Lymphatic System

Question 1

lymphatic capillaries

Answer 1

microscopic, closed-ended tubes, parallel the networks of the blood capillaries.

squamous epithelial tissues (endothelium) - thin walls allow tissue fluid from interstitial space to enter lymphatic capillaries.

leads to lymphatic vessels

Question 2

lymphatic vessels

Answer 2

similar to veins, but thinner.

3 layers: endothelial lining, middle layer of smooth muscle and elastic fiber, and outer layer of connective tissue.

have semilunar valves which prevent backflow of lymph.

leads to lymph nodes.

Question 3

lymphatic trunk

Answer 3

after leaving lymph nodes, vessels merge into larger lymphatic trunks.

drain lymph from the lymphatic vessels, named for the region they serve (lumbar = lower limbs, lower abdominal

Question 4

collecting ducts - thoracic & lymphatic

Answer 4

trunks join one of the two collecting ducts: thoracic & right lymphatic.

thoracic is longer and larger of the two
right lymphatic

Question 5

lacteal

Answer 5

a lymphatic capillary that absorbs dietary fats in the villi of the small intestine.

Question 6

bronchomediastinal & intercostal trunk

Answer 6

drains lymph from portions of the thorax

Question 7

intestinal trunk

Answer 7

drains lymph from abdominal viscera

Question 8

jugular trunk

Answer 8

drains lymph from neck & head

Question 9

lumbar trunk

Answer 9

drains lymph from from lower limbs

Question 10

subclavian trunk

Answer 10

drains lymph from upper limb

Question 11

R & L subclavian veins + R & L internal jugular veins

Answer 11

once lymph has been cleaned through lymph system, they are returned to the blood through these veins

Question 12

Relationship between tissue fluid and lymph

Answer 12

lymph is tissue fluid which has entered a lymphatic capillary

Question 13

4 forces which account for the flow of lymph through the lymphatic system

Answer 13

o Fluid that contains water and dissolved substances leaves bloodstream in the capillary bed via diffusion & filtration

o Proteins cause osmotic pressure in interstitial space to increase, resulting in the flow from the blood capillaries to the interstitial space.

o This results in an increase of hydrostatic pressure in the interstitial space since water always moves to an area of greater osmotic pressure.

o Increasing interstitial (hydrostatic) pressure forces fluid into the lymphatic capillaries.

Question 14

Explain how lymph flow can be obstructed and state the consequences of lymphatic obstruction

Answer 14

edema caused by surgical removal of portions of the lymphatic system, or blockage by parasites.

Question 15

lymph node structure and function: afferent lymphatic vessel

Answer 15

lymphatic vessels LEADING to a node

Question 16

lymph node structure and function: efferent lymphatic vessel

Answer 16

lymphatic vessels LEAVING the node

Question 17

capsule

Answer 17

encloses the lymph node (kind of like a cell wall) and sends extensions called trabeculae into the node to separate it into compartments

Question 18

cortex

Answer 18

superficial region located deep to the capsule and consists of compartments containing germinal centers and sinuses

Question 19

germinal center / nodules

Answer 19

B CELLS

also called nodules, are dense masses of lymphocytes and macrophages in the compartments of a lymph node that constitute the functional units of the node

Question 20

hilum

Answer 20

indented region in a bean-shaped node

Question 21

medulla

Answer 21

T CELLS

central portion of the lymph node

Question 22

sinus

Answer 22

complex network of chambers and channels in the compartments of a lymph node though which lymph circulates as it passes through the node

Question 23

identify the major lymph node groups or chains on diagrams

Answer 23

o Cervical region: (chin area) – associated with lymphatic vessels that drain the skin of the scalp and face, as well as tissues of the nasal cavity and pharynx

o Axillary region: UNDERARM receive lymph from vessels that drain the upper limbs, the wall of the thorax, the mammary glands (breasts) and upper wall of the abdomen

o Supratrochlear region: ELBOW AREA - superficially on medial side of elbow. Large in children in response to infections acquired through cuts & scrapes on hands.

o Inguinal: GROIN AREA - receive lymph from lower limbs, external genitalia, lower abdominal wall

o Pelvic cavity: PELVIC AREA (above inguinal)- follow iliac blood vessels – receive lymph from vessels of pelvic viscera

o Abdominal cavity: ABDOMINAL AREA - form chains along mesenteric arteries and abdominal aorta. Receive lymph from abdominal viscera

o Thoracic cavity: UPPER CHEST AREA - in mediastinum and along trachea and bronchi. Receive lymph from thoracic viscera and from internal wall of the thorax

Question 24

name the major organs of the lymphatic system, state their location and function

Answer 24

lymph nodes - in groups or chains along the paths of larger lymphatic vessels, filter foreign particles and debris from lymph; produce and house lymphocytes that destroy foreign particles and in lymph; house macrophages that engulf and destroy foreign particles and cellular debris carried in lymph

thymus - in mediastinum superior to heart, houses lymphocytes; differentiates thymocytes into T lymphocytes

spleen - upper left portion of abdominal cavity, to the side (lateral) and posterior to stomach; blood reservoir houses macrophages that remove foreign particles, damaged red blood cells, and cellular debris from the blood. contains lymphocytes

Question 25

distinguish between specific and nonspecific defense mechanisms

Answer 25

nonspecific - protect against many types of pathogens, attacks all the same

specific - protects against particular pathogens and are responsible for the type of resistance called immunity

Question 26

6 nonspecific defense mechanisms: species resistance

Answer 26

species resistance - species is resistant to certain diseases that other species are susceptible (ex, humans can get measles, gonorrhea, syphilis, but not animals)

Question 27

6 nonspecific defense mechanisms: mechanical barrier

Answer 27

mechanical barrier - unbroken skin and mucous membranes prevent the entrance of some infectious agents. fluids wash away before they can firmly attach to tissues

Question 28

6 nonspecific defense mechanisms: chemical barrier

Answer 28

chemical barrier - enzymes in various body fluids kill pathogens. gastric juice (low pH from HCl), tears (lysozyme, destroys bacteria), interferons (blocks replication of viruses), defensins (damage bacterial cell walls and membranes), collectins (grab onto microbes), and complement (stimulates inflammation, attracts phagocytes, enhances phagocytosis).

Question 29

6 nonspecific defense mechanisms: natural killer cells

Answer 29

natural killer cells - distinct type of lymphocyte that secrets perforins that lyse virus-infected cells and cancer cells

Question 30

6 nonspecific defense mechanisms: inflammation

Answer 30

inflammation - tissue response to injury that prevents the spread of infectious agents into nearby tissues

Question 31

6 nonspecific defense mechanisms: phagocytosis

Answer 31

phagocytosis - neutrophils, monocytes, macrophages engulf & destroy foreign particles and cells

Question 32

6 nonspecific defense mechanisms: fever

Answer 32

fever - elevated body temp inhibits microbial growth and increases phagocytic activity

Question 33

origin, site of differentiation, location and function of T-lymphocytes

Answer 33

Origin: Stem cells in red bone marrow give rise to lymphocyte precursors.

Site of differentiation: Precursors go to the thymus, where they are processed to become T cells.

Primary location: lymphatic tissues; 70-80% of circulating lymphocytes in blood

Primary function: provide CELLULAR immune response in which T cells interact directly with the antigen-bearing agents to destroy them

Question 34

origin, site of differentiation, location and function of B-lymphocytes

Answer 34

Origin: Red bone marrow

Site of differentiation: some lymphocyte precursors are processed within the bone marrow to become B cells.

Primary location: lymphatic tissue; 20-30% of circulating lymphocytes in blood

Primary functions: provide HUMORAL immune response in which B cells interact indirectly, producing antibodies that destroy antigens or antigen bearing agents

Question 35

IgG location, function

Answer 35

plasma & tissue fluid; defends against bacteria, viruses, and toxins; activates complement

Question 36

IgA location, function

Answer 36

exocrine gland secretions, defends against bacteria and viruses

Question 37

IgM

Answer 37

plasma; reacts with antigens on some red blood cell membranes following mismatched blood transfusions; activates complement

Question 38

IgD

Answer 38

surface of most B-cells, functions in B cell activation

Question 39

IgE

Answer 39

exocrine gland secretions; promotes inflammation and allergic reactions

Question 40

discuss the ways that antibodies act: direct attack

apn

Answer 40

agglutination: antigens clump
precipitation: antigens become insoluble
neutralization: antigens lose toxic properties

Question 41

discuss the ways that antibodies act: activation of complement (antibodies combined with antigens)

ocaln

Answer 41

opsonization: alters antigen cell membranes so cells are more susceptible to phagocytosis
chemotaxis: attracts macrophages and neutrophils into the region
agglutination: clumping of antigen-bearing cells
lysis: rapid movement of water and ions into foreign cell causing osmotic rupture of foreign cells
neutralization: altering molecular structure of viruses, making them harmless

Question 42

discuss the ways that antibodies act: localized changes

Answer 42

inflammation - helps prevent the spread of antigens

Question 43

b cell function

Answer 43

divides repeatedly, expanding its clones, uses cytokines from T cells to proliferate

B cells differentiate further into plasma cells which secrete antibodies (or immunoglobins) which combine w/ antigens on the pathogen and react against it

Question 44

helper T cell function

Answer 44

specialized T cell which becomes activated when its antigen receptor combines with displayed foreign antigen. once activated, stimulates B cells to produce antibodies specific for the displayed antigen

Question 45

macrophage function

Answer 45

phagocytizes a bacterium, digesting it in its lysosomes. baterial antigens exit the lysosomes and move to the macrophages surface.

Question 46

T cells function

Answer 46

recognizes whether antigens are foreign or self; attack directly (cellular), activates B cells (which activate macrophages)

Question 47

cytotoxic cell function

Answer 47

recognizes and combines with nonself antigens that cancerous cells display on their surfaces near certain MHC proteins. cytokines (secretions) from helper T cells activate cytotoxic T cell, which makes it proliferate, enlarging its clone of cells. bind to the surfaces of antigen bearing cells, where they release perforin which cuts porelike openings, destroying the cells

Question 48

memory cell function (dormant cell)

Answer 48

provide future immune protection. once activated (from exposure to antigen), it immediately divides and differentiates into a cytotoxic T cell.

Question 49

mast cell function

Answer 49

produce biochemicals (histamines) that cause the changes associated with inflammation (vasodilation and edema)

Question 50

primary vs secondary immune response

Answer 50

primary: when B cells or T cells first encounter an antigen for which they are specialized to react. during this response, antibodies are produced for several weeks - Later, some remain dormant (memory cells)

Secondary immune response: occurs rapidly if antigen is encountered later because memory cells are present. if identical antigen is encountered in the future, clones of memory cells enlarge

Question 51

4 major types of immunity: naturally acquired active immunity

Answer 51

mechanism: exposure to live pathogens
result: stimulation of an immune response with symptoms of a disease

you get the disease, and you develop immunity

Question 52

4 major types of immunity: artificially acquired active immunity

Answer 52

mechanism: exposure to vacine containing weakened or dead pathogens or their components
result: stimulation of an immune response without the symptoms of a disease

Question 53

4 major types of immunity: artificially acquired passive immunity

Answer 53

mechanism: injection of gamma globulin containing antibodies or antitoxin
result: short-term immunity without stimulating immune response

Question 54

4 major types of immunity: naturally acquired passive immunity

Answer 54

mechanisms: antibodies passed to fetus from pregnant woman with active immunity or to newborn through breast milk from women with active immunity
result: short-term immunity for newborn without stimulating immune response

Question 55

immunological changes that take place during an allergic reaction

Answer 55

immune response to a nonharmful substance (hypersensitive)

type 1 - anaphylactic - immediate reaction: overproduced IgE antibodies in response to certain allergens. causes severe inflammation and hives, hay fever, asthma, exzema, or gastric disturbances.
- 1st exposure sensitizes B cells, subsequent exposure causes allergic reactions

Takes 1 -3 hrs to develop
Type 2 - antibody dependent cytotoxic reactions - antigen binds to cell, stimulating phagocytosis and complement-mediated lysis of antigen. transfusion reaction to mismatched blood.

Type 3 - immune complex reactions - phagocytosis and lysis cannot clear widespread antigen antibody complexes from circulation, which blocks small vessels and damages tissues they reach

Type 4 - Delayed reaction allergy: common household or industrial chemicals or cosmetics - foreign substances activate T cells in skin, T cells and macrophages release chemical factors that cause eruptions and inflammation of the skin (dermatitis) (takes 48 hrs)

Question 56

immunological changes that take place during a tissue rejection reaction

Answer 56

when you have a transplant and your body rejects the tissue and tries to destroy it. transplanted tissue may also produce molecules that harm the recipients tissue - graft-vs-host-disease

Question 57

immunological changes that take place during autoimmune disease

Answer 57

failure to distinguish self from nonself, producing antibodies called autoantibodies. cytotoxic T cells attack and damage body’s tissues and organs

Question 58

4 different transplant types and example of each

Answer 58

types of grafts:

isograpft: from identical twin - bone marrow
autograft: taken from elsewhere in person’s body - skin
allograft: tissue from someone who is not a twin - kidney
xenograft: from different species - pig heart valve