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SystemsSystems1

OutlineOutline

Diversity of SkeletonsDiversity of SkeletonsHydrostatic SkeletonHydrostatic SkeletonExoskeletonsExoskeletonsEndoskeletonsEndoskeletons

Human Skeletal SystemHuman Skeletal SystemAxial SkeletonAxial SkeletonAppendicular SkeletonAppendicular Skeleton

Human Muscular SystemHuman Muscular SystemThe MusclesThe MusclesMuscle ContractionMuscle Contraction

Chapter 20 page 402-415

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SystemsSystems2

Hydrostatic SkeletonHydrostatic Skeleton

FunctionsFunctions

Supports body formSupports body form

Provides resistance for the contraction Provides resistance for the contraction of muscles to act againstof muscles to act against

SourceSource

Some organisms use their fluid-filled Some organisms use their fluid-filled gastrovascular cavitygastrovascular cavity

Others use their fluid-filled coelomOthers use their fluid-filled coelom

3Locomotion in an Earthworm

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Exoskeletons and EndoskeletonsExoskeletons and EndoskeletonsExoskeleton - External SkeletonExoskeleton - External Skeleton

Molluscs - composed of calcium Molluscs - composed of calcium carbonatecarbonate

Arthropods - composed of chitinArthropods - composed of chitin

Endoskeleton - Internal SkeletonEndoskeleton - Internal SkeletonEchinoderms and vertebratesEchinoderms and vertebrates

Mineralized bone and cartilageMineralized bone and cartilage

Grows as the animal growsGrows as the animal grows

­Does not limit space for internal organsDoes not limit space for internal organs

­Supports greater weightSupports greater weight

5Exoskeleton

6The Vertebrate Endoskeleton

Locomotion Locomotion and Support and Support

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Human Skeletal SystemHuman Skeletal System

FunctionsFunctions

Supports and protects the bodySupports and protects the body

Permits movementPermits movement

Provides resistive foundation for Provides resistive foundation for muscles to act againstmuscles to act against

Bones store calcium and phosphate Bones store calcium and phosphate ionsions

Certain bones produce red blood cellsCertain bones produce red blood cells

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SystemsSystems8

Bone Growth and RenewalBone Growth and Renewal

Cartilage structures in early development Cartilage structures in early development act as models for future bonesact as models for future bonesCalcium salts deposited in matrix by Calcium salts deposited in matrix by cartilage cells and later by osteoblastscartilage cells and later by osteoblasts

Endochondral ossificationEndochondral ossification

OsteoclastsOsteoclastsBreak down boneBreak down boneRemove worn cellsRemove worn cellsDeposit calcium in the bloodDeposit calcium in the bloodWork with osteoblasts to heal broken Work with osteoblasts to heal broken bonesbones

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Anatomy of a Long BoneAnatomy of a Long BoneGrossGross

Main shankMain shank­ Thick outer cylinder of compact boneThick outer cylinder of compact bone­ Medullary cavity in centerMedullary cavity in center

Spongy bone at endsSpongy bone at endsDetailsDetails

Compact boneCompact bone­ Unit of structure called osteonUnit of structure called osteon­ Concentric lamellae arranged around central Concentric lamellae arranged around central canalcanal

­ Osteocytes lie in lacunae at lamellar boundariesOsteocytes lie in lacunae at lamellar boundaries Spongy boneSpongy bone­ Numerous bars and plates separated by irregular Numerous bars and plates separated by irregular spacesspaces

­ Spaces filled with red bone marrowSpaces filled with red bone marrow

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11

12The Human Skeleton

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SystemsSystems13

The Axial SkeletonThe Axial Skeleton

Lies in the midline of the bodyLies in the midline of the body

Consists ofConsists of

The skullThe skull

The vertebral columnThe vertebral column

The sternum, andThe sternum, and

The ribsThe ribs

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The SkullThe SkullFormed by cranium and facial bonesFormed by cranium and facial bones

Major bones are named afterMajor bones are named after

­ The lobes of the brain, andThe lobes of the brain, and

­ The facial bonesThe facial bones

Foramen magnumForamen magnum

­Opening at base of skullOpening at base of skull

­Where spinal cord connects to brainWhere spinal cord connects to brain

Bones of cranium surround sinusesBones of cranium surround sinuses

15The Skull

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Vertebral ColumnVertebral Column

Vertebral columnVertebral columnSupports the head and trunkSupports the head and trunkProtects the spinal cord and roots of Protects the spinal cord and roots of spinal nerves spinal nerves

Segments (from superior to inferior)Segments (from superior to inferior)Cervical - NeckCervical - NeckThoracic - ThoraxThoracic - ThoraxLumbar - Small of backLumbar - Small of backSacral - SacrumSacral - SacrumCoccyx - TailboneCoccyx - Tailbone

Intervertebral disks of fibrocartilage Intervertebral disks of fibrocartilage act as paddingact as padding

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Rib CageRib Cage

Protects the heart and lungs, and Protects the heart and lungs, and assists breathingassists breathing

Support by the thoracic vertebrae Support by the thoracic vertebrae Twelve pairs of ribsTwelve pairs of ribs

­ True ribsTrue ribs Connect directly to sternumConnect directly to sternum Seven pairsSeven pairs

­ ““False” ribsFalse” ribs Do not connect directly to sternumDo not connect directly to sternum Five pairsFive pairs

18The Rib Cage

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The Appendicular SkeletonThe Appendicular SkeletonConsists ofConsists of

The bones within the pectoral and pelvic The bones within the pectoral and pelvic girdlesgirdles

The attached limbsThe attached limbs

Pectoral girdle – Bones of the shoulderPectoral girdle – Bones of the shoulder

AnteriorAnterior

Supports the arms and handsSupports the arms and hands

Pelvic girdle - Bones of the pelvisPelvic girdle - Bones of the pelvis

PosteriorPosterior

Supports the legs and feetSupports the legs and feet

20Bones of the Pectoral Girdle,

the Arm, and the Hand

21Bones of the Pelvic Girdle,

the leg, and the Foot

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Classification of JointsClassification of Joints

Fibrous JointsFibrous Joints ImmovableImmovableBetween cranial bonesBetween cranial bones

Cartilaginous Joints Cartilaginous Joints Slightly MovableSlightly MovableBetween vertebraeBetween vertebrae

Synovial Joints Synovial Joints Freely MovableFreely MovableBones separated by a cavityBones separated by a cavity

Ligaments bind bones together at jointLigaments bind bones together at joint

23The Knee Joint

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Human Muscular SystemHuman Muscular SystemSkeletal musclesSkeletal muscles

Attached to the skeleton by cable-like Attached to the skeleton by cable-like fibrous connective tissue called tendonsfibrous connective tissue called tendons

Arranged in antagonistic pairsArranged in antagonistic pairs

­ Can only contract, cannot pushCan only contract, cannot push

­ When one muscle contracts, it stretches its When one muscle contracts, it stretches its antagonistic partnerantagonistic partner

A muscle at “rest” exhibits tone (minimal A muscle at “rest” exhibits tone (minimal contraction)contraction)

A muscle in tetany is at maximum sustained A muscle in tetany is at maximum sustained contractioncontraction

25Antagonistic Muscles