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PowerPoint® Lecture Slides Prepared by Patty Bostwick-Taylor, Florence-Darlington Technical College CHAPTER 3 Cells and Tissues © 2012 Pearson Education, Inc. Concepts of the Cell Theory •A cell is the basic structural and functional unit of living organisms. •The activity of an organism depends on the collective activities of its cells. •Continuity of life has a cellular basis. © 2012 Pearson Education, Inc. Anatomy of the Cell •Cells are not all the same. •All cells share general structures. •All cells have three main regions •Nucleus •Cytoplasm •Plasma membrane © 2012 Pearson Education, Inc. Nucleus Cytoplasm Plasma membrane (a) © 2012 Pearson Education, Inc. Figure 3.1a The Nucleus •The nucleus is the control center of the cell •Contains genetic material (DNA) •Three regions •Nuclear envelope (membrane) •Nucleolus •Chromatin © 2012 Pearson Education, Inc. Nuclear envelope Chromatin Nucleolus Nucleus Nuclear pores Rough ER (b) © 2012 Pearson Education, Inc. Figure 3.1b The Nucleus •Nuclear envelope (membrane) •Barrier of the nucleus •Consists of a double membrane •Contains nuclear pores that allow for exchange of material with the rest of the cell © 2012 Pearson Education, Inc. The Nucleus •Nucleoli •Nucleus contains one or more nucleoli •Sites of ribosome assembly •Ribosomes migrate into the cytoplasm through nuclear pores © 2012 Pearson Education, Inc. The Nucleus •Chromatin •Composed of DNA and protein •Present when the cell is not dividing •Scattered throughout the nucleus •Condenses to form chromosomes when the cell divides © 2012 Pearson Education, Inc. Plasma Membrane •The plasma membrane is a fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment •Barrier for cell contents •Also contains proteins, cholesterol, and glycoproteins © 2012 Pearson Education, Inc. Extracellular fluid (watery environment) Glycoprotein Glycolipid Cholesterol Sugar group Polar heads of phospholipid molecules Bimolecular lipid layer containing proteins Nonpolar tails of phospholipid molecules © 2012 Pearson Education, Inc. Channel Proteins Filaments of cytoskeleton Cytoplasm (watery environment) Figure 3.2 Cytoplasm •Cytoplasm is the material outside the nucleus and inside the plasma membrane •Site of most cellular activities © 2012 Pearson Education, Inc. Cytoplasm •Contains three major elements •Cytosol •Fluid that suspends other elements •Organelles •Metabolic machinery of the cell •“Little organs” that perform functions for the cell •Inclusions •Chemical substances such as stored nutrients or cell products © 2012 Pearson Education, Inc. Chromatin Nuclear envelope Nucleolus Nucleus Plasma membrane Smooth endoplasmic reticulum Cytosol Lysosome Mitochondrion Rough endoplasmic reticulum Centrioles Ribosomes Golgi apparatus Secretion being released from cell by exocytosis Microtubule Peroxisome Intermediate filaments © 2012 Pearson Education, Inc. Figure 3.4 Cytoplasmic Organelles •Mitochondria •“Powerhouses” of the cell •Change shape continuously •Carry out reactions where oxygen is used to break down food •Provides ATP for cellular energy © 2012 Pearson Education, Inc. Cytoplasmic Organelles •Ribosomes •Made of protein and RNA •Sites of protein synthesis •Found at two locations •Free in the cytoplasm •As part of the rough endoplasmic reticulum © 2012 Pearson Education, Inc. Cytoplasmic Organelles •Lysosomes •Contain enzymes produced by ribosomes •Packaged by the Golgi apparatus •Digest worn-out or non-usable materials within the cell © 2012 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 •Microfilaments (largest) •Intermediate filaments •Microtubules (smallest) © 2012 Pearson Education, Inc. (b) Intermediate filaments (a) Microfilaments (c) Microtubules Tubulin subunits Fibrous subunits Actin subunit 7 nm Microfilaments form the blue network surrounding the pink nucleus. © 2012 Pearson Education, Inc. 10 nm Intermediate filaments form the purple batlike network. 25 nm Microtubules appear as gold networks surrounding the cells’ pink nuclei. Figure 3.7a-c Fibroblasts Rough ER and Golgi apparatus No organelles Nucleus Erythrocytes (a) Cells that connect body parts © 2012 Pearson Education, Inc. Figure 3.8a Epithelial cells Nucleus Intermediate filaments (b) Cells that cover and line body organs © 2012 Pearson Education, Inc. Figure 3.8b Skeletal muscle cell Contractile filaments Nuclei Smooth muscle cells (c) Cells that move organs and body parts © 2012 Pearson Education, Inc. Figure 3.8c Fat cell Lipid droplet Nucleus (d) Cell that stores nutrients © 2012 Pearson Education, Inc. Figure 3.8d Lysosomes Macrophage Pseudopods (e) Cell that fights disease © 2012 Pearson Education, Inc. Figure 3.8e Processes Rough ER Nerve cell Nucleus (f) Cell that gathers information and controls body functions © 2012 Pearson Education, Inc. Figure 3.8f Flagellum Nucleus Sperm (g) Cell of reproduction © 2012 Pearson Education, Inc. Figure 3.8g Solutions and 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 •Intracellular fluid nucleoplasm and cytosol •Interstitial fluid fluid on the exterior of the cell © 2012 Pearson Education, Inc. Selective Permeability •Selective permeability means the plasma membrane allows some materials to pass while excluding others. •This permeability influences movement both into and out of the cell. © 2012 Pearson Education, Inc. Cell Physiology: Membrane Transport •Membrane transport movement of substances into and out of the cell •Cell membranes are selectively permeable (some substances can pass through but others cannot) •Two basic methods of transport •Passive processes •No energy is required •Active processes •Cell must provide metabolic energy (ATP) © 2012 Pearson Education, Inc. Passive Processes •Diffusion •Particles tend to distribute themselves evenly within a solution •Movement is from high concentration to low concentration, or down a concentration gradient © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 3.9 Passive Processes •Filtration • Water and solutes are forced through a membrane by fluid, or hydrostatic pressure • A pressure gradient must exist • Solute-containing fluid is pushed from a high-pressure area to a lower pressure area © 2012 Pearson Education, Inc. Active Processes •Active transport occurs when substances are transported that are unable to pass by diffusion •Substances may be too large •Substances may not be able to dissolve in the fat core of the membrane •Substances may have to move against a concentration gradient •ATP is used for transport © 2012 Pearson Education, Inc. 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 © 2012 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 PLAY © 2012 Pearson Education, Inc. A&P Flix™: Mitosis Protein Synthesis •Gene DNA segment that carries a blueprint for building one protein •Proteins have many functions •Building materials for cells •Act as enzymes (biological catalysts) •RNA is essential for protein synthesis © 2012 Pearson Education, Inc. Transcription and Translation •Transcription •Transfer of information from DNA’s base sequence to the complimentary base sequence of mRNA •Three-base sequences on mRNA are called codons © 2012 Pearson Education, Inc. Transcription and Translation •Translation •Base sequence of nucleic acid is translated to an amino acid sequence •Amino acids are the building blocks of proteins © 2012 Pearson Education, Inc. Body Tissues •Tissues •Groups of cells with similar structure and function •Four primary types •Epithelial tissue (epithelium) •Connective tissue •Muscle tissue •Nervous tissue © 2012 Pearson Education, Inc. Epithelial Tissues •Locations •Body coverings •Body linings •Glandular tissue •Functions •Protection •Absorption •Filtration •Secretion © 2012 Pearson Education, Inc. Classification of Epithelia •Number of cell layers •Simple one layer •Stratified more than one layer © 2012 Pearson Education, Inc. Apical surface Basal surface Simple Apical surface Basal surface Stratified (a) Classification based on number of cell layers © 2012 Pearson Education, Inc. Figure 3.17a Classification of Epithelia •Shape of cells •Squamous •flattened •Cuboidal •cube-shaped •Columnar •column-like © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 3.17b Connective Tissue •Found everywhere in the body •Includes the most abundant and widely distributed tissues •Functions •Binds body tissues together •Supports the body •Provides protection © 2012 Pearson Education, Inc. Connective Tissue Types •Bone (osseous tissue) •Composed of •Bone cells in lacunae (cavities) •Hard matrix of calcium salts •Large numbers of collagen fibers •Functions to protect and support the body © 2012 Pearson Education, Inc. Bone cells in lacunae Central canal Lacunae Lamella (a) Diagram: Bone © 2012 Pearson Education, Inc. Photomicrograph: Cross-sectional view of ground bone (300×). Figure 3.19a Connective Tissue Types •Hyaline cartilage •Most common type of cartilage •Composed of •Abundant collagen fibers •Rubbery matrix •Locations •Larynx •Entire fetal skeleton prior to birth •Functions as a more flexible skeletal element than bone © 2012 Pearson Education, Inc. Chondrocyte (Cartilage cell) Chondrocyte in lacuna Lacunae Matrix (b) Diagram: Hyaline cartilage © 2012 Pearson Education, Inc. Photomicrograph: Hyaline cartilage from the trachea (500×). Figure 3.19b Connective Tissue Types •Elastic cartilage •Provides elasticity •Location •Supports the external ear •Fibrocartilage •Highly compressible •Location •Forms cushion-like discs between vertebrae © 2012 Pearson Education, Inc. Chondrocytes in lacunae Chondrocites in lacunae Collagen fiber Collagen fibers (c) Diagram: Fibrocartilage © 2012 Pearson Education, Inc. Photomicrograph: Fibrocartilage of an intervertebral disc (110×). Figure 3.19c Connective Tissue Types •Blood (vascular tissue) •Blood cells surrounded by fluid matrix called blood plasma •Fibers are visible during clotting •Functions as the transport vehicle for materials © 2012 Pearson Education, Inc. Blood cells in capillary Neutrophil (white blood cell) White blood cell Red blood cells Red blood cells Monocyte (white blood cell) (h) Diagram: Blood © 2012 Pearson Education, Inc. Photomicrograph: Smear of human blood (1300×) Figure 3.19h Muscle Tissue •Function is to produce movement •Three types •Skeletal muscle •Cardiac muscle •Smooth muscle © 2012 Pearson Education, Inc. Muscle Tissue Types •Skeletal muscle •Under voluntary control •Contracts to pull on bones or skin •Produces gross body movements or facial expressions •Characteristics of skeletal muscle cells •Striated •Multinucleate (more than one nucleus) •Long, cylindrical cells © 2012 Pearson Education, Inc. Nuclei Part of muscle fiber (a) Diagram: Skeletal muscle © 2012 Pearson Education, Inc. Photomicrograph: Skeletal muscle (approx. 300×). Figure 3.20a Muscle Tissue Types •Cardiac muscle •Under involuntary control •Found only in the heart •Function is to pump blood •Characteristics of cardiac muscle cells •Striated •One nucleus per cell •Cells are attached to other cardiac muscle cells at intercalated disks © 2012 Pearson Education, Inc. Intercalated discs Nucleus (b) Diagram: Cardiac muscle © 2012 Pearson Education, Inc. Photomicrograph: Cardiac muscle (430×). Figure 3.20b Muscle Tissue Types •Smooth muscle •Under involuntary muscle •Found in walls of hollow organs such as stomach, uterus, and blood vessels •Characteristics of smooth muscle cells •No visible striations •One nucleus per cell •Spindle-shaped cells © 2012 Pearson Education, Inc. Smooth muscle cell Nuclei (c) Diagram: Smooth muscle © 2012 Pearson Education, Inc. Photomicrograph: Sheet of smooth muscle (approx. 300×). Figure 3.20c Nervous Tissue •Composed of neurons and nerve support cells •Function is to send impulses to other areas of the body •Irritability •Conductivity •Support cells called neuroglia insulate, protect, and support neurons © 2012 Pearson Education, Inc. Brain Nuclei of supporting cells Spinal cord Cell body of neuron Nuclei of supporting cells Cell body of neuron Neuron processes Neuron processes Diagram: Nervous tissue © 2012 Pearson Education, Inc. Photomicrograph: Neurons (150×) Figure 3.21 Tissue Repair (Wound Healing) •Regeneration •Replacement of destroyed tissue by the same kind of cells •Fibrosis •Repair by dense (fibrous) connective tissue (scar tissue) •Whether regeneration or fibrosis occurs depends on: •Type of tissue damaged •Severity of the injury © 2012 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 © 2012 Pearson Education, Inc.