Transcript Cells 2014
Essentials of Human Anatomy & Physiology Seventh Edition Elaine N. Marieb Cells Modified by S. Mendoza 8/2013 Lecture Slides in PowerPoint by Jerry L. Cook Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings OBJECTIVES Objectives checklist can be found on page 55 – 56 of your textbook. To be successful on Chapter 3 Test, these need to be mastered. Cell Anatomy Cell Theory: - All organisms are composed of cells. - All cells come from pre-existing cells. - Cells are the smallest unit of life 1st Discovery of a Cell In 1661, King Charles II of England commisioned Sir Christopher Wren to create a series of microscopical studies – later found he didn’t have the time and passed this project onto someone else. . . . . Which made history. In late 1600’s Robert Hooke, at age 26, was the first person to find, name, and describe cells. Hooke was self educated prodegy and found cells by using primitive microscope to look at a cork. King Charles only wanted him to perform insect studies; however, Hooke looked at everything!! Including fabric, leaves, glass, flint, and even frozen urine. 3 Main Cell Structures 1. Plasma Membrane (Cell Membrane) 2. Cytoplasm (with embedded organelles) 3. Nucleus – Control center – Genetic info Cell Structure/Organelles • Endoplasmic Reticulum (SER & RER) • Golgi Apparatus • Lysosomes & Peroxisomes • Mitochondria • Ribosome • Cytoskeleton (Microfilaments) • Centrioles • Plasma Membrane • Nucleus Cytology - The study of the structure and function of cells - Human body contains both somatic and sex cells. - Somatic cells: All body cells of an organism - Sex cells: Gametes (Sperm and Egg) The Diversity of Cells in the Human Body Figure 3.1 Cell Diversity Figure 3.7; 1, 2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.19a Cell Diversity Figure 3.7; 3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.19b Cell Diversity Figure 3.7; 4, 5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.19c Cell Diversity Figure 3.7; 6, 7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.19d Introduction to 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 Disorders can happen due to a problem with a cell organelle and its function Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.1 Anatomy of the Cell Cells are not all the same All cells share general structures Cells are organized into three main regions Nucleus Cytoplasm Plasma membrane Figure 3.1a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.2 Control center of the cell – if lose this cell goes into apoptosis 1. The Nucleus Contains genetic material (DNA) Three regions Nuclear membrane Nucleolus Chromatin Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.1b Slide 3.3 Nuclear Membrane Barrier of nucleus Consists of a double phospholipid membrane (double membrane barrier) Contain nuclear pores that allow for exchange of material with the rest of the cell – this is selectively permeable Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.4 Nucleoli Nucleus contains one or more nucleoli Sites of ribosome production Ribosomes then migrate to the cytoplasm through nuclear pores to make proteins Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.5 Chromatin When cell is not dividing, DNA is combined with protein to form bumpy threads called chromatin. Scattered throughout the nucleus Chromatin condenses to form chromosomes when the cell divides Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.6 Plasma Membrane Maintains the boundaries of the cell Barrier for cell contents Phospholipid bilayer interspersed with proteins Impermeable to water soluble substances Permeable to lipid soluble substances Be able to label all the structures shown on the cell membrane diagram in your notes (even if it is NOT the same exact diagram) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.7a Plasma Membrane Hydrophilic/polar (loves/attracted to water) vs. Hydrophobic/nonpolar (hates/repelled by water) Polar head and non polar tails make phospholipids self orienting in body fluids Very important for membrane construction and repair to happen correctly Plasma Membrane Cholesterol (see diagram in notes) Stabilizes bilayer by immobilizing phospholipids Peripheral Proteins Enzymes that act as catalysts for reactions Peripheral proteins Stuck on membrane surface or on other proteins and act as binding sites for hormones or chemical messengers (these act as enzymes mentioned earlier) Can also have mechanical functions Changing cell shape Example:Muscle contraction Integral Proteins Proteins that extend through the width of the membrane (transmembrane) Known as INTEGRAL proteins have transport functions Can cluster to form pores/channels through which water, small water soluble molecules & ions can pass Act as carriers that bind to a molecule & help it move through Glycoproteins Glycoproteins (sugar-proteins) Branching sugar groups attached to a protein (Cellular ID cards) Examples of functions: Determine blood type Act in cell recognition Unwilling receptors for toxins, viruses, & bacteria Memorize: Plasma/Cell Membrane Membrane Specializations Plasma Membrane Specializations Microvilli Define:Finger-like extensions Function:increase surface area for nutrient absorption/waste exchange Location:Found on surface of absorptive cells such as small intestine & kidney tubules Figure 3.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.8a Microvilli Plasma Membrane Specializations Tight Junctions (zonula occludens) Form impermeable junctions to prevent passage of molecules Imp: prevent free passage of molecules - digestive enzymes & bacteria kept away from cells Example location: lining of digestive tract Figure 3.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.8b Plasma Membrane Specializations Desmosomes Function:Form mechanical junction or adhesion layers Imp: prevent separation of tissues due to mechanical stress Examples: skin, heart muscle, neck of uterus Figure 3.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.8b Plasma Membrane Specializations Gap junctions Provide for direct passage of chemical substances between adjacent cells Figure 3.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.8b Plasma Membrane Specializations Gap junctions Cells are connected by Connexons: hollow cylinders (transmembrane) / integral Important Allowing direct passage of molecules,etc. Figure 3.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.8b Plasma Membrane Specializations Gap junctions Importance: allowing smooth synchronization due to ion passage Found in electrically excitable tissues (heart, smooth muscle, embryonic) Figure 3.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.8b 3. Cytoplasm Material outside the nucleus and inside the plasma membrane & site of most cellular activities Cytosol Fluid that suspends other elements Organelles Metabolic machinery of the cell Inclusions Non-functioning units = chemical substances that vary from cell to cell Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.9 Cytoplasmic Organelles Figure 3.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.10 CYTOPLASMIC ORGANELLES Label the cytoplasmic organelles and know their functions. EXOCYTOSIS Bulk transport of substances OUT of the cell Examples: Producing proteins to secrete to surroundings: Digestive enzymes in stomach, saliva, insulin, sweat Excreting waste from cell to blood Golgi apparatus aids in secretion & storage then exocytosis excretes them from cell to where ever they are needed Active Transport - exocytosis Figure 3.11 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.29b ENDOCYTOSIS Bulk transport of material INTO cell Material is engulfed to form a vacuole – it does not ever go through the membrane Vacuole can then join with a lysosome so it can digest the food Active Transport -endocytosis Figure 3.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.30b Tonicity Tonicity compares the concentrations of the water molecules on the inside and outside of the cell (osmosis is movement of H2O) The terms can also be used to describe the concentrations of what is dissolved in the water (but we will describe everything in terms of the water conc.) IMPORTANT INFO: Just remember: All Substances ALWAYS move from high to low concentration in passive processes (No ATP) Complete your tonicity foldable using the info on the next 7 slides along with the diagram provided for you Then use it to study ISOTONIC Concentration of water molecules is EQUAL on both sides of membrane Pressure on membrane is equal from both sides so no net water motion (no change in cell shape or structure) HYPERTONIC ( have a higher solute and lower water concentration than the cells do) in other words, water concentration will be more concentrated inside of the cell than outside the cell SO: Pressure on the inside of the membrane causes water to move OUT of the cell Problem: the cell will CRENATE aka. shrivel up Crenation Crenate: blood cells are shriveling because water is leaving They are dehydrating HYPOTONIC ( have a lower solute and higher water concentration than the cells do) in other words, water concentration will be less concentrated inside of the cell than outside the cell SO: Pressure on the outside of the membrane causes water to move INTO the cell Problem: the cell will LYSE aka. rupture Hypotonic Notice RBC is very plump No dent in center osmosis#Osmosis#Osmosis#Osmosis Tonicities READ page 69 & study it. You need to understand tonicity and the results of the different solutions on our cells.