a & p ch 5 skeleton student version
TRANSCRIPT
© 2012 Pearson Education, Inc.
The Skeletal System
• Parts of the skeletal system• Bones (skeleton)• Joints• Cartilages• Ligaments
• Two subdivisions of the skeleton• Axial skeleton• Appendicular skeleton
http://www.youtube.com/watch?v=8d-RBe8JBVs
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Functions of Bones
• Support the body• Protect soft organs
• Skull and vertebrae for brain and spinal cord• Rib cage for thoracic cavity organs
• Allow movement due to attached skeletal muscles• Store minerals and fats
• Calcium and phosphorus• Fat in the internal marrow cavity
• Blood cell formation (hematopoiesis)
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Bones of the Human Body• The adult skeleton has 206 bones• Two basic types of bone tissue
1. Compact bone
2. Spongy bone• Small needle-like pieces of bone
• Many open spaces
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Classification of Bones on the Basis of Shape
• Bones are classified as:• Long• Short• Flat• Irregular
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Classification of Bones• Long bones
• Typically longer than they are wide• Shaft with heads situated at both ends• Contain mostly compact bone• All of the bones of the limbs
(except wrist, ankle, and bones)
• Example:• Femur• Humerus
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Classification of Bones• Short bones
• Generally cube-shaped• Contain mostly spongy bone• Includes bones of the wrist and ankle• Sesamoid bones are a type of short bone which form within tendons (patella)
• Example:• Carpals• Tarsals
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Classification of Bones• Flat bones
• Thin, flattened, and usually curved• Two thin layers of compact bone surround a layer of spongy bone
• Example: • Skull• Ribs• Sternum
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Classification of Bones• Irregular bones
• Irregular shape• Do not fit into other bone classification categories
• Example:• Vertebrae • Hip bones
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Anatomy of a Long Bone• Diaphysis
• Shaft• Composed of compact bone
• Epiphysis • Ends of the bone
• Composed mostly of spongy bone
Figure 5.3a
Distalepiphysis
Diaphysis
Proximalepiphysis
Articularcartilage
Spongy bone
EpiphyseallinePeriosteum
Compact boneMedullarycavity (linedby endosteum)
(a)
http://www.youtube.com/watch?v=owlpf6zHgyw
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Anatomy of a Long Bone
• Periosteum• Outside covering of the diaphysis• Fibrous connective tissue membrane
• Perforating (Sharpey’s) fibers• Secure periosteum to underlying bone
• Arteries• Supply bone cells with nutrients
• http://www.youtube.com/watch?v=8A0rRIpjutY&feature=relmfu
© 2012 Pearson Education, Inc. Figure 5.3c
Yellowbone marrow
Compact bone
Perforating(Sharpey’s)fibers
Nutrientarteries
Periosteum
Endosteum
(c)
© 2012 Pearson Education, Inc. Figure 5.3b
Compact bone
Spongy bone
Articularcartilage
(b)
Anatomy of a Long Bone
• Articular cartilage• Covers the external surface of the epiphyses
• Made of cartilage
• Decreases friction at joint surfaces
© 2012 Pearson Education, Inc. Figure 5.3a
Distalepiphysis
Diaphysis
Proximalepiphysis
Articularcartilage
Spongy bone
EpiphyseallinePeriosteum
Compact boneMedullarycavity (linedby endosteum)
(a)
• Epiphyseal plate• Flat plate of
hyaline cartilage seen in young, growing bone
• Epiphyseal line• Remnant of
the epiphyseal plate
• Seen in adult bones
Anatomy of a Long Bone
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Anatomy of a Long Bone
•Marrow (medullary) cavity •Cavity inside of the shaft•Contains yellow marrow (mostly fat) in adults
•Contains red marrow for blood cell formation in infants
• In adults, red marrow is situated in cavities of spongy bone and epiphyses of some long bones
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Microscopic Anatomy of Compact Bone
•Osteon (Haversian system)•A unit of bone containing central canal and matrix rings
•Central (Haversian) canal•Opening in the center of an osteon•Carries blood vessels and nerves
•Perforating (Volkmann’s) canal•Canal perpendicular to the central canal•Carries blood vessels and nerves
© 2012 Pearson Education, Inc. Figure 5.4a
CompactbonePeriostealblood vesselPeriosteum
Perforatingfibers
Central (Haversian) canal
Perforating(Volkmann’s) canalBlood vessel
Spongy bone
Blood vessel continues intomedullary cavity containing marrow
Lamellae
(a)
Osteon(Haversian system)
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Microscopic Anatomy of Bone
•Lacunae•Cavities containing bone cells (osteocytes)•Arranged in concentric rings called lamellae
•Lamellae•Rings around the central canal•Sites of lacunae
•http://www.youtube.com/watch?v=cNdwwVCpld8&feature=relmfu
© 2012 Pearson Education, Inc. Figure 5.4b
Lamella
CanaliculusLacunaCentral (Haversian) canal
(b)
Osteocyte
© 2012 Pearson Education, Inc. Figure 5.4c
Osteon
Lacuna
Centralcanal
Interstitiallamellae
(c)
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Microscopic Anatomy of Bone
•Canaliculi •Tiny canals•Radiate from the central canal to lacunae•Form a transport system connecting all bone cells to a nutrient supply
•http://www.youtube.com/watch?v=CQhUINnTdZI&feature=relmfu
© 2012 Pearson Education, Inc. Figure 5.4b
Lamella
CanaliculusLacunaCentral (Haversian) canal
(b)
Osteocyte http://www.youtube.com/watch?v=ylmanEGjRuY&feature=relmfu
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Formation of the Human Skeleton
• In embryos, the skeleton is primarily hyaline cartilage
•During development, much of this cartilage is replaced by bone – called ossification
•Cartilage remains in isolated areas•Bridge of the nose•Parts of ribs•Joints
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Bone Growth (Ossification)
•Epiphyseal plates allow for lengthwise growth of long bones during childhood•New cartilage is continuously formed•Older cartilage becomes ossified
•Cartilage is broken down•Enclosed cartilage is digested away, opening up a medullary cavity
•Bone replaces cartilage through the action of osteoblasts
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Bone Growth (Ossification)
•Bones are remodeled and lengthened until growth stops•Bones are remodeled in response to two factors•Blood calcium levels•Pull of gravity and muscles on the skeleton
•Bones grow in width (called appositional growth)
© 2012 Pearson Education, Inc. Figure 5.5
In a fetusIn an embryo
Bone collar
Hyalinecartilagemodel
Bone startingto replacecartilage
In a child
Medullarycavity
New center ofbone growth
Hyalinecartilage
Epiphysealplate cartilage
Growthin bonelength
New boneforming
Invadingbloodvessels
Epiphysealplatecartilage
Articularcartilage
Spongybone
New boneforming
Growthin bonewidth
http://www.youtube.com/watch?v=t5_3sNLtfxQ
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Types of Bone Cells
•Osteocytes—mature bone cells•Osteoblasts—bone-forming cells•Osteoclasts—giant bone-destroying cells
•Break down bone matrix for remodeling and release of calcium in response to parathyroid hormone
•Bone remodeling is performed by both osteoblasts and osteoclasts
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Bone Fractures
•Fracture—break in a bone•Types of bone fractures
•Closed (simple) fracture—break that does not penetrate the skin
•Compound fracture—broken bone penetrates through the skin
•Bone fractures are treated by reduction and immobilization
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Common Types of Fractures
•Comminuted—bone breaks into many fragments
•Compression—bone is crushed•Depressed—broken bone portion is pressed inward
• Impacted—broken bone ends are forced into each other
•Spiral—ragged break occurs when excessive twisting forces are applied to a bone
•Greenstick—bone breaks incompletely
http://www.youtube.com/watch?v=c5Q5GPwAS4k
Setting a bone: http://www.youtube.com/watch?v=nQVihuOUQkU&feature=related
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Comminuted fracture
Compression fracture
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Depressed fracture
Impacted fracture
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Spiral fracture
Greenstick fracture
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Logan’s leg – spiral, comminuted (he had fragments) & impacted
© 2012 Pearson Education, Inc. Figure 5.7
Internalcallus(fibroustissue andcartilage)
Hematomaforms.
Fibrocartilage callus forms.
Bony callus forms.
Bone remodeling occurs.
1 2 3 4
Hematoma
Bonycallus ofspongybone
Spongybonetrabecula
Newbloodvessels
Externalcallus
Healedfracture
Healing of bone fractures
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Joints
•Articulations of bones•Functions of joints
•Hold bones together•Allow for mobility
•Two ways joints are classified•Functionally•Structurally
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Features of Synovial Joints
•Articular cartilage (hyaline cartilage) covers the ends of bones
•Articular capsule encloses joint surfaces and lined with synovial membrane
•Joint cavity is filled with synovial fluid•Reinforcing ligaments
© 2012 Pearson Education, Inc. Figure 5.31
Acromion of scapula
Ligament
Bursa
Ligament
Tendon sheath
Tendon of biceps muscle
Humerus
Fibrous layer of the articular capsule
Synovial membrane
Articular (hyaline) cartilage
Joint cavity containing synovial fluid
© 2012 Pearson Education, Inc. Figure 5.32a
NonaxialUniaxialBiaxialMultiaxial
(a) Plane joint
(a)
Flat articular surfaces, slipping or gliding movements, intercarpal joints of wrist is best example
© 2012 Pearson Education, Inc. Figure 5.32b
NonaxialUniaxialBiaxialMultiaxial
(b)
HumerusUlna
(b) Hinge joint
One cylindrical surface & one trough-shaped surface, angular movement in one plane, elbow, ankle, phalanges
© 2012 Pearson Education, Inc. Figure 5.32c
NonaxialUniaxialBiaxialMultiaxial
(c)
(c) Pivot joint
UlnaRadius
Rounded end of one bone fits into a sleeve or ring of another, pivoting movement, proximal radioulnar joint
© 2012 Pearson Education, Inc. Figure 5.32e
NonaxialUniaxialBiaxialMultiaxial
(e)
Carpal
(e) Saddle joint
Metacarpal #1
Saddle like surfaces that fit together, side to side & back & forth movements, carpometacarpal joints of thumb (twiddle thumbs to see movements)
© 2012 Pearson Education, Inc. Figure 5.32f
NonaxialUniaxialBiaxialMultiaxial
(f)
Head of humerus
Scapula
(f) Ball-and-socket joint
One spherical head fits into round socket of other, rotational movement (multiaxial), intercarpal joints of shoulder & hip
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Knee Replacement
• Basic knee anatomy• http://www.youtube.com/watch?v=Xxyww3qAt0o• • Knee replacement surgery explained with diagram• • http://www.youtube.com/watch?v=wWQTm6qAPss• • Knee replacement surgery video - graphic but wonderfully explained & only 10 minutes. Let kids who don't want to see this go to either another room or to the lab area of the room.
• http://www.youtube.com/watch?v=vJGJJOA1Me0
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Skeletal System Disorders & Diseases
•Osteoarthritis – disease of the aged; degeneration of articular cartilage
•Bursitis – inflammation of bursae•Rickets – disease of children in which bones fail to calcify; caused by vitamin D deficiency (needed to absorb Ca from intestines into blood)
•Osteoporosis - the creation of new bone doesn't keep up with the removal of old bone. Most common in post menopausal white & Asian women.
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Osteoarthritis
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Bursitis
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Rickets
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Osteoporosis
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Importance of appropriate dietary Ca & strength of bones when young:
•Your bones are in a constant state of renewal — new bone is made and old bone is broken down.
•When you're young, your body makes new bone faster than it breaks down old bone and your bone mass increases.
•Most people reach their peak bone mass by their early 20s. As people age, bone mass is lost faster than it's created.
•How likely you are to develop osteoporosis depends partly on how much bone mass you attained in your youth. The higher your peak bone mass, the more bone you have "in the bank" and the less likely you are to develop osteoporosis as you age.
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Developmental Aspects of the Skeletal System
•At birth, the skull bones are incomplete•Bones are joined by fibrous membranes called fontanels
•Fontanels are completely replaced with bone within two years after birth
© 2012 Pearson Education, Inc. Figure 5.34
Frontal bone of skull
Mandible
RadiusUlna
Humerus
Femur
Tibia
Hip bone
Vertebra
Ribs
Scapula
Clavicle
Occipital bone
Parietal bone
© 2012 Pearson Education, Inc. Figure 5.35a
© 2012 Pearson Education, Inc. Figure 5.35b
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The Axial Skeleton
•Forms the longitudinal axis of the body•Divided into three parts
•Skull•Vertebral column•Bony thorax
© 2012 Pearson Education, Inc. Figure 5.8a(a) Anterior view
Phalanges
Metatarsals
Tarsals
Fibula
Tibia
Patella
Femur
Metacarpals
Phalanges
Carpals
UlnaRadius
Vertebra
Humerus
Rib
Sternum
Scapula
Clavicle
Facial bones
Cranium
Skull
Thoracic cage(ribs andsternum)
Vertebralcolumn
Sacrum
© 2012 Pearson Education, Inc. Figure 5.8a(a) Anterior view
Phalanges
Metatarsals
Tarsals
Fibula
Tibia
Patella
Femur
Metacarpals
Phalanges
Carpals
UlnaRadius
Vertebra
Humerus
Rib
Sternum
Scapula
Clavicle
Facial bones
Cranium
Skull
Thoracic cage(ribs andsternum)
Vertebralcolumn
Sacrum
• Composed of 126 bones
• Limbs (appendages)
• Pectoral girdle• Pelvic girdle
The Appendicular Skeleton
© 2012 Pearson Education, Inc. Figure 5.8b(b) Posterior view
Fibula
Tibia
Femur
Metacarpals
Phalanges
Carpals
RadiusUlna
Vertebra
Humerus
Rib
Scapula
Clavicle
Cranium
Bones ofpectoralgirdle
Upperlimb
Bones ofpelvicgirdle
Lowerlimb
© 2012 Pearson Education, Inc. Figure 5.8a(a) Anterior view
Phalanges
Metatarsals
Tarsals
Fibula
Tibia
Patella
Femur
Metacarpals
Phalanges
Carpals
UlnaRadius
Vertebra
Humerus
Rib
Sternum
Scapula
Clavicle
Facial bones
Cranium
Skull
Thoracic cage(ribs andsternum)
Vertebralcolumn
Sacrum
© 2012 Pearson Education, Inc. Figure 5.8a(a) Anterior view
Phalanges
Metatarsals
Tarsals
Fibula
Tibia
Patella
Femur
Metacarpals
Phalanges
Carpals
UlnaRadius
Vertebra
Humerus
Rib
Sternum
Scapula
Clavicle
Facial bones
Cranium
Skull
Thoracic cage(ribs andsternum)
Vertebralcolumn
Sacrum
• Composed of 126 bones
• Limbs (appendages)
• Pectoral girdle• Pelvic girdle
The Appendicular Skeleton
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The Skull
•Two sets of bones•Cranium•Facial bones
•Bones are joined by sutures•Only the mandible is attached by a freely movable joint
© 2012 Pearson Education, Inc. Figure 5.9
Coronal suture
Parietal bone
Lambdoidsuture
Temporal bone
Squamous suture
Occipital bone
Zygomatic process
External acoustic meatus
Mastoid process
Styloid process
Mandibular ramus
Frontal bone
Sphenoid bone
Ethmoid bone
Lacrimal bone
Nasal bone
Zygomatic bone
Maxilla
Alveolarprocesses
Mandible (body)Mental foramen
© 2012 Pearson Education, Inc. Figure 5.10
Sphenoidbone
Temporal bone
Internalacoustic meatus
Parietal bone
Occipital bone
Foramen magnum
Jugular foramen
Foramen ovale
Sella turcica
Optic canal
Frontal bone
Cribriform plate
Crista galliEthmoidbone
© 2012 Pearson Education, Inc. Figure 5.11
Maxilla(palatine process)Hard
palatePalatine bone
Zygomatic bone
Temporal bone(zygomatic process)
Vomer
Mandibular fossa
Styloid process
Mastoid process
Temporal bone
Parietal bone
Occipital boneForamen magnum
Occipital condyle
Jugular foramen
Carotid canal
Foramen ovale
Sphenoid bone(greater wing)
Maxilla
© 2012 Pearson Education, Inc. Figure 5.12
Coronal suture
Parietal bone
Nasal bone
Sphenoid bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Alveolar processes
Vomer
Inferior nasal concha
Middle nasal conchaof ethmoid bone
Temporal bone
Optic canal
Superior orbital fissure
Frontal bone
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Skull Links to videos & practice• Calvaria bones explained
• http://www.youtube.com/watch?v=9I0t9N-GIRM&feature=plcp• Facial bones exlained
• http://www.youtube.com/watch?v=0oEAyhcHqbE&feature=plcp
• Interactive Practice• http://msjensen.cehd.umn.edu/webanatomy/skeletons_skulls/skull_lateral_7_m.html
• Interactive Practice: roll-over• http://www.gwc.maricopa.edu/class/bio201/skull/antskul.htm
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The Fetal Skull
•The fetal skull is large compared to the infant’s total body length•Fetal skull is 1/4 body length compared to adult skull which is 1/8 body length
•Fontanels—fibrous membranes connecting the cranial bones•Allow skull compression during birth•Allow the brain to grow during later pregnancy and infancy
•Convert to bone within 24 months after birth
© 2012 Pearson Education, Inc. Figure 5.15a
Frontal bone
Parietalbone
(a)
Occipitalbone
Anteriorfontanel
Posterior fontanel
© 2012 Pearson Education, Inc. Figure 5.15b
Anterior fontanel
Frontalbone
SphenoidalfontanelParietal bone
Posteriorfontanel
OccipitalboneMastoidfontanel
Temporal bone
(b)
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http://www.youtube.com/watch?v=rfuT3d63-oo
http://www.youtube.com/watch?v=ViAV9a9Ota8
Craniosynostosis• Explanation video & Jack’s story
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© 2012 Pearson Education, Inc.