Lymphatic System

Question 0

Lymph Formation

Answer 0

• plasma filters out of capillaries b/c of pressure
• called interstitial (tissue) fluid
• much goes to blood, rest to lymphatic system as lymph
• enters network of tiny tube distributed in tissue spaces
  
  • called lymphatic capillaries
  • more porous than blood capillaries

Question 1

Lymph

Answer 1

• fluid formed in tissue spaces and re-enters bloodstream

- transported by lymphatic vessels

Question 2

Lymph Movement

Answer 2

• one way, not a circular route
• from capillaries to larger and larger (lymphatic venules and veins)
• empty into terminal vessels (empty into large veins of neck)

1) Right Lymphatic Duct
- RUE, R side of head, neck, upper torso
2) Thoracic Duct
- rest
- largest lymphatic vessel
- Cisterna chyli
- temp. lymph holding area in ab.

Question 3

Lacteals

Answer 3

• lymphatic capillaries in wall of small intestine

- transport fats obtained from food to the bloodstream

Question 4

Lymph Nodes

Answer 4

• located in cluster along pathway of lymphatic vessels
• locations–>cervical, submandibular, axillary, parasternal, inguinal, popliteal
• biological filtration–>cells alter contents of filtered fluid
• afferent lymphatic vessels–>4, deliver lymph to node
• slowly filtrate through space surrounding nodules
• efferent lymphatic vessels–>1, how lymph exits
• filtered so bacteria, cancer cells, and damaged tissue cells are removed and prevented from entering blood

Question 5

Thymus

Answer 5

• small organ located in medistinum
• source of lymphocytes before birth
• produces T cells
  
  • Thymosins (H) secreted by thymus stimulates development
• vital and central role in immunity
• gradually replaced by fat and connective tissue–>involution

Question 6

Tonsils

Answer 6

• in a protective ring under mucous membrane in mouth and back of throat
• palatine–>on each side of throat
• pharyngeal–>aka adenoids (if swollen), post. opening of nasal cavity
• lingual–>near base of tongue
• protect against bacteria around opening to nasal/oral cavity
• 1st line of defense from exterior

Question 7

Spleen

Answer 7

• largest lymphoid organ, high in LUQ
• rich blood supply (500mL)

Function

• removes by filtration (phagocytosis)
• bacteria, foreign substances
• destroys worn out RBC
• salvages iron from Hb for future use
• reservoir for blood