Lecture 6: Lymphoid System/Immunity Flashcards
(108 cards)
1
Q
Lymphatic Vessels
A
Carries lymph, that has leaked out of capillaries. from peripheral tissues to the venous system
2
Q
Lymph
A
Fluid similar to plasma but does not have plasma proteins
3
Q
Why doesn’t lymph contain plasma proteins?
A
They can’t leave the blood vessels
4
Q
What does lymph contain?
A
Glucose
Hormones
Electrolytes
5
Q
What does the lymphoid system produce, maintain, and distribute?
A
Lymphocytes
6
Q
Where does the lymphoid system return fluid and solutes to?
A
The blood
7
Q
Another function of the lymphoid system:
A
Distribut hormones, nutrients, and waste products from their tissues of origin to the general circulation
8
Q
Which lymphatic vessels have valves?
A
Contractile vessels
9
Q
Thoracic Duct
A
Left upper body
Lower body
10
Q
Right Lymphatic Duct
A
Right upper body
11
Q
3 Classes of Lymphocytes
A
T cells
B cells
NK cells
12
Q
T Cells Derived In…
A
Thymus
13
Q
B Cells Derived In…
A
Bone marrow (bursa)
14
Q
General Types of T Cells (4)
A
Cytotoxic
Helper
Suppressor
Memory
15
Q
Cytotoxic T Cells
A
Directly attack foreign infected cells
Cause lysis/destruction
16
Q
Helper T Cells
A
Stimulate T and B cells to become active
Attract macrophages
17
Q
Suppressor T Cells
A
Inhibit T and B cells
Secrete chemicals that moderate immune response once it is active
18
Q
Memory T Cells
A
Respond to previously encountered antigens by cloning more T cells
Turn into cytotoxic or helper cells if they recognize certain bacteria
19
Q
What percent of lymphocytes are T cells?
A
80%
20
Q
What percent of lymphocytes are B cells?
A
10-15%
21
Q
B Cells
A
Differentiate (change) into plasma cells
22
Q
Plasma Cells
A
Produce and secrete antibodies that bind to and help destroy foreign cells and infected cells
23
Q
What percent of lymphocytes are NK cells?
A
5-10%
24
Q
Natural Killer Cells
A
Attack foreign cells, virus-infected cells, and cancer cells
25
Immunological Surveillance
Activity of NK cells
26
Where do lymphocytes constantly move around?
Blood
Lymph/Lymph nodes
Peripheral tissue
Lymphoid organs
27
Life Span of Lymphocytes
Years to decades
28
Where are blood cells produced?
Red bone marrow
29
Hemocytoblasts
Produce stem cells that can travel to the thymus (then become T cells)
Some stay in bone marrow to become B cells and NK cells
30
Lymphoid Tissue
Connective tissues containing large numbers of lymphocytes (macrophages)
31
Lymphoid Organs
Lymph nodes
Thymus gland
Spleen
32
Lymph Nodes
About 400 in body
| Filters lymph from extremities before it reaches the trunk/torso
33
MALT
Mucosa-Associated Lymphoid Tissue
| Collections of lymphoid tissue in digestive, respiratory, urinary tracts
34
Types of Tonsils
Pharyngeal
Lingual
Palentine
35
Tonsillectomy
Removal of tonsils
| Slight risk of damage to internal carotid artery
36
Where do lymph nodes lie?
Along lymphatic vessels
37
What happens in a lymph node?
Lymph flows through several regions and is filtered
| It then warns the immune system of any pathogens
38
What do macrophages in lymph nodes do?
Removes 99% of antigens in the lymph before it reaches the veins and then present the antigens to lymphocytes
39
Spleen
Largest lymphoid organ with good blood supply
40
What are the functions of the spleen? (3)
Macrophages phagocytize and recycle damaged/old RBCs
Stores iron
Exposes B and T cells to antigens/microorganisms in blood
41
What does the spleen contain?
Red Pulp
| White Pulp
42
Red Pulp
Lots of red blood cells
43
White Pulp
Lymphoid tissue (lymphocytes)
44
What is the spleen hard to fix if ruptured?
Its soft tissue doesn't like to hold stitches
45
2 Types of Immune Defenses
Innate Defenses
| Adaptive Defenses
46
Innate Defenses
Nonspecific
47
Adaptive Defenses
Specific
48
7 Types of Nonspecific Defenses
```
Physical barriers
Phagocytes
Immunological surveillance
Interferons
Complement
Inflammatory response
Fever
```
49
Physical Barriers
Pathogens must cross skin or mucous membrane to enter body
50
How is the skin used as a physical barrier?
Multiple layers of cells, keratin, desmosomes
| Oil and sweat gland secretions
51
How do desmosomes work as a physical barrier?
Their interlocking creates a barrier
52
How are mucous membranes used as a physical barrier?
Mucous secretions
| Stomach acid
53
Types of Phagocytes
Neutrophils
Eosinophils (microphages)
Macrophages
54
Reticuloendothelial System
Removing bacteria
| Also called monocyte-macrophage system
55
Fixed Macrophages
Stay in certain part of body and wait for antigen to approach it
56
Free Macrophages
Travel through body
57
Functions of Phagocytes (3)
Bind to pathogen and phagocytize
Bind to pathogen and wait for other cells to assist
Release chemicals to destroy pathogen
58
Immunological Surveillance
NK cells recognize abnormal antigens in cells and then attack those cells, whether they are self or bacterial
59
NK Cell Activation Process (3)
Recognition of antigen and adhesion to cell
Realignment of golgi apparatus toward target cells
Secretion of perforin via exocytosis
60
What does perforin do when secreted?
Perforates plasma membrane of a foreign cell making it unable to maintain homeostasis
61
Interferons
Proteins released form activated lymphocytes, macrophages, and viral-infected cells
Warn other cells of a virus in the body
62
Where do interferons bind to?
Membrane receptors in normal cell and use a second messenger to cause production of antiviral proteins which interfere with viral replication
63
What do interferons act like when released?
Hormones
64
What is the complement system made up of?
11 plasma proteins
65
How do complement reactions occur?
If a complement is activated by contact with antibody-coated cells (fastest) or contact with bacterial capsules
66
What do complement reactions result in?
MAC
67
MAC
Membrane Attack Complex (pore in bacteria)
| Forms multiple holes in bacterium plasma membrane
68
What does MAC enhance?
Phagocytosis (opsonization) by making cells easier targets for macrophages and microphages
69
What does MAC trigger?
Histamine release by basophils and mast cells which increases local inflammation and blood flow
70
Inflammation
Tissue response to injury or infection
Release of chemicals from damaged cells
Release of histamine and heparin from mast cells
71
Result of Inflammation (5)
```
Redness
Heat
Swelling
Pain
Loss of function
```
72
Inflammation Protective Result
Capillaries allow clotting proteins and complement to enter wound site
Phagocytes are attracted
73
How does clotting help inflammation?
It walls off the area, slowing the spread of bacteria
74
What regulates body temp?
Hypothalamus
75
What do pyrogens do?
They are circulating proteins that can trigger hypothalamus to increase body temp
76
How are pyrogens secreted?
By macrophages
77
What does a fever indicate?
It is a signal that an infection is being fought
78
Functions of a Fever (2)
Increased metabolic activity
| Inhibition of bacterial and viral activity
79
What results in an increase of metabolic activity?
Increased activity of immune cells
| Increased speed of chemical reactions
80
Specific Defenses
Activity of T cells and B cells
81
What type of immunity are T cells?
Cell-mediated
82
What type of immunity are B cells?
Antibody-mediated
83
Active Immunity
Your body develops immunity
84
Naturally Acquired Active Immunity
Through environment exposure to pathogens
85
Induced Active Immunity
Through vaccines containing heat killed/treated/neutralized pathogens
86
Passive Immunity
Antibodies come from other source
87
Naturally Acquired Passive Immunity
Antibodies acquired from the mother through placenta and breast feeding
88
Induced Passive Immunity
By an injection of antibodies (meds create antibodies)
89
4 Properties of Immunity
Specificity
Versatility
Memory
Tolerance
90
Specificity of Immunity
T and B cells respond to one specific antigen
91
Versatility of Immunity
T and B cells can respond to millions of different antigens
92
Memory of Immunity
In an immune response some cells are produced to fight and some to act as memory cells for future exposure
93
Tolerance of Immunity
Immune cells do not respond to self antigens unless an autoimmune disease is acquired
94
What must happen before T cells can be activated?
They must encounter an antigen that is presented to them by an infected cell or a phagocyte
95
MHC Proteins
Major histocompatibility complex
| Continuously synthesized and added to plasma membrane
96
What is required to activate T cells?
T cell sensitization exposure
| Chemicals released by macrophages
97
What do B cells have sticking off of them?
Antigens
98
How are B cells sensitized?
Encounter with foreign antigen
99
How are B cells activated?
Encounter with helper T cells
100
What do activated T cells allow B cells to do?
Attack
101
What happens when B cells are activated?
They divide, producing populations of plasma cells and memory B cells
102
Plasma Cells
Produce antibodies specific to the antigen being attacked
103
Antibodies
Y shaped
2 pairs of polypeptide chains (heavy & light)
Constant and variable regions
104
Antigen-Binding Site
Variable region
Tips of chains
Region that will stick to antigen to form antigen-antibody complex that can cause agglutination
105
Action of Antibody (7)
```
If bonded to antigen..
Neutralization
Precipitation/Agglutination
Activation of complement
Attraction of phagocytes
Opsonization
Stimulates inflammation
Prevention of bacterial or viral adhesion to external surfaces
```
106
What does neutralization do?
Prevent viruses from entering cells
107
Agglutination is...
Clumping
108
Opsonization
Makes phagocytes easier
