lymphatic system

Question 1

function of lymphatic system

Answer 1

to collect some of the fluid that escapes from the blood capillaries and return it to the circulatory system, plays an important role in the body’s internal defence against disease causing organisms.

lymphatic system is a one way system: carrying fluid away from the tissues

Question 2

lymphatic system consists of:

Answer 2

• network of lymph capillaries
• lymph vessels
• lymph nodes
• lymph
• lymphatic tissue
• lymphocytes
• macrophages

Question 3

lymph capillaries

Answer 3

network of lymph capillaries joined to larger lymph vessels (also called lymphatic vessels or lymphatics)

Question 4

lymph vessels

Answer 4

vessel that collects lymph from the lymph capillaries, have valves preventing back flow, lymph travels slowly in vessels, blind ended tubes

Question 5

lymph nodes

Answer 5

located along the length of some lymph vessels (also called lymph glands), bean shaped structure found on the lymphatic vessels; it is involved in protection against infection

occur at intervals of the vessels, numerous amounts in neck, armpits, groin and around alimentary canal, 1 - 25 mm, surrounded by a capsule of connective tissue that extends into the nodes making a framework

Question 6

lymph

Answer 6

colourless fluid that circulated through the lymphatic vessels before returning to the blood, this fluid is collected from the tissues as fluid tends to leak out the arterial end of a blood capillary due to high pressure in the vessel, some returns to the capillary at the venous end though

Question 7

lymphatic tissue

Answer 7

tissue contains lymphocytes and macrophages; found in lymph nodes, bone marrow, tonsils, spleen and thymus

Question 8

lymphocytes

Answer 8

a type of white blood cell

Question 9

macrophages

Answer 9

a phagocytic cell derived from a monocyte (another type of white blood cells)

Question 10

where does the lymph go to?

Answer 10

lymph goes back to the subclavian vein

Question 10

movement of lymph

Answer 10

highly permeable, protein and disease causing organisms in the intercellular fluid can easily pass through the walls of the lymph capillaries into the lymph

lymph is moved through vessels as a result of smooth muscle, skeletal muscle and valves

smooth muscle layer of vessel contracts which pushes the lymph through vessels

skeletal muscles surrounding muscles contract which provide additional force

valves prevent back flow

Question 11

what is in the framework of lymph nodes?

Answer 11

within the framework is lymphoid tissue which contains lymphocytes, macrophages and plasma cells

Question 11

where does lymph enter the lymph node?

Answer 11

lymph enters through the vessels on the convex side of lymph node, lymph passes through several nodes before entering circulatory system

Question 11

what role does the lymphatic system play in defence against disease?

Answer 11

lymph contains cell debris, foreign particles and microorganisms (some which can cause disease) that have penetrated the body’s external defences

large particles like bacteria get trapped in the meshwork of fibres inside the lymph nodes as lymph flows through the nodes

large phagocyctic cells called macrophages destroy these particles through the process of phagocytosis, the projections of the macrophages ingest the particles which then is destroyed by enzymes, this is an immune response

when infections occur, lymphocyte number increases, which causes lymph nodes to become swollen and sore, lymphocytes made in thymus and by bone marrow