mbbs ims msu

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Cells and tissue

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mbbs ims msu

  1. 1. Cells and Tissues
  2. 2.  Cells and Tissues  Carry out all chemical activities needed to sustain life.  Cells are the building blocks of all living things  Tissues are groups of cells that are similar in structure and function  Structure reflects function
  3. 3.  Anatomy of the Generalized Cell  Cells are not all the same  All cells share general structures  Cells are organized into three main regions  Nucleus  Cytoplasm  Plasma membrane
  4. 4. Barrier for cell contents Double phospholipid layer (fat – water) Hydrophilic heads Hydrophobic tails Other materials in plasma membrane Protein Cholesterol Glycoproteins
  5. 5. Microvilli Finger-like projections that increase surface area for absorption Small intestine and nephrons of kidney
  6. 6.  Control center of the cell ◦ Contains genetic material (DNA)  Three regions ◦ Nuclear membrane ◦ Nucleolus ◦ Chromatin
  7. 7. Barrier of nucleus Consists of a double phospholipid membrane Contain nuclear pores that allow for exchange of material with the rest of the cell – selectively permeable
  8. 8. Nucleoli Nucleus contains one or more nucleoli Sites of ribosome production Ribosomes then migrate to the cytoplasm through nuclear pores Chromatin (when not dividing)  Composed of DNA and protein  Scattered throughout the nucleus  Chromatin condenses to form chromosomes when the cell divides
  9. 9.  Material outside the nucleus and inside the plasma membrane  Cytosol  Fluid that suspends other elements  Organelles  Metabolic machinery of the cell  Inclusions  Non-functioning units – fat, pigments…..
  10. 10.  Ribosomes  Made of protein and RNA  Sites of protein synthesis  Found at two locations ◦ Free in the cytoplasm ◦ Attached to rough endoplasmic reticulum
  11. 11.  Endoplasmic reticulum (ER)  Fluid-filled tubules for carrying substances  Two types of ER ◦ Rough Endoplasmic Reticulum ◦ Studded with ribosomes  Site where building materials of cellular membrane are formed ◦ Smooth Endoplasmic Reticulum ◦ Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of drugs
  12. 12.  Golgi apparatus  Modifies and packages proteins
  13. 13.  Lysosomes  Contain enzymes that digest nonusable materials within the cell  Peroxisomes  Membranous sacs of oxidase enzymes ◦ Detoxify harmful substances ◦ Break down free radicals (highly reactive chemicals)  Replicate
  14. 14.  Mitochondria ◦ “Powerhouses” of the cell ◦ Change shape continuously ◦ Carry out reactions where oxygen is used to break down food ◦ Provides ATP for cellular energy
  15. 15.  Cytoskeleton ◦ Network of protein structures that extend throughout the cytoplasm ◦ Provides the cell with an internal framework
  16. 16.  Cytoskeleton  Three different types  Microfilaments  Intermediate filaments  Microtubules
  17. 17.  Centrioles  Rod-shaped bodies made of microtubules  Direct formation of mitotic spindle during cell division  Cellular Projections  Not found in all cells  Used for movement ◦ Cilia moves materials across the cell surface ◦ Flagellum propels the cell

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