Lymphatic System

Question 1

Lymphatic vessels (lymphatics)

Answer 1

Elaborate network of drainage vessels that that collect the excess-protein containing interstitial fluid and return it to blood

Question 2

Lymph

Answer 2

What it interstitial fluid is called once it enters the lymphatic vessels

Question 3

T/F: The lymphatic vessels form a one-way system in which lymph flows only toward the heart.

Answer 3

True

Question 4

Lymphatic capillaries

Answer 4

Microscopic, blind-ended vessels that weave between the tissue cells and blood capillaries to collect excess tissue fluid; highly permeable.

Question 5

Where lymphatic capillaries absent from?

Answer 5

Bones and teeth

Question 6

What makes lymphatic capillaries so permeable?

Answer 6

1. The endothelial cells forming the walls of lymphatic capillaries are not tightly joined. They form easily opened minivalves
2. Collagen filaments anchor the endothelial cells to surrounding structures so that any increase in interstitial fluid volume opens the minivalves, rather than causing the lymphatic capillaries to collapse.

Question 7

Lacteals

Answer 7

Special set of lymphatic capillaries that trasnport absorbed fat from small intestine to the blood

Question 8

Chyle

Answer 8

Fatty lymph that drains from the villi of intestinal mucosa

Question 9

What is the order of the vessels that lymph flows through, from smallest to largest?

Answer 9

1. Lymphatic capillaries
2. Collecting lymphatic vessels
3. Lymphatic trunks
4. Lymphatic ducts

Question 10

Collecting lymphatic vessels

Answer 10

Channels of the lymphatic system that transport lymph from lymphatic capillaries through lymph nodes before converging with other collecting lymphatic vessels to form the larger lymphatic trunks.

Have the same three tunics as veins, but thinner walls and more internal valves.

Question 11

Lymphatic trunks

Answer 11

Largest collecting vessels in lymphatic system, drain fairly large areas of the body.

Question 12

What are the major lymphatic trunks?

Answer 12

the paired lumbar, bronchomediastinal, subclavian, and jugular trunks, and the single intestinal trunk

Question 13

Right lymphatic duct

Answer 13

Drains lymph from the right upper limb and right side of the head and thorax

Question 14

Thoracic duct

Answer 14

Receives lymph from entire body except the right upper limb and right side of the head and thorax

Question 15

Cisterna chyli

Answer 15

An enlarged sac at the base of the thoracic duct; the origin of the thoracic duct

Question 16

What are the main functions of lymphatic vessels?

Answer 16

1. Return excess tissue fluid to the blood
2. Return leaked proteins to the blood
3. Carry pathogens to lymph nodes
4. Carry absorbed fat from the intestine to the blood (through lacteals)

Question 17

Lymphoctyes

Answer 17

Main warriors of immune system, consist of T cells and B cells

Question 18

T lymphocytes (T cells)

Answer 18

Manage the immune response, some directly attack and destroy infected cells

Question 19

B lymphocytes (B cells)

Answer 19

Protect the cell body by production plasma cells

Question 20

Plasma cells

Answer 20

Cells that secrete antibodies into the blood

Question 21

Macrophages

Answer 21

Phagocytize foreign substances and help activate T cells

Question 22

Dendritic cells

Answer 22

Capture antigens and bring them back to lymph nodes

Question 23

Stroma

Answer 23

The network that supports the other cell types in lymphoid organs and tissues

Question 24

Lymphoid tissue function

Answer 24

1. Houses lymphocytes and provides a site where they can be activated and proliferate
2. Furnishes an ideal surveillance vantage point for lymphocytes and macrophages

Question 25

Diffuse lymphoid tissue

Answer 25

Found in virtually every body organ; a loose arrangement of lymphoid cells and some reticular fibers`

Question 26

Lymphoid follicles

Answer 26

Solid, spherical bodies consisting of tightly packed lymphoid cells and reticular fibers

Question 27

Primary lymphoid organs

Answer 27

Where B and T cells mature (red bone marrow for B cells, thymus for T cells)

Question 28

Secondary lymphoid organs

Answer 28

Where mature lymphocytes first encounter their antigens and are activated (lymph nodes, spleen, MALT)

Question 29

Lymph nodes

Answer 29

Lymphoid organs that cleanse lymph and activate the immune system, hundreds embedded in connective tissue throughout the body

Question 30

What are the two histologically distinct regions of a lymph node?

Answer 30

Cortex and medulla

Question 31

Afferent lymphatic vessels

Answer 31

Located on the convex side of the lymph node, where lymph enters. These outnumber efferent vessels

Question 32

Hilum

Answer 32

Indented region on the concave side of the lymph node, where lymph exits

Question 33

Efferent lymphatic vessels

Answer 33

Lymphatic vessels that convey lymph out of the concave side of a lymph node at the hilum.

Question 34

Spleen

Answer 34

Largest lymphoid organ; provides a site for immune surveillance, lymphocyte activation, and erythrocyte destruction.

Question 35

Which vessels serve the spleen?

Answer 35

Splenic artery, splenic vein

Question 36

White pulp

Answer 36

Area in the spleen where immune functions take place, composed mostly of lymphocytes suspended on reticular fibers

Question 37

Red pulp

Answer 37

Area in the spleen where worn-out red blood cells and bloodborne pathogens are destroyed

Question 38

Mucosa-associated lymphoid tissue (MALT)

Answer 38

A set of distributed lymphoid tissues strategically located in mucous membranes throughout the body; helps protect from pathogens that seek to enter the body

Question 39

What are the largest collections of MALT?

Answer 39

Tonsils, appendix, Peyer's patches

Question 40

Tonsils

Answer 40

A ring of lymphoid tissue around the entrance to the pharynx (throat); gather and remove many of the pathogens entering the pharynx in food or in inhaled air

Question 41

Palatine tonsils

Answer 41

Located on either side at the posterior end of the oral cavity. These are the largest tonsils and the ones most often infected

Question 42

Lingual tonsil

Answer 42

The collective term for a lumpy collection of lymphoid follicles at the base of the tongue

Question 43

Pharyngeal tonsil

Answer 43

In the posterior wall of the nasopharynx.

Question 44

Tubal tonsils

Answer 44

Surround the openings of the auditory tubes into the pharynx.

Question 45

Peyer's patches

Answer 45

Large clusters of lymphoid follicles, structurally similar to tonsils that are located in the wall of the distal portion of the small intestine

Question 46

Appendix

Answer 46

A tubular offshoot of the first part of the large intestine, contains a high concentration of lymphoid follicles. In an ideal position (1) to prevent bacteria (present in large numbers in the intestine) from breaching the intestinal wall, and (2) to generate many “memory” lymphocytes for long-term immunity

Question 47

Thymus

Answer 47

- Bilobed lymphatic organ that has important functions primarily during childhood. - Found in the inferior neck and extends into the superior thorax - Where T lymphocyte precursors mature to become immunocompetent lymphocytes