The Lymphatic system and Immunity

Question 1

The lymphatic system transports excess fluid out of the interstitial spaces and returns it to the…

Answer 1

Blood stream

Question 2

Lymphatic vessels are found in bone? T or F

Answer 2

False

Question 3

What are the two primary lymphoid organs?

Answer 3

Bone marrow and Thymus

Question 4

Where are the lymphocytes produced?

Answer 4

Bone marrow, Lymph nodes

Question 5

Name types of our first line of physical barriers or ‘innate (non-specific) defence’ of the body

Answer 5

skin, mucous membranes, hair, sweat, mucus

Question 6

What do the lymphatic vessels have which prevent backflow of lymph?

Answer 6

Valves

Question 7

Which direction do the lymphatic vessels move in?

Answer 7

One direction to the heart

Question 8

Lymph from lymphatic vessels drains into one of two collecting ducts. Which are the two collecting ducts?

Answer 8

Right lymphatic duct and Thoracic (left) duct

Question 9

What is it called when tissue fluid accumulates in the interstitial space?

Answer 9

Oedema

Question 10

Name two types of lymphocytes

Answer 10

T cells, B cells

Question 11

Name two types of Innate, internal defences

Answer 11

Antimicrobial proteins, Natural killer cells

Question 12

Components of the Lymphatic system

Answer 12

Lymph, lymphatic vessels, lymphatic tissue, red bone marrow

Question 13

Functions of lymphatic system

Answer 13

• Drains excess interstitial fluid from the tissue space back into the blood
• Immune responses

Question 14

What are lymph trunks?

Answer 14

They are formed as lymph vessels converge after leaving lymph nodes

Question 15

What are the 5 lymph trunks?

Answer 15

-Lumbar
-Interstitial
-Bronchomediastinal
-Jugular
-Subclavian

Question 16

Lumbar trunks

Answer 16

Drain the lower limb, pelvic organs, kidneys, adrenal glands and abdominal wall

Question 17

Interstitial trunks

Answer 17

Responsible for the stomach, intestines, pancreas, spleen and parts of liver

Question 18

Bronchmediastinal trunks

Answer 18

Responsible for the thoracic wall, heart and lungs

Question 19

Subclavian trunks

Answer 19

Responsible for upper limbs

Question 20

Jugular trunks

Answer 20

Responsible for head and neck

Question 21

Formation of lymph

Answer 21

• More fluid filters out of the blood into the interstitial fluid than returns so excess fluid drains into lymphatic vessels to become lymph
• Proteins are too large to leave blood vessels so interstitial fluid only contains a small amount of protein

Question 22

Flow of lymph

Answer 22

-Lymph drains into venous blood through the right lymphatic duct and the thoracic duct at the junction of the internal jugular and subclavian veins
1. Blood capillaries
2. Interstitial spaces
3. Lymphatic capillaries
4. Lymphatic vessels
5. Lymphatic trunks or ducts
6. Junction of the internal jugular and subclavian veins

Question 23

Primary lymphatic organs

Answer 23

Where stem cells divide and become immunocompetent e.g red bone marrow, thymus

Question 24

Secondary lymphatic organs

Answer 24

Sites where most immune responses occur e.g lymph nodes, spleen

Question 25

Innate immunity

Answer 25

External physical and chemical barriers provided by skin and muscous membranes.
As well as internal defences e.g antimicrobial substances, natural killer cells, inflammation

Question 26

First line of defence- Skin and mucus membranes

Answer 26

-The epidermis provides a physical barrier to the entrance of microbes
-The periodic shedding of epidermal cells helps remove microbes at the skin surface
-Mucous membranes and cilia, saliva and urine etc act to remove any pathogens that have infiltrated the broken skin

Question 27

Second line of defence- Internal defences

Answer 27

1. Antimicrobial substances
2. Natural killer cells
3. Phagocytes
4. Inflammation

Question 28

T cells

Answer 28

-Develop from primary lymphatic organs
-Mature in the Thymus
-Mature T cells exit the Thymus as helper T cells

Question 29

B cells

Answer 29

-Develop from primary lymphatic organs
-B cells complete their development in red bone marrow throughout life

Question 30

Types of adaptive immunity

Answer 30

Cell-mediated
Antibody mediated immunity

Question 31

Cell-mediated (adaptive immunity)

Answer 31

• Begins with activation of a small number of T cells by a specific antigen
• It undergoes clonal selection forming clones of cells that can recognise the same antigen as the original lymphocyte
• Some of the T cells become effector cells and some become memory cells. Forming clones of both
• Effector cells can carry out immune responses that result on elimination of the intruder

Question 32

Antibody-mediated immunity

Answer 32

• B cells in lymph nodes, spleen or lymphatic tissue become activated
• Undergoing clonal selection forming a clone of plasma cells and memory cells
• The plasma cells secrete antibodies which circulate in the lymph of blood to reach that site of invasion
• Memory cells don’t secrete antibodies but instead they proliferate and differentiate into plasma and memory B cells
• Plasma cells do secrete antibodies- our antibody action sends this five classes of antibodies and their actions

Question 33

The 4 types of antibody actions

Answer 33

Neutralising antigens
Immobilising bacteria
Activating complements
Enhancing phagocytosis

Question 34

Neutralising antigens

Answer 34

Blocks of neutralises toxins and prevents attachment of viruses to body cells

Question 35

Immobilising bacteria

Answer 35

Antigens reactions are on cilia e.g the bacteria lose their mobility

Question 36

Activating complements

Answer 36

An antigen antibody reaction which activates the complement system.
These complement proteins cause a cascade reaction which means that one reaction triggers another and brings about phagocytosis, cytolysis and inflammation (effector functions)

Question 37

What enhances the action of phagocytosis

Answer 37

Antibodies

Question 38

Types of adaptive immunity

Answer 38

Naturally acquired active immunity- antibodies developed in response to an infection
Naturally acquired passive immunity- which is transferred from mother to foetus across the placenta or milk
Artificially acquired active immunity- vaccination stimulates production of antibodies
Artificially acquired passive immunity- where you have intravenous injection of immunoglobulins or antibodies

Question 39

Ageing and the immune system (5 things)

Answer 39

• Increased susceptibility to infection and malignancies
• Response to vaccine decreased- less responsive to antigens as we age
• Lower levels of immune system function
• T and B cells become less responsive to antigens
• Antibodies do not increase as rapidly in response to antigens