lymph, lymph nodes filter lymph)

24

Structure of spleen

Splenic pulp = parenchyma of spleen
- Divided into red and white pulp

25

White pulp of spleen

Lymphatic tissue - mostly lymphocytes involved in immune responses

26

Red pulp of spleen

Part that filters blood

Deals with disposing worn-out RBCs and bloodborne pathogens

27

Spleen functions
- CHIPS

Cleanses blood
Hematopoietic organ in fetal life
Immune surveillance and response
Platelet storage
Storage site for RBCs

28

Thymus functions

Lymphopoiesis - T-lymphocytes only
Production of thyroid hormone, thymosin

29

Thymus size and age

Size varies with age:
Increases in childhood and is most active

Stop growing during adolescence and then atrophies

30

Thymus differences vs. other lymphatic organs

Functions strictly in T-lymphocyte maturation
Does not directly fight antigens

31

Involution (shrinkage) of thymus

Max weight occurs at puberty

After puberty, gradual loss of lymphocytes and reticular cells are replaced by adipose tissue

32

Lymphatic vessels
- Direction of flow
- What do they include

One way system in which lymph flows to the heart

Lymph vessels include:
Microscopic, permeable, blind ended capillaries (sealed at one end)
Lymphatic collecting vessels
Trunks and ducts

33

Lymphatic capillaries
- Characteristics
- 1 way gates

Permeable
Loosely joined endothelial minivalves
Withstand interstitial pressure and remain open

Minivalves function as 1 way gates:
- Allow fluid to enter capillaries
- Do not allow lymph fluid to escape from capillaries

34

Efferent lymph capillaries

Drain organs
Begin as blind-ended capillaries
Drain lymph away from the organ: in direction retrograde to arterial flow

35

Lymphangitis
Lymphadenitis

-gitis = inflammation of lymph vessels
-denitis = inflammation of lyph nodes

36

During inflammation, what can lymph capillaries absorb?
What are lacteals?

Absorb: cell debris, pathogens, cancer cells

Lacteals - specialized lymph capillaries present in intestinal mucosa
Absorb digested fat and deliver chyle to blood

37

Name the major lymphatic trunks

Paired lumbar
Bronchomediastinal trunk
Subclavian
Jugular
Single intestinal trunk

38

Drainage of lymph from:
Both sides of the lower half of body:
Gut

- Lumbar lymph trunks
- intestinal lymph trunk

39

Right lymphatic duct

Drains upper right arm and right side of head and thorax