BIOL355 Lecture Notes - Lecture 20: Lipofuscin, Quadriceps Femoris Muscle, Lysosome
21 Apr 2017
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Lecture 20: consist of strongly cross-linked molecules (lipids, proteins, dna, ca(cid:374)(cid:374)ot (cid:271)e (cid:271)roke(cid:374) dow(cid:374) (cid:271)y lysoso(cid:373)es (cid:862)(cid:272)ellular gar(cid:271)age(cid:863, very insoluble. Stored lysosomes or shunted out to cytoplasm where accumulates. Can make up to 30% of cytoplasm volume in old cells. Older cell with 30% lipofuscin in cytoplasm and when cell division occurs both daughter cells will have 15% of lipofuscin. Lipofuscin is a brown-yellow material that accumulates progressively over time in lysosomes of post mitotic cells such as neurons and cardiac myocytes. Fluorescence images of transverse frozen sections of quadriceps muscle. Images for lipofuscin analysis for 27-month old vs 3-month old mice. Premise : with increase age have formation of new cross-links between or within macromolecules (protein, dna, lipids) They are long lived and stiffen tissues that have matrix that are rich in these proteins: these include: skeletal muscle, tendons, joints, bone, heart, arteries, lung, skin and lens of eye.
