Lymphatic System (EXAM #2)

Question 1

Overview of the Lymphatic System?

Answer 1

• Lymphatic system consists of:
  
  • One way network of lymphatic vessels that collect ~10% of the extracellular fluid that leaked out from cardiovascular capillaries and return this fluid (now termed lymph) to the venous blood
  • Lymph nodes along the vessel network that cleanse lymph as it passes through them
    
    • Contain T & B lymphocytes that identify and remove bacteria, viruses, cancer cells
• Lymphoid cells, tissues and organs support the functions of the lymphatic system

Question 2

What are the 2 types of Body Fluid Compartments?

Answer 2

1. Intracellular Fluid
2. Extracellular Fluid

Question 3

Intracellular Fluid

Answer 3

Fluid found within cells (~40% of body weight)

Question 4

Extracellular Fluid

Answer 4

• Fluid found outside of cells
  
  1. Blood Plasma
  2. ISF (interstitial fluid)
  3. Lymph

Question 5

Blood Plasma

Answer 5

• ~5% of body weight)
• Fluid in blood
• Some exits capillaries to form ISF

Question 6

ISF (interstitial fluid)

Answer 6

• ~15% of body weight
• Fluid between cells within the body (except blood cells which are surrounded by plasma)
• Some moves into lymphatic capillaries to form lymph

Question 7

Lymph

Answer 7

• ~1% of body weight
• Fluid inside lymphatic vessels
• Returned to blood plasma

Question 8

Lymphatic Circulation (PART 1)

Answer 8

• Lymph enters lymphatic capillaries (closed ended vessels that project into cardiovascular capillary beds)
  
  • Lymphatic capillaries in the small intestine also play a role in fat absorption
• Lymphatic capillaries connect to larger lymphatic collecting vessels that have one-way valves

Question 9

Lymphatic Circulation (PART 2)

Answer 9

• Lymph nodes along collecting vessels filter lymph (bacteria, debris)
  
  • Transports lymph fluid AWAY from tissues to:
    1. Right Lymphatic Duct
    2. Thoracic Duct
• Fluid flows through lymphatic collecting vessels largely as a result of body movements (muscle
  contractions) that move the fluid toward the heart. One-way valves in the collecting vessels prevent back
  flow of lymph.

Question 10

Right Lymphatic Duct

Answer 10

• Lymph from the right side of the head, chest,and arm
• Drains into right subclavian vein re-entering circulation

Question 11

Thoracic Duct

Answer 11

• Lymphs from below the ribs and the entire left side of the body
• Collecting vessels from below the ribs coverage to an enlarged lymph vessel = cisterna chyli (this is the most inferior portion of the thoracic duct)
• The thoracic duct drains into the left subclavian vein reentering blood circulation

Question 12

One Way Route back to Blood (Circulation)

Answer 12

1. Lymphatic capillaries
   ↓
2. Lymphatic collecting vessels (with valves)
   ↓
3. Lymphatic ducts
   ↓
4. Subclavian veins

Question 13

Lymphoid Tissues & Organs

Answer 13

• Contain many lymphocytes and play a key role in the body’s immune system
• Include:
  
  1. Primary lymphoid organs and tissues
  2. Secondary lymphoid organs and tissues

Question 14

Primary lymphoid organs and tissues

Answer 14

• Locations where lymphoid stem cells divide and mature (become immunocompetent)
• Include:
  
  1. Red Bone Marrow
  2. Thymus Gland
• Mature lymphocytes move into blood stream and migrate to the secondary lymphoid organs/tissues

Question 15

Red Bone Marrow

Answer 15

• All lymphocyte stem cells arise here
• Site of B lymphocyte proliferation (mitosis) maturation

Question 16

Thymus Gland

Answer 16

• Early in development (fetal stage) lymphocyte stem cells migrate here
• Site of T lymphocyte proliferation (mitosis) and maturation

Question 17

Secondary Lymphoid Organs and Tissues

Answer 17

• Where lymphocytes detect and remove pathogens
• Locations where lymphocytes are activated and proliferate further
• Includes:
  
  1. Lymph nodes
  2. Spleen
  3. Mucosal Associated Lymphoid Tissue (MALT)

Question 18

Lymph nodes

Answer 18

• Small masses of lymphoid tissue along lymphatic collecting vessels
• High concentrations of lymph nodes are located in:
  
  • Cervical (neck), axillary (armpit), inguinal (groin), intestinal, pelvic regions

Question 19

Spleen

Answer 19

• Located in left side of abdominal cavity just below diaphragm next to stomach
• Filters (cleans) blood by removing pathogens (organisms that can cause disease like bacteria or viruses), old and defective blood cells, and cellular derbis

Question 20

Mucosal Associated Lymphoid Tissue (MALT)

Answer 20

• Trap and remove pathogens at points of entry into the body
• Includes tonsils, appendix, and other lymphoid tissues on mucous membranes
• e.g. aggregated lymphoid nodules (Peyer’s patches) in the small intestine
• e.g. tonsils: form a ring around the pharynx
  
  • Pharyngeal (1)
  • Palatine (2)
  • Lingual (1)

Question 21

Pharyngeal (1)

Answer 21

In posterior nasopharynx (referred to adenoids when infected/swollen)

Question 22

Palatine (2)

Answer 22

In oropharynx - used to be commonly removed

Question 23

Lingual (1)

Answer 23

Bumpy nodules on posterior part (base) of tongue