LYMPHOID SYSTEM

Question 1

what is the lymphoid system?

Answer 1

a sort of ‘overflow’ system that provides for the drainage of surplus tissue fluid and leaked plasma proteins to the bloodstream, as well as for the removal of debris from cellular deposition and infection

Question 2

what is the order of lymphatic drainage?

Answer 2

lymphatic capillaries —> lymph vessels —(lymph nodes)—> lymph trunks —> thoracic duct/right lymphatic duct —> venous angle

Question 3

what is the venous angle?

Answer 3

junction between the subclavian and internal jugular veins

Question 4

what trunk do the head and neck drain to?

Answer 4

jugular trunk

Question 5

what trunk does the upper limb drain to?

Answer 5

subclavian trunk

Question 6

what trunk do the lungs, heart, trachea, and mediastinum drain to?

Answer 6

bronchomediastinal trunk

Question 7

what trunk do the lower limbs, pelvis, and kidneys drain to?

Answer 7

lumbar trunk

Question 8

what trunk do the intestines drain to?

Answer 8

intestinal trunk

Question 9

what is a lymphatic plexus?

Answer 9

a network of lymphatic capillaries that originates blindly in the extra cellular (intracellular) spaces of most tissues

Question 10

what allows plasma proteins, bacteria, cellular debris, and even whole cells (esp. lymphocytes) to readily enter lymphatic capillaries?

Answer 10

lymphatic capillaries are formed of a highly attenuated endothelium lacking a basement membrane, along with a surplus of tissue fluid

Question 11

describe lymphatic vessels

Answer 11

= thin-walled vessels with abundant lymphatic valves that compromise a nearly body-wide network to drain lymph from the lymphatic capillaries

Question 12

what gives lymphatics a beaded appearance?

Answer 12

the vessels bulge where each of the closely spaced valves occur giving it a beaded appearance

Question 13

what are lymphatic trunks?

Answer 13

large collecting vessels that receive lymph from multiple lymphatic vessels

Question 14

where are lymphatic vessels and capillaries NOT found?

Answer 14

teeth, bone, bone marrow, the CNS

Question 15

where does tissue fluid from the CNS drain into?

Answer 15

cerebrospinal fluid

Question 16

what is lymph?

Answer 16

the tissue fluid that enters lymph capillaries and is conveyed by lymphatic vessels. usually clear, watery and slightly yellow. has a similar composition to blood plasma

Question 17

what are lymph nodes?

Answer 17

small masses of lymphatic tissue located along the course of lymphatic vessel. where lymph is filtered on its way to the venous system

Question 18

what are lymphoid organs?

Answer 18

parts of the body that produce lymphocytes

Question 19

what traverses lymph nodes?

Answer 19

deep and superficial lymphatic vessels as they course proximally. become larger was they merge with vessels drinking adjacent regions

Question 20

right lymphatic duct

Answer 20

• drains lymph from the body’s right upper quadrant (right side of head, neck and throat plus the right upper limb)
• at the root of the neck, it enters the right venous angle

Question 21

what is the right venous angel?

Answer 21

the junction of the right internal jugular and right subclavian veins

Question 22

thoracic duct

Answer 22

drains lymph from the rest of the body. the lymphatic trucks draining the lower half of the body merge in the abdomen, sometimes forming a dilated collecting sac, the cisterna chyli —> from this sac (if present), or from the merger of the trunks, the thoracic duct ascends into and then through the thorax to enter the left venous angle

Question 23

what is the left venous angle?

Answer 23

the junction of the left internal jugular and left subclavian veins

Question 24

name 2 additional functions of the lymphoid system

Answer 24

1. absorption and transport of dietary fat

2. formation of a defence mechanism for the body

Question 25

name 8 lymph node groups

Answer 25

1. cervical (neck)
2. mesenteric
3. axillary (armpit)
4. cubital
5. iliac
6. inguinal (groin)
7. lumbar
8. popliteal

Question 26

what is primary lymphoid tissue?

Answer 26

red bone marrow + the thymus gland

Question 27

primary lymphoid tissue functions

Answer 27

• where lymphocytes are formed and mature
• provide an environment for stem cells to divide into B and T cells
• both B and T cells are ‘born’ in bone marrow
• B cells mature in bone marrow whereas T cells mature in the thymus

Question 28

secondary lymphoid tissues

Answer 28

lymph nodes, tonsils, Peyer’s patches, musosa associated lymphoid tissue (MALT)

Question 29

functions of secondary lymphoid tissues

Answer 29

• a series of filters monitoring the contents of the extracellular fluids (ie. lymph, tissue fluid, blood)
• where lymphocytes are activated

Question 30

what are Peyer’s patches?

Answer 30

large masses of confluent lymphoid follicles found in the walls of the ileum.