Ward Anatomy/Histo Flashcards
(168 cards)
1
Q
Granulocytes
A
Neutrophils, eosinophils, and basophils > terminal cells
2
Q
Non-granular leukocytes
A
Lymphocytes and monocytes > can still divide
3
Q
Process of neutrophils leaving circulation
A
- Neutrophils express L-selectin and selectin receptors on their surface
- Endothelial cells express selectin receptors and E and P selectin on their surface
- Selectin binding slows down the neutrophil, making it roll across the endothelium
- Chemokines secreted by endothelial cells activate LFA-1 on the neutrophil surface
- Integrin and ICAM-1 firmly tether neutrophils to the endothelial surface
- Histamine and heparin are released by mast cells near injuries
- This makes the endothelium leaky as gaps develop
- A neutrophil extends a pseudopod between adjacent endothelial cells and pulls itself through the gap
- Chemo-attractants in peripheral tissues direct neutrophils where they are needed
4
Q
Primary granules
A
Lysosomes
5
Q
Neutrophil phagocytosis
A
- Neutrophils are able to recognize some bacteria or other pathogens innately. Other times they may be bound to immunoglobulins or complement before they can be phagocytosed
- Antibody receptors on neutrophil surface bind the pathogen and the neutrophil extends pseudopodia
- Pseudopodia surround pathogen and pull it into a phagosome
- Primary and secondary granules fuse with phagosome and kill/digest the pathogen inside a phagolysosome
- Debris can be exocytosed or kept in the neutrophil as a residual body
- Process often kills the neutrophil as well, creating pus
6
Q
Secondary granules
A
Specific - allow a cell to carry out its function
7
Q
Neutrophil secondary granules
A
Collaginase, phospholipase, lysozyme, other bacteriostatic/bactericidal enzymes (other granules contain phosphatase and metalloproteases that help it migrate out of blood vessels)
8
Q
Function of eosinophils
A
- Fight parasites and mitigate allergic reactions
- Degrades histamine and antigen-Ab complexes to reduce inflammation and limit immune reactions
9
Q
Major basic protein function
A
Induces mast cell degranulation
10
Q
Eosinophil cationic protein function
A
Creates pores in target cell membranes, ribonuclease against viruses
11
Q
Eosinophil peroxidase function
A
Creates ROS to damage/kill targets
12
Q
Where are eosinophils found?
A
LCT of digestive tract and reserve force in bone marrow
13
Q
What secondary granules do basophils release?
A
- Heparin (anticoagulant)
- Histamine (vasodilation)
- Leukotrienes (cause prolonged constriction of respiratory smooth muscle)
- Peroxidase
- Eosinophil chemotactic factor
- Neutrophil chemotactic factor
14
Q
What do basophils and mast cells do?
A
Initiate allergic reactions when they respond to antibodies released by plasma cells
15
Q
Monocyte function
A
Monocyte-derived cells and microglia phagocytose pathogens and cellular debris; Monocytes present antigen to T helper cells (CD4) via MHCII
16
Q
B lymphocyte function
A
- i. Release immunglobulins and differentiate into peripheral plasma cells
- Phagocytose antigens and present them on MHCII
17
Q
B lymphocyte markers and surface proteins
A
- LFA-1 (integrin) and selectin
- Ig alpha and beta
- CD19-22, 40, 127/IL-7
- PD-1
18
Q
LFA-1 and selectins function
A
Allows naive B cells to leave bloodstream as they differentiate
19
Q
Ig alpha and beta function
A
Immunoglobulins form a transmembrane BCR with variable antigen sites to allow the B cell to do its job
20
Q
CD19, 20, 21
A
marker/coreceptor for B cell activation
21
Q
CD22, PD-1
A
inhibit B cell activity
22
Q
CD40
A
Costimulatory, active in proliferating B cells, helps DCs and macrophages produce cytokines
23
Q
CD127/IL-7 receptor alpha
A
Marker of B cell development
24
Q
Plasma cells
A
- B lymphocytes that have been activated by a helper T cell and enter peripheral circulation
- Located in pathogen-rich LCT like GI and resp
- release antibodies to bind and mark a variety of pathogens
25
Appearance of plasma cells
Large, circular, clock-face nucleus with clear Golgi body within pale pink cytoplasm
26
Erythrocytes appearance
pinkish, biconcave discs without nucleus
27
Reticulocytes appearance
immature RBCs containing basophilic granules
28
Platelets appearance
small central purple region and pale blue peripheral region; no nucleus
29
Neutrophils appearance
bi or tri-lobed nucleus in relatively clear appearing cytoplasm
30
Eosinophils appearance
multi-lobed nucleus with eosinophilic granules
31
Basophils appearance
multi-lobed nucleus obscured by many basophilic granules
32
Monocytes appearance
kidney-shaped nucleus in clear cytoplasm lacking granules
33
Lmyphocytes appearance
Non-granular leukocyte with large spherical nucleus and thin rim of pale blue cytoplasm
34
Where do T lymphocytes differentiate?
In the thymus
35
T lymphocytes function
Involved in cell-mediated immunity because their surface proteins recognize antigens presented on MHC of other phagocytic cells
36
T lymphocyte markers/surface proteins
- LFA-1 and selectins
- CD2, 3, 5, 28, 152/CTLA-4
- TCR
- FASL
37
CD2
marks T cells in thymus and interacts with adhesion molecules on other cells
38
CD3
T cell co-receptor helps to activate cytotoxic and helper T cells
39
What kind of T cell has CD4? What MHC does it use?
Helper T cell; MHC II
40
What kind of T cell has CD8? What MHC does it use?
Cytotoxic T cell; MHC I
41
Where are elevated levels of CD5 seen?
Lymphocytic leukemia
42
CD28
costimulatory molecule - activates T cells
43
CD152/CTLA-4
inhibitory molecule that competes with CD28 binding
44
Cytotoxic T cell function
Respond to antigens by killing infected, invasive or non-self cells
45
What happens once cytotoxic T cells are active and expressing CD38?
release lymphokines (recruit other immune cells), perforins (create holes in target cell), and granzymes (fragment DNA)
46
FASL surface protein
Triggers apoptosis in target cells
47
What cells are a major problem in graft-host rejection?
Cytotoxic T cells
48
Helper T cell function
Divide and recruit B, T, NK cells after recognizing antigens presented on MHCII
49
Th1 cell function
Activate macrophages
50
Th2 cell function
trigger B cells to become plasma or memory B cells
51
Memory T cells and marker
- Have been previously exposed to their surface antigen and can be found in lymph nodes and peripheral tissues, awaiting re-activation
- CD45(RO)
52
Suppressor T cell function and marker
- Suppress autoimmune self-reactivity and inflammmation
- Can suppress activity of other T cells, DCs, antibody formation by B cells(may result from having DC present a self-antigen to naïve T cell)
- CD152(CTLA-4): inhibitory molecule - constantly expressed in regulatory T cells
53
NK cell function
- Pre-programmed to destroy cells transformed by viruses or certain types of cancer when those transformations alter the expression of MHC1 surface proteins
- Release perforins and granzymes to punch holes in target cell membranes and fragment their DNA
54
NK surface proteins
KIR, FASL, CD16, CD56 (NCAM)
55
KIR
killer Ig-like receptor that recognizes MHC
56
CD16
triggers events that lead to cell lysis following Ab recognition
57
CD56/NCAM
helps NK cell adhesion (and growth of axons)
58
Delta granules of platelets
- Serotonin (vasoconstriction)
| - ADP (platelet aggregation)
59
Alpha granules of platelets
- Fibrinogen
- Coagulation factors - allow fibrinogen to create a mesh around the platelet plug (XIII)
- PDGF - stimulates division of nearby fibroblasts and smooth muscle cells to promote healing
60
Hematocrit
- packed RBCs
| - 45%
61
Plasma
- extracellular content
| - 55%
62
Buffy coat
- leukocytes and platelets
| - <1%
63
Plasma with clotting factors removed
Serum
64
Plasma function
Helps in immune and clotting function, as well as transport and maintaining osmotic pressure of blood
65
Albumin function
Maintains osmotic pressure of blood and transports hormones, bilirubin, and drugs
66
Erythrocyte function
Transport O2 and CO2
67
Hemoglobin function
Provides O2 to body
68
Red bone marrow function
Produces RBCs
69
Erythropoietin function
Increases rate of RBC creation
70
Thrombopoietin
Helps megakaryocytes produce platelets
71
Order of cell type from most to least ABUNDANT
- erythrocytes
- platelets
- neutrophils
- lymphocytes
- monocytes
- eosinophils
- basophils
72
Order of cell type from biggest to smallest
- NK cells
- monocytes
- neutrophils
- eosinophils
- basophils
- lymphocytes (can be bigger than monocytes, but usually here)
- erythrocytes
- platelets
73
Type A blood
- A antigen
| - Anti B antibodies
74
Type B blood
- B antigen
| - Anti-A antibodies
75
Type AB blood
- A and B antigens
| - No antibodies (universal receiver)
76
Type O blood
- no antigens
| - Anti A and B antibodies (universal donor)
77
Developmental landmarks of prenatal hemopoiesis
1. Primordial phase (week 2)
2. Hepatosplenothymic phase (month 2)
3. Medullolymphatic phase (month 5)
78
Primordial phase of hemopoiesis
- Blood islands form in mesoderm of yolk sac.
- lining of each island forms endothelial cells and cells inside develop into fetal erythrocytes.
- Fetal erythrocytes: larger than adult, retain nuclei, contain fetal hemoglobin (binds strongly to O2).
79
Hepatosplenothymic phase of hemopoiesis
In 6th week, liver produces fetal erythrocytes, granulocytes, platelets. Later the spleen produces erythrocytes, granulocytes, and platelets.
80
Medullolymphatic phase of hemopoiesis
- Bone marrow becomes primary source for all blood cells and platelets by 5th month.
- By the end of the 2nd trimester, the thymus begins producing T lymphocytes
81
Post-natal hemopoiesis
- After birth, blood formation is restricted to the bone marrow and thymus.
- Production of fetal hemoglobin halts.
- Lymphocytes migrate and mature in thymus, spleen, lymph nodes, tonsils, or appendix.
- If bone marrow is damaged or cannot meet the body’s need for blood, the liver, spleen, or lymph organs can resume hemopoiesis.
82
Adult bone marrow is less hemopoietic because it regresses from ___________ _____ _________ to fat-storing ________ _________ over time (esp in long bones)
hemopoietic red marrow; yellow marrow
83
Adult marrow is primarily found in...
vertebral bodies and pelvis, sternum, ribs
84
All blood cells develop from a primitive...
Hemopoietic Stem Cell (HSC) aka the Pluripotent Hemopoietic Stem Cell (PPSC)
85
Multipotent progenitor cells
- Come from HSCs
- Referred to as CFUs (colony-forming units)
- Two types:
1. Common Myeloid Progenitor (CMP, CFU-GEMM)
2. Common Lmyphoid Progenitor (CLP, CFU-L)
86
Derivatives of CLP cells
1. Pre-B cell >> B lymphocytes >> Plasma cells
2. Pre-T cell >> Thymocytes >> T lymphocytes
3. Pre-NK cell >> Natural Killer (NK) cells
87
Derivatives of CMP cells
1. Granulocyte/Monocyte Progenitor cell (GMP, CFU-GM) >> granulocytes and monocytes
2. Megakaryocyte/erythrocyte progenitor (MEP)
88
Derivatives of GMP cells
1. Predendritic cell (Pro-DC, can also come from CLP) >> DCs
2. Neutrophil progenitor (CFU-G) >> several steps >> Neutrophils
3. Basophil/Mast cell progenitor (BMCP)
4. Eosinophil progenitor (CFU-Eo) >> several steps >> Eosinophils
5. Monocyte progenitor (CFU-M) >> Monocyte >> Macrophages (migrate peripherally)
89
Derivatives of BMCP cells
1. Basophil progenitor (CFY-Ba) >> several steps >> Basophils
2. Mast cell progenitor (MCP, in spleen) >> Mast cells (migrate peripherally)
90
Derivatives of MEP cells
1. Megakaryocyte Progenitor (MKP, CFU-Meg) >> Megakaryoblast >> Megakaryocyte >> Platelets
2. Erythrocyte Progenitor (ErP, CFU-E) >> several steps >> Erythrocytes
91
Hemopoiesis of erythrocytes are up-regulated by...
erythropoietin, other growth factors, hypoxia, gain in altitude, blood loss
92
How long does it take to go from erythrocyte progenitor to erythrocyte?
1 week
93
These are found in bone marrow surrounding macrophages to clean debris
Erythroblastic islands
94
Cells mature and then migrate into _________ __________ of marrow to enter circulation.
Sinusoidal capillaries
95
Necessary components for production of RBCs
- Iron
- Folic acid
- Vitamin B12
- Protein precursors
96
Maturation process of a RBC
Proerythroblast>>basophilic erythroblast>>polychromatophilic erythroblast>>orthochromatophilic erythroblast (normoblast)>>reticulocyte>>erythrocyte
97
What does a proerythroblast look like?
- Large and round nucleus
| - Basophilic cytoplasm (making ribosomes)
98
What does a basophilic erythroblast look like?
- Smaller nucleus
| - More basophilic - peak # of ribosomes
99
What does a polychromatophilic erythroblast look like?
- Smaller nucleus
| - Pinkish - start of Hb translation
100
What does an orthochromatophilic erythroblast look like?
- nucleus extruded
| - pink in slight bluish background
101
What does a reticulocyte look like?
- No nucleus
| - Pink with basophilic inclusions = ribosomes
102
What does a mature erythrocyte look like?
- No nucleus
| - pink cytoplasm, biconcave
103
Granulocytes develop from granulocyte/monocyte progenitor cells AKA
Myeloblasts
104
What do myeloblasts look like?
- Large nuclei
| - Lack granules in cytoplasm
105
Maturation of granulocytes (neutrophils/eosinophils)
Myeloblast >> promyelocyte >> myelocyte >> metamyelocyte >> band(stab) cell >> neutrophil/eosinophil
106
What does a myeloblast look like?
- Round nucleus
| - Bluish as ribosomes are produced; Golgi may be visible
107
What does a promyelocyte look like?
- Round nucleus
| - Blue for ribosomes; Golgi visible
108
What does a myelocyte look like?
- Flattened oval nucleus
- Neutrophils: pale blue cytoplasm
- Eosinophils: eosinophilic granules more prominent
109
What does a metamyelocyte look like?
- Indented nucleus
- Neutrophils: pale blue cytoplasm
- Eosinophils: eosinophilic granules more prominent
110
What does a band(stab) cell look like?
- Horseshoe-shaped nucleus
- Neutrophils: pale blue cytoplasm
- Eosinophils: eosinophilic granules more prominent
111
Hemopoiesis of thrombocytes
CMP >> megakaryocyte/erythrocyte progenitor >> megakaryocyte progenitor >> megakaryoblast >> megakaryocyte >> platelets
112
Megakaryoblasts
Chromosomes replicate repeatedly w/o cell division >> exist only in bone marrow
113
Mature megakaryocytes release...
Cytoplasmic fragments (platelets) into bone marrow sinusoids
114
How long do platelets circulate?
7-10 days
115
Protective surface mechanisms of immune system
Epithelial linings: skin and mucous membranes of Respiratory, GI, UG tracts (lysozyme, mucus, structural barrier)
116
Innate immune system components
- Cells: neutrophils, eosinophils, basophils, macrophages, and mast cells
- Proteins & peptides: complement, acute phase proteins, and cytokines
117
Adaptive immune system components
- Builds on the innate immune system to build large numbers of lymphocytes with specificity for a particular antigen.
- consists of cellular and humoral responses
118
Lymphatic organs and tissues
- Bone marrow (myeloid tissue)
- Lymph capillaries & vessels
- Lymph nodes
- Mucosa Associated Lymphoid Tissue
- Spleen
- Thymus
119
Cellular response components
APCs and T lymphocytes
120
Humoral response
B lymphocytes, plasma cells, antibodies
121
How do dendritic cells get rid of pathogens?
- use pseudopodia to sample the external environment.
- attack pathogens in the tissue and present antigens on their surface for to activate the adaptive immune response by other leukocytes.
122
Memory B cells
circulate and pass through lymphoid organs for several years. If they re-encounter their antigen, they divide to produce plasma cells once again. This is the secondary immune response.
123
B lymphocyte development
- If surface antibody recognizes self >> apoptosis to avoid autoimmune reaction
- If does not recognize self >> naive B cell leave bone marrow and circulates through blood and lymphoid tissue to fine non-self antigens
- If does not encounter a non-self antigen >> death
- If found, B cell activates, divides, and becomes a plasma cell or memory B cell
124
Positive selection of T cell
-Measure interaction with self-antigen to see if they will be able to interact with APCs
125
Negative selection of T cell
-If interact with self too strongly >> undergo negative selection and become apoptotic
126
Once T cells survive they...
Leave the thymic medulla >> circulate >> reach lymphoid organs >> if recognize specific antigen, they proliferate to create...Memory T cells, helper T cells, cytotoxic T cells, or regulatory (suppressor) T cells
127
Memory T cells (CD45RO)
migrate to lymph nodes and wait to be triggered in the future.
128
Helper T cells (CD4+)
if antibody receptor and CD4 surface molecules (interact with MHC II surface molecules of APCs) are co-activated, they recruit other immune cells to the area.
129
Cytotoxic T cells (CD8+)
if antibody receptor and CD8 surface molecules (interact with MHC I surface molecules) are co-activated, they will release perforins, enzymes, and free radicals to kill non-self, infected, or cancerous cells.
130
Regulatory (suppressor) T cells
modulate activity of the immune response with CD152 (CTLA-4), an inhibitory surface protein.
131
Pre-NK cells develop from...
CLP cells in bone marrow and possibly thymus and lymph nodes
132
Capsule of thymus
DICT with trabeculae subdividing lobes into lobules
133
Blood-thymus barrier composed of...
- Capillaries: continuous capillaries with tight junctions and thick basal lamina.
- Surrounded by epithelial reticular cells (ERCs)
134
Epithelial reticular cells provide...
Mechanical supporting framework for lymphocytes
135
Cortex of thymus
- Darker outer area
- Macrophages
- Small T cells enveloped by Epithelial Reticular Cells
136
Medulla of thymus
- Lighter inner area
- Large T cells
- Hassall’s corpuscles
137
Epithelial reticular cells
- Large, pale nuclei within eosinophilic cytoplasm.
- ERCs form 3-dimensional “corrals” around multiple T cells to promote differentiation and proliferation.
- Create the blood-thymus barrier.
- Thymic (Hassall’s) corpuscles are from keratinized ERCs and increase in size and number with age
138
Role of the thymus and T cell development
- Immunoincompetent T cells enter the circulating blood and travel to the thymus.
- They pass though the vasculature and enter the thymus at the corticomedullary junction to become thymocytes.
- Thymocytes migrate to the periphery of the cortex, where positive selection occurs.
- Surviving cells move deeper into the medulla as they mature and undergo negative selection.
- Few survive
- Self-reactivity of T cells is an excellent reason to have a blood-thymus barrier.
- ERCs secrete hormones that regulate T cell maturation, proliferation and function within the thymus and peripheral lymphoid tissues. (thymulin, thymopoietin, thymosins)
139
MALT
- Non-encapsulated lymphocyte clusters found in the mucosa layer of several organ systems.
- Allows lymphocytes to interact with antigens and antigen presenting cells (APCs) by sampling antigenic material as it enters the body.
- Initiates both antibody-mediated and cytotoxic immune responses as appropriate.
140
Subtypes of MALT
-Tonsils: Palatine, Pharyngeal, Lingual, Tubal
-BALT = Bronchi-associated lymphoid tissue
-NALT = Nasal-associated lymphoid tissue
-GALT = Gut-associated lymphoid tissue
>>Lymph follicles along digestive tract
>>Peyer patches in ileum
-TALT: Tear duct –associated lymphoid tissue
-CALT: Conjunctiva-associated lymphoid tissue
-MALT of the urogenital tract (no snappy abbreviation as yet).
141
Waldeyer's Ring
Interrupted circle of protective lymphoid tissue at the upper ends of the respiratory and alimentary tracts
142
Lymph nodes function
Sample lymphatic fluid from body tissues for foreign antigens
143
Lymph nodes composition
- Fibrous CT capsule
- Stroma = meshwork of reticular ribers that forms the framework of the node
- Parenchyma = cortex, paracortex, and medulla; cells - B, T, APCs, and macrophages
- afferent lymphatic vessels - leave through hilum
- arteries and veins enter and exit through hilum (B and T lymphocytes reach the node via these vessels)
144
What does having valves in afferent and efferent vessels do?
Prevents retrograde flow of lymph back into the node
145
Primary lymphoid follicles
Naïve B lymphocyte clusters with no germinal center.
146
Secondary lymphoid follicles
form in response to antigenic challenge.
147
Germinal centers
pale center of Memory B cells isotype switching and dividing to make plasma cells.
148
Mantle
dense accumulation of small lymphocytes migrating away from the germinal center.
149
High endothelial venules
allow lymphocytes to leave circulation and enter lymph node
>>B cells - cortex
>>T cells - stay in paracortex
>>APCs - migrate to paracortex to interact with helper T cells (Activated Helper T cells proliferate and newly-formed T cells migrate to the medullary sinuses to leave node)
150
Medulla composition
Large tortuous lymph sinuses surrounded by lymphoid cells organized into medullary cords
151
Medullary cords
lymphocytes, plasma cells, macrophages supported by reticular fibers
152
APCs and lymphocytes migrate to ________ _______ and exit via efferent lymphatics
Medullary sinuses
153
Spleen is protected (and sometimes lacerated) by ribs...
8-11
154
What does the spleen do?
- Filters blood
- Forms lymphoid cells
- Eliminates or deactivates blood-borne antigens
- Destroys aged platelets and erythrocytes
- Participates in fetal hemopoiesis
155
External structure of spleen
-Covered by visceral peritoneum and capsule
>>DICT (thicker at hilum)
>>trabeculae extend from capsule into internal splenic sinuses
156
Internal structure of spleen
- Reticular fibers (type III collagen)
| - red pulp and white pulp, separated from each other by marginal zone
157
What purpose do the reticular fibers provide?
allows the spleen’s cells to be anchored without losing too much space
158
White pulp
- Pale-staining strips of lymphocytes and macrophages that surround central arteries are peri-Arterial Lymphatic Sheaths (PALS)
- Lymphatics screen blood for antigens
159
Where are T cells restricted in spleen?
To PALS to identify virus-infected cells or bacteria in circulation
160
How do lymphocytes migrate back into the bloodstream?
Through small marginal sinuses
161
Once central arteries enter the red pulp...
They lose their PALS and branch into penicillar arteries
162
Penicillar aa
Have sheath of macrophages just before they open to splenic sinuses
163
Splenic sinuses
large discontinuous capillaries with incomplete basal lamina.
164
Cells and plasma leave sinuses to...
Mingle with cells of splenic cords or Bilroth (lymphocytes, macrophages, plasma cells) clustered around reticular fibers
165
Splenic sinuses converge...
Form small veins >> combine >> splenic v.
166
Damaged or old RBCs that cannot re-enter sinuses are...
destroyed by macrophages
167
In red pulp, Hb...
Released, transported to liver (unconjugated on albumin) for recycling/excretion
168
In red pulp, iron...
Released and stored in liver or transported to hemopoietic tissues for new RBCs
