List of abbreviations
of micros-
specialist terms
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Dr. med.
H. Jastrow

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Overview heterolysosome (Heterolysosoma):
Pages with explanations are linked to the text below the images if available! (Labelling is in German)
of a macrophage (rat)
adrenal gland (rat)
alveolar macrophage with primary
and heterolysosomes (rat)
detail large hetero-
lysosome (rat)
macrophage of the tela
submucosa gastrici (rat)
detail: hetero-
lysosome (rat)
Sertoli cell (rat)
macrophage with large autophagolyso-
somes in connective tissue (rat)
detail thereof:
phagolysosome 1 (rat)
lysosome 2 (rat)
lysosome 3 (rat)
heterolysosome + primary lyso-
somes human pharyngeal tonsil
large phagolysosome of
a Kupffer cell in liver (rat)
detail: phagolysosome heterolysosome as
phagophore (human)
other phagophore
heterolysosome with tu-
bules parotid gland (rat)
Heterolysosomes (Terminologia histologica: Heterolysosoma) are no longer called secundary lysosomes. They are relatively large heterogenous more or less spherical organelles of variable electron-density. The diameter of cut heterolysosomes ranges from 0.3 to 2 µm thus it is considerably larger than that of lysosomes proper which were called primary lysosomes before. Heterolysosomes are bordered by a double, i.e. unit membrane and derive from lysosomes when fusing with other material.
There are two possible ways of this process:
1. Heterolysosomes which originate from lysosomes when fusing with endocytotic vesicles in a process termed heterophagy (which means uptake of material from outside the cell for further degradation) are called phagolysosomes = phagosomes (Terminologia histologica: Phagosomae = Heterophago[lyso]somae). These large organells are formed in case phagocyting cells draw very large particles with diameters of several micrometers like bacteria or other whole cells into their cytoplasm. This happens for example when old or misformed erythrocytes are degraded by macrophages. A special phagosome is a phagophore which is characterized by several layers of its bordering membrane.
2. Heterolysosomes which originate from lysosomes when fusing with cell organells or other cytoplasmatic material in a process termed autophagy (self-degradation for destruction of cell-own material) are named auto(phago)lysosomes (Terminologia histologica: Autophago[lyso]somae.
Heterolysosomes are present in all cells of animals with exception of erythrocytes. Their number is high in microphages (e.g. neutrophilic granulocytes) and macrophages as well as other phagocyting cells of the reticulohistiocytic and reticuloendothelial systems and Sertoli-cells of the testis.
Heterolysosomes are the intracellular compartment of digestion, i.e. over 50 different enzymes of the fused (primary) lysosomes work on the internalized and mixed-up material. Heterolysosomes are important for destruction of foreign organic substances and particles which were internalized by phagocytosis/pinocytosis or they serve for destruction of cell-own materials/organells. The appearance of heterolysosomes is very variable since it depends on the material which is destroyed. Multivesicular bodies seem to be a special form of heterolysosomes which destroy small vesicles. Some heterolysosomes show remainings of attacked cell organells or lipid droplets. The intracellular digestion process is able to rewin  a lot of important basic components (e.g. amino acids) from protein degradation. Thus a very considerable amount of different substances is transported through the membrane of heterolysosomes for recycling in the cytoplasm. Other (smaller) substances of which the cell wants to get rid are transported into the heterolysosomes. During time heterolysosomes get smaller more condensed and filled with indigestible products like lipofuszin and finally they become residual bodies = telolysosomes (Terminologia histologica: Telolysosomae = Corpuscula residualia).

--> (primary) lysosomes - telolysosomes, cytoplasm, Golgi-apparatus, macrophages
--> Electron microscopic atlas Overview
--> Homepage of the workshop

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