the lymphatic system

Question 1

what does the lymphatic system contain?

Answer 1

-lymphatic vessels and lymphoid tissues and organs

Question 2

what role does the lymphatic system play in the body?

Answer 2

-transports escaped fluids from the cardiovascular system back to the blood
-plays role in body defence and resistance to disease
-the vessels pick up excess lymph and return it to blood-flows one way only towards the heart
-if fluids are not picked up, oedema occurs as fluid accumulates in tissues

Question 3

lymph capillaries

Answer 3

-weave between tissue cells and blood capillaries
-fluid leaks into lymph capillaries

Question 4

distribution of lymphatic vessels

Answer 4

-lymphatic vessels collect lymph from lymph capillaries
-return fluid to the circulatory veins near the heart

Question 5

how does the body drain?

Answer 5

-right lymphatic duct drains the lymph from the right arm and the right side of the heart and thorax
-thoracic duct drains lymph from the body

Question 6

describe lymphatic vessels

Answer 6

-thin walled
-low pressure
-larger vessels have valves

Question 7

lymph transport aided by:

Answer 7

1. skeletal muscles
2. pressure changes in thorax during breathing
3. smooth muscle in walls of lymphatics

Question 8

what is the role of the lymph nodes?

Answer 8

-lymph nodes filter lymph before it is returned to the blood

Question 9

what are the harmful materials that are filtered?

Answer 9

1. bacteria
2. viruses
3. cancer cells
4. foreign substances

Question 10

defence cells with lymph nodes

Answer 10

1. macrophages
2. lymphocytes

Question 11

macrophages

Answer 11

-in the medulla
-engulf and destroy bacteria, viruses and other foreign substances in lymph

Question 12

lymphocytes

Answer 12

-in the follicles
-respond to foreign substances in lymph

Question 13

primary lymphoid organs

Answer 13

-bone marrow
-thymus

Question 14

bone marrow

Answer 14

-lymphatic cells are generated
-stem cells mature into B lymphocytes and pre-T lymphocytes

Question 15

thymus

Answer 15

-produces hormones like thymosin that mature T lymphocytes

Question 16

secondary lymphoid organs

Answer 16

-spleen

Question 17

spleen

Answer 17

-red pulp stores platelets and acts as a blood reservoir

Question 18

macrophages in red pulp

Answer 18

-filters and cleans blood of bacteria, viruses, debris
-destroys worn out red blood cells
-site for lymphocyte proliferation and immune surveillance in white pulp

Question 19

lymphoid organs

Answer 19

-mucosa associated lymphoid tissue (MALT)
-tonsils
-peyer’s patches
-appendix

Question 20

tonsils

Answer 20

-trap and remove bacteria and other foreign pathogens entering the throat
-tonsilitis results when the tonsils become congested with bacteria

Question 21

peyer’s patches

Answer 21

-similar lymphoid follicles are found in the appendix
-macrophages capture and destroy bacteria in the intestine

Question 22

appendix

Answer 22

-acts a sentinel to protect respiratory and digestive tracts from foreign matter

Question 23

how do lymphatic vessels form?

Answer 23

-they form from budding off the veins

Question 24

when are lymph nodes present?

Answer 24

-lymph nodes present by fifth week of development

Question 25

what are the first lymphoid organs that develop?

Answer 25

-the thymus
-the spleen

Question 26

birth and the lymphoid system

Answer 26

-other lymphoid organs are poorly developed around the time of birth
-the ability of immunocompetent cells to recognize foreign antigens and is genetically determined

Question 27

how does the immune system develop in life?

Answer 27

-efficiency of the immune response wanes in old age, and infection, cancer, immunodeficiencies, and auto autoimmune diseases become more prevalent