Module 10 - Lymphatic System

Question 1

The 5 structures of the lymphatic system include:

Answer 1

1. lymphatic vessels
2. red bone marrow
3. thymus
4. spleen
5. lymph nodes

Question 2

What are the 3 functions of the lymphatic system?

Answer 2

1. drain tissue spaces of excess interstitial fluid
2. transport dietary fats and fat-soluble vitamins from the gastrointestinal tract through the blood
3. protect the body from microorganisms and cancer cells through immune responses

Question 3

What is microcirculation?

Answer 3

• at tissues, fluid is pushed out of the capillaries by the pressure of blood = filtration
• proteins are too big to leave the blood
• O2, CO2 and glucose move down their concentration gradient

Question 4

What is lymph?

What is interstitial fluid?

Answer 4

• fluid found immediately around tissue cells is called interstitial fluid
• excess interstitial fluid enters lymphatic capillaries
• fluid circulating through lymphatic vessels is called lymph

Question 5

What are lymphatic capillaries?

Answer 5

• highly permeable capillaries found between tissue cells
• closed at one end
• cells overlap –> open like a swing door when interstitial fluid pressure is high and close when fluid enters

Question 6

What is the flow of lymph?

Answer 6

1. lymphatic capillaries to
2. lymphatic vessles (larger) to
3. lymphatic ducts to
4. right or left subclavian vein to
5. vena cava

lymph flow occurs by skeletal muscle contractions and respiratory movements

Question 7

What is the right lymphatic duct?

Answer 7

it drains the right arm, chest and head

Question 8

What is the thoracic duct?

Answer 8

it drains the left arm, chest, torso and lower limbs

Question 9

Where is the thymus located? What is its function?

Answer 9

• its located in the mediastinum (posterior to the sternum and medial to the lungs)
• functions in immunity –> produces T lymphocytes (T cells)

Question 10

What are lymph nodes? What is their function?

Answer 10

• oval structures located along the length of lymphatic vessels
• scattered throughout the body
• rich in lymphocytes (T cells and B cells)
• function in immunity –> filter lymph and remove foreign substances

Question 11

How does lymph travel?

Answer 11

Lymph enters the afferent lymphatic vessels and leave through the efferent lymphatic vessels

Question 12

What is the spleen? Where is it located? What are its three functions?

Answer 12

• largest mass of lymphatic tissue in the body
• located between the stomach and the diaphragm
• functions:
  1. blood reservoir (holds ~200mL)
  2. degradation of aged and damaged red blood cells and platelets
  3. immunity (houses macrophages that engulf bacteria and lymphocytes)