Anatomy - Physiology of the Skeletal System

8/6/2019 Anatomy - Physiology of the Skeletal System

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Anatomy and Physiology I

Unit 7: The Skeletal System

Physiology of the Skeletal System


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Skeletal System

Bones are made of severaltissues

Primarily made of collagen andhydroxyapatite -Ca10(PO4)6(OH)2

About 206 bones in the humanbody


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Functions of Skeletal System

SUPPORT: Hard framework that supports and anchorsthe soft organs of the body.

PROTECTION: Surrounds organs such as the brain andspinal cord.

MOVEMENT: Allows for muscle attachment thereforethe bones are used as levers.

STORAGE: Minerals and lipids are stored within bone

material.

BLOOD CELL FORMATION: The bone marrow isresponsible for blood cell production.


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Parts of the Skeletal System

Axial skeleton

Skull and bones that support it

Includes vertebra and ribs 80 bones

Appendicular skeleton

Limbs

126 bones


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Features of a Long Bone:

Epiphysis: Ends of the

bone.

Diaphysis: The shaft of

the bone which surrounds

the medullary cavity.

Articular Cartilage:

Cushions the ends of the

bones and allows for

smooth movement.

Epiphyseal Plate:

Areas made of cartilage

allowing for the growth of

the bone.


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Joints

Where bone meets bone

Ligament holds bone to bone

Types of joints: Immovable - skull

Ball-and-socket - shoulder

Hinge - knee Pivot forearm

Gliding - vertebrae


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Cartilage


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Bone Structure

Periosteum hard outer covering Cells for growth and repair

Compact bone hard strong layer

Bone cells, blood vessels, protein with Ca and P

Spongy bone at ends of long bones Has small open spaces to lighten weight

Marrow cavity hollow in middle of long bones


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Bone Marrow

Red marrow produces blood cells and

clotting factors

F

ound in humerus, femur, sternum, ribs,vertebrae, pelvis

Produces RBC 2 million per second

Yellow marrow stores fat

Found in many bones


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Bone Structure


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Haversian System

Structure of compact bone

Rings of bone tissue with blood vessels

and nerves in the center


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Haversian System


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Bone Development

Initial skeleton of cartilage in infants

Replaced with bone by osteoblasts

More than 300 bones at birth fuse to 206

Always growing and breaking down Osteoblasts form new bone cells Osteoclasts break bone cells down

Osteocytes mature bone cells


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Broken Bones

Fracture is a break of the bone Simple or Complex fracture

Regrowth of bone:

Spongy bone forms in first few days Blood vessels regrow and spongy bone hardens

Full healing takes 1-2 months


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Homeostatic Imbalances

Rickets

Disease of children due to a lack of vitamin D.

Calcium is not deposited in bones.

Bones become soft.Bowing of the bones, and other deformities occur.


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Osteomalacia

Rickets of adults.

Due to a lack of vitamin D.Calcium is not deposited in the bones.

Bones become brittle.


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OsteoporosisBone reabsorption is greater than bone deposition.

Due to any of the following:

Lack of estrogen in women.

Lack of exercise to stress the bones.Inadequate intake of calcium and phosphorus.

Abnormalities of vitamin D metabolism.

Loss of muscle mass.


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Age Related Dysfunctions

Arthritis:

Osteoarthritis- 90% of pop. By age 40

chronic inflammation of articular cartilage

can be normal age-dependent change

can also be pathology due to ?

Age-related changes

decrease blood supplytrauma


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Osteoarthritis


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Osteoporosis

Decline in Bone Density

Bone Resorption > Bone Deposition

Increase Risk for Fracture

compression fractures of vertebrae

hip fractures

Role of calcium, vitamin D, estrogen, exercise

Calcitonin vs. Parathyroid Hormone


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Osteoporosis

Anatomy - Physiology of the Skeletal System

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