* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PowerPoint to accompany Hole’s Human Anatomy and
Survey
Document related concepts
Tissue engineering wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Biochemical switches in the cell cycle wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell encapsulation wikipedia , lookup
Signal transduction wikipedia , lookup
Cell culture wikipedia , lookup
Cell nucleus wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell growth wikipedia , lookup
Cell membrane wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Endomembrane system wikipedia , lookup
Transcript
Chapter 3 Lecture PowerPoint Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3.1: Introduction • The basic organizational structure of the human body is the cell. • There are 50-100 trillion cells in the human body. • Differentiation is when cells specialize. • As a result of differentiation, cells vary in size and shape due to their unique function. 2 3.2: A Composite Cell Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Also called a ‘typical’ cell • Major parts include: • Nucleus • contains DNA Phospholipid bilayer Flagellum Nucleus Chromatin Nuclear envelope Nucleolus Rough Endoplasmic reticulum Centrioles Mitochondrion Smooth Endoplasmic reticulum • Cytoplasm • cellular contents between plasma membrane & nucleus • Cell membrane • selective barrier Ribosomes Cell membrane Basal body Microtubules Microvilli Secretory vesicles Cilia Golgi apparatus Microtubule Microtubules Lysosomes 3 Cell Membrane (aka Plasma Membrane) • Outer limit of the cell • Controls what moves in and out of the cell • Selectively permeable • Phospholipid bilayer • Water-soluble “heads” form surfaces (hydrophilic) • Water-insoluble “tails” form interior (hydrophobic) • Permeable to lipid-soluble substances • Cholesterol stabilizes the membrane • Proteins: • Receptors • Pores, channels and carriers • Enzymes • CAMS • Self-markers 4 Cell Membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extracellular side of membrane Fibrous protein Glycolipid Carbohydrate Glycoprotein “Heads” of phospholipid Double layer of Phospholipid molecules “Tails” of phospholipid Cell membrane (a) Cell membrane (b) a: © Biophoto Associates/Photo Researchers, Inc. Cholesterol Globular molecules protein Cytoplasmic side of membrane Hydrophobic fatty acid “tail” Hydrophilic Phosphate “head” 5 Cell Membrane Electrochemical Gradient • due to selective permeability • difference in concentration of chemicals across membrane • difference in distribution of charges across the membrane • difference is the membrane potential Cell Adhesion Molecules (CAMs) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Guide cells on the move • Selectin – allows white blood cells to “anchor” • Integrin – guides white blood cells through capillary walls • Important for growth of embryonic tissue • Important for growth of nerve cells White blood cell Attachment (rolling) Selectin Carbohydrates on capillary wall Adhesion receptor proteins Adhesion Integrin Blood vessel lining cell Exit Splinter 7 Cytoplasm • Cytosol = water • Organelles = solids Cytoplasm is really like a Jello fruit salad where the Jello is the cytosol and the fruits (oranges, grapes, bananas, maybe walnuts, etc.) are the organelles. 8 Organelles Endoplasmic Reticulum (ER) • Connected, membrane-bound sacs, canals, and vesicles • Transport system • Rough ER Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Membranes Membranes • Studded with ribosomes • Smooth ER • Lipid synthesis • Added to proteins arriving from rough ER • Break down of drugs Ribosomes (b) (c) Ribosomes • Free floating or connected to ER • Provide structural support and enzyme activity to amino acids to form protein (protein synthesis) 9 Organelles Golgi apparatus • Stack of flattened, membranous sacs • Modifies, packages and delivers proteins Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Vesicles • Membranous sacs • Store substances Mitochondria • Membranous sacs with inner partitions • Generate energy Inner membrane Cristae Outer membrane (a) (b) a: © Bill Longcore/Photo Researchers, Inc. 10 Organelles Lysosomes • Enzyme-containing sacs • Digest worn out cell parts or unwanted substances Centrosome • Two rod-like centrioles • Used to produce cilia and flagella • Distributes chromosomes during cell division Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Peroxisomes • Enzyme-containing sacs • Break down organic molecules Centriole (cross-section) Centriole (longitudinal section) (a) (b) a: © Don W. Fawcett/Visuals Unlimited 11 Organelles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cilia • Short hair-like projections • Propel substances on cell surface Flagellum • Long tail-like projection • Provides motility to sperm (a) a: © Oliver Meckes/Photo Researchers, Inc. 12 © Colin Anderson/Brand X/CORBIS Organelles Microfilaments and microtubules • Thin rods and tubules • Support cytoplasm • Allows for movement of organelles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Microtubules Inclusions • Temporary nutrients and pigments Microfilaments © M. Schliwa/Visuals Unlimited 13 Cell Nucleus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Is the control center of the cell • Nuclear envelope • Porous double membrane • Separates nucleoplasm from cytoplasm • Nucleolus • Dense collection of RNA and proteins • Site of ribosome production Nucleus Nuclear envelope Nucleolus • Chromatin • Fibers of DNA and proteins • Stores information for synthesis of proteins Chromatin Nuclear pores (a) 14 3.3: Movements Into and Out of the Cell Passive (Physical) Processes • Require no cellular energy and include: • Simple diffusion • Facilitated diffusion • Osmosis • Filtration Active (Physiological) Processes • Require cellular energy and include: • Active transport • Endocytosis • Exocytosis • Transcytosis 15 Simple Diffusion • Movement of substances from regions of higher concentration to regions of lower concentration • Oxygen, carbon dioxide and lipid-soluble substances Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Permeable membrane A B (1) Solute molecule Water molecule A B (2) Time A B (3) 16 Animation: How Diffusion Works Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 17 Facilitated Diffusion • Diffusion across a membrane with the help of a channel or carrier molecule • Glucose and amino acids Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Region of higher concentration Transported substance Region of lower concentration Protein carrier molecule Cell membrane 18 Animation: How Facilitated Diffusion Works Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 19 Osmosis • Movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration • Water moves toward a higher concentration of solutes Selectively Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protein molecule Water molecule permeable membrane A A B B (1) (2) Time 20 Animation: How Osmosis Works Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 21 Osmosis and Osmotic Pressure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Osmotic Pressure – ability of osmosis to generate enough pressure to move a volume of water • Osmotic pressure increases as the concentration of nonpermeable solutes increases • Isotonic – same osmotic pressure • Hypertonic – higher osmotic pressure (water loss) • Hypotonic – lower osmotic pressure (water gain) (a) (b) (c) © David M. Phillips/Visuals Unlimited 22 Filtration • Smaller molecules are forced through porous membranes • Hydrostatic pressure important in the body • Molecules leaving blood capillaries Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary wall Blood pressure Tissue fluid Blood flow Larger molecules Smaller molecules 23 Active Transport • Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentration • Sugars, amino acids, sodium ions, potassium ions, etc. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Carrier protein Binding site Cell membrane Region of higher concentration Region of lower concentration Phospholipid molecules Transported particle (a) Carrier protein with altered shape Cellular energy (b) 24 Active Transport: Sodium-Potassium Pump • Active transport mechanism • Creates balance by “pumping” three (3) sodium (Na+) OUT and two (2) potassium (K+) INTO the cell • 3:2 ratio 25 Animation: How the Sodium-Potassium Pump Works Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 26 Secondary Active Transport • uses the energy stored in a concentration gradient – the gradient is established through active transport • symporters move substances in the same direction while antiporters move substances in opposite directions Endocytosis • Cell engulfs a substance by forming a vesicle around the substance • Three types: • Pinocytosis – substance is mostly water • Phagocytosis – substance is a solid • Receptor-mediated endocytosis – requires the substance to bind to a membrane-bound receptor Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell Particle membrane Nucleus Nucleolus Phagocytized particle Vesicle 28 Endocytosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell Particle membrane Phagocytized particle Vesicle Nucleus Nucleolus Receptor-ligand combination Molecules outside cell Vesicle Receptor protein Cell membrane Cell membrane indenting Cytoplasm (a) (b) (c) 29 (d) Exocytosis • Reverse of endocytosis • Substances in a vesicle fuse with cell membrane • Contents released outside the cell • Release of neurotransmitters from nerve cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endoplasmic reticulum Golgi apparatus Nucleus 30 Transcytosis • Endocytosis followed by exocytosis • Transports a substance rapidly through a cell • HIV crossing a cell layer Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. HIV-infected white blood cells Anal or vaginal canal Viruses bud HIV Receptor-mediated endocytosis Lining of anus or vagina (epithelial cells) Cell membrane Exocytosis Receptor-mediated endocytosis Virus infects white blood cells on other side of lining 31 3.4: The Cell Cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Series of changes a cell undergoes from the time it forms until the time it divide • Stages: • Interphase • Mitosis • Cytokinesis G2 phase S phase: genetic material replicates G1 phase cell growth Proceed to division Remain specialized Apoptosis Cytokinesis Restriction checkpoint 32 Interphase • Very active period • Cell grows • Cell maintains routine functions • Cell replicates genetic material to prepare for nuclear division • Cell synthesizes new organelles to prepare for cytoplasmic division • Phases: • G phases – cell grows and synthesizes structures other than DNA • S phase – cell replicates DNA 33 Mitosis • Produces two daughter cells from an original somatic cell • Nucleus divides – karyokinesis • Cytoplasm divides – cytokinesis • Phases of nuclear division: • Prophase – chromosomes form; nuclear envelope disappears • Metaphase – chromosomes align midway between centrioles • Anaphase – chromosomes separate and move to centrioles • Telophase – chromatin forms; nuclear envelope forms 34 Mitosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Late Interphase Cell has passed the restriction checkpoint and completed DNA replication, as well as replication of centrioles and mitochondria, and synthesis of extra membrane. (a) Early Interphase of daughter cells— a time of normal cell growth and function. Restriction checkpoint Nuclear envelope Chromatin fibers Centrioles Cleavage furrow Prophase Chromosomes condense and become visible. Nuclear envelope and nucleolus disperse. Spindle apparatus forms. Aster Microtubules (e) (b) Centromere Late prophase Spindle fiber Sister chromatids Chromosomes Nuclear envelopes Telophase and Cytokinesis Nuclear envelopes begin to reassemble around two daughter nuclei. Chromosomes decondense. Spindle disappears. Division of the cytoplasm into two cells. (d) (c) Mitosis Cytokinesis G1 phase Anaphase Sister chromatids separate to opposite poles of cell. Events begin which lead to cytokinesis. Metaphase Chromosomes align along equator, or metaphase plate of cell. © Ed Reschke S phase G2 phase Interphase 35 Animation: Mitosis and Cytokinesis Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 36 Cytoplasmic Division • Also known as cytokinesis • Begins during anaphase • Continues through telophase • Contractile ring pinches cytoplasm in half 37 Animation: Control of the Cell Cycle Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 38 3.5: Control of Cell Division • Cell division capacities vary greatly among cell types • Skin and blood cells divide often and continually • Neuron cells divide a specific number of times then cease • Chromosome tips (telomeres) that shorten with each mitosis provide a mitotic clock • Cells divide to provide a more favorable surface area to volume relationship • Growth factors and hormones stimulate cell division • Hormones stimulate mitosis of smooth muscle cells in uterus • Epidermal growth factor stimulates growth of new skin • Contact (density dependent) inhibition • Tumors are the consequence of a loss of cell cycle control 39 Tumors • Two types of tumors: • Benign – usually remains Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. localized • Malignant – invasive and Normal cells (with hairlike cilia) can metastasize; cancerous • Two major types of genes cause cancer: • Oncogenes – activate other genes that increase cell division Cancer cells • Tumor suppressor genes – normally regulate mitosis; if inactivated they are unable to regulate mitosis • Cells are now known as “immortal” © Tony Brain/Photo Researchers, Inc.; 40 Animation: How Tumor Suppressor Genes Block Cell Division Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 41 3.6: Stem and Progenitor Cells • Stem cell: • Can divide to form two new stem cells • Self-renewal • Can divide to form a stem cell and a progenitor cell • Totipotent – can give rise to every cell type • Pluripotent – can give rise to a restricted number of cell types • Progenitor cell: • Committed cell • Can divide to become any of a restricted number of cells • Pluripotent 42 Stem and Progenitor Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sperm Sebaceous gland cell Egg Progenitor cell Progenitor cell Fertilized egg Skin cell Stem cell Progenitor cell Progenitor cell Stem cell Neuron Progenitor cell Progenitor cell Astrocyte Progenitor cell Progenitor cell Progenitor cell Bone cells Progenitor cell one or more steps Fibroblasts (a connective tissue cells) Blood cells and platelets produces another stem cell (self-renewal) 43 3.7: Cell Death Apoptosis: • Programmed cell death • Acts as a protective mechanism • Is a continuous process 44