Lymphatic and Immune System Flashcards
1
Q
what are the functions of the lymphatic system?
A
- transport and house lymphocytes and other immune cells
- return excess fluid in body tissues to blood to maintain blood volume
2
Q
what are the components of lymph?
A
water, dissolved solutes, and small amount of protein
3
Q
what are lymphatic capillaries?
A
small, closed-ended vessels that absorb interstitial fluid
4
Q
how do lymphatic capillaries differ from blood capillaries?
A
lymphatic capillaries are slightly larger and lack a basement membrane
5
Q
what are lacteals?
A
lymphatic capillaries in GI tract that absorb lipid soluble substances
6
Q
what are the tunics of lymphatic vessels?
A
same as blood vessels (intima, media, externa)
7
Q
how do lymphatic vessels prevent pooling and back flow?
A
utilize valves
8
Q
how does the lymphatic system move lymph
A
- skeletal muscles and respiratory pumps
- pulsatile movement of blood in nearby arteries
- rhythmic contraction of smooth muscle in larger lymph vessel walls
9
Q
What are the major lymphatic trunks?
A
- jugular trunks: drain lymph from head and neck
- subclavian trunks: drain upper limbs, breasts, thoracic wall
- bronchomediastinal trunks: drain deep thoracic structures
- intestinal trunks: drain most abdominal structures
- lumbar trunks: drain lower limbs, abdominopelvic wall, and pelvic organs
10
Q
What is the largest type of lymphatic vessel?
A
lymphatic ducts
11
Q
what is the function of lymphatic ducts?
A
to bring lymph to venous blood circulation
12
Q
what are the two lymphatic ducts?
A
right lymphatic duct and thoracic duct
13
Q
what is the function of the right lymphatic duct?
A
- drains upper right quadrant of body
- delivers lymph to junction of right subclavian and right internal jugular veins
14
Q
what vessel contains cisterna chyli?
A
the thoracic duct
- found at base, receive lipid rich chyle from GI tract
15
Q
what is lymphedema?
A
accumulation of interstitial fluid due to interference with lymphatic drainage
16
Q
what are primary lymphatic structures?
A
involved in formation and maturation of lymphocytes
- red bone marrow and thymus
17
Q
what are secondary lymphatic structures?
A
- do not form lymphocytes but house them and other immune cells
- sites of immune response initiation
- lymph nodes, spleen, tonsils, and lymphatic nodules
18
Q
Where is red bone marrow located?
A
located between trabeculae of spongy bone
- in flat bones of skull, ribs, and sternum, vertebrae, heads of femur and humerus
19
Q
Why is the thymus important in lymphatic functioning?
A
involved in T-lymphocyte maturation
20
Q
what makes up the thymus?
A
- consists of two thymic lobes, each surrounded by CT capsule
- trabeculae of capsules subdivide into lobules w/ cortex and medulla regions
21
Q
How do lymphatic organs differ from other lymphatic structures?
A
organs have a complete capsule of dense irregular CT while other structures have an incomplete capsule or lack one
22
Q
what is the function of lymph nodes?
A
filer lymph and remove unwanted substances
23
Q
where are lymph nodes located?
A
located along deep and superficial pathways of lymph vessels
24
Q
how are lymph nodes arranged?
A
occur in clusters receiving lymph from body regions
25
what are the different lymph node clusters?
- cervical lymph nodes: receive lymph from head and neck
- axillary lymph nodes: receive lymph from breast, axilla, and upper limbs
- inguinal lymph nodes: receive lymph from lower limbs and pelvis
26
What are the types of lymphatic vessels found in lymph nodes?
afferent lymphatic vessels: bring lymph to node
efferent vessel: drains a lymph node
27
what surrounds a lymph node?
dense ct capsule that encloses node; contain trabeculae which subdivide node into compartments
28
what are the layers of a lymph node cortex?
germinal center
- supported by reticular fibers
- houses proliferating B lymphocytes and some macrophages
surrounding mantle zone
- contains T lymphocytes, macrophages, and dendritic cells
cortical sinuses
- tiny open channels lined by macrophages
29
what structures are found in the medulla of a lymph node?
medullary cords: ct fibers that support B lymphocytes, T lymphocytes, and macrophages
30
What are medullary sinuses?
tiny open channels lined with macrophages
31
how does lymph flow through nodes
- enters through several afferent vessels
- lymph is monitored for presence of foreign material
- lymph exits node through efferent vessel
32
what is the largest lymphatic organ?
the spleen
33
what are the tissues of the spleen and how do they differ?
white pulp
- clusters of T and B lymphocytes and macrophages around central artery
Red pulp
- contains erythrocytes, platelets, macrophages, and B lymphocytes
- storage site for erythrocytes and platelets
34
What two structures are found in red pulp?
- splenic cords: cells and reticular ct in red pulp
- splenic sinusoids: very permeable capillaries
35
How does the spleen monitor blood?
- white pulp monitors it for foreign materials and bacteria
- macrophages in sinusoids of red pulp remove particles
36
what is the path of blood flow through the spleen?
splenic artery, central artery, sinusoids, venules, splenic vein
37
How do the tonsils assist in lymphatic functioning?
immune surveillance of inhaled and ingested substances
38
what are the three tonsils?
- pharyngeal tonsil: in nasopharynx
- palatine tonsils: in postolateral oral cavity
- lingual tonsils: along posterior third of tongue
39
what are lymphatic nodules?
- clusters of lymphatic cells with some extracellular matrix
- found in every body organ
- help defend against infection
- in some areas, group together to form larger structures
40
What is MALT?
mucosa associated lymphatic tissue
- located in gastrointestinal, respiratory, genital, and urinary tracts
- help defend against foreign substances
- prominent in small intestines, especially ileum
41
What are prions?
fragments of infectious proteins
- neither cells nor viruses
- cause disease in nervous tissue (mad cows disease)
42
What are cytokines?
small proteins that regulate immune activity
- produced by cells of both innate and adaptive immune system
43
what are the effects of cytokines?
- signaling cells
- controlling development and behavior of immune cells
- regulating inflammatory response
- destroying cells
44
what are the two types of immunity?
innate and adaptive
45
what factors differentiate the two types of immunity
- cells involved
- specificity of cell response
- mechanisms of eliminating harmful substances
- amount of time for response
46
What is innate immunity?
non specific immunity, first and second lines of defense
- skin
-inflammatory response
- NKC, phagocytic cells
47
what is adaptive immunity?
specific immunity
- lymphocytes
- antibodies
- macrophages
- contact with antigen causes lymphocyte proliferation
48
How do neutrophils and macrophages function?
destroy engulfed pathogens
- respiratory burst produces reactive oxygen-containing molecules that help destroy microbes
- degraded residue released by exocytosis
49
How do dendritic cells function?
destroy particles and then present fragments
- antigens are presented on dendritic cell surface to T lymphocytes which is necessary for initiating adaptive immunity
50
How do Basophils and mast cells function?
promote inflamation
- release granules containing chemicals
- chemicals increase movement of fluid from blood to injured tissue
- histamine increases vasoconstriction and cap. permeability
- heparin acts as anticoagulant
51
where are basophils and mast cells found?
- basophils circulate in blood
- mast cells reside in CT, mucosa, internal organs
52
How do natural killer cells function?
- destroy virus/bacteria infected cells, tumor cells, tumor of transplanted tissue
- kill by releasing cytotoxic chemicals
53
How do eosinophils function?
attack multicellular parasites
- degranulate, release enzymes, and other toxic substances
- participate in immune response of allergy and asthma
54
What are the branches of adaptive immunity?
- cell-mediated immunity: involving T-lymphocytes
- humoral immunity: involving B-lymphocytes, plasma cells, and antibodies
55
what is an antigenic determinant?
- also called an epitope
- specific site on antigen recognized by immune system
- each has a different shape
- pathogenic organisms can have multiple
56
what is an immunogen?
antigen that induces an immune response
57
what are haptens?
small foreign molecules that induce an immune response when attached to a carrier molecule in host ex: toxin in poison ivy
58
what are receptor complexes?
receptors on B-lymphocytes and T-lymphocytes that each bind one specific antigen
- about 100,000 per cell
59
How does each lymphocyte make contact with an antigen?
- B-lymphocytes make direct contact with antigen
- T-lymphocytes have antigen presented by another cell
60
What are the subtypes of T-lymphocytes?
- helper T-lymphocytes (CD4+ cells): assist in cell-mediated, humoral, and innate immunity
- Cytotoxic T-lymphocytes (CD8+ cells): release chemicals that destroy cells
- other types are memory T-cells and regulatory T-cells
61
What types of cells present antigens
- all nucleated cells of the body
- antigen-presenting cells: immune cells that present to helper T cells and cytotoxic T cells
62
What is required for an T cell to bind to an antigen?
a major histocompatibility complex
63
what are the two types of MHCs?
MHC I: found on all nucleated cells
MHC II: found on APCs w/ MHC I
64
What are MHC I molecules and how are they made?
- glycoproteins
- have genetically determined structure that is unique to individual
- continuously synthesized and modified by Rough ER
65
How does MHC I work?
display fragments of proteins that were bound in ER
- if fragments are from endogenous proteins, immune system recognizes them as "self" and ignores them
- if fragments are from an infectious agent, immune system considers the antigen "nonself"
66
What are MHC II molecules and how are they made?
- also glycoproteins
- exogenous antigens brought into cell through endocytosis
- phagosome merges with lysosome, forming a phagolysosome
- substance digested into peptide fragments
- fragments "loaded: onto MHC II within vesicle which merges with plasma membrane
67
What are the three main events in the life of a lymphocyte?
- formation and maturation of lymphocytes
- activation of lymphocytes
- effector response: action of lymphocytes to eliminate antigen
68
how are lymphocytes activated?
- in secondary lymphatic structures they are exposed to antigen and become activated
- replicate to form identical lymphocytes
69
How does the B-cell effector response differ from that of T-cells?
T-lymphocytes migrate to site of infection while B-lymphocytes stay in secondary structure and release large quantities of antibodies which are transported to site of infection
70
Where do lymphocytes become immunocompetent?
B-lymphocytes: bone marrow
T-lymphocytes: thymus
71
What are the steps for the primary humoral immune response?
- B-lymphocytes with specific receptors bind to antigen
- binding event activates the lymphocyte to undergo clonal selection
- a large number of clones are produced
72
what happens to B cells after the primary humoral response?
- most B cells become plasma cells which produce antibodies
- some B cells become long-lived memory cells
73
what occurs during the secondary humoral responses
- memory cells are long-lived
- a second exposure causes a rapid response
- the secondary response is stronger and longer lasting
74
what is active immunity?
occurs when B cells encounter antigens and produce antibodies
- can be naturally acquired during bacterial and viral infections or artificially acquired from vaccines
75
what is passive immunity?
occurs when antibodies are obtained from someone else
- acquired naturally from mother to fetus or artificially from immune serum or gamma globulin
- immunological memory does not occur
76
what are monoclonal antibodies?
- antibodies prepared for clinical testing or diagnostic services
- produced from descendants of a single cell line
- can be used to diagnose pregnancy and as treatment after exposure to hepatitis and rabies
77
what is the structure of an antibody?
- four amino acid chains linked by disulfide bonds
- two identical amino acid chains are linked to form a heavy chain
- other two identical chains are light chains
- specific antigen binding sites are present
78
what are the five immunoglobulin classes?
- IgM
- IgA
- IgD
- IgG
- IgE
(MADGE)
79
What are the actions of the Fc region of antibodies
- complement fixation: can bind complement for activation
- opsonization: certain antibody classes can make it more likely target cell will be seen by phagocytic cells
- activation of NK cells
80
what occurs in cell-mediated immune response?
- antigens must be presented by macrophages to an immunocompetent T cell
- T cell must recognize non self and self
- after antigen binding, clones form but different classes of cells are produced
81
what are the T cell clones produced during cell-mediated immunity
cytotoxic T cells
- specialized in killing infected cells
- insert a toxic chemical (perforin)
Helper T cells
- recruit other cells to fight the invaders
- interact directly with B cells
Regulatory T cells
- release chemicals to suppress the activity of B and T cells
- stop the immune response to prevent uncontrolled activity
