Exam 4: Lymphatic System

Question 1

Tonsils

Answer 1

–Secondary lymphatic structures found in pharynx

–Not completely surrounded by capsule

–Help protect against foreign substances inhaled or ingested

–Have invaginated outer edges, tonsillar crypts

–Contain lymphatic nodules

Question 2

What are tonsillar crypts?

Answer 2

Increase surface area to trap material

Question 3

What do some lymphatic nodules contain?

Answer 3

Germinal Centers

Question 4

What are the three types of tonsils?

Answer 4

Pharyngeal Tonsil

Palatine Tonsil

Lingual Tonsil

Question 5

Pharyngeal Tonsil

Answer 5

• in posterior wall of nasopharynx
• when enlarged, termed adenoids

Question 6

Palatine Tonsil

Answer 6

•in posterolateral oral cavity

Question 7

Lingual Tonsil

Answer 7

•along posterior one-third of tongue

Question 8

Answer 8

Phayngeal Tonsils

Question 9

Answer 9

Palatine Tonsils

Question 10

Answer 10

Lingual Tonsils

Question 11

MALT

Answer 11

–Mucosa-associated lymphatic tissue

Question 12

Where is MALT located?

Answer 12

–in gastrointestinal, respiratory, genital, and urinary tracts

•found in lamina propria of the mucosa

Question 13

What does MALT do?

Answer 13

–Help defend against foreign substances

Question 14

Where is MALT prominent?

Answer 14

–small intestines, especially ileum

•Peyer patches, found here

Question 15

What is the general structure of the lymphatic system?

Answer 15

•Consists of red bone marrow, thymus, lymph, lymphatic vessels, lymph nodes, spleen, tonsils, MALT

Question 16

What are the functions of the lymphatic system?

Answer 16

1. Drain excess interstitial fluid
2. Transport dietary lipids
3. Carries out our immune responses

Question 17

Flow of lymph: More fluid out of the blood capillaries than returns to them by

Answer 17

–More fluid filters out of blood capillaries than returns to them by reabsorption

Question 18

How much excess fluid drains into lymphatic vessels and become lymph?

Answer 18

About 3L a day

Question 19

What is an important function of the lymphatic vessesls?

Answer 19

to return lost plasma proteins to blood stream

Question 20

What are the 2 pumps that aid in flow of lymph (also in venous return)

Answer 20

• Skeletal muscle pump – milking action
• Respiratory pump – pressure changes during breathing

Question 21

Lymphatic vessels contain

Answer 21

valves

Question 22

Lymph organs and tissues: 2 Groups based on function

Answer 22

Primary Lymphatic Organs

Secondary Lymphatic Organs

Question 23

Primary Lymphatic Organs

Answer 23

• Sites where stem cells divide and become immunocompetent
• Red bone marrow and thymus

Question 24

Scondary Lymphatic Organs

Answer 24

• Sites where most immune response occurs
• Lymph nodes, spleen, tonsils, MALT

Question 25

Where is red bone marrow located

Answer 25

–Located within spaces between trabeculae in sections of spongy bone * in flat bones of skull, vertebrae, ribs, and sternum * proximal epiphyses of humerus and femur

Question 26

What is red bone marrow responsible for?

Answer 26

–Responsible for hemopoiesis •produces erythrocytes, platelets, granulocytes, and agranulocytes

Question 27

T-lymphocytes and B-lymphocytes

Answer 27

* two major types of lymphocytes * T-lymphocytes migrating to thymus to complete maturation

Question 28

Thymus Anatomy: Outer Cortex

Answer 28

–composed of large number of T cells * Immature T cells migrate here from red bone marrow where they proliferate and begin to mature * Dendritic cells derived from monocytes assist in T cell maturation * Specialized epithelial cells help educate T cells through positive selection – only about 25% survive * Macrophages clear out dead and dying cells

Question 29

Thymus Anatomy: Medulla

Answer 29

•More mature T cells migrate here from cortex More epithelial cells, dendritic cells and macrophages

Question 30

Thymus shrinks with age from g in infants to g in old age

Answer 30

70g to 3g

Question 31

Secondary Lymphatic Organs: Lymph Nodes

Answer 31

–Located along lymphatic vessels –Scattered throughout body

Question 32

Lymph Node Anatomy

Answer 32

Stroma Parenchyma

Question 33

Lymph node anatomy: stroma

Answer 33

•supporting connective tissue –Capsule (dense irregular connective tissue), trabeculae, reticular fibers and fibroblasts

Question 34

Lymph node anatomy: parenchyma

Answer 34

•functional part –Outer cortex – aggregates of B cells called lymphatic nodules (follicles) – site of plasma cell and memory B cell formation –Inner cortex – mainly T cells and dendritic cells –Medulla – B cells, antibody producing plasma cells from cortex, and macrophages

Question 35

Lymph Flow through the lymph nodes

Answer 35

–Enters node through afferent lymphatic vessels –Makes its way through lymph node sinuses –Lymph continuously monitored for presence of foreign material –Macrophages •remove foreign debris from the lymph –Lymph exiting lymph node through efferent vessel –May enter nearby lymph node in cluster

Question 36

Lymph Flow through lymph nodes: If lymphocyte contacts foreign substance

Answer 36

* immune response generated * lymphocytes undergoing cell division –especially in germinal centers * some remaining in lymph node * others transported in lymph and blood –reach areas of infection

Question 37

Lymph Flow Through Lymph Nodes: Swollen lymph nodes

Answer 37

* become tender with infection * sign that lymphocytes proliferating and fighting infection * can palpate swollen superficial lymph nodes

Question 38

Secondary Lymphatic Organs: Spleen

Answer 38

–Largest single mass of lymphatic tissue in the body –Stroma –Parenchyma

Question 39

Spleen Stroma

Answer 39

–capsule, trabeculae, reticular fibers, and fibroblasts

Question 40

spleen: parenchyma

Answer 40

made of white pulp and red pulp

Question 41

White Pulp

Answer 41

•– lymphatic tissue –(lymphocytes and macrophages) –B cells and T cells carry out immune function –Contains a central artery

Question 42

Red Pulp

Answer 42

contains erythrocytes, platelets, macrophages, and B-cells

Question 43

Red Pulp: Macrophages

Answer 43

remove ruptured, worn out or defective blood cells

Question 44

Red Pulp: Cells housed in reticular connective tissue...

Answer 44

Form Splenic Cords

Question 45

Red Pulp: Splenic Sinusoids

Answer 45

–permeable capillaries, so blood cells easily exit –drain to small venules leading to splenic vein

Question 46

Red Pulp: In charge of production of blood cells during

Answer 46

fetal life