Download Chapter 6 Notes from PowerPoint o Skeleton: Overview o Functions

Chapter 6 Notes from PowerPoint
o Skeleton: Overview
o Functions of the Skeleton
• Support
• Protection
• Blood cell production
• Storage
• Movement
o Anatomy of a Long Bone
o Bone Growth and Repair
o Surface Features of Bones
o Skeleton: Overview
o Classification
• Long – longer than they are wide
• Short – cube shaped
• Flat – plate-like, with broad surfaces
• Irregular – varied shapes
• Round – circular in shape
o Skeleton: Overview
o Anatomy of a Long Bone
• Periosteum – tough, connective tissue covering
• Epiphysis – expanded portion at the ends of bones
• Diaphysis – portion between the epiphyses
• Medullary cavity – hollow portion of diaphysis containing yellow marrow
• Articular cartilage – layer of hyaline cartilage where bones join together
• Endosteum – lines the medullary cavity and the spaces of spongy bone
o Skeleton: Overview
• Compact Bone
 Lacunae – contain bone cells (osteocytes)
 Lamellae – concentric layers of matrix containing collagen fibers and mineral salts
 Blood vessels and nerves enter the central canal
• Spongy Bone
 Contains bony bars and plates called trabeculae
 Trabeculae follow lines of stress, giving bones strength
o Skeleton: Overview
o Bone Growth and Repair
• Osteoprogenitor cells – unspecialized cells
• Osteoblasts – bone forming cells
• Osteocytes – mature bone cells
• Osteoclasts – break down bone
o Skeleton: Overview
• Bone Development and Growth
 Ossification – formation of bone
 Intramembranous ossification
Bone forms between two sheets of fibrous connective tissue
Form bones of the skull
 Endochondral ossification
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Form most bones of the human body
Hyaline cartilage models are replaced by bone
 Epiphyseal plate
 Band of cartilage in the epiphyses of long bones
 Long bone growth continues until plate is ossified
 Appositional growth – increase in bone diameter
Skeleton: Overview
• Remodeling of Bones
 Bone is continually being broken down and built up again
 Osteoclasts remove worn cells and deposit calcium in the blood
 Osteoblasts remove calcium from the blood and form new bone
 Three important hormones regulating bone growth
 Parathyroid hormone
 Calcitonin
 Growth hormone
Skeleton: Overview
• Bone Repair
 Required after it fractures (breaks)
 Steps involved in bone repair
 Hematoma
 Fibrocartilaginous callus
 Bony callus
 Remodelling
 Naming of fractures
 Complete – bone is broken through
 Incomplete – bone is not separated into two parts
 Simple – does not pierce the skin
 Compound – pierces the skin
 Impacted – broken ends are wedged into each other
 Spiral – ragged break due to twisting of bone
 Reduction – repair of a fracture
Closed reduction – re-aligning bone fragments without surgery
Open reduction – surgical repair of the bone using plates, screws, or pins
Axial Skeleton
Lies in the midline of the body
Bones of the axial skeleton
• Skull
• Hyoid bone
• The vertebral column
• The thoracic cage
• Middle ear bones
Axial Skeleton
• Skull
 Formed by the cranium and the facial bones
 Sinuses
 Air spaces within the bones
 Lined by mucous membranes
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Reduce the weight of the skull
Give the voice a resonant sound
Paranasal sinuses
Maxillary
Frontal
Sphenoidal
Ethmoidal
Mastoid sinuses
Axial Skeleton
• Bones of the Cranium
 Protects the brain
 Sutures – immovable joints
 Composed of eight bones
 Frontal bone
 Parietal bones
 Occipital bone
 Temporal bones
External auditory meatus
Mandibular fossa
Mastoid process
Styloid process
Zygomatic process
 Sphenoid bone
 Ethmoid bone
Crista galli
Cribriform plate
Perpendicular plate
Superior and middle nasal conchae
• Axial Skeleton
• Bones of the Face
 Maxillae
 Alveolar process
 Palatine process
 Palatine bones
 Zygomatic bones
 Lacrimal bones
 Nasal bones
 Vomer bone
 Inferior nasal conchae
 Mandible
 Mandibular condyle
 Coronoid process
• Skeletal Muscles of the Body
• Hyoid bone
 Superior to larynx
 Only bone in the body that does not articulate with another bone
 Anchors the tongue
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 Site of attachment for muscles associated with swallowing
Axial Skeleton
• Vertebral Column (Spine)
 Supports rib cage
 Serves as a point of attachment for the pelvic girdle
 Protects the spinal cord
 Consists of a series of separate bones named for their location
 Seven cervical (neck)
 Twelve thoracic (chest)
 Five lumbar (lower back)
 Five sacral
 Three to five coccygeal
 Normal curvatures
• Axial Skeleton
 Normal curvatures
 Cervical and lumbar – convex anteriorly
 Thoracic and sacral – concave anteriorly
 Provide support and balance
 Abnormalities
Lordosis – exaggerated lumbar curvature
Kyphosis – increased roundness of the thoracic curvature
Scoliosis – abnormal lateral curvature that occurs most often in the thoracic
region
• Axial Skeleton
• Intervertebral Disks
 Prevent vertebrae from grinding against one another
 Absorb shock
 Allow motion between vertebrae
• Vertebrae
 Body – anterior portion
 Vertebral foramin – canal for spinal cord
 Bony projections serve as sites for muscle attachment
 Atlas (C1) – supports the head; allows head movement up and down
 Axis (C2) - serves as a pivot for the atlas; allows head movement from side to side
 Sacrum – fused sacral vertebrae; forms posterior wall of the pelvic cavity
 Coccyx – formed from a fusion of three to five vertebrae
• Axial Skeleton
• The Rib Cage
 Protects the heart and lungs
 Provides support for the bones of the pectoral girdle
 The ribs
 Twelve pair that connect to the thoracic vertebrae
 True ribs – upper seven pairs connect directly to the sternum by costal cartilages
 False ribs – next five pair that attach indirectly to the sternum or not at all (“floating”
ribs)
 The sternum
 Flat, blade-shaped bone
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Composed of three bones that fuse
Manubrium
Body
Xiphoid process
Appendicular Skeleton
Pectoral Girdle
• Clavicles
 Articulate medially with the manubrium
 Only attachment to the axial skeleton
 Serves as a brace for the scapula and stabilizes the shoulder
• Scapulae
 Spine
 Acromion process
 Coracoid process
 Glenoid cavity
Appendicular Skeleton
Upper Limb
• Humerus
 Long bone of the arm
 Head articulates with the glenoid cavity of the scapula
 Greater and lesser tubercles serve as attachments for muscles
 Intertubercular groove holds a tendon from the biceps brachii
 Deltoid tuberosity attaches the deltoid
 Capitulum articulates with the head of the radius
 Trochlea articulates with the ulna
 Coronoid fossa
 Olecranon fossa
Appendicular Skeleton
• Radius
 Lateral side of the forearm
 Head articulates with the capitulum of the humerus and fits into the radial notch of the ulna
 Radial tuberosity attaches a tendon from the biceps brachii
 Ulnar notch articulates with the head of the ulna
 Styloid process attaches ligaments that run to the wrist
• Ulna
 Longer bone of the forearm
 Coronoid process articulates with the coronoid fossa when elbow is flexed
 Olecranon process articulates with the olecranon fossa when the elbow is extended
 Trochlear notch articulates with the trochlea of the humerus
 Head articulates with the ulnar notch of the radius
 Styloid process attaches ligaments that run to the wrist
Appendicular Skeleton
• Hand
 Wrist (carpus) contains eight small bones
 Metacarpal bones form the palm
 Phalanges
 Bones of the fingers
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 The thumb has only two phalanges (proximal and distal)
 The other fingers have three phalanges each (proximal, middle, and distal)
Appendicular Skeleton
Pelvic Girdle
• Coxal bones
 Ilium
 Ischium
 Pubis
 Pubic symphysis
 Obturator foramen
• Gender differences
 Female has broader hips
 Female pelvis is wider
 Female inlet and outlet of the true pelvis are wider
 Female pelvic cavity is more shallow
 Female bones are lighter and thinner
 Female pubic arch is wider
Appendicular Skeleton
Lower Limb
• Femur
 Longest and strongest bone in the body
 Head fits into acetabulum of coxal bone
 Greater and lesser trochanters attach muscles of the thigh and buttocks
 Linea aspera attaches several muscles
 Medial and lateral epicondyles attach muscles and ligaments
 Lateral and medial condyles articulate with the tibia
 Patellar surface articulates with the patella
Appendicular Skeleton
• Tibia
 Medial bone of the lower leg
 Bears the weight from the femur
 Medial and lateral condyles articulate with the femur
 Tibial tuberosity attach patellar ligaments
 Anterior crest
 Medial malleolus articulates with the talus in the foot
• Fibula
 Lateral to the tibia
 Stabilizes ankle
Appendicular Skeleton
• Foot
 Seven tarsal bones
 Only the talus can move freely
 The calcaneus and the talus support the weight of the body
 Five metatarsal bones form the instep
 The phalanges form the toes
 Big toe has only two
 Three each in other toes
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 Joints (Articulations)
Classification according to the amount of movement
• Synarthrosis – immovable
• Amphiarthrosis – slightly moveable
• Diarthrosis – freely moveable
Classification according to structure
• Fibrous
• Cartilaginous
• Synovial
Joints (Articulations)
• Fibrous – fibrous connective tissue
 Fibrous connective tissue joins bone to bone
 Typically immovable
 Sutures of the cranium
 Coronal – between the parietal bones and the frontal bone
 Lambdoidal – between the parietal bones and the occipital bone
 Squamosal – between each parietal bone and each temporal bone
 Sagittal – between the parietal bones
 Joints formed by each tooth in its socket
Joints (Articulations)
• Cartilaginous
 Bones are joined by fibrocartilage or hyaline cartilage
 Usually slightly moveable
• Synovial
 Bones do not touch each other
 Bones are separated by a joint cavity
 Usually freely moveable
Joints (Articulations)
 Types of synovial joints
 Saddle joint
 Ball-and-socket joint
 Pivot joint
 Hinge joint
 Gliding joint
 Condyloid joint
Joints (Articulations)
 Movements permitted by synovial joints
 Angular movements
Flexion
Extension
Adduction
Abduction
 Circular movements
Circumduction
Rotation
Supination
Pronation
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Special movements
Inversion and eversion
Elevation and depression
Effects of Aging
Cartilage and bone tend to deteriorate
Articular cartilage may not function properly, resulting in arthritis
• Osteoarthritis – deterioration of the articular cartilage
• Rheumatoid arthritis – synovial membrane becomes inflamed
• Gout – excessive buildup of uric acid
Osteoporosis is common
Homeostasis
Functions of the Skeletal System
• Protection of internal organs
• Bones assist in all phases of respiration
• Bones store and release calcium
• Bones assist the lymphatic system and immunity
• Bones assist digestion
• The skeleton is necessary to locomotion
Homeostasis
Functions of Other Systems
• The integumentary and the muscles assist in protecting internal organs
• The digestive system absorbs calcium from food and the endocrine system regulates the storage of
calcium in the bones
• Movement of the bones is only possible because of the contraction of skeletal muscle