Cells and Tissue

1. Cells and Tissue

2. Cells Made up of 4 elements C,O,H,N smaller elements Ca2+, Fe 60% water, essential for life Bathed in dilute saltwater solution = interstitial fluid Exchanges between blood and cells through interstitial fluid http://www.guardian.co.uk/science/2009/jan/08/stem-cells-bone-marrow-heart-attack

3. Cells Range in length - 2μm-1+m Structure reflects function Disc Threadlike extensions Toothpick shaped Function varies Phagocytosis Synthesize hormones Cleanse blood http://www.wereyouwondering.com/what-is-the-smallest-cell-in-the-human-body/ http://www.ngfn.de/englisch/glossar443.htm

4. Anatomy of Generalized Cell No 2 cell types the same, some functions common to all Nucleus, Cytoplasm, Plasma membrane Figure 3.4

5. Anatomy of Generalized CellNucleus Control center Gene-containing Genetic material DNA Instructions for building proteins Necessary for cell reproduction Usually round or oval, but conforms to shape of cell Nuclear Envelope Nucleoli Chromatin

6. NucleusNuclear Envelope Nucleus bound by double membrane Space between layers filled with fluid Nuclear pores – points where two layers fuse Selectively permeable, but large pores Encloses nucleoplasm – suspends nuclear elements

7. NucleusNucleoli Small, round body Site for ribosome assembly Ribosomes migrate to cytoplasm, site of protein synthesis

8. NucleusChromatin When cell not dividing, DNA associated with proteins Loose coiling of DNA and proteins called chromatin When cell is dividing, DNA and proteins condense to form chromosomes

9. Plasma Membrane Separates cell from surroundings Lipid bilayer (tail to tail) – protein molecules float Phospholipids Cholesterol – keeps membrane fluid Figure 3.2

10. Plasma MembranePhospholipid bilayer Semi-permeable Heads of phospholipids hydrophilic – attracted to water in extra and intercellular fluid Tails are hydrophobic – avoid water and line up in center Structure keeps polar molecules from passing through membrane

11. Plasma MembraneProteins in membrane Specialized function of membrane Receptors Enzymes Anchors Transport Channels Glycoproteins – sugars attached to proteins Surface of cell sticky, fuzzy = glycocalyx Determine blood type, receptors bacteria, viruses, toxins bind to Cell to cell interaction See changes here when cell becomes cancerous

12. Plasma MembraneSpecializations Microvilli – fingerlike projections that increase SA (intestines) for absorption, speed Membrane junctions Tight junctions – impermeable junctions, bind cells together, small intestine digestive enzymes into blood Gap Junctions – Communication, chemical signals or nutrients pass directly. Neighbors connected through connexons – hollow proteins –heart and embryonic cells Desmosomes – Anchoring, prevents cells prone to stress from separating - skin Buttons of PM with fine protein filaments. Thick filaments from plaques on one to side to other Figure 3.3

13. Cytoplasm Outside nucleus, inside PM Factory area 3 major elements Cytosol Organelles Inclusions

14. CytoplasmCytosol Semitransparent fluid suspends other things Mostly water Nutrients Other solutes

15. CytoplasmOrganelles and Inclusions Organelles Metabolic machinery Specialized functions Inclusions Chemical substances that vary depending on cell type Most stored nutrients or cell products Lipids-fat cells Glycogen – liver & muscle cells Pigments (melanin) – skin & hair

16. OrganellesMitochondria Double membrane = two PM, side by side OM smooth IM has cristae Enzymes dissolved in fluid w/in mitochondria and in cristae catalyze rxns Oxygen used to break down food Energy converted to ATP and heat Powerhouse of cell Liver and muscle have tons of mitochondria, unfertilized egg has only a few – WHY? http://academic.brooklyn.cuny.edu/biology/bio4fv/page/mito.htm

17. OrganellesRibosomes Bilobed, dark bodies rRNA and proteins Site of protein synthesis Float free or attached to RER – synthesize different proteins

18. OrganellesEndoplasmic Reticulum System of fluid filled cisterns Connected to NM Network for carrying substances (mostly proteins) Two types: RER SER https://illnessesanimalsplants.wikispaces.com/Endoplasmic+Reticulum?f=print

19. OrganellesEndoplasmic Reticulum - RER Ribosomes Proteins made enter cistern, proper conformation, transport vesicle Abundant is cells that export protein products - pancreas

20. OrganellesEndoplasmic Reticulum - SER NO protein synthesis Membrane factory – building material for membranes synthsized Lipid synthesis – cholesterol and fat synthesis and breakdown Detoxification of drugs and pesticides Common in liver and glands that produce steroid-based hormones

21. OrganellesGolgi Apparatus Flattened membranous sacs Close to nucleus, traffic director to proteins Modifies and packages proteins from RER depending on function Proteins tagged for excretion build up in secretory vesicles that pinch off, to PM Mucus Digestive enzymes of pancreas Proteins and phospholipids for PM Packages digestive enzymes in lysosomes – remain in cell Figure 3.6

22. OrganellesLysosomes and Peroxisomes • Lysosomes – bags containing digestive enzymes • Demolition sites – digest unused or old organelles, invaders • Abundant in phagocytes • Peroxisomes – Oxidase enzymes, use O2 to detoxify harmful substances – alcohol • Common in kidney cells - detoxification • Disarm free radicals – highly reactive chemicals with unpaired electrons, damage proteins and nucleic acids • Byproduct of metabolism • Convert free radicals to H2O2, Catalase converts to H2O

23. OrganellesCytoskeleton Protein network in cytoplasm Shape, supports organelles, machinery for intracellular transport 3 types Microtubules Overall shape and distribution of organelles Microfilaments Cell motility and changes in shape Intermediate Filaments Rope-like, desmosomes, resist pulling forces

24. OrganellesCentrioles Paired Rod shaped close to nucleus In mitosis, direct formation of mitotic spindle Cilia – projections on some cells, move substances along cell surface – respiratory cells Flagella – Longer than cilia, motility - sperm Other Structural Elements