SEM 1 - B - Lymphatics - Chyle, Lymph, Major Lymphatic Ducts (lymbar, cisterna chyli, thoracic, lymphatic ducts)

Question 1

The lymphatic (lymphoid) system Where are T and B lymphocyte cells produced? Where do they mature? What happens after both T and B cells have become immunologically competent?

Answer 1

T and B cells are both produced in the bone marrow T cells then migrate to thymus to become immunologically competent B cells remain in the bone marrow to mature Eventually the cells from the thymus and marrow will go into the lymph nodes and circulate around the body

Question 2

Name primary and secondary lymphoid organs?

Answer 2

Primary lympoid organs - thymus and bone marrow Secondary lymphoid organs - lymph nodes, spleen, tonsils, peyers patches in the gut (intestinal lympoid tissue),

Question 3

What is the ring of lymphoid tissue in the tonsils known as?

Answer 3

Waldeyers ring

Question 4

What is lymph? What veins does it drain into?

Answer 4

Lymph is the fluid that circulates throughout the lymphatic system. It is formed when the interstitial fluid (the fluid which lies in the interstices of all body tissues) is collected through lymph capillaries. It is then transported through larger lymphatic vessels to lymph nodes, where it is cleaned by lymphocytes, before emptying ultimately into the right or left venous angles where it mixes back with the blood. LYMPH IS THE EXCESS INTERSTITiAL FLUID COLLECTED THROUGH LYMPH CAPILLARIES IN THE CAPILLARY BED

Question 5

So, lymph is fluid lost from the capillary bed which is collected by lymph capillaries into the lymphoid system What colour is lymph?

Answer 5

Lymph collected from the tissues is usually clear Lymph collected from the small intestines is usually milky/white

Question 6

Why is milk collected from the small intestine milky/white and what is it known as?

Answer 6

This lymph is known as chyle and looks milky white because it contains a high content of fat due to lipid droplets

Question 7

Once the lymph is collected from the lymphatic capillaries, how does it move around the body to reach the right and left subclavian veins? What direction does lymph move from the peripheries?

Answer 7

The lymph drains into small lymphatic vessels which join to form larger lymphatic vessels which pass through lymph nodes Lymph moves from periphery towards the midline and eventually the upper thorax

Question 8

As the lymphatic vessels pass through lymph nodes, what do the lymph nodes do and how?

Answer 8

Lymph nodes contain lymphocytes and macrophages which help removed damaged cells and pathogens before the lymph is returned to the bloodstream

Question 9

Slow lymph flow through node may lead to cancer cells forming secondary tumours within nodes Why is there there slow lymph flow through lymph nodes?

Answer 9

This is because when lymph enters the node, it enters a trabeculated space and therefore moves slowly

Question 10

What is chyle?

Answer 10

This is a milky fluid containing fat droplets which drains from the lacteals of the small intestine into the lymphatic system

Question 11

What are the five main ducts of the lymphatic system?

Answer 11

Lumbar trunks Cisterna chyli Thoracic duct Right and left lymphatic ducts

Question 12

What do the lumbar trunks drain into? What does this structure drain into and where does its name come from?

Answer 12

The lumbar trunks drain into the cisterna chyli The cisterna chyli also drains the chyle (milky lymph containing fat droplets) from the intestinal trunk hence the name The cisterna chyle is the large lump which continues into the thoracic duct

Question 13

What areas of the body drain into the right lymphatic trunk? What three smaller lymphatic vessels drain into the right lymphatic trunk?

Answer 13

The right upper limb - right subclavian trunk The right side of the head and neck - right jugular trunk The right side of the thorax and upper part of the right side of the abdominal wall - right bronchomediastinal trunk

Question 14

What three trunks drain into the right lymphatic duct? Where does the right lymphatic duct drain?

Answer 14

Right jugular, subclavian and bronchomediastinal trunks The right lymphatic duct drains into the right venous angle which is at the angle between the right subclavian and right internal jugular vein (right brachiocephalic vein)

Question 15

The left lymphatic duct is continous with the thoracic duct although has inputs from what other lymphatic vessels?

Answer 15

The left subclavian trunk The left jugular trunk The left bronchomediastinal trunk

Question 16

Each region of the body and each organ has its own small local groups of lymph nodes Lymph drains from these nodes to larger, more central groups of nodes What two vessels does the thoracic duct run between?

Answer 16

The thoracic duct runs between the azygous vein and descending aorta Both pass through diaphragm at T12 vertebral level via the aortic hiatus

Question 17

Lymph follows veins in the limbs and follows arteries in the abdomen What is special about lymph drainage in the pelvis?

Answer 17

When it comes to the pelvis, some of the lymph will follow ligamenets or fascial tissue and drain elsewhere

Question 18

Which group of nodes do the foregut midgut and hingut drain to? What are these nodes known as in relation to the aorta?

Answer 18

Lymph from the foregut drains to the coeliac trunk nodes Lymph from the midgut drains to the superior mesenteric nodes Lymph from the hindgut drains to the inferior mesenteric nodes These are all pre-aortic nodes

Question 19

Why is lymph draining to nodes from the kidney known as para-aortic nodes and not pre-aortic nodes?

Answer 19

This is because these nodes are lateral to the aorta

Question 20

What are the lymph nodes in the brain known as?

Answer 20

There are no lymph nodes in the brain - hence head and neck lymphatics Brain is already protected by the blood brain barrier