HEME (Cell Types)

Question 0

Erythrocyte (RBC)

Life Span, Structure (4), Functions (2)?

Answer 0

Life Span = 120 days.

• NO nucleus
• Biconcave
• Cl-HCO3 Antiporter on memb (export of HCO3)
• Large SA : V (rapid gas exchange)
• Gas Exchange
• O2 + CO2 carrying

Question 1

Reticulocyte

Def’n, Marker For?

Answer 1

Immature erythrocyte.

MARKER FOR: Erythroid proliferation

Question 2

Thrombocyte (Platelet)

Derivation, Life Span,
Structure (3, incl 2 granule types), Function,
Storage?

Answer 2

Derived from Megakaryocytes.

Life Span = 8-10 days.

• NO nucleus
• 2 types of granules:
  
  • Dense / Delta Granules: c/tn ADP + Ca
  • Alpha Granules: c/tn Fibrinogen (binds to Gp IIb/IIIa Complex)
    + VWF (binds to Gp Ib Complex)
• Platelet Membrane Glycoproteins: surface glycoproteins found on
  platelets that bind fibrinogen + VWF and function as receptors for platelet adhesion to collagen.
  (= key role in hemostasis)
• Hemostasis

STORAGE: Spleen (1/3 of platelet pool stored in spleen)

Question 3

Neutrophil

Chars (6), Path Variations (2)?

Answer 3

CHARS:

• Short-lived
• Very motile
• Phagocytic
• Bactericidal
• Have membrane Oxidases
• 3 types of Granules (lysosomes): large, spherical + azurophilic

PATH VAR:

• Band Cells
• Hypersegmented Polyps

Question 4

Monocyte

Chars?

Answer 4

CHARS:

- Extensive “frosted glass” cytoplasm

Question 5

Macrophage

Location, Chars (2), Activation By, Functions (4)?

Answer 5

Long life IN TIS.

CHARS:

• Ruffled memb
• Cytoplasm with vacuoles + vesicles

ACTIV BY: γ-interferon

• APCs (via MHC II)
• PHAG of bacteria, senescent RBCs + cell debris
• Scavenging of damaged cells / tis
• Granuloma formation

Question 6

Dendritic Cell

Structure (2), Function?

Answer 6

• Long cytoplasmic arms
• MHC II + Fc receptor on surface

** Link b/w Innate + Adaptive immune systems **
“Professional” highly phagocytic APCs (via MHC II)

Question 7

Eosinophil

Functions (3)?

Answer 7

• Defense against Helminth infections
• Phag of antigen-antibody complexes
  (ie antibody-coated parasites)
• Limit reaction following Mast Cell degranulation
  (thr production of arylsulfatases + histaminases)

Question 8

Basophil

Chars (3 constituents of granules), Function?

Answer 8

CHARS: Basophilic granules containing:

• Heparin (anticoagulant)
• Histamine (vasodilator) + other vasoactive amines
• Leukotrienes
• Mediation of Allergic Rxs

Question 9

NK Cell

Enhancers (3), Targets (2 General + 3 Org), Mech (2)?

Answer 9

** Only lymphocyte member of Innate immune system **

ENHANCERS (activity enhanced by):

• IL-2
• IL-12
• Interferon-a + -b

TARGETS:
Cell surfaces with:
- NO MHC-1
- Nonspecific activation signal

• INTRACELLULAR bacteria (antibody-coated target cells)
• Viruses
• Tumor cells

MECH:

• APOPTOSIS of target cells, using granzymes + perforin
• Ab-dependent cell-mediated cytotoxicity

Question 10

T Lymphocyte (80% of circulating lymphocytes)

Differentiation / Subtypes (3), Functions (2 General)?

Answer 10

• Helper (CD 4) T cells: produce IL-2
• Cytotoxic (CD 8) T cells
• Regulatory T cells

CELLULAR Immunity:

• Hypersensitivity Rxs (Type 4)
• Organ Rejection: Acute + Chronic

Question 11

CD4 T Cells

APC/MHC Recognition, Functions (2), Bind?

Answer 11

Recognition of MHC II.

• Secretion of cytokines -> Macrophage activation
• “Help” Plasma Cells make antibody

BIND: gp120

Question 11

CD8 T Cells

APC/MHC Recognition, Functions?

Answer 11

Recognition of MHC I.

• Directly kill VIRUS-INFECTED cells

Question 12

B Lymphocyte

Differentiation / Subtypes (2), Functions (4), Storage Sites (3)?

Answer 12

(Upon antigen encounter)

• Plasma cells
• Memory cells

HUMORAL Immunity:

• APC (via MHC II)
• Ab production
  
  • > Bacteria Opsonization
  • > Virus Neutralization (IgG)
  • > Mast Cell Sensitization (IgE)
  • > Complement Activation (IgG + IgM)
• Hypersensitivity Rxs:
  
  • Type 1 / Allergy (IgE)
  • Type 2 / Cytotoxic (IgG)
  • Type 3 / Immune Complex (IgG)
• Organ Rejection: HYPERacute

STORAGE:

• Unencapsulated lymphoid tis
• Lymph node follicles
• Spleen white pulp

Question 13

Plasma Cell

Structure (5), Neoplasm?

Answer 13

• Off-center nucleus (“fried-egg” appearance)
• “Clock-face” chromatin distribution
• Intracytoplasmic inclusions c/tning Ig
• Abundant RER
• Well-developed + intensely-staining golgi apparatus

Multiple Myeloma

Question 16

Mast Cell

Location, Granule Constituents (3), Stim by (7),
Function,↑Seen In?

Answer 16

** Very sensitive cells **

ALL CONNECTIVE TIS in body, however esp concentrated in:

    - Subepithelial connective tis
    - Perivascular connective tis

GRANULE CONSTITUENTS:

• Heparin
• Histamine
• • Eosinophil chemotactic factors

STIM:

• C3a, C4a, C5a
• IgE (when cross-linked with antigen)
• Heat / Cold
• UV light
• Trauma
• Venoms
• Drugs (eg Morphine)
• Mediation of Allergic Rxs in LOCAL TIS (Type 1 H-S)

↑SEEN IN:
- PV

Question 17

Blast

Def’n,↑Seen In?

Answer 17

Large immature cells w punched-out nuclei.
Usually enter circ -> High WBC Count.

↑SEEN IN:
- Acute Leukemia (neoplastic prolif of blasts -> > 20% blasts in BM)

Question 18

Lymphoblast

Chars,↑Seen In?

Answer 18

CHARS:
- + nuclear staining for TdT (a DNA Polymerase)

↑SEEN IN:
- ALL (neoplastic prolif of lymphoblasts -> > 20% in BM)

Question 19

Myeloblast

Chars,↑Seen In?

Answer 19

CHARS:

• • cytoplasmic staining for myeloperoxidase (MPO).
• ** Crystal aggregates of MPO may be seen as ‘Auer Rods’ ***

↑SEEN IN:
- AML (neoplastic prolif of myeloblasts -> > 20% in BM)

Question 20

Granulocyte

↑Seen In (4):

Answer 20

↑SEEN IN:

• CML
• ET
• PV
• Myelofibrosis (IMMATURE granulocytes)

Question 21

Megakaryocyte

Def’n,↑Seen In?

Answer 21

BM cell responsible for Platelet production.

↑SEEN IN:
- Myelofibrosis