Exam 2 (Ch. 20)

Question 1

What are the three parts of the lymphatic system?

Answer 1

Lymphatic vessels
lymph
lymph nodes

Question 2

an elaborate network of drainage vessels that collect the excess protein-containing interstitial fluids and return it to blood

Answer 2

lymphatic vessels

Question 3

interstitial fluid that enters the lymphatic capillaries

Answer 3

lymph

Question 4

cleanse lymph

Answer 4

lymph nodes

Question 5

name the 2 primary functions of lymphoid tissue

Answer 5

(1) houses and provides proliferation sites for lymphocytes
(2) surveillance vantage points for lymphocytes & macrophages as they monitor lymph flowing through lymphoid tissue

Question 6

what is the direction of fluid flow in lymphatic vessels

Answer 6

-towards the heart
capillaries > collecting lymphatic vessels > lymphatic trunks > lymphatic ducts > venous circulation

Question 7

where does the right lymphatic duct drain from

Answer 7

drains lymph from the right upper limb and right side of the head & thorax

Question 8

where does the thoracic duct drain from

Answer 8

receives lymph from the rest of the body

Question 9

blind-ended vessels that weave between the tissues of cells and blood capillaries to collect excess tissue fluid: highly permeable

Answer 9

lymphatic capillaries

Question 10

what is the structure of lymphatic capillaries

Answer 10

similar to blood capillaries but more permeable due to minivalves and lacteals

Question 11

specialized lymph capillaries in intestinal mucosa; absorb digested fat and deliver fatty lymph (chyle) to the blood

Answer 11

lacteals

Question 12

what are minivalves

Answer 12

made by endothelial cells loosely overlapping and anchored by collagen filaments to surrounding connective tissues

Question 13

how is lymph transport similar to transport in the venous system

Answer 13

both are low pressure systems that have valves to prevent backflow

Question 14

how is lymph transport different from transport in the venous system

Answer 14

-lymph movement is slower than blood in veins
-lymph has a passive flow driven by body movements while the venous system is powered by a pump (the heart)

Question 15

mechanisms that help propel lymph

Answer 15

-milking action of skeletal muscle
-pressure changes in the thorax during breathing
-valves that prevent backflow
-pulsations of nearby arteries
-contractions of smooth muscle in walls of lymphatics

Question 16

which organs are primary

Answer 16

red bone marrow and the thymus

Question 17

which organs are secondary

Answer 17

lymph nodes, spleen, MALT, and diffuse lymphoid tissues

Question 18

what occurs in primary organs

Answer 18

B and T cells mature; both originate in red bone marrow- where B cells also mature while T cells mature in the thymus

Question 19

what occurs in secondary organs

Answer 19

mature lymphocytes first encounter their antigen and become activated

Question 20

what is the most important secondary lymphoid organ

Answer 20

the lymph nodes

Question 21

what important events take place in the lymph nodes

Answer 21

(1) cleanses the lymph- acts as filters for lymph as it is transported back to blood, prevents unwanted substances from being delivered to blood & transported to other body systems
(2) immune system activation- offers a place for lymphocytes to become activated (transported via dendritic cells)

Question 22

what is the shape of lymphocytes

Answer 22

vary in shape and size, but mostly bean shaped

Question 23

what is the external fibrous capsule that surrounds lymph nodes called

Answer 23

the capsule

Question 24

what is the stroma of a lymph node

Answer 24

internal framework of reticular fibers that support the population of lymphocytes

Question 25

what do capsule fibers extend into

Answer 25

extend inwardly as trabeculae that divides the node into compartments

Question 26

what are the 2 distinct regions of a lymph node

Answer 26

the cortex and the medulla

Question 27

superficial vs deep area of the cortex in the lymph nodes

Answer 27

superficial area contains densely packed follicles with germinal centers filled with dividing B cells; deeper area contains T cells in transit/houses dendritic cells

Question 28

what does the medulla of the lymph nodes contain

Answer 28

medullary cords that contain B and T lymphocytes and lymph sinuses

Question 29

channels between afferent and efferent lymphatic vessels of a lymph node; contains crisscrossing reticular fibers that macrophages reside on

Answer 29

lymph sinuses

Question 30

what is the fluid flow in the lymph nodes

Answer 30

-lymph enters the convex side of the node via afferent vessels -travels through large subcapsular sinus and into smaller sinuses found in the cortex and medulla -enters the medullary sinuses -exits the concave side at hilum via efferent vessels

Question 31

where are lymph nodes located

Answer 31

mostly embedded deep in connective tissue in clusters along lymphatic vessels -large clusters of nodes occur near the body surface in the inguinal, axillary and cervical regions

Question 32

what is the largest lymphoid organ

Answer 32

the spleen

Question 33

what is the most important function of the spleen

Answer 33

blood cleansing function; cleanses blood of aged/ defective blood cells & platelets (macrophages remove debris)

Question 34

what are the other functions of the spleen

Answer 34

-site of lymphatic proliferation and immune surveillance/response -stores breakdown products of RBCs that are later recycled -stores blood platelets and monocytes for release into blood when needed -may be sites for fetal erythrocyte production

Question 35

what is white pulp

Answer 35

site where immune function occurs- contains lymphocytes attached to reticular fibers, clusters found around central arteries

Question 36

what is red pulp

Answer 36

site where old blood cells and bloodborne pathogens are destroyed

Question 37

what is red pulp composed of

Answer 37

rich in RBCs and macrophages, composed of splenic cords that separate blood filled splenic sinusoids

Question 38

what does MALT stand for

Answer 38

mucosa-associate lymphoid tissue

Question 39

what is the purpose of MALT

Answer 39

it is a set of distributed lymphoid tissues located in mucosa membranes throughout the body that provide protection from pathogens trying to enter the body

Question 40

what are the names of the largest MALT collections in the body

Answer 40

(1) tonsils (2) peyers patches (aggregated lymphoid nodules) (3) appendix

Question 41

location of the tonsils

Answer 41

form a ring of tissue around the entrance to the pharynx

Question 42

location of Peyer's patches

Answer 42

clusters of lymphoid follicles in wall of distal portion of small intestine

Question 43

location of the appendix

Answer 43

offshoot of the first part of the large intestine

Question 44

what are the specific names of the tonsils

Answer 44

-palatine tonsils -lingual tonsils -pharyngeal tonsils -tubal tonsils

Question 45

clinically relevant info. of the tonsils

Answer 45

(1)palatine; posterior end of the oral cavity, largest of the tonsils and most often infected (2)lingual-;lumpy collection of follicles at base of tongue (3)pharyngeal; located in posterior wall of nasopharynx (4) tubal; surround openings of auditory tunes into pharynx

Question 46

what is the function of the thymus

Answer 46

lymphoid organ where T cells mature

Question 47

where is the thymus located

Answer 47

found in the inferior neck and extends into the superior thorax where it partially overlies the heart deep to the sternum

Question 48

what are the 3 ways that the thymus is different from other lymphoid organs

Answer 48

(1) has no follicles because it lacks B cells (2) does not directly fight antigens (3) stroma consists of epithelial cells rather than reticular fibers- provides the physical and chemical environment in which T cells mature