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Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College Chapter 3 Cells and Tissues © 2015 Pearson Education, Inc.

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Presentation on theme: "Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College Chapter 3 Cells and Tissues © 2015 Pearson Education, Inc."— Presentation transcript:

1 Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College Chapter 3 Cells and Tissues © 2015 Pearson Education, Inc.

2 Cells  Cells are the structural units of all living things  The human body has 50 to 100 trillion cells © 2015 Pearson Education, Inc.

3 Four Concepts of the Cell Theory 1.A cell is the basic structural and functional unit of living organisms. 2.The activity of an organism depends on the collective activities of its cells. 3.According to the principle of complementarity, the biochemical activities of cells are dictated by the relative number of their specific subcellular structures. 4.Continuity of life has a cellular basis. © 2015 Pearson Education, Inc.

4 Chemical Components of Cells  Most cells are composed of four elements: 1.Carbon 2.Hydrogen 3.Oxygen 4.Nitrogen  Cells are about 60% water © 2015 Pearson Education, Inc.

5 Anatomy of a Generalized Cell  In general, a cell has three main regions or parts: 1.Nucleus 2.Cytoplasm 3.Plasma membrane © 2015 Pearson Education, Inc.

6 Figure 3.1a Anatomy of the generalized animal cell nucleus. Nucleus Cytoplasm Plasma membrane (a)

7 The Nucleus  Control center of the cell  Contains genetic material known as deoxyribonucleic acid, or DNA  DNA is needed for building proteins  DNA is necessary for cell reproduction  Three regions: 1.Nuclear envelope (membrane) 2.Nucleolus 3.Chromatin © 2015 Pearson Education, Inc.

8 Figure 3.1b Anatomy of the generalized animal cell nucleus. Nucleus Rough ER Nuclear envelope Chromatin Nucleolus Nuclear pores (b)

9 The Nucleus  Nuclear envelope (membrane)  Consists of a double membrane that bounds the nucleus  Contains nuclear pores that allow for exchange of material with the rest of the cell  Encloses the jellylike fluid called the nucleoplasm © 2015 Pearson Education, Inc.

10 The Nucleus  Nucleoli  Nucleus contains one or more nucleoli  Sites of ribosome assembly  Ribosomes migrate into the cytoplasm through nuclear pores to serve as the site of protein synthesis © 2015 Pearson Education, Inc.

11 The Nucleus  Chromatin  Composed of DNA and protein  Present when the cell is not dividing  Scattered throughout the nucleus  Condenses to form dense, rod-like bodies called chromosomes when the cell divides © 2015 Pearson Education, Inc.

12 Plasma Membrane  Transparent barrier for cell contents  Contains cell contents  Separates cell contents from surrounding environment © 2015 Pearson Education, Inc.

13 Plasma Membrane  Fluid mosaic model is constructed of:  Phospholipids  Cholesterol  Proteins  Sugars © 2015 Pearson Education, Inc.

14 Figure 3.2 Structure of the plasma membrane. GlycoproteinGlycolipid Cholesterol Channel Cytoplasm (watery environment) Filaments of cytoskeleton Proteins Extracellular fluid (watery environment) Sugar group Polar heads of phospholipid molecules Bimolecular lipid layer containing proteins Nonpolar tails of phospholipid molecules

15 Concept Link © 2015 Pearson Education, Inc.

16 Plasma Membrane  Fluid mosaic model  Phospholipid arrangement  Hydrophilic (“water-loving”) polar “heads” are oriented on the inner and outer surfaces of the membrane  Hydrophobic (“water-hating”) nonpolar “tails” form the center (interior) of the membrane

17 © 2015 Pearson Education, Inc. Plasma Membrane  Fluid mosaic model  Phospholipid arrangement  The hydrophobic interior makes the plasma membrane impermeable to most water-soluble molecules

18 © 2015 Pearson Education, Inc. Plasma Membrane  Fluid mosaic model  Proteins  Responsible for specialized functions  Roles of proteins  Enzymes  Receptors  Transport as channels or carriers

19 © 2015 Pearson Education, Inc. Plasma Membrane  Fluid mosaic model  Sugars  Glycoproteins are branched sugars attached to proteins that abut the extracellular space  Glycocalyx is the fuzzy, sticky, sugar-rich area on the cell’s surface

20 © 2015 Pearson Education, Inc. Plasma Membrane Junctions  Membrane junctions  Cells are bound together in three ways: 1.Glycoproteins in the glycocalyx act as an adhesive or cellular glue 2.Wavy contours of the membranes of adjacent cells fit together in a tongue-and-groove fashion 3.Special membrane junctions are formed, which vary structurally depending on their roles

21 © 2015 Pearson Education, Inc. Plasma Membrane Junctions  Membrane junctions  Tight junctions  Impermeable junctions  Bind cells together into leakproof sheets  Prevent substances from passing through extracellular space between cells

22 © 2015 Pearson Education, Inc. Plasma Membrane Junctions  Membrane junctions  Desmosomes  Anchoring junctions that prevent cells from being pulled as a result of mechanical stress  Created by buttonlike thickenings of adjacent plasma membranes

23 © 2015 Pearson Education, Inc. Plasma Membrane Junctions  Membrane junctions  Gap junctions  Allow communication between cells  Hollow cylinders of proteins (connexons) span the width of the abutting membranes  Molecules can travel directly from one cell to the next through these channels

24 © 2015 Pearson Education, Inc. Figure 3.3 Cell junctions. Microvilli Connexon Underlying basement membrane Extracellular space between cells Gap (communicating) junction Plasma membranes of adjacent cells Desmosome (anchoring junction) Tight (impermeable) junction

25 © 2015 Pearson Education, Inc. Cytoplasm  The material outside the nucleus and inside the plasma membrane  Site of most cellular activities

26 © 2015 Pearson Education, Inc. Cytoplasm  Contains three major elements 1.Cytosol  Fluid that suspends other elements 2.Organelles  Metabolic machinery of the cell  “Little organs” that perform functions for the cell 3.Inclusions  Chemical substances, such as stored nutrients or cell products

27 © 2015 Pearson Education, Inc. Figure 3.4 Structure of the generalized cell. Chromatin Nucleolus Nuclear envelope Nucleus Plasma membrane Rough endoplasmic reticulum Ribosomes Golgi apparatus Secretion being released from cell by exocytosis Peroxisome Intermediate filaments Microtubule Centrioles Mitochondrion Lysosome Cytosol Smooth endoplasmic reticulum

28 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Organelles  Specialized cellular compartments  Many are membrane-bound  Compartmentalization is critical for organelle’s ability to perform specialized functions

29 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Mitochondria  “Powerhouses” of the cell  Change shape continuously  Mitochondrial wall consists of a double membrane with cristae on the inner membrane  Carry out reactions where oxygen is used to break down food  Provides ATP for cellular energy

30 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Ribosomes  Bilobed dark bodies  Made of protein and ribosomal RNA  Sites of protein synthesis  Found at two locations:  Free in the cytoplasm  As part of the rough endoplasmic reticulum

31 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Endoplasmic reticulum (ER)  Fluid-filled cisterns (tubules or canals) for carrying substances within the cell  Two types:  Rough ER  Smooth ER

32 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Endoplasmic reticulum (ER)  Rough endoplasmic reticulum  Studded with ribosomes  Synthesizes proteins  Transport vesicles move proteins within cell  Abundant in cells that make and export proteins

33 © 2015 Pearson Education, Inc. Figure 3.5 Synthesis and export of a protein by the rough ER. Ribosome mRNA Rough ER Protein Transport vesicle buds off Protein inside transport vesicle As the protein is synthesized on the ribosome, it migrates into the rough ER cistern. In the cistern, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein). The protein is packaged in a tiny membranous sac called a transport vesicle. The transport vesicle buds from the rough ER and travels to the Golgi apparatus for further processing. Slide 1

34 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Endoplasmic reticulum (ER)  Smooth endoplasmic reticulum  Functions in lipid metabolism  Detoxification of drugs and pesticides

35 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Golgi apparatus  Appears as a stack of flattened membranes associated with tiny vesicles  Modifies and packages proteins arriving from the rough ER via transport vesicles  Produces different types of packages  Secretory vesicles (pathway 1)  In-house proteins and lipids (pathway 2)  Lysosomes (pathway 3)

36 © 2015 Pearson Education, Inc. Figure 3.6 Role of the Golgi apparatus in packaging the products of the rough ER. Rough ERCisterns Proteins in cisterns Membrane Transport vesicle Lysosome fuses with ingested substances. Golgi vesicle containing digestive enzymes becomes a lysosome. Golgi apparatus Pathway 1 Secretory vesicles Proteins Secretion by exocytosis Golgi vesicle containing proteins to be secreted becomes a secretory vesicle. Golgi vesicle containing membrane components fuses with the plasma membrane and is incorporated into it. Plasma membrane Extracellular fluid Pathway 2 Pathway 3

37 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Lysosomes  Membranous “bags” packaged by the Golgi apparatus  Contain enzymes produced by ribosomes  Enzymes can digest worn-out or nonusable cell structures  House phagocytes that dispose of bacteria and cell debris

38 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Peroxisomes  Membranous sacs of oxidase enzymes  Detoxify harmful substances such as alcohol and formaldehyde  Break down free radicals (highly reactive chemicals)  Free radicals are converted to hydrogen peroxide and then to water  Replicate by pinching in half or budding from the ER

39 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Cytoskeleton  Network of protein structures that extend throughout the cytoplasm  Provides the cell with an internal framework  Three different types of elements: 1.Microfilaments (largest) 2.Intermediate filaments 3.Microtubules (smallest)

40 © 2015 Pearson Education, Inc. Figure 3.7 Cytoskeletal elements support the cell and help to generate movement. Actin subunit 7 nm Fibrous subunits Tubulin subunits 10 nm 25 nm Microfilaments form the blue batlike network. (a) Microfilaments (b) Intermediate filaments(c) Microtubules Intermediate filaments form the purple network surrounding the pink nucleus. Microtubules appear as gold networks surrounding the cells’ pink nuclei.

41 © 2015 Pearson Education, Inc. Cytoplasmic Organelles  Centrioles  Rod-shaped bodies made of microtubules  Generate microtubules  Direct the formation of mitotic spindle during cell division

42 © 2015 Pearson Education, Inc. Table 3.1 Parts of the Cell: Structure and Function (1 of 5).

43 © 2015 Pearson Education, Inc. Table 3.1 Parts of the Cell: Structure and Function (2 of 5).

44 © 2015 Pearson Education, Inc. Table 3.1 Parts of the Cell: Structure and Function (3 of 5).

45 © 2015 Pearson Education, Inc. Table 3.1 Parts of the Cell: Structure and Function (4 of 5).

46 © 2015 Pearson Education, Inc. Table 3.1 Parts of the Cell: Structure and Function (5 of 5).

47 © 2015 Pearson Education, Inc. Cell Extensions  Surface extensions found in some cells  Cilia move materials across the cell surface  Located in the respiratory system to move mucus  Flagella propel the cell  The only flagellated cell in the human body is sperm  Microvilli are tiny, fingerlike extensions of the plasma membrane  Increase surface area for absorption Nucleus Flagellum Sperm (g) Cell of reproduction

48 © 2015 Pearson Education, Inc. Cell Diversity  The human body houses over 200 different cell types  Cells vary in length from 1/12,000 of an inch to over 1 yard (nerve cells)  Cell shape reflects its specialized function

49 © 2015 Pearson Education, Inc. Cell Diversity  Cells that connect body parts  Fibroblast  Secretes cable-like fibers  Erythrocyte (red blood cell)  Carries oxygen in the bloodstream Rough ER and Golgi apparatus No organelles Nucleus Fibroblasts Erythrocytes (a) Cells that connect body parts

50 © 2015 Pearson Education, Inc. Cell Diversity  Cells that cover and line body organs  Epithelial cell  Packs together in sheets  Intermediate fibers resist tearing during rubbing or pulling Nucleus Intermediate filaments Epithelial cells (b) Cells that cover and line body organs

51 © 2015 Pearson Education, Inc. Cell Diversity  Cells that move organs and body parts  Skeletal muscle and smooth muscle cells  Contractile filaments allow cells to shorten forcefully Nuclei Contractile filaments Skeletal muscle cell Smooth muscle cells (c) Cells that move organs and body parts

52 © 2015 Pearson Education, Inc. Cell Diversity  Cell that stores nutrients  Fat cells  Lipid droplets stored in cytoplasm Lipid droplet Nucleus Fat cell (d) Cell that stores nutrients

53 © 2015 Pearson Education, Inc. Cell Diversity  Cell that fights disease  Macrophage (a phagocytic cell)  Digests infectious microorganisms Lysosomes Macrophage (e) Cell that fights disease Pseudo- pods

54 © 2015 Pearson Education, Inc. Cell Diversity  Cell that gathers information and controls body functions  Nerve cell (neuron)  Receives and transmits messages to other body structures Processes Rough ER Nucleus (f) Cell that gathers information and controls body functions Nerve cell

55 © 2015 Pearson Education, Inc. Cell Diversity  Cells of reproduction  Oocyte (female)  Largest cell in the body  Divides to become an embryo upon fertilization  Sperm (male)  Built for swimming to the egg for fertilization  Flagellum acts as a motile whip Nucleus Flagellum Sperm (g) Cell of reproduction

56 © 2015 Pearson Education, Inc. Cell Physiology  Cells have the ability to:  Metabolize  Digest food  Dispose of wastes  Reproduce  Grow  Move  Respond to a stimulus

57 © 2015 Pearson Education, Inc. Membrane Transport  Solution—homogeneous mixture of two or more components  Solvent—dissolving medium; typically water in the body  Solutes—components in smaller quantities within a solution

58 © 2015 Pearson Education, Inc. Membrane Transport  Intracellular fluid  Nucleoplasm and cytosol  Solution containing gases, nutrients, and salts dissolved in water  Interstitial fluid  Fluid on the exterior of the cell  Contains thousands of ingredients, such as nutrients, hormones, neurotransmitters, salts, waste products

59 © 2015 Pearson Education, Inc. Membrane Transport  The plasma membrane is a selectively permeable barrier  Some materials can pass through while others are excluded  For example:  Nutrients can enter the cell  Undesirable substances are kept out

60 © 2015 Pearson Education, Inc. Membrane Transport  Two basic methods of transport  Passive processes  No energy (ATP) is required  Active processes  Cell must provide metabolic energy (ATP)

61 © 2015 Pearson Education, Inc. Passive Processes  Diffusion  Particles tend to distribute themselves evenly within a solution  Driving force is the kinetic energy (energy of motion) that causes the molecules to move about randomly

62 © 2015 Pearson Education, Inc. Passive Processes  Diffusion  Molecule movement is from high concentration to low concentration, or down a concentration gradient  Size of molecule and temperature affects the speed of diffusion  The smaller the molecule, the faster the rate of diffusion  The warmer the molecule, the faster the rate of diffusion

63 © 2015 Pearson Education, Inc. Passive Processes  Example of diffusion:  Pour a cup of coffee and drop in a cube of sugar  Do not stir the sugar into the coffee; leave the cup of coffee sitting all day, and it will taste sweet at the end of the day.  Molecules move by diffusion and sweeten the entire cup

64 © 2015 Pearson Education, Inc. Passive Processes  Molecules will move by diffusion if any of the following applies:  The molecules are small enough to pass through the membrane’s pores (channels formed by membrane proteins)  The molecules are lipid-soluble  The molecules are assisted by a membrane carrier

65 © 2015 Pearson Education, Inc. Passive Processes  Types of diffusion  Simple diffusion  An unassisted process  Solutes are lipid-soluble or small enough to pass through membrane pores

66 © 2015 Pearson Education, Inc. Passive Processes  Types of diffusion (continued)  Osmosis—simple diffusion of water  Highly polar water molecules easily cross the plasma membrane through aquaporins  Water moves down its concentration gradient Water molecules Lipid bilayer (d) Osmosis, diffusion of water through a specific channel protein (aquaporin) or through the lipid bilayer

67 © 2015 Pearson Education, Inc. Passive Processes  Osmosis—A Closer Look  Isotonic solutions have the same solute and water concentrations as cells and cause no visible changes in the cell  Hypertonic solutions contain more solutes than the cells do; the cells will begin to shrink  Hypotonic solutions contain fewer solutes (more water) than the cells do; cells will plump (a) RBC in isotonic solution (b) RBC in hypertonic solution (c) RBC in hypotonic solution

68 © 2015 Pearson Education, Inc. Passive Processes  Types of diffusion (continued)  Facilitated diffusion  Transports lipid- insoluble and large substances  Glucose is transported via facilitated diffusion  Protein membrane channels or protein molecules that act as carriers are used Lipid- insoluble solutes Small lipid- insoluble solutes (b) Carrier-mediated facilitated diffusion via protein carrier specific for one chemical; binding of substrate causes shape change in transport protein (c) Channel- mediated facilitated diffusion through a channel protein; mostly ions, selected on basis of size and charge

69 © 2015 Pearson Education, Inc. Passive Processes  Filtration  Water and solutes are forced through a membrane by fluid, or hydrostatic pressure  A pressure gradient must exist  Solute-containing fluid (filtrate) is pushed from a high- pressure area to a lower-pressure area  Filtration is critical for the kidneys to work properly

70 © 2015 Pearson Education, Inc. Active Processes  Sometimes called solute pumping  Requires protein carriers to transport substances that:  May be too large to travel through membrane channels  May not be lipid-soluble  May have to move against a concentration gradient  ATP is used for transport

71 © 2015 Pearson Education, Inc. Active Processes  Active transport  Amino acids, some sugars, and ions are transported by protein carriers known as solute pumps  ATP energizes solute pumps  In most cases, substances are moved against concentration (or electrical) gradients

72 © 2015 Pearson Education, Inc. Active Processes  Example of active transport is the sodium- potassium pump  Sodium is transported out of the cell  Potassium is transported into the cell Na + -K + pump Na + Extracellular fluid K+K+ Na + K+K+ K+K+ K+K+ P P ATP ADP Binding of cytoplasmic Na + to the pump protein stimulates phosphorylation by ATP, which causes the pump protein to change its shape. The shape change expels Na + to the outside. Extracellular K + binds, causing release of the phosphate group. Loss of phosphate restores the original conformation of the pump protein. K + is released to the cytoplasm, and Na + sites are ready to bind Na + again; the cycle repeats. Cytoplasm Slide 1

73 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport: substances are moved without actually crossing the plasma membrane  Exocytosis  Endocytosis  Phagocytosis  Pinocytosis

74 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport (continued)  Exocytosis  Moves materials out of the cell  Material is carried in a membranous sac called a vesicle  Vesicle migrates to plasma membrane  Vesicle combines with plasma membrane  Material is emptied to the outside  Refer to Pathway 1 in Figure 3.6 (b) Electron micrograph of a secretory vesicle in exocytosis (190,000 × )

75 © 2015 Pearson Education, Inc. Figure 3.6 Role of the Golgi apparatus in packaging the products of the rough ER. Rough ERCisterns Proteins in cisterns Membrane Transport vesicle Lysosome fuses with ingested substances. Golgi vesicle containing digestive enzymes becomes a lysosome. Golgi apparatus Pathway 1 Secretory vesicles Proteins Secretion by exocytosis Golgi vesicle containing proteins to be secreted becomes a secretory vesicle. Golgi vesicle containing membrane components fuses with the plasma membrane and is incorporated into it. Plasma membrane Extracellular fluid Pathway 2 Pathway 3

76 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport (continued)  Endocytosis  Extracellular substances are engulfed by being enclosed in a membranous vescicle  Vesicle typically fuses with a lysosome  Contents are digested by lysosomal enzymes  In some cases, the vesicle is released by exocytosis on the opposite side of the cell

77 © 2015 Pearson Education, Inc. Figure 3.13a Events and types of endocytosis. Plasma membrane Lysosome Pit Ingested substance Detached vesicle Vesicle Extracellular fluid Cytosol Release of contents to cytosol Vesicle fusing with lysosome for digestion Transport to plasma membrane and exocytosis of vesicle contents Membranes and receptors (if present) recycled to plasma membrane 1 (a) 2 3 Slide 1

78 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport (continued)  Types of endocytosis 1.Phagocytosis—“cell eating”  Cell engulfs large particles such as bacteria or dead body cells  Pseudopods are cytoplasmic extensions that separate substances (such as bacteria or dead body cells) from external environment  Phagocytosis is a protective mechanism, not a means of getting nutrients Pseudopod Bacterium or other particle Extracellular fluid Cytoplasm

79 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport (continued)  Types of endocytosis 2.Pinocytosis—“cell drinking”  Cell “gulps” droplets of extracellular fluid containing dissolved proteins or fats  Plasma membrane forms a pit, and edges fuse around droplet of fluid  Routine activity for most cells, such as those involved in absorption (small intestine)

80 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport (continued)  Types of endocytosis 3.Receptor-mediated endocytosis  Method for taking up specific target molecules  Receptor proteins on the membrane surface bind only certain substances  Highly selective process of taking in substances such as enzymes, some hormones, cholesterol, and iron

81 © 2015 Pearson Education, Inc. Active Processes  Vesicular transport (continued)  Types of endocytosis 3.Receptor-mediated endocytosis  Both the receptors and target molecules are in a vesicle  Contents of the vesicles are dealt with in one of the ways shown in the next figure Membrane receptor

82 © 2015 Pearson Education, Inc. Cell Life Cycle  Cycle has two major periods 1.Interphase  Cell grows  Cell carries on metabolic processes  Longer phase of the cell cycle 2.Cell division  Cell replicates itself  Function is to produce more cells for growth and repair processes  Cell life cycle is a series of changes the cell experiences from the time it is formed until it divides

83 © 2015 Pearson Education, Inc. DNA Replication  Genetic material is duplicated and readies a cell for division into two cells  Occurs toward the end of interphase KEY: Adenine Thymine Cytosine Guanine Old (template) strand Newly synthesized strand New strand forming Old (template) strand DNA of one chromatid

84 © 2015 Pearson Education, Inc. DNA Replication  DNA uncoils into two nucleotide chains, and each side serves as a template  Nucleotides are complementary  Adenine (A) always bonds with thymine (T)  Guanine (G) always bonds with cytosine (C)  For example, TACTGC bonds with new nucleotides in the order ATGACG

85 © 2015 Pearson Education, Inc. 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

86 © 2015 Pearson Education, Inc. Stages of Mitosis  Prophase  First part of cell division  Chromatin coils into chromosomes  Chromosomes are held together by a centromere  A chromosome has two strands  Each strand is called a chromatid

87 © 2015 Pearson Education, Inc. Stages of Mitosis  Prophase (continued)  Centrioles migrate to the poles to direct assembly of mitotic spindle fibers  Mitotic spindles are made of microtubules  Spindle provides scaffolding for the attachment and movement of the chromosomes during the later mitotic stages  Nuclear envelope breaks down and disappears

88 © 2015 Pearson Education, Inc. Stages of Mitosis  Metaphase  Chromosomes are aligned in the center of the cell on the metaphase plate  Metaphase plate is the center of the spindle midway between the centrioles  Straight line of chromosomes is now seen

89 © 2015 Pearson Education, Inc. Stages of Mitosis  Anaphase  Centromere splits  Chromatids move slowly apart and toward the opposite ends of the cell  Anaphase is over when the chromosomes stop moving

90 © 2015 Pearson Education, Inc. Stages of Mitosis  Telophase  Reverse of prophase  Chromosomes uncoil to become chromatin  Spindles break down and disappear  Nuclear envelope reforms around chromatin  Nucleoli appear in each of the daughter nuclei

91 © 2015 Pearson Education, Inc. Stages of Mitosis  Cytokinesis  Division of the cytoplasm  Begins during late anaphase and completes during telophase  A cleavage furrow forms to pinch the cells into two parts  Cleavage furrow is a contractile ring made of microfilaments

92 © 2015 Pearson Education, Inc. Stages of Mitosis  Two daughter cells exist at the end of cell division  In most cases, mitosis and cytokinesis occur together  In some cases, the cytoplasm is not divided  Binucleate or multinucleate cells result  Common in the liver  Mitosis gone wild is the basis for tumors and cancers

93 © 2015 Pearson Education, Inc. Spindle microtubules Chromosome, consisting of two sister chromatids Fragments of nuclear envelope Daughter chromosomes Figure 3.15 Stages of mitosis. CentriolesChromatin Centrioles Forming mitotic spindle Centromere Plasma membrane Nuclear envelope Nucleolus Spindle pole Metaphase plate Nucleolus forming Cleavage furrow Spindle Sister chromatids Nuclear envelope forming Interphase Early prophase Late prophase MetaphaseAnaphase Telophase and cytokinesis Slide 1

94 © 2015 Pearson Education, Inc. Protein Synthesis  DNA serves as a blueprint for making proteins  Gene: DNA segment that carries a blueprint for building one protein or polypeptide chain  Proteins have many functions  Fibrous (structural) proteins are the building materials for cells  Globular (functional) proteins act as enzymes (biological catalysts)

95 © 2015 Pearson Education, Inc. Protein Synthesis  DNA information is coded into triplets  Triplets  Contain three bases  Call for a particular amino acid  For example, a DNA sequence of AAA specifies the amino acid phenylalanine

96 © 2015 Pearson Education, Inc. Protein Synthesis  Most ribosomes, the manufacturing sites of proteins, are located in the cytoplasm  DNA never leaves the nucleus in interphase cells  DNA requires a decoder and a messenger to build proteins, both are functions carried out by RNA (ribonucleic acid)

97 © 2015 Pearson Education, Inc. Protein Synthesis  How does RNA differ from DNA? RNA:  Is single-stranded  Contains ribose sugar instead of deoxyribose  Contains uracil (U) base instead of thymine (T)

98 © 2015 Pearson Education, Inc. Role of RNA  Transfer RNA (tRNA)  Transfers appropriate amino acids to the ribosome for building the protein  Ribosomal RNA (rRNA)  Helps form the ribosomes where proteins are built  Messenger RNA (mRNA)  Carries the instructions for building a protein from the nucleus to the ribosome

99 © 2015 Pearson Education, Inc. Role of RNA  Protein synthesis involves two major phases:  Transcription  Translation  We will detail these two phases next

100 © 2015 Pearson Education, Inc. Protein Synthesis  Transcription  Transfer of information from DNA’s base sequence to the complementary base sequence of mRNA  Only DNA and mRNA are involved  Triplets are the three-base sequence specifying a particular amino acid on the DNA gene  Codons are the corresponding three-base sequences on mRNA

101 © 2015 Pearson Education, Inc. Protein Synthesis  Example of transcription:  DNA triplets AAT-CGT-TCG  mRNA codonsUUA-GCA-AGC

102 © 2015 Pearson Education, Inc. Protein Synthesis  Translation  Base sequence of nucleic acid is translated to an amino acid sequence  Amino acids are the building blocks of proteins As the ribosome moves along the mRNA, a new amino acid is added to the growing protein chain. Released tRNA reenters the cytoplasmic pool, ready to be recharged with a new amino acid. mRNA specifying one polypeptide is made on DNA template. mRNA leaves nucleus and attaches to ribosome, and translation begins. Incoming tRNA recognizes a complementary mRNA codon calling for its amino acid by binding via its anticodon to the codon. mRNA Nuclear membrane Nuclear pore Nucleus (site of transcription) DNA Amino acids Cytoplasm (site of translation) Synthetase enzyme Correct amino acid attached to each species of tRNA by an enzyme Growing polypeptide chain Peptide bond tRNA “head” bearing anticodon Large ribosomal subunit Codon Portion of mRNA already translated Small ribosomal subunit Direction of ribosome advance; ribosome moves the mRNA strand along sequentially as each codon is read. Met Gly Ser Phe Ala

103 © 2015 Pearson Education, Inc. Protein Synthesis  Translation (continued)  Steps correspond to Figure 3.16 (step 1 covers transcription) 2.mRNA leaves nucleus and attaches to ribosome, and translation begins 3.Incoming tRNA recognizes a complementary mRNA codon calling for its amino acid by binding via its anticodon to the codon.

104 © 2015 Pearson Education, Inc. Protein Synthesis  Translation (continued)  Steps correspond to Figure As the ribosome moves along the mRNA, a new amino acid is added to the growing protein chain. 5.Released tRNA reenters the cytoplasmic pool, ready to be recharged with a new amino acid.

105 © 2015 Pearson Education, Inc. Body Tissues  Tissues  Groups of cells with similar structure and function  Four primary types: 1.Epithelial tissue (epithelium) 2.Connective tissue 3.Muscle tissue 4.Nervous tissue

106 © 2015 Pearson Education, Inc. Epithelial Tissues  Locations:  Body coverings  Body linings  Glandular tissue  Functions:  Protection  Absorption  Filtration  Secretion

107 © 2015 Pearson Education, Inc. Epithelium Characteristics  Cells fit closely together and often form sheets  The apical surface is the free surface of the tissue  The lower surface of the epithelium rests on a basement membrane  Avascular (no blood supply)  Regenerate easily if well nourished

108 © 2015 Pearson Education, Inc. Classification of Epithelia Basal surface Apical surface Basal surface Apical surface Simple Stratified (a) Classification based on number of cell layers  Number of cell layers  Simple one layer  Stratified more than one layer

109 © 2015 Pearson Education, Inc. Classification of Epithelia  Shape of cells  Squamous  Flattened, like fish scales  Cuboidal  Cube-shaped, like dice  Columnar  Column-like Squamous Cuboidal Columnar (b) Classification based on cell shape

110 © 2015 Pearson Education, Inc. Figure 3.17c Classification and functions of epithelia. Diffusion and filtration Secretion in serous membranes Protection Secretion and absorption; ciliated types propel mucus or reproductive cells Protection; these tissue types are rare in humans Protection; stretching to accommodate distension of urinary structures (c) Function of epithelial tissue related to tissue type Number of layers Cell shape One layer: simple epithelial tissues More than one layer: stratified epithelial tissues Squamous Cuboidal Columnar Transitional

111 © 2015 Pearson Education, Inc. Simple Epithelia  Simple squamous  Single layer of flat cells  Location—usually forms membranes  Lines air sacs of the lungs  Forms walls of capillaries  Forms serous membranes (serosae) that line and cover organs in ventral cavity  Functions in diffusion, filtration, or secretion in membranes

112 © 2015 Pearson Education, Inc. Figure 3.18a Types of epithelia and their common locations in the body. Nucleus of squamous epithelial cell Basement membrane Air sacs of lungs Nuclei of squamous epithelial cells (a) Diagram: Simple squamous Photomicrograph: Simple squamous epithelium forming part of the alveolar (air sac) walls (275×).

113 © 2015 Pearson Education, Inc. Simple Epithelia  Simple cuboidal  Single layer of cube-like cells  Locations:  Common in glands and their ducts  Forms walls of kidney tubules  Covers the surface of ovaries  Functions in secretion and absorption; ciliated types propel mucus or reproductive cells

114 © 2015 Pearson Education, Inc. Figure 3.18b Types of epithelia and their common locations in the body. Nucleus of simple cuboidal epithelial cell Basement membrane Simple cuboidal epithelial cells Basement membrane Connective tissue (b) Diagram: Simple cuboidal Photomicrograph: Simple cuboidal epithelium in kidney tubules (250×).

115 © 2015 Pearson Education, Inc. Simple Epithelia  Simple columnar  Single layer of tall cells  Goblet cells secrete mucus  Location:  Lines digestive tract from stomach to anus  Mucous membranes (mucosae) line body cavities opening to the exterior  Functions in secretion and absorption; ciliated types propel mucus or reproductive cells

116 © 2015 Pearson Education, Inc. Figure 3.18c Types of epithelia and their common locations in the body. Basement membrane Mucus of a goblet cell Nucleus of simple columnar epithelial cell Simple columnar epithelial cells (c) Diagram: Simple columnar Photomicrograph: Simple columnar epithelium of the small intestine (575×).

117 © 2015 Pearson Education, Inc. Simple Epithelia  Pseudostratified columnar  All cells rest on a basement membrane  Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification  Location:  Respiratory tract, where it is ciliated and known as pseudostratified ciliated columnar epithelium  Functions in absorption or secretion

118 © 2015 Pearson Education, Inc. Figure 3.18d Types of epithelia and their common locations in the body. (d) Diagram: Pseudostratified (ciliated) columnar Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (560×). Basement membrane Pseudo- stratified epithelial layer Cilia Connective tissue

119 © 2015 Pearson Education, Inc. Stratified Epithelia  Stratified squamous  Named for cells present at the free (apical) surface, which are flattened  Functions as a protective covering where friction is common  Locations—lining of the:  Skin (outer portion)  Mouth  Esophagus

120 © 2015 Pearson Education, Inc. Figure 3.18e Types of epithelia and their common locations in the body. Basement membrane Connective tissue Stratified squamous epithelium (e) Diagram: Stratified squamous Photomicrograph: Stratified squamous epithelium lining of the esophagus (140×). Nuclei

121 © 2015 Pearson Education, Inc. Stratified Epithelia  Stratified cuboidal—two layers of cuboidal cells; functions in protection  Stratified columnar—surface cells are columnar, and cells underneath vary in size and shape; functions in protection  Stratified cuboidal and columnar  Rare in human body  Found mainly in ducts of large glands

122 © 2015 Pearson Education, Inc. Stratified Epithelia  Transitional epithelium  Composed of modified stratified squamous epithelium  Shape of cells depends upon the amount of stretching  Functions in stretching and the ability to return to normal shape  Locations: urinary system organs

123 © 2015 Pearson Education, Inc. Figure 3.18f Types of epithelia and their common locations in the body. Basement membrane Connective tissue Transi- tional epithelium Transitional epithelium (f) Diagram: Transitional Photomicrograph: Transitional epithelium lining of the bladder, relaxed state (270×); surface rounded cells flatten and elongate when the bladder fills with urine.

124 © 2015 Pearson Education, Inc. Glandular Epithelium  Gland  One or more cells responsible for secreting a particular product  Secretions contain protein molecules in an aqueous (water-based) fluid  Secretion is an active process

125 © 2015 Pearson Education, Inc. Glandular Epithelium  Two major gland types  Endocrine gland  Ductless; secretions diffuse into blood vessels  All secretions are hormones  Examples include thyroid, adrenals, and pituitary

126 © 2015 Pearson Education, Inc. Glandular Epithelium  Two major gland types  Exocrine gland  Secretions empty through ducts to the epithelial surface  Include sweat and oil glands, liver, and pancreas  Includes both internal and external glands

127 © 2015 Pearson Education, Inc. Connective Tissue  Found everywhere in the body  Includes the most abundant and widely distributed tissues  Functions:  Provides protection  Binds body tissues together  Supports the body

128 © 2015 Pearson Education, Inc. Connective Tissue Characteristics  Variations in blood supply  Some tissue types are well vascularized  Some have a poor blood supply or are avascular  Extracellular matrix  Nonliving material that surrounds living cells

129 © 2015 Pearson Education, Inc. Extracellular Matrix  Two main elements 1.Ground substance—mostly water along with adhesion proteins and polysaccharide molecules 2.Fibers  Produced by the cells  Three types: 1.Collagen (white) fibers 2.Elastic (yellow) fibers 3.Reticular fibers (a type of collagen)

130 © 2015 Pearson Education, Inc. Connective Tissue Types  From most rigid to softest, or most fluid:  Bone  Cartilage  Dense connective tissue  Loose connective tissue  Blood

131 © 2015 Pearson Education, Inc. Connective Tissue Types  Bone (osseous tissue)  Composed of:  Osteocytes (bone cells) sitting in lacunae (cavities)  Hard matrix of calcium salts  Large numbers of collagen fibers  Functions to protect and support the body

132 © 2015 Pearson Education, Inc. Figure 3.19a Connective tissues and their common body locations. Bone cells in lacunae Central canal Lacunae Lamella (a) Diagram: Bone Photomicrograph: Cross-sectional view of ground bone (165×)

133 © 2015 Pearson Education, Inc. Connective Tissue Types  Cartilage  Less hard and more flexible than bone  Found in only a few places in the body  Chondrocyte (cartilage cell) is the major cell type

134 © 2015 Pearson Education, Inc. Connective Tissue Types  Hyaline cartilage  Hyaline cartilage is the most widespread type of cartilage  Composed of abundant collagen fibers and a rubbery matrix  Locations:  Larynx  Entire fetal skeleton prior to birth  Epiphyseal plates  Functions as a more flexible skeletal element than bone

135 © 2015 Pearson Education, Inc. Figure 3.19b Connective tissues and their common body locations. Chondrocyte (cartilage cell) Chondrocyte in lacuna Matrix Lacunae Photomicrograph: Hyaline cartilage from the trachea (400×) (b) Diagram: Hyaline cartilage

136 © 2015 Pearson Education, Inc. Connective Tissue Types  Elastic cartilage (not pictured)  Provides elasticity  Location:  Supports the external ear  Fibrocartilage  Highly compressible  Location:  Forms cushionlike discs between vertebrae of the spinal column

137 © 2015 Pearson Education, Inc. Figure 3.19c Connective tissues and their common body locations. Chondro- cytes in lacunae Collagen fibers Chondrocytes in lacunae Collagen fiber Photomicrograph: Fibrocartilage of an intervertebral disc (150×) (c) Diagram: Fibrocartilage

138 © 2015 Pearson Education, Inc. Connective Tissue Types  Dense connective tissue (dense fibrous tissue)  Main matrix element is collagen fiber  Fibroblasts are cells that make fibers  Locations:  Tendons—attach skeletal muscle to bone  Ligaments—attach bone to bone at joints and are more elastic than tendons  Dermis—lower layers of the skin

139 © 2015 Pearson Education, Inc. Figure 3.19d Connective tissues and their common body locations. Ligament (d) Diagram: Dense fibrous Photomicrograph: Dense fibrous connective tissue from a tendon (475×) Collagen fibers Nuclei of fibroblasts Collagen fibers Tendon

140 © 2015 Pearson Education, Inc. Connective Tissue Types  Loose connective tissue types  Areolar tissue  Most widely distributed connective tissue  Soft, pliable tissue like “cobwebs”  Functions as a universal packing tissue and “glue” to hold organs in place  Layer of areolar tissue called lamina propria underlies all membranes  All fiber types form a loose network  Can soak up excess fluid (causes edema)

141 © 2015 Pearson Education, Inc. Figure 3.19e Connective tissues and their common body locations. Mucosa epithelium Lamina propria Fibers of matrix Nuclei of fibroblasts Elastic fibers Collagen fibers Fibroblast nuclei (e) Diagram: Areolar Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (270×)

142 © 2015 Pearson Education, Inc. Connective Tissue Types  Loose connective tissue types  Adipose tissue  Matrix is an areolar tissue in which fat globules predominate  Many cells contain large lipid deposits with nucleus to one side (signet ring cells)  Functions  Insulates the body  Protects some organs  Serves as a site of fuel storage

143 © 2015 Pearson Education, Inc. Figure 3.19f Connective tissues and their common body locations. Nuclei of fat cells Vacuole containing fat droplet Nuclei of fat cells (f) Diagram: Adipose Photomicrograph: Adipose tissue from the subcutaneous layer beneath the skin (570×)

144 © 2015 Pearson Education, Inc. Connective Tissue Types  Loose connective tissue types  Reticular connective tissue  Delicate network of interwoven fibers with reticular cells (like fibroblasts)  Locations:  Forms stroma (internal framework) of organs, such as these lymphoid organs:  Lymph nodes  Spleen  Bone marrow

145 © 2015 Pearson Education, Inc. Figure 3.19g Connective tissues and their common body locations. Spleen (g) Diagram: Reticular Photomicrograph: Dark-staining network of reticular connective tissue (400×) Reticular cell Blood cell Reticular fibers White blood cell (lymphocyte) Reticular fibers

146 © 2015 Pearson Education, Inc. Connective Tissue Types  Blood (vascular tissue)  Blood cells surrounded by fluid matrix known as blood plasma  Soluble fibers are visible only during clotting  Functions as the transport vehicle for the cardiovascular system, carrying:  Nutrients  Wastes  Respiratory gases

147 © 2015 Pearson Education, Inc. Figure 3.19h Connective tissues and their common body locations. Photomicrograph: Smear of human blood (1290×) (h) Diagram: Blood Blood cells in capillary White blood cell Red blood cells Neutrophil (white blood cell) Red blood cells Monocyte (white blood cell)

148 © 2015 Pearson Education, Inc. Muscle Tissue  Function is to contract, or shorten, to produce movement  Three types: 1.Skeletal muscle 2.Cardiac muscle 3.Smooth muscle

149 © 2015 Pearson Education, Inc. Muscle Tissue Types  Skeletal muscle  Voluntarily (consciously) controlled  Attached to the skeleton and pull on bones or skin  Produces gross body movements or facial expressions  Characteristics of skeletal muscle cells  Striations (stripes)  Multinucleate (more than one nucleus)  Long, cylindrical shape

150 © 2015 Pearson Education, Inc. Figure 3.20a Type of muscle tissue and their common locations in the body. Nuclei Part of muscle fiber Photomicrograph: Skeletal muscle (195×) (a) Diagram: Skeletal muscle

151 © 2015 Pearson Education, Inc. Muscle Tissue Types  Cardiac muscle  Involuntarily controlled  Found only in the heart  Pumps blood through blood vessels  Characteristics of cardiac muscle cells  Striations  Uninucleate, short, branching cells  Intercalated discs contain gap junctions to connect cells together

152 © 2015 Pearson Education, Inc. Figure 3.20b Type of muscle tissue and their common locations in the body. Intercalated discs Nucleus Photomicrograph: Cardiac muscle (475×) (b) Diagram: Cardiac muscle

153 © 2015 Pearson Education, Inc. Muscle Tissue Types  Smooth (visceral) muscle  Involuntarily controlled  Found in walls of hollow organs such as stomach, uterus, and blood vessels  Peristalsis, a wavelike activity, is a typical activity  Characteristics of smooth muscle cells  No visible striations  Uninucleate  Spindle-shaped cells

154 © 2015 Pearson Education, Inc. Figure 3.20c Type of muscle tissue and their common locations in the body. Smooth muscle cell Nuclei Photomicrograph: Sheet of smooth muscle (285×) (c) Diagram: Smooth muscle

155 © 2015 Pearson Education, Inc. Nervous Tissue  Composed of neurons and nerve support cells  Function is to receive and conduct electrochemical impulses to and from body parts  Irritability  Conductivity  Support cells called neuroglia insulate, protect, and support neurons

156 © 2015 Pearson Education, Inc. Figure 3.21 Nervous tissue. Brain Spinal cord Nuclei of supporting cells Cell body of neuron Neuron processes Nuclei of supporting cells Neuron processes Cell body of neuron Diagram: Nervous tissue Photomicrograph: Neurons (320×)

157 © 2015 Pearson Education, Inc. Summary of Tissues  Figure 3.22 summarizes the tissue types and functions in the body

158 © 2015 Pearson Education, Inc. Figure 3.22 Summary of the major functions and body locations of the four tissue types: epithelial, connective, muscle, and nervous tissues. Nervous tissue: Internal communication Brain, spinal cord, and nerves Muscle tissue: Contracts to cause movement Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters Connective tissue: Supports, protects, binds other tissues together Muscles attached to bones (skeletal) Muscles of heart (cardiac) Muscles of walls of hollow organs (smooth) Lining of GI tract organs and other hollow organs Skin surface (epidermis) Bones Tendons Fat and other soft padding tissue

159 © 2015 Pearson Education, Inc. Tissue Repair (Wound Healing)  Tissue repair (wound healing) occurs in two ways: 1.Regeneration  Replacement of destroyed tissue by the same kind of cells 2.Fibrosis  Repair by dense (fibrous) connective tissue (scar tissue)

160 © 2015 Pearson Education, Inc. Tissue Repair (Wound Healing)  Whether regeneration or fibrosis occurs depends on: 1.Type of tissue damaged 2.Severity of the injury  Clean cuts (incisions) heal more successfully than ragged tears of the tissue

161 © 2015 Pearson Education, Inc. Events in Tissue Repair  Inflammation  Capillaries become very permeable  Clotting proteins migrate into the area from the bloodstream  A clot walls off the injured area  Granulation tissue forms  Growth of new capillaries  Phagocytes dispose of blood clot and fibroblasts  Rebuild collagen fibers

162 © 2015 Pearson Education, Inc. Events in Tissue Repair  Regeneration of surface epithelium  Scab detaches  Whether scar is visible or invisible depends on severity of wound

163 © 2015 Pearson Education, Inc. Regeneration of Tissues  Tissues that regenerate easily  Epithelial tissue (skin and mucous membranes)  Fibrous connective tissues and bone  Tissues that regenerate poorly  Skeletal muscle  Tissues that are replaced largely with scar tissue  Cardiac muscle  Nervous tissue within the brain and spinal cord

164 © 2015 Pearson Education, Inc. Development Aspects of Cells and Tissues  Growth through cell division continues through puberty  Cell populations exposed to friction (such as epithelium) replace lost cells throughout life  Connective tissue remains mitotic and forms repair (scar) tissue  With some exceptions, muscle tissue becomes amitotic by the end of puberty  Nervous tissue becomes amitotic shortly after birth.

165 © 2015 Pearson Education, Inc. Developmental Aspects of Cells and Tissues  Injury can severely handicap amitotic tissues  The cause of aging is unknown, but chemical and physical insults, as well as genetic programming, have been proposed as possible causes

166 © 2015 Pearson Education, Inc. Developmental Aspects of Cells and Tissues  Neoplasms, both benign and cancerous, represent abnormal cell masses in which normal controls on cell division are not working  Hyperplasia (increase in size) of a tissue or organ may occur when tissue is strongly stimulated or irritated  Atrophy (decrease in size) of a tissue or organ occurs when the organ is no longer stimulated normally


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