anatomy of the lymphatic system

Question 1

lymphatic tissues and organs

Answer 1

• lymph vessels
• lymph nodes and nodules (follicles)
• thymus
• spleen
• bone marrow
• tonsils
• GALT

Question 2

lymphatic functions

Answer 2

• drain excess fluids from body tissues
• recirculate proteins from blood capillaries
• absorb emulsified fat via lacteals in intestinal villi
• body defense mechanism: humoral immunity (B cells) and cell-mediated immunity (T cells)

Question 3

compare the structure of lymphatic vessels to cardiovascular vessels

Answer 3

lymphatic:

• begin blindly at the blood capillaries (no connection to blood)
• endothelial cells have no basal lamina, cells have gaps between them (no junctional complexes), and there is little smooth muscle in general => allows things to pass more easily through

Question 4

where does lymph enter blood circulation, and through which veins?

Answer 4

• lymph enters blood at the junction of the internal jugular and subclavian veins on the left and right sides
• enters via the jugular, subclavian, and bronchomediastinal trunks

Question 5

how is lymph drainage different on the R and L sides of the body?

Answer 5

• bilaterally symmetrical above the umbilicus; occurs through jugular, subclavian, and bronchomediastinal trunks on the R and L sides
• all lymph below the umbilicus goes to the left side via the thoracic duct

Question 6

where does lymph from the superficial body wall flow first?

Answer 6

• axillary or superficial inguinal nodes
• then will pierce the investing fascia to go to deep lymphatic vessels that follow arteries/veins

Question 7

describe the path of lymph from superficial fascia below the umbilicus

Answer 7

afferent lymphatics => superficial inguinal nodes in superficial fascia => efferent lymphatics through deep fascia => deep inguinal nodes at femoral sheath (all lymph from lower extremities converges here)

Question 8

what is the pecinate line?

Answer 8

separates gut and body wall

same as the cloacal line in the embryo

above: lymph => internal iliac vessels
below: lymph => superficial inguinals

Question 9

what is the major route of all lymph from the lower body up to the diaphragm/thoracic duct?

Answer 9

aortic lymphatics (a plexus on the aorta and inferior vena cava) => cysterna chyli

Question 10

what is the route of GI lymph?

Answer 10

mesentery lymph nodes/vessels => aortic lymph vessels => cisterna chyli => thoracic duct

Question 11

what lymph from the thorax does/does not drain through the thoracic duct?

Answer 11

yes: thoracic body wall
no: heart, lungs, liver

Question 12

what is the path of lymph drainage from the upper extremity?

Answer 12

superficial and deep lymph => axillary lymph nodes => subclavian trunk => veins of neck

Question 13

what is the path of lymph drainage from the heart and lungs?

Answer 13

bronchomediastinal trunk

Question 14

what are the possible paths of lymph drainage from the breast (normal and exceptions)?

Answer 14

1. axillary nodes => subclavian trunk
2. opposite breast
3. parasternal nodes deep to the body wall/ribcage => bronchomediastinal trunk
4. superficial inguinal nodes

Question 15

what is the path of drainage of lymph from the head/neck?

Answer 15

jugular trunk

Question 16

name 3 less intuitive paths for lymph

Answer 16

1. breast lymph => deep parasternal nodes
2. anterior intercostal lymph => deep parasternal nodes (b/c the thoracic duct is posterior and far away)
3. esophagus => bronchomediastinal trunk or thoracic duct