Neutrophils

how many stages of neutrophil maturation are there?

6

what are the stages of neutrophil maturation?

myeloblast

promyelocyte

myelocyte

metamyelocyte

band

seg

what happens as neutrophils mature?

the nucleoli disappear

chromatin condenses

the round nucleus indents

blue lacy cytoplams replaced by light pink granular cytoplasm

what three main cytokines regulate neutrophils?

IL-3

GM-CSF

G-CSF

characterstics of myeloblast

earliest precursor

high N:C ratio

lacy round nucleus

visible nucleoli

deep blue agranular cytoplasm

golgi next to nucleus visible

characterstics of promyelocyte

N:C ratio high

round, coarse nucleus

still visible nucleoli

azurophilic primary granules appear

azurophilic granules

reddish-purple colored granules

characterstics of myelocyte

nucleus and N:C ratio decreases

indistinct nucleoli

nucleus starts to get flat or indented

goligi still viisble

secondary granules appear near the nucleus (pinkish red/pinkish purple)

less azurophilic granules

secretory vesicles

what is the last stage that neutrophils can divide or go through mitosis?

myelocyte

characteristics of metamyelocytes

nucleus indentation

nucleus is clumped, dark purple, and coarse

no nucleoli

secondary granules are mainly seen

pinkish tan cytoplasm

what stages are in the mitotic pool?

myeloblasts

myelocytes

promyelocytes

what stages are in the storage pool?

metamyleocytes

bands

segs

what controls concentration?

illness and inflammation

increased IL-1 and TNF stimulate G-CSF which creates more neutrophils

what is the ratio of neutrophils in the peripheral blood?

half in marginating pool

half in circulating pool

what are neutrophils in the marginating pool doing?

they are slowly rolling along the vessel walls (locomotion) with the help of adhesion proteins

what are neutrophils doing in the circulating pool?

circulating freely

neutrophils in tissue

traveled from marginating pool

no signal means cell death

lifespan can be increased by GM-CSF/G-CSF

neutropenia

decrease in neutrophils

caused by chemotherapy

less than 1.8×10^9/L

agranulocytosis

decrease in granulocytes

granulocytosis

increase in granulocytes

neutrophilia

increase in neutrophils

caused by bacterial infection

greater than 7.0 × 10^9/L

what are the main functions of neutrophils?

phagocytosis

adherence

diapedisis

chemotaxis

locomotion

adherence

flowing freely along vessels

activated by inflammatory cytokines and chemokines

helps neutrophils travel to the infection site

diapedisis

go through vessel walls

chemotaxis

migration in reponse to chemical stimulation (chemokines)

migration/locomotion

activation of vascular endothelial cells

neutrophil activation

binding to vessels

trasendothelial migration

phagocytosis

the PAMPs recognize the PRRs

can also recognize through opsonization

pathogen is absorbed and broken down

what are the step of phagocytosis

recognition

phagosome is created when pathogen is absorbed

phagolysosome created when lysosomal enzymes bing to phagosome

breakdown of pathogen

exocytosis of broken down pathogen

what are the cellular products produced in phagocytosis?

superoxide and H2O2

lactoferrin

lysozyme

myeloperoxidase

leukocyte alkaline phosphate