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The Animal Body and How It Moves
Chapter 22
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Outline
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Animal Body Plan
Vertebrate Body Organization
Vertebrate Organ Systems
Epithelium
Connective Tissue
Muscle Tissue
Nerve Tissue
Skeletal System
 Bones and Muscles
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Radial Versus Bilateral Symmetry
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Radial Symmetry - body parts are arranged
around a central axis.
Bilateral Symmetry - body has a right and left
half that are mirror images of each other.
 Allows different organs to be located in
different parts of the body.
 Allows for more efficient movement.
 Allows for cephalization - evolution of
definite head and brain area.
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Body Cavity Versus No Cavity
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Presence of body cavity allows dramatic
expansion of portions of digestive tract.
 Allows for more storage and time for
enzymatic activity for enhanced digestion.
- Allows animals to eat more during safe
periods.
 Allows space for gonad expansion.
- Diverse breeding strategies.
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Body Cavity Versus No Cavity
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Kinds of Body Cavities
 Acoleomates - No body cavity.
 Pseudocoelomate - Body cavity located
between endoderm and mesoderm.
 Coelomates - Body cavity forms entirely
within mesoderm.
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Nonsegmented Versus Segmented Bodies
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Advantages of early embryonic segmentation:
 Each segment may develop a more or less
complete set of adult organ systems.
 Locomotion is more effective because of
increased flexibility.
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Protostomes Versus Deuterstomes
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Deuterstomes evolved from protostomes
more than 630 mya. Differ fundamentally in
three aspects of embryonic growth.
 Cleavage
 Blastophore determination of body axis
 Developmental fate of embryo
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Vertebrate Body Organization
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General Architecture
 Food flows from in tube from mouth to anus.
- Suspended in coelom, divided into:
 Thoracic cavity (heart and lungs)
 Abdominal cavity (stomach intestines)
- Supported by skeleton made up of jointed
bones.
- Skull protects brain.
- Vertebral column protects spinal cord.
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Vertebrate Body Organization
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Tissues
 Cells of same type organized into tissues.
 Three fundamental layers
- Endoderm
- Mesoderm
- Ectoderm
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Vertebrate Body Organization
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Adult tissues grouped into four general
classes:
 Epithelial
 Connective
 Muscle
 Nerve
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Vertebrate Body Organization
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Organs
 Body structures composed of several
different tissues grouped together into a
larger structural and functional unit.
Organ Systems
 Group of organs that work together to carry
out important function.
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Vertebrate Organ Systems
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Skeletal
 Bones, Skull, Cartilage, Ligaments
Circulatory
 Heart, Blood Vessels, Blood
Endocrine
 Pituitary, Adrenal, Thyroid Glands
Nervous
 Nerves, Brain, Spinal Cord
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Vertebrate Organ Systems
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Respiratory
 Lungs, Trachea
Immune
 Lymphocytes, Macrophages, Antibodies
Digestive
 Mouth, Esophagus, Stomach, Intestines,
Liver, Pancreas
Urinary
 Kidneys, Bladder
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Vertebrate Organ Systems
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Muscular
 Skeletal, Cardiac, and Smooth Muscle
Reproductive
 Testes, Ovaries
Integumentary
 Skin, Hair, Nails, Sweat Glands
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Epithelium
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Outside of body covered with cells developed
from embryonic ectoderm tissue.
Body cavity lined with cells developed from
embryonic mesoderm tissue.
Hollow inner core of digestive tract lined with
cells developed from embryonic endoderm
tissue.
Collectively termed epithelium.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Epithelium
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Epithelium Functions:
 Protect tissues from dehydration and
mechanical damage.
 Provide sensory surfaces.
 Secrete materials.
Types of Epithelial Cells:
 Squamous
 Cubodial
 Columnar
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Epithelium
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Three general kinds of Epithelial Tissue:
 Simple Epithelium
- Single cell layer thick - lining lungs and
major body cavities.
 Stratified Epithelium
- Complex layer of cells - skin.
 Glands
- Secretion
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Connective Tissue
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Connective tissue cells fall into three
functional categories:
 Immune System - Defense
 Skeletal System - Support
 Blood and Fat - Storage and Distribution
Immune System
 Macrophages - Engulf and digest invaders.
 Lymphocytes - Produce antibodies and
attack virus-infected cells.
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Connective Tissue
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Skeletal Connective Tissue
 Fibroblasts - Secrete structurally strong
proteins into spaces between cells.
 Cartilage - Collagen matrix forms long
parallel arrays along lines of stress.
 Bone - Collagen fibers coated with calcium
phosphate.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Connective Tissue
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Storage and Transport Connective Tissues
 Adipose Tissue - Fat accumulating cells.
 Erthrocytes - Red blood cells that transport
oxygen and carbon dioxide in blood.
- Move in plasma.
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Muscle Tissue
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Distinguishing characteristics of muscle cells
is abundance of contractible protein fibers
(Microfilaments).
 Shortening of fibers produces considerable
force.
Kinds of Muscle Cells
 Smooth - Microfilament loosely organized.
 Skeletal and Cardiac - Microfilaments
bunched into myofibrils (Striated Muscle).
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Nerve Tissue
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Composed of two types of cells:
 Neurons - Specialized for transmission of
nerve impulses.
 Glial Cells - Supply neurons with nutrients,
support, and insulation.
Neuron plasma membranes are rich in ionselective channels that maintain voltage
difference between cell interior and exterior.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Nerve Tissue
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Each neuron composed of:
 Cell Body - Contains nucleus.
 Dendrites - Bring nerve impulses to cell.
 Axon - Carries nerve impulses away.
- Nerve is made of axons of many neurons.
Gaps (synapses) separate neurons.
Neurons communicate by passing
neurotransmitters across the gap.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Types of Skeletons
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Hydraulic - Fluid-filled cavity encircled by
muscle fibers.
Exoskeletons - Rigid hard case surrounding
body.
Endoskeletons - Rigid internal skeleton.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Types of Skeletons
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Human Skeleton
 Made up of 206 individual bones.
- Axial Skeleton (80 bones) support main
body axis.
 Skull, Backbone, and Rib Cage.
- Appendicular Skeleton (126 bones)
support arms and legs.
 Pectoral girdle
 Pelvic girdle
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Structure of Bone
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Bone is produced when needle-shaped
crystals surround and impregnate collagen
fiber.
 Outer bone layer is dense and compact
(compact bone).
 Interior of bone is open lattice structure
(spongy bone).
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Structure of Bone
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New Bone Formed in Two Stages:
 Collagen secreted by osteoblasts which lay
down matrix of fibrils.
 Calcium minerals impregnate fibrils.
- Layers form as series of tubes around
narrow central channel (Haversian
Channel) running parallel to length of
bone.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Structure of Bone
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Two cell types responsible for bone
remodeling during growth:
 Osteoblasts - Deposit bone.
 Osteoclasts - Secrete enzymes that digest
organic matrix of bone, liberating calcium
for reabsorption.
Osteoporosis - Excessive bone loss usually
associated with aging.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Bone Structure
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Kinds of Muscle
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Skeletal Muscle - Move bones of the skeleton.
 Each muscle fiber consists of many
elongated myofibrils, in turn composed of
many myofilaments.
- Contains protein filaments actin and
myosin.
Cardiac Muscle - Composed of chains of
single cells organized into fibers that branch
and interconnect.
 Coupled by gap junctions.
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Kinds of Muscle
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Smooth Muscle - Contain long, spindleshaped cells. Individual myofilaments are not
aligned into orderly assemblies, but into
sheets.
 Some contract only when stimulated by a
nerve or hormone.
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Kinds of Muscle
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Tendons
 Straps of densely connective tissue
attaching muscles to bones.
 Bones pivot about flexible joints, pulled back
and forth by muscles.
- Origin attached by tendon to stationary
bone.
- Insertion attached to bone that moves
during muscle contraction.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Skeletal Muscle Organization
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Skeletal Muscle Organization
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Muscles in movable joints of vertebrates are
attached in opposing pairs:
 Flexors and Extensors
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How Muscles Work
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When myosin filaments contract heads of
myosin filaments move first, moving them
closer in the direction of the flex.
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How Muscles Work
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Nerve fibers embedded in surface of muscle
fiber forming neuromuscular junction.
 When signal reaches end of neuron,
neuron releases acetylcholine into gap
separating neuron from muscle.
- Depolarization
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
How Muscles Work
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Role of Calcium Ions in Contraction
 When muscle is relaxed, attachment sites
for myosin heads are physically blocked by
tropomyosin.
- In order to contract a muscle, troponin
must move tropomyosin.
 Complex regulated calcium ion
concentration.
++ in
 Muscle fibers store Ca
sarcoplasmic reticulum.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Calcium Controls Muscle Contraction
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Review
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Animal Body Plan
Vertebrate Body Organization
Vertebrate Organ Systems
Epithelium
Connective Tissue
Muscle Tissue
Nerve Tissue
Skeletal System
 Bones and Muscles
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Copyright © McGraw-Hill Companies
Permission required for reproduction or display
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies