Lecture 16- Lymphatic System

Question 1

Immune system

Answer 1

Set of defences to prevent or reduce damage or disease

Question 2

Innate immunity

Answer 2

Set of defences that are present from birth and recognize common characteristics of many pathogens

Question 3

Adaptive immunity

Answer 3

Involves T and B lymphocytes that can help the immune response learn, adapt and remember previous pathogens

Question 4

What is interstitial fluid that does not circulate back into the blood is collected by?

Answer 4

Lymphatic vessels

Question 5

Three parts the lymphatic system consists of:

Answer 5

Network of lymphatic vessels

Lymph

Lymphatic cells and organs

Question 6

Lymphatic capillaries

Answer 6

Found between tissue cells and blood capillaries in loose connective tissue

Large molecules can pass through

Flow into collecting lymphatic vessel and carry the lymph to lymphatic trunks

Question 7

Lymphatic trunks

Answer 7

Drains fairly large areas of the the body and eventually empty the lymph back int the circulatory system via the right lymphatic duct or thoracic duct

Question 8

Lymphatic vessels

Answer 8

Low pressure vessels that use the same mechanisms as veins to return the lymph to circulatory system

Skeletal muscle compression
Pressure changes during breathing
Valves to prevent backflow

Question 9

Lymphocytes

Answer 9

Arise in red bone marrow and mature into T cells (thymus) or B cells (bone marrow)

Question 10

T cells

Answer 10

Manage immune responses and some also attack and destroy infected cells

Question 11

B cells

Answer 11

When they encounter an antigen they can activate into plasma cells which secrete antibodies, which mark antigens for destruction by phagocytosis or other means

Question 12

Natural killer cells

Answer 12

In at immune cells that are cytotoxic (cell killing)

Question 13

Macrophages

Answer 13

Can act as phagocytes and help to activate T lymphocytes

Question 14

Dendritic cells

Answer 14

Found in lymphoid tissue, play a role in t lymphocyte activation (reporter cells)

Question 15

Reticular cells

Answer 15

Produce reticular fibres that make up the stroma, the network that supports the other cells types in lymphoid tissues (maintains lymph nodes)

Question 16

Lymphoid tissues

Answer 16

house and provide a proliferation site for lymphocytes and furnish an ideal surveillance site for lymphocytes and macrophages.

Diffuse lymphoid- found in nearly every body organ
Lymphoid follicles- may form part of larger lymphoid organs

Question 17

Lymph nodes

Answer 17

act as filters to remove and destroy micro-organisms and other debris for the lymph before it is transported back to the bloodstream.

Question 18

Buboes

Answer 18

inflamed, swollen, tender lymph nodes that result when nodes are overwhelmed by what they are trying to destroy.

Question 19

Spleen

Answer 19

Largest lymphoid organ locate din upper left sid of abdominal cavity

main function is to remove old and defective red blood cells and platelets as well as foreign matter and debris from the blood. also provides site for
lymphocyte proliferation and immune surveillance.

Surrounded by fibrous capsule and contains bot lymphocytes found in white pulp and macrophages found in red pulp

Question 20

White pulp

Answer 20

Site where immune function occurs

Question 21

Red pulp

Answer 21

Site where old blood cells and bloodborn pathogens are destroyed

Question 22

Mucosa-associated lymphoid tissues (MALT)

Answer 22

set of lymphoid tissues located in mucous membranes throughout the body.

Question 23

Tonsils

Answer 23

simplest lymphoid organs, forming a ring of lymphoid tissue around the opening to the
pharynx.

They gather and remove many of the pathogens entering the pharynx in food or inhaled air.

Question 24

Tonsillar crypts

Answer 24

pockets of epithelium that catch bacteria and food particles to train immune cells against potential pathogens.

Question 25

Peyers patches

Answer 25

Clusters of aggregated lymphoid nodules

found in the wall of the ileum (the distal portion of the small intestine).

Question 26

Appendix

Answer 26

located off the first part of the large intestine and contains large numbers of lymphoid follicles.

It appears to play a role in maintaining the normal flora of the intestines, rather than simply trying to destroy them.

Question 27

Thymus

Answer 27

secretes hormones that cause T lymphocytes to become immunocompetent.

most active during childhood, stops growing during adolescence and gradually atrophies in adulthood. continues to function but more slowly.

Question 28

How does the thymus differ from other lymphoid organs?

Answer 28

It has no B cells and, therefore, no follicles.

It is not directly involved in fighting antigens.

The stroma of the thymus consists of epithelial cells, not reticular fibres, to contain immature T lymphocytes.

Question 29

Major histocompatibility complex (MHC) proteins

Answer 29

Expressed on the outside of cells

T lymphocytes use MHCs to check on health of cells

Question 30

What kind of proteins do all nucleated cells have?

Answer 30

Class I MHC proteins.

Cells present a few cytoplasmic proteins on MHC I so T lymphocytes can see if the cell is infected.

Question 31

What kind of protein do dendritic cells, macrophages and B cells have?

Answer 31

Class II MHC proteins.

Pathogens that get engulfed by these cells are digested into smaller pieces and antigens are presented on MHC II.

Question 32

Immunocompetence

Answer 32

Recognition of specific antigens

Question 33

Self tolerance

Answer 33

Ensuring they do to attack the body’s own cells

Question 34

Positive selection

Answer 34

in the outer cortex of the thymus, which allows only T lymphocytes that recognize MHC proteins to survive.

Question 35

Negative selection

Answer 35

in the inner medulla of the thymus, which allows only T cells that do not recognize self-antigen proteins to survive.

Question 36

What is the thymus made up of?

Answer 36

made up of thymic lobules containing an outer cortex of rapidly dividing T cells and an inner medulla where self-reactive T cells are removed.