Chapter 20: Lymphatic system and lymphoid organ and tissue

Question 1

lymphatic capillaries

Answer 1

similar to blood capillaries except they are VERY permeable (take up proteins, cell debris, pathogens and cancer cells). Anchored by collagen filaments, prevents collapse of capillaries; increased ECF volume opens mini-valves.

Question 2

Collecting lymphatic vessels

Answer 2

Similar to vein, except they have thinner walls, with more internal valves.
Travel with superficial veins
Deep vessels travel with arteries
Nutrients supplied from branching Vasa Vasorum

Question 3

Lymphatic Trunks

Answer 3

Formed by union of largest collecting ducts.

Question 4

Lymphatic ducts

Answer 4

Lymph is delivered into one of the two large ducts.
The right lymphatic duct drains right upper arm and right side of head and thorax
The thoracic duct arises a cisterna chyli; drains rest of body

Question 5

Source of Lymph

Answer 5

the lymph is formed when the interstitial fluid is collected through the lymph capillaries. It is then transported through lymph vessels to ;lymph nodes before emptying ultimately into the right or the left subclavian vein, where it mixes back with blood.

Question 6

Composition of lymph

Answer 6

comparable to blood plasma. the lyph is formed in teh human digetive system called chyle and is rich in triglycerides (fats) and looks milky white.

Question 7

Lymphocytes

Answer 7

main warriors of immune system. Arise in red bone marrow

Question 8

T Cells (T lymphocytes)

Answer 8

manage immune response

attack and destroy infected cells

Question 9

B Cells (B lymphocytes)

Answer 9

Produce plasma cell, which secrete antibodies. Antibodies mark antigens for destruction by phagocytosis.

Question 10

lymphoid tissues

Answer 10

provide structural basis of immune system. House phagocytic cells and lymphocytes.

Question 11

Lymphoid Organs

Answer 11

Spleen, thymus, tonsils and others

Question 12

Lymphoid Tissue

Answer 12

Houses and provides production site for lymphocytes
Surveillance vantage point for lymphocytes and macrophages
Largely reticular connective tissue

Question 13

Two main types of lymphoid tissue

Answer 13

Diffuse lymphoid tissue and lymphoid follicles

Question 14

Diffuse Lymphoid Tissue

Answer 14

Tissue of lymphoid cells and reticular fibers in every body organ.

(larger collections in lamina propria of mucous membranes)

Question 15

Follicular lymphoid tissues

Answer 15

Are solid, spherical bodies of tightly packed lymphoid cells and reticular fibers.
May form part of larger lymphoid organs
Isolated aggregations of peyers patches

Question 16

Location of lymph nodes

Answer 16

found throughout body, but the largest groupings are found in the neck, armpits and groin areas.

Question 17

function of lymph nodes

Answer 17

Major sites of B, T and other immune cells.
Lymph nodes are important for the proper function of the immune system, acting as filters for foreign particle and cancer cells. Lymph nodes do not deal with toxicity which is primarily dealt with by the liver and kidneys.

Question 18

Structure of Lymph Nodes

Answer 18

small bean shaped glands or bulb that tend to occur in clusters much like grapes.

Question 19

Spleen

Answer 19

• largest lymphoid organ.
• Served by splenic artery and vein, which enter and exit at the hilum.
• the spleen is the site of lymphocyte proliferation and immune surveillance and response.
• Cleanses blood of aged cells platelets
• macrophages remove debris

Question 20

Thymus

Answer 20

Important functions early in life

• found in inferior neck; extends into mediastinum; partially overlies heart
• increases in size and most active during childhood
• stops growing during adolescence, then gradually atrophies
• still produces immunocompetent cells, but slowly

Question 21

Tonsils

Answer 21

Contain follicles with germinal centers
are not fully encapsulated
trap and destroy bacteria and particulate matter
allow immune cells to build memory for pathogens

Question 22

Peyer’s patches

Answer 22

cluster of lymphoid follicle
in wall of distal portion of small intestine
Similar structures are also found in the appendix
destroy bacteria, preventing them from breaching intestinal wall
generate “memory” lymphocytes

Question 23

Types of lymphatic vessels

Answer 23

lymphatic capillaries
collecting lymphatic vessels
lymphatic trunks