lymphatics

Question 1

what are the functions of the lymphatic system?

Answer 1

• Drains excess interstitial fluid (up to 3L per day) back into venous circulation.
• Involved in transporting dietary lipids from GI tract to blood (as well as hormones0
• Involved in immune responses that protect against invasion

Question 2

what is the main disadvantage of the lymphatic system?

Answer 2

plays a role in the spread of malignancy

Question 3

describe the oncotic and hydrostatic pressure at the arterial and venous end of the capillary bed

Answer 3

o Arterial end: high hydrostatic pressure and low oncotic pressure. Fluid moves out of the capillary into the interstitum to form ISF.
o Venous end: low hydrostatic pressure and high oncotic pressure

Question 4

how much fluid is taken in and out of the capillary bed each day? what is the excess?

Answer 4

excess 3L/day
o 17 litres taken in per day
o 20 litres removed per day

Question 5

describe the structure of lymphatic capillaries

Answer 5

• Lymphatic capillaries are one-way tubes
• Made of an endothelial tube. Either have a discontinuous basement membrane or no basement membrane at all – v permeable

Question 6

describe the composition of lymph

Answer 6

same as interstitial fluid

Question 7

what do lymphatic capillaries join together to form?

Answer 7

join together to form lymphatic collecting ducts

Question 8

what’s the difference between lymphatic capillaries and ducts?

Answer 8

ducts have valves

Question 9

what’s the difference between veins and lymphatic ducts?

Answer 9

• Ducts have valves – more than veins bc they’re at a lower pressure than veins and there’s no heart pumping lymph around.

Question 10

why do ducts need valves?

Answer 10

needed to stop backflow of lymph into the capillary beds

Question 11

put the lymphatic vessels in order of biggest to smallest

Answer 11

• Lymphatic duct  lymphatic trunk  lymph nodes  lymph collecting vessels  lymphatic capillaries

Question 12

what is elephantitis and what causes it?

Answer 12

• Roundworm infection of lymph nodes blocking the lymphatic drainage so interstitial fluid builds up in the tissues.

Question 13

what are lymph nodes?

Answer 13

small masses of lymphoid tissue located along the length of the lymphatic vessels through which lymph is filtered

Question 14

what surrounds each lymph node?

Answer 14

fibrous capsule

Question 15

what divides lymph nodes into different segments?

Answer 15

trabeculae

Question 16

what are the 2 different sections of a lymph node?

Answer 16

outer cortex and inner medulla

Question 17

what cells are found in the cortex of lymph nodes?

Answer 17

lymphocytes

Question 18

describe the passage of lymph into, through and out of a lymph node

Answer 18

o Afferent vessel  cortex  medulla  efferent vessel

Question 19

why do lymph nodes swell?

Answer 19

During infection, you get more lymphocytes to the nodes so there’s swelling of the lymph nodes

Question 20

where does the thoracic duct run?

Answer 20

in the posterior mediastinum

between the descending aorta and azygous vein

Question 21

what is the cisterna chyli?

Answer 21

the beginning of the thoracic duct in the abdomen

Question 22

what is the left venous angle?

Answer 22

where the internal jugular vein joins the subclavian vein and they form an angle

Question 23

what parts of the body drain into the left venous angle?

Answer 23

3/4 - all abdomen, both legs, left side of thorax, left upper limb, left side of the head and neck drain into the left venous angle

Question 24

what parts of the body drain into the right venous angle?

Answer 24

Remaining ¼ drains via the right lymphatic trunk

Question 25

what is a chylothorax?

Answer 25

Any sort of laceration or disruption to the thoracic duct, it leaks lymph into the thoracic cavity

Question 26

what are the superficial lymph nodes?

Answer 26

cervical, axillary and inguinal

Question 27

where are the superficial cervical lymph nodes found?

Answer 27

gathered around the external jugular vein | found on the superficial surface of the SCM

Question 28

describe the passage of vessels from the superficial lymph nodes to the deep lymph nodes?

Answer 28

afferent vessels into the superficial lymph nodes | efferent vessels into the deep lymph nodes

Question 29

where are the deep cervical lymph nodes found?

Answer 29

vertical chain along the IJV

Question 30

where is the internal jugular vein?

Answer 30

• Underneath the SCM is the IJV in the carotid sheath with the common carotid artery and the vagus nerve

Question 31

what is the right jugular trunk?

Answer 31

efferent vessels from the deep cervical lymph nodes

Question 32

when are lymph nodes most readily palpable?

Answer 32

when fighting infection

Question 33

how do infected lymph nodes feel?

Answer 33

Firm, tender, enlarged and warm.

Question 34

how do lymph nodes with malignancies feel?

Answer 34

Firm, non-tender, matted (i.e. stuck to each other), fixed (i.e. not freely mobile but rather stuck down to underlying tissue), and increase in size over time.

Question 35

what are the primary sites of metastatic neck disease?

Answer 35

mucosal areas of the upper digestive tract.

Question 36

what type of cancer is metastatic neck disease?

Answer 36

squamous cell carcinoma

Question 37

what does radical neck dissection involve?

Answer 37

removal of SCM, IJV and the spinal accessory nerve and the cervical lymph nodes.

Question 38

what are the most common procedures for radical neck dissection?

Answer 38

2 procedures in common use today are the modified radical (leave 1+ structure) and the selective neck dissections (leave 1+ LN group).

Question 39

what drains into the axillary lymph nodes?

Answer 39

* Important bc 75% of lymph from the breasts drain to these | * Other 25% drain to the parasternal lymph nodes

Question 40

what are the axillary lymph nodes and what drains into them?

Answer 40

* Humeral – close to axillary pulse. Most lymph from the upper limb comes here * Pectoral – lymph from anterior chest wall (aka breast) * Subscapular – posterior chest wall.

Question 41

describe the route of the lymph once it drains out of the axillary lymph nodes

Answer 41

All of these drain towards central  apical which are just below the clavicle  supraclavicular nodes  right venous angle (on the left side they’ll drain towards the left venous angle)

Question 42

what is a radical mastectomy

Answer 42

removal of all breast tissue, along with the nipple, axillary lymph nodes and a portion of pectoralis major. This is rarely performed today.

Question 43

what is a modified radical mastectomy?

Answer 43

removal of breast, nipple and most axillary lymph nodes.

Question 44

what is the sentinel lymph node?

Answer 44

the first lymph node a tumour reaches

Question 45

how is sentinel lymph node identification carried out?

Answer 45

* Known tumour is injected with radioactive substance or dye * Allowed to drain and see where the dye goes * Remove these nodes and the tumour. Less extensive than removing all the nodes

Question 46

where are the inguinal lymph nodes found?

Answer 46

in the femoral triangle

Question 47

what drains into the inguinal lymph nodes

Answer 47

• Drain all the lymph from the lower limb and external genitalia

Question 48

what are the 2 groups of the inguinal lymph nodes

Answer 48

o Horizontal – (run superficial to inguinal ligament). Superficial lymphatics from anterior abdominal wall, the perineum, and the external genitalia (excl. testes) o Vertical – lie along termination great saphenous vein

Question 49

where do the testes and ovaries develop?

Answer 49

Both testes and ovaries start development in the posterior abdominal wall and then descend

Question 50

where do the testicular and ovarian artery come from and why?

Answer 50

as they descend they take their blood supply with them – testicular and ovarian artery come from the abdominal aorta at L2

Question 51

where does lymph from the testes drain?

Answer 51

Travels back up with the testicular vein to the para-aortic or the lumbar lymph node - lymph nodes around the aorta

Question 52

where does lymph from the scrotum go?

Answer 52

goes to the superficial inguinal nodes

Question 53

where does lymph from the internal and external iliac nodes drain?

Answer 53

drains into the common iliac nodes and then the lumbar nodes.

Question 54

where does lymph from the GI tract drain?

Answer 54

• Lymph from the GI tract drains into the pre-aortic lymph nodes (celiac, superior mesenteric and inferior mesenteric nodes)

Question 55

where does lymph from intestinal and right and left lumbar trunks drain?

Answer 55

into cisterna chyli

Question 56

what is the largest lymphoid organ?

Answer 56

spleen

Question 57

where is the spleen located?

Answer 57

located in the left hypochondrium, deep to the 9th-11th ribs

Question 58

what happens in the spleen?

Answer 58

o lymphocyte proliferation | o RBC filtration, destruction and storage.

Question 59

where is the thymus gland found?

Answer 59

superior mediastinum

Question 60

what happens to the thymus gland after puberty?

Answer 60

• After puberty the thymus gland undergoes progressive atrophy and is replaced by fat.