Chapter 20: Lymphatic System

Question 1

What are the 4 main parts of the lymphatic system?

Answer 1

Network of lymphatic vessels
Lymph (fluid)
Lymphnodes
Lymph Organs

Question 2

Name 4 primary functions of the lymphatic system?

Answer 2

Return interstitial fluid back to the blood
Return leaked plasma protein back to the blood
Part of the immune system
Production of lymph

Question 3

What happens when interstital fluid enters the lymphatic vessels?

Answer 3

It is now called lymph

Question 4

What are lymphatic vessels?

Answer 4

One-way system, carry fluid towards the heart

Question 5

What are 3 types of lymphatic vessels and their size?

Answer 5

Lymphatic capillaries (smallest)
Lymphatic collecting vessels (medium)
lymphatic trunks and ducts (largest)

Question 6

What are lymphatic capillaries?

Answer 6

Blind-ended tubes of adjacent endothelial cells that overlap and form small flap-like vales

Entwined within capillary beds

Question 7

Where does all lymph travel?

Answer 7

Into one of two large lymphatic ducts - right lymphatic duct and thoracic duct

Question 8

What does the right lymphatic duct drain?

Answer 8

Drains upper arm and right side of head and thorax

Question 9

What is the thoracic duct?

Answer 9

Comes from the cisterna chyli and carries fluids that have been collected from the rest of the body

Question 10

Where do the lymphatic ducts empty into? Why?

Answer 10

Venous circulation close to the heart where pressure is almost 0

Question 11

What allows lymph transport? Name 3 things

Answer 11

pulsation of nearby arteries
contraction of smooth muscle in walls of the lymphatics
contraction of nearby skeletal muscles

Question 12

What is the speed of lymphatic transport? How much lymph is returned to the blood stream each day?

Answer 12

Sporadic and slow

Roughly 3L/day

Question 13

What are lymphoid cells? And what are the 2 main parts

Answer 13

Lymphocytes are the major warrior of the immune system

T cells and B Cells

Question 14

What is the main function of t and b cells?

Answer 14

Protect against foreign antigens

Question 15

What is the role of a t cell?

Answer 15

Manage immune response

Attack and destroy foreign cells

Question 16

What is the role of a b cell?

Answer 16

Give rise and produce plasma cells

Question 17

What is the function of a plasma cell? Who produces plasma cells?

Answer 17

Make antibodies

Produced by B cells

Question 18

What are the 5 types of lymphoid cells

Answer 18

t cells
b cells
macrophages
dendritic cells
reticular cells

Question 19

What is the role of macrophages?

Answer 19

Phagocytize foreign substances and help activate t-cells

Question 20

What is the role of dendritic cells?

Answer 20

Capture antigens and deliver these to lymph nodes

Question 21

What is the role of reticular cells?

Answer 21

Produce the stroma that supports other cells in lymphoid organs

Question 22

What are the 2 main functions of lymphoid tissues?

Answer 22

House and provide proliferation site for lymphocytes

Vantage point for surveillance

Question 23

What are the 2 main types of lymphoid tissue?

Answer 23

Diffuse Lymphatic Tissue
Lymphatic Follicles (Also called lymphoid Follicles)

Question 24

What is lymphatic tissue? Where is it found?

Answer 24

Made up of scattered reticular tissue

Found everywhere in the body

Question 25

Describe lymphatic follicles? What do they do?

Answer 25

Solid spherical body, contain germinal center | Often form parts of larger lymphoid organs

Question 26

What are lymph nodes?

Answer 26

Principle lymphoid organs of the body

Question 27

Where are lymph nodes found?

Answer 27

Embedded in connective tissue and in clusters along lymphatic vessels

Question 28

What body surfaces can you find lymph nodes?

Answer 28

Axillary, Cervical, Inguinal

Question 29

What are the 2 main functions of lymph nodes?

Answer 29

Filter lymph - macrophages destroy microrganisms and debris | Immune System - activate lymphocytes and attack antigens

Question 30

What is the structure of a lymph node?

Answer 30

Bean shaped external fibrous capsule Trabeculae extending inward, dividing into compartments

Question 31

2 Distinct Regions of Lymph Nodes

Answer 31

Cortex and Medullary Cords

Question 32

What does the cortex of a lymph node contain?

Answer 32

Follicles with germinal center dividing b cells deeper cortex holds t cells in transit

Question 33

Where are t cells continuously circulating?

Answer 33

Blood, lymph nodes, lymphatic stream

Question 34

Where are the medullary cords?

Answer 34

Extend inward from the cortex

Question 35

What do medullary cords contain?

Answer 35

b cells, t cells, plasma cells

Question 36

What do the lymph sinuses in the medulla contain?

Answer 36

macrophages

Question 37

How does fluid move through a lymphnode?

Answer 37

1. Fluid enters convex side via afferent vessels 2. Fluid travels through subscapsular sinus 3. Fluid moves to smaller sinuses 4. Exits at concave side called hilus via efferent vessels

Question 38

Why are there fewer vessels leaving than entering?

Answer 38

Causes slowing of the fluid to give lymphocytes and macrophages plenty of time for access to the fluid to carry out their surveillance and clean up functions

Question 39

What are the lyphoid organs

Answer 39

``` Spleen Thymus Tonsils Peyer's Patches Appendix Bone marrow Lymph nodes ```

Question 40

What is the largest lymphoid organ?

Answer 40

Spleen

Question 41

What vessels serve the spleen? Where do they enter and exit?

Answer 41

Splenic artery and vein, which enter and exit via the hilus

Question 42

What are the functions of the spleen?

Answer 42

``` Site of lymphosite proliferation Site of immune surveilance and response Cleanses blood Stores the breakdown products of RBCs (iron) for later use Stores platelets ```

Question 43

What does the spleen cleanse blood of?

Answer 43

Aged cells, platelets, debris

Question 44

In the fetus, what is the spleen the site of?

Answer 44

erythrocyte/rbc production

Question 45

What does the spleen contain?

Answer 45

lymphocytes macrophages very large numbers of erythrocytes

Question 46

What are the 2 main areas of the spleen?

Answer 46

White Pulp | Red Pulp

Question 47

What is the white pulp?

Answer 47

Clustered around central arteries Contains mostly lymphocytes sitting on reticular fibers important in immune functions

Question 48

Where is red pulp found?

Answer 48

Found in blood filled venous sinuses and in splenic cords

Question 49

What is the primary cell of red pulp? What is their function?

Answer 49

Macrophages whose job is disposal of RBC's and bloodborne pathogens

Question 50

What is the thymus made up of?

Answer 50

Outer cortex and inner medulla

Question 51

What does the cortex of the thymus contain?

Answer 51

Densely packed lymphocytes and a few scattered macrophages

Question 52

What does the medulla of the thymus contain?

Answer 52

Fewer lymphocytes

Question 53

What is the role of thymic corpuscles?

Answer 53

Regulation of t cell development

Question 54

What is the function of the thymus?

Answer 54

T cell maturation, does not directly fight antigens

Question 55

What are the cells of the thymus called? What is their role?

Answer 55

Thymocytes, they provide optimal environment for t cells to become immunocompetent

Question 56

Describe the tonils

Answer 56

simpest lymphoid organ contain follicles and germinal centers not fully encapsulated

Question 57

How are tonsillar crypts formed?

Answer 57

Outer epithelial tissue invaginates (folds inward)

Question 58

What is the role of a tonsillar crypt?

Answer 58

trap and destroy bacteria and particulate matter

Question 59

What are Peyer's Patches?

Answer 59

Clusters of lymphoid follicles | found in the wall of distal portions of the small intestine

Question 60

What is the function of peyer's patches?

Answer 60

destroy bacteria to prevent their movement across the intestinal wall Generate memory lymphocytes

Question 61

What does the appendix have concentrated in it's walls?

Answer 61

lymphoid follicles

Question 62

what is the role of the appendix?

Answer 62

Same as Peyer's Patches, Destruction of bacteria and generation of memory lymphocytes

Question 63

What is MALT

Answer 63

mucosa associated lymphatic tissue

Question 64

What are types of MALT?

Answer 64

Peyer's Patches tonsils appendix lymphoid nodules in wall of bronchi

Question 65

What is the function of MALT?

Answer 65

Protection of passage ways that are open to outside world

Question 66

Name 4 homeostatic imbalances of the lymphatic system

Answer 66

Lymphedema Buboes Elephantiasis Hodgkin's Disease

Question 67

What is lymphedema

Answer 67

Prevention of normal return of lymph to the blood, causes sever localized edema

Question 68

What are Buboes

Answer 68

NOT swollen glands, but infected lymph nodes, main symptom of bubonic plague

Question 69

What is elephantiasis

Answer 69

Tropical disease where lymphatics of lower limbs become clogged with a parasitic round worm

Question 70

What is Hodgkin's Disease? How is it treated?

Answer 70

Malignancy of lymphoid tissues | Treated with chemo and radiation

Question 71

What are the symptoms of Hodgkin's Disease

Answer 71

Swollen lymphnodes fatigue intermittent fevers night sweats

Question 72

Which is the smallest lymphatic vessel?

Answer 72

lymphatic capillaries