lymph

Question 1

what is the function of the lymphatic system

Answer 1

tissue drainage and

return of plasma proteins
absorbed fat transport
from the gut

immunity

Question 2

what would happen without the lymphatic system

Answer 2

capillaries are fenestrated so fluid and plasma proteins leak out (high hydrostatic pressure) into the extracellular space
this leads to swelling of parts of the body if the fluid isnt removed
contraction of muscles increases pressure and forces fluid around the channels - ensures swelling is reduced

Question 3

what regulated capillary flow into the bed

Answer 3

smooth muscle in the arterioles

Question 4

absorbed fat transport from the gut

Answer 4

lymph returning from the small intestine is laden with absorbed fats
these drain into the SVC and eventually to the liver for absorption

Question 5

immunity

Answer 5

lymphoid tissues

lymphocytes are generated and mature

Question 6

generation of lymphocytes

Answer 6

thymus and bone marrow (1y)
lymph nodes (2y)
spleen (2y)
peyer's patches (2y) - in the wall of the intestine
tonsils

Question 7

composition of lymph

Answer 7

fluid and plasma proteins only, gains lymphocytes as it flows through lymphatic capillaries and channels, fats added in the S intestine

Question 8

flow in the lymphatic system

Answer 8

similar to that in veins - relies on muscle contraction, pressure changes and gravity
unidirectional (valves)
flow into extracellular spaces increases during infection due to protein accumulation, this drives increased lymph flow and the immune response in nodes

Question 9

location and positioning of lymph nodes

Answer 9

lymphatic vessels periodically transverse lymph nodes
normally parallel to the arterial blood supply of a region
nodes can be isolated or grouped
groups occur at the bases of major arterial trunks

Question 10

what is a lymph node

Answer 10

swelling around the capillaries and act as filters

immunological functions of lymph

Question 11

lymph nodes and cancer

Answer 11

cancer cells can be drained into the lymph node, stick there and start to multiply
node becomes cancerous and metastatic tumours form
cancer becomes systemic

Question 12

what is a lymphoid follicle

Answer 12

centres for white cell development

Question 13

deep lymph nodes

Answer 13

~450 lymph nodes in a yound adult
250 in abdomen, chiefly associated with mesenteries (contents of GI tract contain lots of unecessary substances that may require an immune response)

2 major routes of drainage: superficial and deep

Question 14

superficial lymph nodes

Answer 14

e.g. inguinal nodes located in and around the femoral triangle at the base of the lower limb

Question 15

lymph node pathology

Answer 15

1y tumours: lymphomas e.g. Hodgkins
non-Hodgkins - tumour in the node that didn’t originate in the node
2y tumours as a result of metastasis from other sites
infections such as TB and glandular fever
inflammatory hyperplasia (over reacting lymph node)

Question 16

drainage routes

Answer 16

initially drainage is symmetrical from limbs, head and neck and trunk
as a rule, deep lymphatic drainage follows routes of arterial supply
ultimately all lymph congregates into 2 large lymph ducts
these empty into the venous system at the subclavian junction

Question 17

which areas drain into the right lymphatic duct

Answer 17

right upper quadrant of the body

Question 18

which areas drain into the thoracic duct

Answer 18

whole body apart from right upper quadrant

Question 19

spleen

Answer 19

largest lymphatic organ
upper left quadrant of the abdomen
lots of smooth muscle
contains large amount of blood, routinely discharged by smooth muscle action
histology of white pulp is similar to a lymph node (immune function of the spleen)

Question 20

where is there no lymph drainage from

Answer 20

epithelium, cartilage, bone or CNS

majority of spleen and liver