The lymphatic system

Question 1

What is lymph and what is it composed of?

Answer 1

A fluid similar to blood plasma, containing lymphocytes, water, electrolytes, waste from the cells and some proteins, although far fewer plasma proteins than blood plasma

Question 2

What is lymph formed from?

Answer 2

It is formed from the blood plasma and tissue fluid

Question 3

Does lymph return as venous or arterial flow?

Answer 3

Venous

Question 4

What speed relative to blood flow does lymph circulate?

Answer 4

Much slower

Question 5

What actions generate lymphatic flow?

Answer 5

Indirect:
Pressure gradients
Muscleskeletal pump
Respiratory pump

Direct:
Contraction of smooth muscle and valves in vessel walls

Question 6

What structural differences are there between veins and lymphatic vessels?

Answer 6

Lymphatic vessels are thinner and have more valves inside of them

Question 7

What are the two main lymphatic ducts?

Answer 7

Right lymphatic duct, thoracic duct

Question 8

Where does lymph enter back into the bloodstream?

Answer 8

Right and left subclavian veins

Question 9

What is the structure of lymph nodes?

Answer 9

Small bean shaped organs (0.5-2.5cm long) with a convex face receiving 4-5 afferent lymph vessels and a concave face where an artery enters and a vein and efferent lymph vessel leave. Inside, large clusters of lymphocytes and macrophages called lymph modules are separated and encased by a fibrous capsule and reticular tissue.

Question 10

What is the function of lymph nodes?

Answer 10

Detoxification and filtration of lymph

Question 11

How many efferent vessels does each lymph node have?

Answer 11

One

Question 12

What is the largest lymphatic organ?

Answer 12

The spleen

Question 13

What is the internal structure of the spleen?

Answer 13

Venous sinuses called red pulp, and white pulp

Question 14

What is red pulp?

Answer 14

Storage areas of red blood cells in the spleen

Question 15

What is white pulp?

Answer 15

Storage areas of white blood cells in the spleen

Question 16

What are the main functions of the spleen?

Answer 16

Controlling the levels of white blood cells, red blood cells and platelets
Screening the blood removing old or damaged red blood cells
Storing iron for future use
Storage of blood (≈350mL)
Erythropiesis

Question 17

How does the spleen help screen the blood?

Answer 17

By extracting microbes and destroying them with phagocytosis

Question 18

How does the spleen aid in haematopoiesis?

Answer 18

By enabling leukocytes to complete maturation

Question 19

How much excess fluid is filtered out from blood capillaries each day?

Answer 19

3-4 L

Question 20

What are the lymphatic organs?

Answer 20

Red bone marrow, spleen, thymus, tonsil

Question 21

Where are lymphocytes located?

Answer 21

Some are fixed in lymphoid organs and other circulate through the blood and lymph allowing them to ‘patrol’ all areas of the body

Question 22

Why do lymphatic vessels have more valves than blood vessels?

Answer 22

They have a slower and weaker flow of fluid so need more valves to prevent backflow

Question 23

What routes do lymphatic vessels of the viscera follow?

Answer 23

They follow the arteries, forming plexuses around them

Question 24

What routes do lymphatic vessels generally follow in the skin?

Answer 24

The same as veins through subcut tissue

Question 25

Where do the lumbar lymph trunks drain lymph from?

Answer 25

Lower limbs, pelvic region, kidneys and adrenal glands

Question 26

Where does the intestinal lymph trunk receive fluid from?

Answer 26

The stomach, intestines, pancreas, spleen and liver

Question 27

What fluid does the intestinal lymph truck receive?

Answer 27

Chyle, lymph mixed with ingested fats

Question 28

Where do the bronchomediastinal lymph trunks drain lymph from?

Answer 28

The lungs, mediastinal organs, mammary glands and thoracic wall

Question 29

Where do the subclavian lymph trunks receive lymph from?

Answer 29

Upper limbs and axilla

Question 30

Where do the jugular lymph trunks drain lymph from?

Answer 30

The head and neck

Question 31

Where is the cisterna chyli located?

Answer 31

Anterior to L2

Question 32

What are the primary lymphatic organs?

Answer 32

Sites where lymphocytes are activated. Red bone marrow and thymus

Question 33

What are the secondary lymphatic organs?

Answer 33

Sites where most immune responses occur. Lymph nodes, spleen and tonsils.

Question 34

What are the specific regions of the body associated with clusters or particular abundance of lymph nodes?

Answer 34

Pericranial ring
Cervical nodes
Tracheal nodes
Axillary nodes
Deep nodes
Inguinal nodes
Femoral nodes

Question 35

Where is the thymus located?

Answer 35

Directly behind the sternum, extending from the top of the sternum to the 4th costal cartilage

Question 36

What lymphocytes develop in the thymus?

Answer 36

T lymphocytes

Question 37

Where is the spleen located?

Answer 37

In the left hypochondrium of the abdomen, lying between the diaphram, stomach and kidneys

Question 38

What is the purpose of the lymphatic system?

Answer 38

To drain and filter the excess interstitial fluid that is not reabsorbed into the capillary bed and return it to venous flow
Transport dietary lipids and lipid soluble vitamins absorbed via the GI tract
Immune response

Question 39

Where in the body does lymph return to the venous circulation?

Answer 39

The left and right subclavian veins

Question 40

What immune cells do lymph nodes contain?

Answer 40

Lymphocytes and macrophages

Question 41

Why are fats absorbed by the lymphatic system?

Answer 41

They are too large to be absorbed straight into the blood stream, they would clog the intestinal capillaries