Immune System Flashcards
(101 cards)
1
Q
Epidermis
A
keratinized stratified squamous epithelium resting on basement membrane, protective shield (outside layer)
2
Q
Dermis
A
loose and dense irregular connective tissue, bulk of skin (middle layer)
3
Q
Hypodermis
A
loose connective tissue, anchors skin to muscle (innermost layer)
4
Q
Functions of the skin (5)
A
Protection
sensation
thermoregulation
excretion
vitamin D synthesis
5
Q
Protection (skin function)
A
mechanical trauma, invasion of pathogens, environmental hazards
6
Q
sensation (skin function)
A
sensory receptors
7
Q
thermoregulation (skin function)
A
maintenance of internal body temp through negative feedback loop
8
Q
excretion (skin function)
A
waste products lost through sweat
9
Q
Vitamin D synthesis (skin function)
A
UV light reaction with modified cholesterol to produce cholecalciferol
10
Q
Layers of Epidermis (5)
A
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
11
Q
stratum basale (Epidermis)
A
deepest layer attached to dermis, closest to blood supply
12
Q
stratum spinosum (Epidermis)
A
several layers thick, appear spiky under microscope, contains dendritic cells, system of intermediate filaments
13
Q
stratum granulosum (Epidermis)
A
1-5 cells thick, initiates keratinization, prominent cytoplasmic granules, keratohyalin granules, lamellar granules, epidermal water barrier, cut off from nutrients
14
Q
stratum lucidum (Epidermis)
A
thin translucent band transition region between s. granulosum and s. corneum, indistinct boundaries between dead keratinocytes, cut off from nutrients (only seen in thick skin)
15
Q
stratum corneum (Epidermis)
A
20-30 cell layers thick, outermost layer, protects against abrasion and penetration, glycolipid from lamellar granules creates near waterproof layer
16
Q
layers of Dermis (2)
A
papillary layer (20% of thickness)
reticular layer (80% of thickness)
17
Q
papillary layer (dermis)
A
loose areolar connective tissue, dermal papillae, raised area of the papillary layer
Meissner corpuscle, free nerve endings, capillaries extend up under epidermis
blisters form between epidermis and papillary layers
18
Q
Reticular layer (dermis)
A
dense irregular connective tissue
collagen and elastic fibers, stria (stretch marks)
blood vessels and accessory structures
19
Q
Epidermal ridges
A
form fingerprints
thick skin dermal papillae are arranged on top of dermal ridges
dermal ridges indent epidermis forming epidermal ridges
provide enhanced grip
pattern in genetically determined
sweat pores on ridges help generate the finger prints
20
Q
cleavage lines
A
are gaps in the bundles of collagen fibers in the dermis
21
Q
flexure lines
A
dermal folds that occur at or near a joint
22
Q
Where is melanin synthesized?
A
synthesized from tyrosine
rate of synthesis increased by UV radiation
packaged in melanosomes and delivered to keratinocytes
23
Q
Why is melanin important to skin?
A
melanin absorbs UV radiation to protect keratinocyte DNA
(shields like an umbrella)
24
Q
Accessory structures of the skin (3)
A
Nails
hair
glands
25
Function of nails
scalelike modifications of epidermis
hard keratin - cells don't flake off
nail matrix - nail growth
clinical indicator of health
26
function of hair
insulation, protection, sensation
movement of hair stimulates sensory nerve endings in bulb
consists of dead keratinized cells
hard keratin- cells don't flake off
27
sebaceous glands
secrete sebum (oily lubricant, liberation slows water loss, bactericidal
28
Eccrine sweat glands
merocrine secretion of sweat
sympathetic regulation
cold sweat = emotional regulation
29
apocrine sweat glands
axillary and anogenital
sympathetic regulation = stress
30
erythema
redness, fever, hypertension, inflammation, allergy, embarrassment
31
pallor
pale
anemia, low blood pressure, anger, fear, stress
32
jaundice
liver disorders
bilirubin accumulation in blood
33
cyanosis
blue
low amounts of hemoglobin and/or red blood cells
34
first line of defense
skin and mucosa
epidermis
mucous membrane
protective chemicals
35
2nd line of defense
internal defenses
phagocytes, natural killer cells, inflammation, antimicrobial proteins, fever
36
3rd line of defense
adaptive defenses specific
humoral immunity (B cells) and cellular immunity (T cells)
37
why is skin important for immune system
first line of defense
physical barrier to pathogens
mucous membrane contains protective chemicals
38
2 categories of leukocytes
granulocytes
agranulocytes
39
function of leukocytes
primary cells repsonsible for immune response
40
structure of leukocytes
derived from hematopoietic stem cells
divide into myeloid and lymphoid stem cells
41
process of phagocytosis
process of engulfing and ingesting target pathogen
phagocytic cell recognizes something as foreign
binds to it and engulfs it in membrane vesicle (phagosome)
phagosome fuses with lysosome in cell (phagolysosome)
42
describe natural killer cells
type of lymphocyte
provide rapid response to virus-infected cells and tumor cells
less picky about cellular targets compared to other lymphocytes in adaptive immune system
activated by abnormal cells and kills unhealthy cells
43
Inflammatory mediators trigger
vasodilation of arterioles (redness and heat)
increased capillary permeability (swelling)
occurrence of pain (possible loss of function)
recruitment of other cells (chemotaxis)
44
2 chemicals causing inflammation
histamine
prostaglandins
45
function of 2 chemicals causing inflammation
increases capillary permeability
attracts/activate other immune cells
increase sensitivity of pain fibers
46
what is 2nd stage of inflammatory response
phagocyte mobilization
47
leukocytosis
neutrophils enter blood from bone marrow
48
margination
neutrophils cling to capillary wall
49
diapedesis
neutrophils flatten and squeeze out of capillaries
50
chemotaxis
neutrophils follow chemical trail
51
importance of interferons (antimicrobial proteins)
help protect uninfected cells from viruses
infected cell produces interferon
interferon protein is packaged in secretory granules and release by exocytosis
neighboring cells bind interferon which stimulates them to "beef up" their cell defenses
52
importance of complement proteins
plasma proteins that help destroy pathogens
opsonization
enhance inflammation
insertion of membrane attack complex into membranes inducing cell lysis
53
fever definition
pyrogens are chemicals released from damaged cells or pathogens that act by establishing a higher than normal body temp, set point in hypothalamus
54
antigen definition
substances that trigger the adaptive immune system
55
immunogenicity
ability to stimulate specific lymphocytes to proliferate
56
reactivity definition
ability to reaction with activated lymphocytes and released antibodies
57
self antigens definition
produced by the body's own cells
58
non self antigens definition
produced by bacteria, viruses, or from substances outside the body
59
how do lymphocytes recognize an antigen?
they have a surface receptor specific to that particular antigen
60
immunocompetence
must be able to recognize one specific antigen
each B or T cell will display a unique surface receptor
all the receptors on one B or T cell are all the same
61
self tolerance
must be unresponsive to self antigens
62
T cell education in thymus (immunocompetence)
MHC are expressed by all cells and are specific to an individual person
thymus cells also have these MHC proteins
T cells die in thymus if they can't recognize self-MHC
survive if they recognize these self MHC proteins on thymus cells
63
positive selection
T cells must recognize self major histocompatibility proteins
64
T cell education in thymus (self tolerance)
T cells express T cell receptor on surface which recognizes foreign antigens and ignores self-antigens
T cells die if they bind self antigens
T cells survive if they ignore self antigens
65
negative selection
T cells must not recognize self-antigens
66
Primary humoral response
activation of naive B lymphocytes
67
how is naive B lymphocytes activated
receptors bind to antigen-specific for that receptor
cell undergoes cell division to form army of clones
68
what do B lymphocyte clones do? (2)
some differentiate into plasma cells which make millions of antibodies
others go dormant as memory B cells which can live many years
69
Secondary Humoral response
memory B cells provide an enhanced response in a second exposure to antigen
70
What's different about secondary humoral response?
more plasma cells produced
1000X more antibodies produced
produced earlier after infection
71
active immunity
B lymphocytes went through the activation process that led antibody production
72
Passive Immunity
B lymphocytes not activated antibodies come from outside source
73
Structure of antibody
composed of 4 polypeptide chains making up 2 identical halves
2 heavy chains and 2 light chains
2 antigen binding sites per antibody
Fab region
Fc region
74
Fab region (antibody) function
forms antigen binding sites and confer specificity for unique antigen
75
Fc region (antibody) function
dictate the type of cell the antibody can bind to
dictates how the antibody functions to eliminate antigens
Fc receptors on some immune cells
76
Why are class 1 MHC important to cellular immunity?
found on all nucleated human cells
all cells synthesize proteins and recycle them
fragments of recycled proteins are displayed at cell surface on MHC I proteins
CD8 T cells recognize this MHC I/antigen complex
77
why are class II MHC important to cellular immunity?
found primarily on antigen-presenting cells
phagocytic cells engulf and digest pathogens and display fragments on the surface
CD4 T cells recognize this MHC II/antigen complex at cell surface
78
physiological activity of cytotoxic T cells
naive CD8 cells activated when they encounter abnormal body cells
clone formation leads to the formation of cytotoxic T cells and memory T cells
activated T cells release cytokines
only T cell that can directly attack and kill abnormal cells
79
physiological activity of helper T cells
naive CD4 cells activated when they encounter antigen-presenting cells display fragments of foreign antigens
clone formation leads to formation of helper and memory T cells
activated T cells release cytokines
Helper T cell activation of B cells if required for full humoral immunity response
80
Lymphatic system
returns leaked fluid to the cardiovascular system
network of lymphatic vessels
lymph
lymph nodes
81
Lymphoid organs (5)
structural basis of immune system
spleen
thymus
tonsils
lymph nodes
MALT
82
how does lymph flow from capillaries back to venous system
excess interstitial fluid is collected by lymphatic vessels
lymphatic vessels carry lymph through lymph nodes before returning lymph to blood
collecting veins --> lymphatic trunks --> lymphatic ducts
lymph empties into subclavian veins close to heart
83
describe lymphoid cells and tissue
overlapping endothelial cells
collagen filaments tie overlapping flaps to surrounding connective tissue
lymphoid tissue contains cells of innate and adaptive defenses (B lymphocytes, T lymphocytes and antigen-presenting cells)
84
when do lymphoid flaps open and close
flaps close when interstitial pressure < lymphatic pressure
flaps open when interstitial pressure > lymphatic pressure
85
define primary lymphoid organs
where B and T lymphocytes mature
both originate in red marrow
B cells mature in red marrow
T cells mature in thymus
86
define secondary lymphoid organs
where mature lymphocytes first encounter antigens and are activated
lymph nodes, tonsils, spleen, peyers patches, appendix
87
function of spleen
site of lymphocyte proliferation, immune surveillance, and blood cleansing
88
White pulp (spleen)
immune function, composed of lymphocytes suspended on reticular fibers, form cuffs around central arteries
89
Red pulp (spleen)
where worn out RBCs and blood-borne pathogens are destroyed by macrophages
90
Lymph Nodes
cleanse the lymph and used for immune system activation
91
How does the spleen filter blood
extracts aged and defective RBCs and platelets, recycled products
macrophages remove debris and foreign materials
erythrocyte production in fetus
92
Lymph Node structure (7)
Capsule, cortex and medulla regions
Lymph flows into node through afferent lymphatic vessels
Flows through cortex, filled with lymphoid follicles
B cells, T cells, macrophages and dendritic cells also diffusely distributed in cortex and medulla
Lymph flows out efferent lymphatic vessels
Blood vessels continually bring new white blood cells
Lymph is screened by lymphocytes and phagocytic cells as it travels one-way through the lymph node
93
MALT (mucosa-associated lymphoid tissue) definition
collection of lymphoid tissue clustered in areas prone to pathogen exposure
94
MALT anatomy and physiology
found in GI tract, respiratory passages, genitourinary organs
included: tonsils, peyers patches, and appendix
composed of spherical clusters of lymphoid follicles (B cells)
95
How does a virus take over a host cell to produce new virus
Binds to ACE2 receptor on cell surface
virus enters cell and releases its genetic info (RNA)
host ribosome translates viral RNA and synthesizes viral proteins
proteins assembled into new viral particles
new virus released to body fluids
96
why is a transplanted organ at risk for rejection
donated tissue is recognized as non-self by recipients immune system
leads to destruction of donated tissue
treated with immunosuppressants
97
autoimmunity
immune system mistakenly sees self antigens as foreign and attacks some body cells
98
allergies
result when your immune system reacts to a substance that is normally harmless
99
first exposure (allergies)
allergen is ingested and processed by antigen-presenting cells
antigen-presenting cell-activated helper T cells
activated T helper cell in turn activates B lymphocyte
activated B lymphocytes become plasma cells and memory cells
memory B and T cells retain memory of exposure to allergen
100
reexposure (allergies)
upon exposure to allergen, B, and T cells activate more quickly
Body reacts strongly with the release of histamine, cytokines, and other mediators causing allergic symptoms
101
Anaphylactic reaction symptoms (6)
sudden drop in BP
weak rapid pulse
constriction of airways and a swollen tongue or throat
skin reactions, hives, itching, discolored skin
nausea, vomiting or diarrhea
dizziness or fainting
