ELAINE N. MARIEB EIGHTH EDITION 3 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY PART B Cells and Tissues

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Selective Permeability  The plasma membrane allows some materials to pass while excluding others  This permeability includes movement into and out of the cell

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cellular Physiology: Membrane Transport  Membrane Transport – movement of substances into and out of the cell  Transport is by two basic methods  Passive transport  No energy is required  Active transport  The cell must provide metabolic energy

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Movement Through Cell Membrane  Passive Mechanisms of transport require no cellular energy  Ex:  Simple Diffusion  Facilitated Diffusion  Osmosis  Filtration

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Diffusion  Molecules move from high concentration to low concentration, or down a concentration gradient  Equilibrium- Molecules tend to distribute themselves evenly within a solution DIFFUSION ANIMATION Figure 3.9 PRESS TO PLAY

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diffusion through the Plasma Membrane Figure 3.10

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Facilitated diffusion  Substances require a protein carrier (or Carrier Molecule) for passive transport  The rate of facilitated diffusion is limited to the number of carrier molecules in the membrane and/or the number of molecules available for transport.  Insulin promotes facilitated diffusion of glucose

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Facilitated Diffusion diffusion across a membrane with the help of a channel or carrier molecule glucose and amino acids

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Osmosis –  simple diffusion of water from area of higher concentration to lower concentration  Osmotic Pressure- the amount of pressure (on surface of liquid) needed to stop osmosis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osmosis movement of water through a selectively permeable membrane from region of higher concentration to region of lower concentration water moves toward a higher concentration of solutes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osmosis 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 hypertonic – higher osmotic pressure hypotonic – lower osmotic pressure isotonic – same osmotic pressure

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport  These are red blood cells in three different solutions:

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport  Hypertonic Solution  Has more solute particles (thus less H 2 O) than a cell in that solution  Result: Plasmolysis- cell shrinks

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport  Hypotonic Solution  Has less solute particles (thus more H 2 O) than a cell in that solution  Result: Cytolysis- cell bursts

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport  Isotonic Solution  Has the same concentration of solute particles as a cell in that solution  Result: Cell remains unchanged

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport  Can you identify the solution each cell is in and explain what happens to each cell?

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Filtration  Water and solutes are forced through a membrane by fluid, or hydrostatic pressure  Ex: Blood pressure forces small molecules & water out through capillary walls creating tissue fluid while larger protein molecules remain inside capillary.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Filtration smaller molecules are forced through porous membranes hydrostatic pressure important in the body molecules leaving blood capillaries

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Transport substances that are unable to pass by diffusion  They may be too large  They may not be soluble in the fat core of the membrane  They may have to move against a concentration gradient  Two common forms of active transport  Solute pumping – Active Transport  Bulk transport – Endocytosis, Exocytosis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Active Mechanisms require cellular energy (ATP)  Active Transport-  Particles move from an area of lower concentration to higher concentration  Up to 40% of cell’s energy supply is used for active transport

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Solute pumping  Amino acids, some sugars and ions are transported by solute pumps  ATP energizes protein carriers, and in most cases, moves substances against concentration gradients ACTIVE TRANSPORT ANIMATION PRESS TO PLAY

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes Figure 3.11

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Bulk transport  Endocytosis  A portion of the cell membrane forms vesicle to carry in particles too large for diffusion or pumping

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Endocytosis Figure 3.13a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Types of endocytosis  Pinocytosis – cell drinking:  Portion of cell membrane becomes indented and surrounds tiny droplets of liquid. Membrane pinches off and carries liquid into cytoplasm where it releases contents  Phagocytosis – cell eating:  Solids are engulfed by indented portion of cell membrane which then pinches off and acts as vesicle to carry & empty solids into cytoplasm

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Bulk transport  Exocytosis  Moves materials out of the cell  Material is carried in a membranous vesicle  Vesicle migrates to plasma membrane  Vesicle combines with plasma membrane  Material is released to the outside

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Exocytosis Figure 3.12a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cell Life Cycle  Cells have two major periods  Interphase  Cell grows  Cell carries on metabolic processes  Cell division  Cell replicates itself  Function is to produce more cells for growth and repair processes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings DNA Replication  Genetic material duplicated and readies a cell for division into two cells  Occurs toward the end of interphase  DNA uncoils and each side serves as a template Figure 3.14

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Events of Cell Division  Mitosis  Division of the nucleus  Results in the formation of two daughter nuclei  Cytokinesis  Division of the cytoplasm  Begins when mitosis is near completion  Results in the formation of two daughter cells

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cell Life Cycle  Interphase  Cell growth  The cell carries out normal metabolic activity (life processes)  Not cell division

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Prophase  Nuclear membrane breaks down  Spindle fibers form  Centrioles move to opposite poles

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Metaphase  Chromosomes line up in middle of cell

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Anaphase  Chromosomes pull apart  Chromosomes move across cell toward opposite poles

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Telophase  Chromosomes arrive at poles  Nuclear membrane reforms  Spindle fibers break down  Cytokinesis- cell divides into 2 new cells

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis Figure 3.15

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis Figure 3.15(cont)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mitosis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stem and Progenitor Cells  Differentiation:  Cellular specialization  DNA turned on/off