Cytology PDF 2024 Veterinary Medicine

‫قال تعالى‪ ((:‬وما أوتيتم من العلم اال قليال))‬ ‫قال تعالى‪ ((:‬انا كل شئ خلقناه بقدر ))‬ ‫‪1‬‬  Cytology Nesma I El-naseery, Ph.D. Professor of Histology Zagazig University, Zagazig, 2024...

‫قال تعالى‪ ((:‬وما أوتيتم من العلم اال قليال))‬ ‫قال تعالى‪ ((:‬انا كل شئ خلقناه بقدر ))‬ ‫‪1‬‬  Cytology Nesma I El-naseery, Ph.D. Professor of Histology Zagazig University, Zagazig, 2024 Veterinary Medicine Cm = 10 mm mm = 1000 µm µm = 1000 nm nm = 10 Angstrom Car Cell Factory 5  Pistons Mitochondrial ATP synthase (the engine) (a machine with organic parts) 6  II- Non- membranous organelles protein cytoskeleton cytoskeleton Synthesize Ribosomes Microtubules Microfilament  Ribosomes Microtubules Microfilament Def small particles, Tubular structure, Fibrous protein 12 nm wide and 25 nm an outer diameter of 24 long nm consisting of (a dense wall 5nm thick and hollow core 14 nm). composed of Proteins and Ribosomal globular α- and ß-tubulin Diverse protein RNA (rRNA) subunits 13 linear protofilaments Site All cells EXCEPT mature All cells All cells blood cells At LM level Too small to be seen Too small to be seen Too small to be seen Basophilic cytoplasm stain with basic dyes At EM level small electron-dense LS: electron dense granules cylindrical structure. Types 1. Free ribosomes Thin filament (Actin) 2. Attached ribosomes Intermediate filament 3. Polyribosomes Thick filament)Myosin)  Ribosomes Microtubules Microfilament Functions Synthesize protein 1- Form the cytoskeleton 1- Form the cytoskeleton for cells. for cells. 2- essential for the growth 2- Muscle contraction. of processes in developing nerve cells as well as for anterograde and retrograde axonal transport of various organelles. 3- form the mitotic spindle. 4- provide the basis for several complex. cytoplasmic components including (centrioles-basal bodies-cilia-flagella). 1-Ribosomes Def.: small particles, 12 nm wide and 25 nm long composed of: Proteins and Ribosomal RNA (rRNA) Site: All cells EXCEPT mature blood cells 11 At LM level : Too small to be seen. Basophilic cytoplasm stain with basic dyes. At EM level : small electron-dense granules, composed of (small and large subunit). large subunit is about twice size of smaller one 12 Synthesis of ribosomes: rRNAs molecules are manufactured in the nucleolus Proteins are synthesized in cytoplasm and then enter the nucleus and associate with rRNAs then released through nuclear pores into the cytosol. Types of ribosomes: 1- Free ribosomes - are free ,floating in cytoplasm, not attached to rER. - Synthesize protein for internal use which necessary for cell own existence. 13 Types of ribosomes: 2- Attached ribosomes - are attached to rER. - Synthesize protein for external use (for export). 3- Polysomes or Polyribosomes - are cluster of 5-100 ribosomes held together by strand of mRNA to form spiral structure. Functions of ribosomes: Ribosomes with the tRNA and mRNA forms the different types of proteins. 14  Microtubule Tubular structure, an outer diameter of 24 nm consisting of (a dense wall 5nm thick and hollow core 14 nm).  Microtubule structure formed of 13 linear protofilaments bundles in parallel to form a cylinder. Each protofilament is made of alternating heterodimers of globular α- and ß-tubulin subunits.  Microtubule structure Microtubules are polar structures + and - end so tubulin subunits polymerize to form microtubules. Microtubules are in a continuous state of polymerization and depolymerization (dynamic instability).  Function of Microtubule 1- Form the cytoskeleton for cells. Microtubules determine the distribution of microfilaments and intermediate filaments,so specifying their polarity 2- Intracellular transport of organelles and vesicles.. Half live of microtubule is 10 minute as it transport vesicles or enzymes which may affect on microtubule protein 3- Microtubules are essential for the growth of processes in developing nerve cells as well as for anterograde and retrograde axonal transport of various organelles. 4- During cell division microtubules form the mitotic spindle. 5- Microtubules provide the basis for several complex cytoplasmic components including (centrioles-basal bodies- cilia-flagella).