4. Lymphatic System

Question 1

What is lymph?

• Where is it created?
• What vessels carries it away?

Answer 1

Created in the interstitial spaces of tissues

Carried away by lymphatic vessels into the general circulation

Question 2

4.7 Place the following lymphatic vessels in order of smallest to largest.

• Lymphatic venules and veins
• Lymphatic ducts (right lymphatic and thoracic)
• Lymphatic capillaries

Answer 2

Smallest to largest

1. Lymphatic capillaries
2. Lymphatic venules and veins
3. Lymphatic ducts (Right lymphatic and thoracic)

Question 3

4. 8 What regions of the body are covered by the following lymphatic vessels?
   - Right lymphatic duct
   - Thoracic Duct

Answer 3

Right Lymphatic Duct - Right head, right arm, and right upper body

Thoracic Duct - Left head, left arm, left upper body, all lower body

Question 4

4.8 What veins do the Right Lymphatic Duct and Thoracic duct drain into, respectively?

Answer 4

Right lymphatic duct into the Right Subclavian vein

Thoracic duct into the Left Subclavian vein

Question 5

4.9 What are lymph nodes?

Answer 5

They are “beads” or “swellings” along certain lymphatic vessels. They are filters that can swell up when active.

Question 6

4.11 Where are lymph nodes most extensive? (Go in the direction of from head to toes)

Answer 6

1. Breast
2. Neck
3. Axilla
4. Abdomen
5. Thorax
6. Pelvis
7. Groin

Question 7

4.12 What are four causes of edema?

Answer 7

1. Excess filtration (Increased Pc)
2. Decreased absorption (Decreased πc)
3. Increased capillary permeability
4. Blocked lymphatics

Question 8

4.12 At a vessel’s arterial end, what two Starling forces are most dominant? What direction do fluids go?

Answer 8

Pc > πc

Causes a net filtration out of the vessel into the interstitial tissues

Question 9

4.12 At a vessel’s venous end, what two Starling forces are most dominant? What direction do fluids travel?

Answer 9

Pc < πc

Causes a net absorption from the tissues back into the vessel

Question 10

4. 15 Where is the thymus located?
   - When is the thymus largest?
   - What occurs to an adult’s thymus?
   - What does it produce?

Answer 10

Thymus located in mediastinum

Largest in puberty; regresses in adults

Produces WBCs, especially T-lymphocytes

Question 11

4. 16 Tonsils
   - What are they?
   - What are the three tonsils in the oral cavity?

Answer 11

Tonsils are essentially clusters of WBCs hanging out in the pharynx.

The three types:

1. Pharyngeal (adenoids)
2. Palatine
3. Lingual

Question 12

4. 17 Spleen
   - Location?
   - Often injured in what kind of trauma?
   - Surgical procedure to remove the spleen?

Answer 12

Located in left upper quad (LUQ)

Often injured in abdominal trauma

Splenectomy = removal of spleen

Question 13

4. 18 GI Tract
   - What diffusion system of lymphoid tissue exists in the GI tract?
   - What populates the lymphoid tissue of this diffusion system?

Answer 13

Mucosa associated lymphoid tissue (MALT)

MALT is populated by T lymphocytes, B lymphocytes, and macrophages - these encounter antigens passing through the GI tract mucosa