L18 : Cells and tissues of the lymphatic system

Question 1

What is the function of lymphatic system?

Answer 1

• Fluid balance
• Transport of fats and fat-soluble vitamins
• protection against pathogens

Question 2

What does the lymphatic system consist of?

Answer 2

• Lymph
• Lymphatic vessels
• Lymphoid tissues and organs
• cells within tissues

Question 3

What is a lymph?

Answer 3

• A thin fluid that resembles plasma
• pH 7.4
• lower amounts of proteins

Question 4

What is a chyle?

Answer 4

• lymph that arises in GI tract
• white, cloudy substance
• contains fats and dissolved lipids (chylomicrons and fat soluble vitamins)

Question 5

How much lymph is produced and recycled each day?

Answer 5

3-4 litres

Question 6

What aids the flow of lymph?

Answer 6

• valves
• smooth muscle in wall
• contraction of muscle for deep lymphs assing through them
• skeletal muscle movement
• pulsation of adjavent arteris

Question 7

What is the characteristics of lymph vessel?

Answer 7

• lie adjacent to cardiovascular vessel
• porous and the tips
• arranged into superficial and deep
  
  • flow from superficial to deep
• valves, smooth muscle and anchoring filament (retiulin fibre)
• no cells in lumen

Question 8

What is a lymphatic duct?

Answer 8

• Large lymphatic vessel that empties lymph into one of the subclavian veins

Question 9

What are the two lymphatic ducts and what are their functions?

Answer 9

• Right Lymphatic Duct : drains lymph from upper right quadrant into right subclavian vein
• Thoracic duct : drains lymph from rest of the body into left subclavian vein

Question 10

What are the clinically important lymph nodes?

Answer 10

• cervical
• inguinal
• axillae

Question 11

What is the characteristics of Lymph nodes?

Answer 11

• kidney shaped
• multiple afferent lymphatic vessels enter convex surface
• 1 efferent lymphatic vessel leaves concave hilum
• has feeding artery and draining vein at hilum
• multiple follicles
• Reticulin

​*hilum - portion of lymph node where efferent vessel exits

Question 12

What is the function of Lymph node?

Answer 12

• Filters lymph as it percolates on its way to the vascular system
• traps and process antigen
• macrophage presents antigen to t cells

Question 13

How does the majority of lymphocytes enter the lymph nodes?

Answer 13

• Majority enter via feeding artery and leave in the efferet lymphatics, some in lymph
• Majority leave via efferevt lymphatics

Question 14

How do dendretic cells enter the Lymph nodes?

Answer 14

they enter with pathogens within lymphs

Question 15

How many lymph nodes are there in th ehuman body?

Answer 15

about 700

Question 16

What is the function of B cell and T cell in Lymph node?

Answer 16

• B cell :
  
  • proliferate to form plasma cells and B memory cells
  • Secrete antibodies
• T cells :
  
  • directly attack cells with antigenic material

Question 17

What is lymphadenopathy?

Answer 17

Enlarged lymph nodes

Question 18

What causes lymphadenopathy?

Answer 18

• germinal centres fill with lymphocytes during infection
• Cancers metastasise to lymph nodes via afferent lymphatics
• lymphoma

Question 19

Where can lymphodenopathy occur ?

Answer 19

all the nodal regions and can affect all lymphatic organs

Question 20

What are the lymphatic organs?

Answer 20

• Thymus
• spleen
• tonsils
• appendix
• payer’s patches

Question 21

What is the characteristics and function of thymus?

Answer 21

Characteristics

• located at superior mediastinum
• stops growing after puberty and replaced with adipose tissue
• only efferent lymphatic vessels

Function

• provide an inductive environment for development of T cells from haemopoietic progenitor cells

Question 22

What is the characteristics and function of spleen?

Answer 22

Characteristics:

• largest lymphatic organ
• rich in blood supply
• inferior to diaphragm, psoterior to stomach
• seperated into white pulp and red pulp
• only efferent lymphatic vessel s

Function

• Immune function
  
  • antigen presentation by APCs
  • activates and poliferates B and T cells
• Haemopoietic functions
  
  • remove and destroys old damage erythrocytes and platelets
  • stores erythrocytes and lymphocytes

Question 23

What is splenectomy and what is the risk associated with it?

Answer 23

• surgery to remove entire spleen
• increase risk of infection by encapsulated bacteria and malaria

Question 24

Which organs can take over the role of spleen?

Answer 24

Liver and bone marrow

Question 25

What is the characteristics and function of tonsils?

Answer 25

Characteristics

• located at oropharyx and nasopharyx
• together forms Waldeyer’s ring

Functions

• prevent pathogen ingress through aural, nasal and oral routes
  *

Question 26

What causes swelling of tonsils?

Answer 26

• Surface epithelia have many m cells
• present antigens to underlying immune cells
• swelling due to B and T cells proliferation

Question 27

What is the characteristics and function of vermiform appendix

Answer 27

Characteristics :

• inferior to and attached to caecum
• nodules reside inferior to surface invaginations
• many M fold cells

Function :

• prevents pathogen ingress from ileum

Question 28

What is the characteristics and function of payer’s patches

Answer 28

Characteristics

• inferior to and attached to side of ileum
• nodules reside inferior to surface domes
• many M-fold cells in epithelial surface

Function

• prevents pathogen ingress through digestion

Question 29

What is a sentinel lymph node?

Answer 29

set of node to which cancer cells are most like to spread from a primary tumour

Question 30

Tissue sample from which node is required for biposy of breast cancer?

Answer 30

pectoral node

Question 31

What is a mastectomy?

Answer 31

surgical removal of breast with malignant epithelial cells

Question 32

What are the ways to remove cancer through sentinel lymph nodes?

Answer 32

• Flurography via pectoral node
• mastectomy using probe

Question 33

What are the types of lymphoedema?

Answer 33