lymphatic and immune system/disorders

Question 1

Lymphatic System

Answer 1

• Lymph
• Lymph vessels
• Lymph nodes
• Lymph organs eg spleen,
thymus
• Lymphoid tissue eg tonsils

Question 2

function of lymphatic system 3

Answer 2

Tissue drainage: Transports excess interstitial fluid (lymph) back to the blood

Immunity: Lymph nodes filters lymph to remove
microorganisms and other foreign particles and acivaate
white blood cells. Lymphatic organs produces and mature white blood cells that destroy invading organisms

Absorption: Fats and fat-soluble vitamins are absorbed from the digestive system into lymph vessels which transports these substances to the venous circulation

Question 3

Lymph Nodes 2

Answer 3

• Filter lymph before it is returned to the blood
• Produce and store white blood cells which destroy
harmful materials that enter lymph vessels
eg Bacteria, Viruses, Cancer cells, Cell debris

Macrophages—engulf and destroy foreign substances

Lymphocytes—provide immune response to specific antigens

Question 4

Immunity

Answer 4

• Specific defence for each type of invader
• Antigen specific—recognizes and acts
against particular foreign substances
• Tolerance—ignore healthy cells
• Memory—recognizes and mounts a
stronger attack on previously encountered
pathogens

antigens
• Any substance capable of exciting the
immune system and provoking an
immune response
• Examples of common antigens
• Foreign proteins (strongest)
• Pollen grains
• Bacteria
• Viruses
• fungi

Cells of the adaptive defence system
Lymphocytes
• Originate in the red bone marrow
• B lymphocytes (B cells)
• T lymphocytes (T cells)

Question 5

B cells

Answer 5

• produce antibodies specific to certain antigens ie hepatitis A
• Initial contact with antigen causes B cell to divide rapidly and most of these cells become antibody producing plasma cells

Antibody: proteins produced by B cells that are released into body fluids where they attach to antigens causing neutralisation, precipitation or agglutination.

The others B cells become memory cells which increases body ability to quickly respond to future invasion

Question 6

T cells

Answer 6

Recognise only one type of antigen and patrol the body

When they encounter an antigen for the first time they become sensitised to it

3 types which assist in fighting specific
antigens

Question 7

Aquired Immunity

Answer 7

• The immune response to an antigen following the first exposure
• Exposure to an antigen for the first leads to a slow and delayed rise in antibody levels
• On subsequent exposures to the same antigen the immune response is much faste rand 10-15 times more powerful
• Active immunity can be
  • Naturally acquired during bacterial and viral
  infections
  • Artificially acquired from vaccines

Question 8

Passive Immunity

Answer 8

• Conferred naturally from a mother to her foetus (naturally acquired)
• Conferred artificially from immune serum or gamma globulin (artificially acquired)

Occurs when antibodies are obtained from someone else

Immunological memory does not occur

Protection provided by “borrowed antibodies”
Examples: antivenom and antitoxin

Question 9

Lymphoedema

Answer 9

• accumulation of lymphatic fluid in tissues causing oedema
• due to damage or removal of lymphatic vessels/nodes which blocks effective drainage of lymph
• common after surgery and radiotherapy for cancer
• breast cancer often leads to lymphoedema of arms
• bowel and reproductive organ cancer can lead to
lymphoedema of legs and groin
• can also be caused by parasites, immobility, allergy, trauma
• treated with compression, massage, physiotherapy

Question 10

Hodgkin’s Lymphoma

Answer 10

• Developing lymphocytes become malignant and multiply in an uncontrolled way
• Primarily occurs in 15-30 year olds
• Symptoms of night sweats, pruritis, fever, weight loss and painless swelling in lymph nodes (neck, groin, axilla)
• Initially involves a single lymph node but progresses to adjacent lymph nodes and finally to other organs via the lymphatic system
• More frequent in mononucleosis (Epstein-Barr virus)
sufferers.
• Treatment involves combination radiation and
chemotherapy
• Good prognosis

Question 11

Non-Hodgkin’s Lymphoma

Answer 11

• 5th most common cancer in men and 6th in women
• Mainly affects people over 50 men (60 plus)
• Symptoms similar to Hodgkin’s lymphoma
• Distinguished by multiple node involvement scattered
throughout the body and a widespread pattern of
metastases, often present at diagnosis
• Intestinal nodes and organs often involved in early stages
• Prognosis varies but not as good as Hodgkins