Transcript Nerve activates contraction

3
Cells and Tissues
PART A
PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University
ESSENTIALS
OF HUMAN
ANATOMY
& PHYSIOLOGY
EIGHTH EDITION
ELAINE N. MARIEB
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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
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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
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The Nucleus
 Control center of the
cell
 Contains genetic
material (DNA)
 Three regions
 Nuclear
membrane
 Nucleolus
 Chromatin
Figure 3.1b
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Nuclear Membrane
 Barrier of nucleus
 Consists of a double phospholipid membrane
 Contain nuclear pores that allow for exchange
of material with the rest of the cell
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Nucleoli
 Nucleus contains one or more nucleoli
 Sites of ribosome production
 Ribosomes then migrate to the cytoplasm
through nuclear pores
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Chromatin
 Composed of DNA and protein
 Scattered throughout the nucleus
 Chromatin condenses to form chromosomes
when the cell divides
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Plasma Membrane
 Barrier for cell contents
 Double phospholipid layer
 Hydrophilic heads
 Hydrophobic tails
 Also contains protein, cholesterol, and
glycoproteins
PRESS
TO PLAY
MEMBRANE STRUCTURE ANIMATION
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Plasma Membrane
Figure 3.2
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Plasma Membrane Specializations
 Microvilli
 Finger-like
projections that
increase surface
area for absorption
Figure 3.3
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Plasma Membrane Specializations
 Membrane junctions
 Tight junctions
 Desmosomes
 Gap junctions
Figure 3.3
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Cytoplasm
 Material outside the nucleus and inside the
plasma membrane
 Cytosol
 Fluid that suspends other elements
 Organelles
 Metabolic machinery of the cell
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Cytoplasmic Organelles
Figure 3.4
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Cytoplasmic Organelles
 Ribosomes
 Made of protein and RNA
 Sites of protein synthesis
 Found at two locations
 Free in the cytoplasm
 Attached to rough endoplasmic reticulum
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Cytoplasmic Organelles
 Endoplasmic reticulum (ER)
 Fluid-filled tubules for carrying substances
 Two types of ER
 Rough Endoplasmic Reticulum
 Studded with ribosomes
 Site where building materials of cellular
membrane are formed
 Smooth Endoplasmic Reticulum
 Functions in cholesterol synthesis and
breakdown, fat metabolism, and detoxification
of drugs
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Cytoplasmic Organelles
 Golgi apparatus
 Modifies and packages proteins
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Cytoplasmic Organelles
 Lysosomes
 Contain enzymes that digest nonusable
materials within the cell
 Peroxisomes
 Membranous sacs of oxidase enzymes
 Detoxify harmful substances
 Break down free radicals
(highly reactive chemicals)
 Replicate by pinching in half
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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
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Cytoplasmic Organelles
 Centrioles
 Rod-shaped bodies made of microtubules
 Direct formation of mitotic spindle during
cell division
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Cellular Projections
 Not found in all cells
 Used for movement
 Cilia moves materials across the cell
surface
 Flagellum propels the cell
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Cell Diversity
Figure 3.8a–b
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Cell Diversity
Figure 3.8c
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Cell Diversity
Figure 3.8d–e
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Cell Diversity
Figure 3.8f–g
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