Transcript Nerve activates contraction

PowerPoint® Lecture Slides
Prepared by Patty Bostwick-Taylor,
Florence-Darlington Technical College
CHAPTER
3
Cells and
Tissues
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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.
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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
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Nucleus
Cytoplasm
Plasma
membrane
(a)
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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
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Nuclear envelope
Chromatin
Nucleolus
Nucleus
Nuclear
pores
Rough ER
(b)
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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
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The Nucleus
•Nucleoli
•Nucleus contains one or more nucleoli
•Sites of ribosome assembly
•Ribosomes migrate into the cytoplasm
through nuclear pores
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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
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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
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Extracellular fluid
(watery environment)
Glycoprotein Glycolipid
Cholesterol
Sugar
group
Polar heads of
phospholipid
molecules
Bimolecular
lipid layer
containing
proteins
Nonpolar tails
of phospholipid
molecules
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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
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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
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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
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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
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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
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Cytoplasmic Organelles
•Lysosomes
•Contain enzymes produced by ribosomes
•Packaged by the Golgi apparatus
•Digest worn-out or non-usable materials
within the cell
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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)
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(b) Intermediate filaments
(a) Microfilaments
(c) Microtubules
Tubulin subunits
Fibrous subunits
Actin subunit
7 nm
Microfilaments form the blue
network surrounding the pink
nucleus.
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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
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Figure 3.8a
Epithelial
cells
Nucleus
Intermediate
filaments
(b) Cells that cover and line body organs
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Figure 3.8b
Skeletal
muscle cell
Contractile
filaments
Nuclei
Smooth
muscle cells
(c) Cells that move organs and body parts
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Figure 3.8c
Fat cell
Lipid droplet
Nucleus
(d) Cell that stores
nutrients
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Figure 3.8d
Lysosomes
Macrophage
Pseudopods
(e) Cell that fights
disease
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Figure 3.8e
Processes
Rough ER
Nerve cell
Nucleus
(f) Cell that gathers information and controls body
functions
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Figure 3.8f
Flagellum
Nucleus
Sperm
(g) Cell of reproduction
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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
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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.
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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)
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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
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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
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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
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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
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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
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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
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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
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Transcription and Translation
•Translation
•Base sequence of nucleic acid is translated
to an amino acid sequence
•Amino acids are the building blocks of
proteins
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Body Tissues
•Tissues
•Groups of cells with similar structure and
function
•Four primary types
•Epithelial tissue (epithelium)
•Connective tissue
•Muscle tissue
•Nervous tissue
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Epithelial Tissues
•Locations
•Body coverings
•Body linings
•Glandular tissue
•Functions
•Protection
•Absorption
•Filtration
•Secretion
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Classification of Epithelia
•Number of cell layers
•Simple  one layer
•Stratified  more than one layer
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Apical surface
Basal
surface
Simple
Apical surface
Basal
surface
Stratified
(a) Classification based on number of cell layers
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Figure 3.17a
Classification of Epithelia
•Shape of cells
•Squamous
•flattened
•Cuboidal
•cube-shaped
•Columnar
•column-like
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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
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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
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Bone cells in
lacunae
Central canal
Lacunae
Lamella
(a) Diagram: Bone
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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
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Chondrocyte
(Cartilage cell)
Chondrocyte
in lacuna
Lacunae
Matrix
(b) Diagram: Hyaline cartilage
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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
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Chondrocytes
in lacunae
Chondrocites in
lacunae
Collagen fiber
Collagen
fibers
(c) Diagram: Fibrocartilage
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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
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Blood cells
in capillary
Neutrophil
(white blood
cell)
White
blood cell
Red blood
cells
Red
blood cells
Monocyte
(white blood
cell)
(h) Diagram: Blood
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Photomicrograph: Smear of human blood (1300×)
Figure 3.19h
Muscle Tissue
•Function is to produce movement
•Three types
•Skeletal muscle
•Cardiac muscle
•Smooth muscle
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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
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Nuclei
Part of muscle
fiber
(a) Diagram: Skeletal muscle
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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
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Intercalated
discs
Nucleus
(b) Diagram: Cardiac muscle
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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
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Smooth
muscle cell
Nuclei
(c) Diagram: Smooth muscle
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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
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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
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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
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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
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