Transcript chapter_41_powerpoint_l

Chapter 41
Locomotion and
Support Systems
Outline
Diversity of Skeletons
Hydrostatic Skeleton
Exoskeletons
Endoskeletons
Human Skeletal System
Axial Skeleton
Appendicular Skeleton
Human Muscular System
The Muscles
Muscle Contraction
Locomotion and
Support Systems
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Hydrostatic Skeleton
Locomotion and
Support Systems
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Functions
Supports body form
Provides resistance for the contraction of muscles
to act against
Source
Some organisms use their fluid-filled
gastrovascular cavity
Others use their fluid-filled coelom
Locomotion in an Earthworm
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Locomotion and
Support Systems
Exoskeletons and Endoskeletons
Exoskeleton - External Skeleton
Molluscs - composed of calcium carbonate
Arthropods - composed of chitin
Endoskeleton - Internal Skeleton
Echinoderms and vertebrates
Mineralized bone and cartilage
Grows as the animal grows
- Does not limit space for internal organs
- Supports greater weight
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Exoskeleton
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The Vertebrate Endoskeleton
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Human Skeletal System
Locomotion and
Support Systems
Functions
Supports and protects the body
Permits movement
Provides resistive foundation for muscles to act
against
Bones store calcium and phosphate ions
Certain bones produce red blood cells
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Bone Growth and Renewal
Locomotion and
Support Systems
Cartilage structures in early development act as
models for future bones
Calcium salts deposited in matrix by cartilage
cells and later by osteoblasts
Endochondral ossification
Osteoclasts
Break down bone
Remove worn cells
Deposit calcium in the blood
Work with osteoblasts to heal broken bones
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Anatomy of a Long Bone
Locomotion and
Support Systems
Gross
Main shank
- Thick outer cylinder of compact bone
- Medullary cavity in center
Spongy bone at ends
Details
Compact bone
- Unit of structure called osteon
- Concentric lamellae arranged around central canal
- Osteocytes lie in lacunae at lamellar boundaries
Spongy bone
- Numerous bars and plates separated by irregular spaces
- Spaces filled with red bone marrow
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Anatomy of a Long Bone
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The Human Skeleton
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The Axial Skeleton
Lies in the midline of the body
Consists of
The skull
The vertebral column
The sternum, and
The ribs
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Support Systems
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Locomotion and
Support Systems
The Skull
Formed by cranium and facial bones
Major bones are named after
- The lobes of the brain, and
- The facial bones
Foramen magnum
- Opening at base of skull
- Where spinal cord connects to brain
Bones of cranium surround sinuses
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The Skull
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Vertebral Column
Locomotion and
Support Systems
Vertebral column
Supports the head and trunk
Protects the spinal cord and roots of spinal
nerves
Segments (from superior to inferior)
Cervical - Neck
Thoracic - Thorax
Lumbar - Small of back
Sacral - Sacrum
Coccyx - Tailbone
Intervertebral disks of fibrocartilage act as
padding
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Rib Cage
Locomotion and
Support Systems
Protects the heart and lungs, and assists
breathing
Support by the thoracic vertebrae
Twelve pairs of ribs
- True ribs
 Connect
 Seven
directly to sternum
pairs
- “False” ribs
 Do
not connect directly to sternum
 Five
pairs
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The Rib Cage
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The Appendicular Skeleton
Locomotion and
Support Systems
Consists of
The bones within the pectoral and pelvic girdles
The attached limbs
Pectoral girdle – Bones of the shoulder
Anterior
Supports the arms and hands
Pelvic girdle - Bones of the pelvis
Posterior
Supports the legs and feet
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Bones of the Pectoral Girdle,
the Arm, and the Hand
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Bones of the Pelvic Girdle,
the leg, and the Foot
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Classification of Joints
Locomotion and
Support Systems
Fibrous Joints
Immovable
Between cranial bones
Cartilaginous Joints
Slightly Movable
Between vertebrae
Synovial Joints
Freely Movable
Bones separated by a cavity
Ligaments bind bones together at joint
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The Knee Joint
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Human Muscular System
Locomotion and
Support Systems
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Skeletal muscles
Attached to the skeleton by cable-like fibrous connective
tissue called tendons
Arranged in antagonistic pairs
- Can only contract, cannot push
- When one muscle contracts, it stretches its antagonistic
partner
A muscle at “rest” exhibits tone (minimal contraction)
A muscle in tetany is at maximum sustained contraction
Human Musculature
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Antagonistic Muscles
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Locomotion and
Support Systems
Microscopic Anatomy and Physiology
Sarcolemma
Plasma membrane
Sarcoplasmic Reticulum
Modified endoplasmic reticulum
Myofibrils
Contractile structures in sarcoplasm
Sarcomeres
Units of contraction
Consist primarily of proteins
- Myosin
- Actin
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Skeletal Muscle Fiber
Structure and Function
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Sliding Filament Model
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Support Systems
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Actin filaments at both ends of sarcomere
 One end of each filament attached to a Z-plate at one end of the
sarcomere
 Other end suspended in sarcoplasm
Myosin filaments suspended in between Z-plates
 Myosin filaments contain cross-bridges which pull the actin filaments
inward
 Causes Z-plates to move toward each other
 Shortens sarcomere
 Sarcomeres stacked together in series and cause myofiber to
shorten
Working muscles require ATP
 Myosin breaks down ATP
 Sustained exercise
- Requires cellular respiration
- Regenerates ATP
Muscle Innervation
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Support Systems
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Neuromuscular junction
The synaptic contact between a nerve fiber and a
muscle fiber
Nerve impulses bring about the release of a
neurotransmitter that cross the synaptic cleft
Signals the muscle fiber to contract
Neuromuscular Junction
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The Role of Calcium and Myosin in
Muscle Contraction
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Review
Diversity of Skeletons
Hydrostatic Skeleton
Exoskeletons
Endoskeletons
Human Skeletal System
Axial Skeleton
Appendicular Skeleton
Human Muscular System
The Muscles
Muscle Contraction
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Support Systems
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Ending Slide Chapter 41
Locomotion and
Support Systems