Golgi Apparatus and Lysosomes PDF

Golgi apparatus Lysosomes Prof. Dr sahar omar 1  Golgi apparatus Lysosomes INTENDED LEARNING OBJECTIVES (ILO) By the end of this lecture the student will be able to: 1. Describe structure of the Golgi apparatus...

Golgi apparatus Lysosomes Prof. Dr sahar omar 1  Golgi apparatus Lysosomes INTENDED LEARNING OBJECTIVES (ILO) By the end of this lecture the student will be able to: 1. Describe structure of the Golgi apparatus and lysosomes by LM and EM 2. Correlate the structure of the Golgi apparatus and lysosomes to their function 3. Interpret the structural changes in Golgi apparatus and lysosomes in the different diseases 2  I cell disease…..defect in Golgi apparatus I cell disease (Inclusion cell disease) results from deficiency in the name tag of the lysosomal enzymes (address) Defective sorting No enzymes in the lysosomes l https://i.dailymail.co.uk/i/pix/2017/08/23/10/437BD62C00000578-0-image-m- 2_1503479586505.jpg Enzymes pass to outside the cell to blood Golgi apparatus It is a membranous organelle http://academic.brooklyn.cuny. edu/biology/bio4fv/page/golgi_ https://gfycat.com/whirlwindtangiblealabamamapturtle-golgi- a.htm apparatus-cell-structure-amoebasisters LM: by silver stain appear as dark brown network slideshare.net/cud2018/all-1st- midterm-slides-prac-histology -By H&E, Golgi complex appears as pale unstained 4 area known as negative Golgi image as in plasma cells & osteoblasts.  Golgi apparatus EM: It is formed of: Golgi stacks, Transfer vesicles Secretory vesicles https://www.desktopclass.com/biology/golgi-apparatus-f-sc-biology- chapter-4-2.html 5 Golgi apparatus 6  EM of Golgi apparatus a) Golgi stacks: 3-10 interconnected membranous sacs. Each stack has a narrow lumen and expanded ends. Each one has: i) Cis-face: forming face (immature), convex and faces the RER ii) Trans-face: mature face. concave and faces the secretory vesicles Cytochemically, Golgi stacks present different enzymes at different cis-trans levels 7  EM of Golgi apparatus b) Transport (transfer) vesicles: - bud from RER and - carry newly synthesized proteins from RER to the cis face of the Golgi c) Secretory vesicles: - bud from trans face of Golgi and - carries secretory protein to the cell membrane for exocytosis Junqueira basic histology textbook Junqueira basic histology textbook and atlas 2016, fig 2-13 and atlas 2016, fig 2-13 FBMS-I 8  Function of Golgi apparatus Post translation modifications and sorting then packages and addresses proteins synthesized in RER http://www.phschool.com/science/biology_place/biocoach/cells/endoreview2.html Junqueira basic histology textbook and atlas fig 2.21 9  Function of Golgi apparatus 1- Post-translation modification of proteins synthesized in RER 2- Sorting out: into either secretory vesicles or primary lysosomes. It adds mannose-6-phosphate to hydrolytic enzymes of lysosomes 3- Recycling of the plasma membrane 10 Junqueira basic histology textbook and atlas fig 2.21  I cell disease…..Golgi apparatus I cell disease (Inclusion cell disease) results from deficiency in the enzyme needed to tag the lysosomal enzymes with mannose 6 phosphate leads to Defective sorting lysosomal enzymes will be secreted out of the cell instead of staying in lysosomes https://i.dailymail.co.uk/i/pix/2017/08/23/10/437BD62C00 000578-0-image-m-2_1503479586505.jpg Does the cell have a digestive system? How can the cell get rid of unwanted substances? 12  Lysosomes a membranous organelle. https://www.yout Lysosomes are membrane-bound vesicles about 0.5 µm in diameter. ube.com/watch?v =cA- Ou_t2sag&feature =youtu.be They contain acidic hydrolytic enzymes act at ph 5. So, lysosomes can breakdown most macromolecules. Number: numerous in phagocytic cells ex. Macrophages, neutrophils. 13 https://peer.tamu.edu//histology/5.%20Lysosomes,%20Smooth%20 Endoplasmic%20Reticulum,%20Mitochondria,.pdf  Lysosomes LM: do not appear in H&E sections But stained by histochemical methods as for acid phosphatases https://www.lsbio.com/antibodies/lamp2-antibody-cd107b-antibody-if-immunofluorescenc wb-western-ihc-plus-ls-b10425/295090 EM: membrane bound moderately electron dense vesicles 14 https://www.pinterest.com/pin/614530311631138983/ Foundation Basic Medical Science-I  Synthesis of Lysosomes Proteins of the hydrolytic lysosomal enzymes are synthesized in RER then pass through transfer vesicles to Cis face of Golgi complex where it is marked by mannose 6 phosphate and sorted to lysosomes. 15 http://203.250.122.194/lecture/histology/htmht1/his02.htm  Function of Lysosomes Fusion of lysosomes with phagosomes http://faculty.ccbcmd.edu/~gkaiser/biotuto formation of heterolysosome rials/eustruct/phagocyt.html EM of heterolysosome : appears as membrane https://jamanetwork.com/journals/j amadermatology/article- bound vesicles with variable electron densities. abstract/531476 https://www.pinterest.com/pin/614530311631138983/ Special membrane lipid, protein, sugar line the membrane 16 https://www.youtube.com/watch?v=cA-Ou_t2sag&feature=youtu.be 17  Function of Lysosomes Autophagic vacuole (autophagosome): If primary lysosome fuses with a membrane bound unwanted cytoplasmic component as an old organelle ex. Mitochondria https://www.stolaf.edu/people/giannini/cell/lys.htm https://www.histology.leeds.ac.uk/cell/cell_organelles.php Here an E.M. image has been taken of a lysosome in the process of breaking down a mitochontria. (image and description provided by John Ross's website 18 http://203.250.122.194/lecture/histology/htmht1/his02.htm  Results of lysosomal fusion Nutrients diffuse through the Residual bodies: lysosomal limiting membrane are formed after digestion of the and enter the cytosol. contents of the heterolysosome. Fate of residual body is either: or b- accumulate in the cytoplasm a- extruded from the cell by exocytosis as lipofuscin pigment 19 http://203.250.122.194/lecture/histology/htmht1/his02.htm  Lipofucsin pigment The lipofuscin pigment that increase with age and so it is present in some long lived cells as nerve cells and heart muscle where large quantities of residual bodies accumulate and form lipofuscin pigment. Functions of lysosomes: 1-Destroying foreign bodies as bacteria https://www.dartmouth.edu/~anatomy/Histo/lab_1/cell/DM S093/popup.html 2-Turn over of cellular components 20  Lysosomes Histology A text and Atlas: Michael H. Ross and Wojciech Pawlina Fig 2.23 Clinical application: Lysosomal storage diseases (defect in 1 or more of the digestive enzymes of lysosomes) 21  Quiz 1 1. Describe the EM structure of Golgi complex Transfer vesicles of the Golgi apparatus A- bud from the cis face B- carry protein to the trans face C- bud from the trans face D- carry protein from RER 22  Quiz 2 A 23-year-old woman complains of recurrent bone pain and increasing abdominal girth. Physical examination reveals enlargement of the patient’s liver and spleen (hepatosplenomegaly). A spleen biopsy reveals large macrophage. The patient carries mutations in the genes for glycosidase. Without this hydrolytic enzyme, glucocerebroside accumulates within which of the following cellular organelles? (A)Autophagic vacuoles (B)Endoplasmic reticulum (C) Lysosomes (D) Mitochondria (E) Peroxisomes 23  Quiz 3 What organelle provides a microenvironment for the posttranslational modification and sorting of membrane and secretory proteins? (A) Golgi apparatus (B) Lysosome (C) Peroxisome (D) Plasma membrane (E) Smooth endoplasmic reticulum New Five Year Program 24  Quiz 4 Specialization of the membrane surrounding the lysosomes include---------------------------------------------- Parts of the Golgi apparatus include ……………..,………………,………... Fusion of lysosome with phagosome results in ………………….. Fusion of lysosome with old organelle is called -------------------- 25  SUGGESTED TEXTBOOKS 1. Junqueira`s Basic Histology; Text and Atlas. 14th edition 2016. 2. Histology A Text and Atlas: Michael H. Ross and Wojciech Pawlina, 7th edition, 2016. 26