Post on 03-Jan-2016
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Skeletal System
Bones – the organ of the skeletal system
Long Bones
-Longer than they are wide-This bone classification reflects the elongated shape of these bones not the overall size.
Long Bones
Epiphysis – the bone ends
Diaphysis – the shaft that forms the long axis of a long bone
Articular Cartilage – hyaline cartilage that coats the end of bones in synovial joints
Periosteum – a tough, vascular covering of fibrous tissue on the surface of the bone
Long Bones
Processes – sites for attachment of ligaments and tendons
Grooves & openings – passageways for blood vessels and nerves
Depressions – articulate with a process of another bone
Long Bones
Medullary Cavity- The center of the diaphysis - Hollow chamber filled with yellow bone marrow
Endosteum -The thin layer of cells that cover the internal bone structures
Long Bones
Compact Bone-solid, strong, and resistantto bending-makes up wall of diaphysis
Spongy Bone -bone made up of bars and plates separated by irregularspaces, which help reduce weight of bone, provide strength, and decrease compression-make up most of the epiphysis
Compact Bone
Osteocyte – bone cells
Osteon – long, cylindrical shaped structures that runparallel to the long axis of the bone
Osteonic Canals – core of the osteon which contains 2 sm blood vessels that supply nutrients to the bone cells
*The osteocytes are spider shaped cells that occupy the small matrix called the lacunae
Compact Bone
Volkmann’s Canal – (perforating canals) extend longitudinally through bone tissue and connectthe blood and nerve supply to the central canals and marrow cavity.
Intramembranous Bones
-Flat bones that develop from sheet-like masses of connective tissue…..exp (bones in skull)
Osteoblasts – bone forming cell that develops around week 8 of embryonic development
Fontanels. . . Soft spots in the baby's skull where the membrane has not yet been ossified.
Endochondral Bones
-The formation of long bones …..Fig 7.5 p127
epiphyseal disk/plate – between the primary and secondary ossification centers
*This cartilaginous disk thickens as a person grows and new cells divide.
osteoclasts – stimulated to reabsorb bone tissue
Bone Function
1. Support & Protection
2. Body Movement – levers
3. Blood Cell Formation – hematopoiesis: process of blood cell formation
*red marrow – functions in formation of red and white blood cells and blood platelets
*hemoglobin – red oxygen carrying pigment*yellow marrow – functions in fat storage, and is
inactive in blood cell production. It replaces red marrow with age.
Bone Function
4. Storage of Inorganic Salts– excess calcium and phosphorus is stored in intracellular matrix of the bone
Read Osteoporosis in text
Organization Of The Skeleton
I. Axial Skeleton – bony and cartilaginous bones that protect and support the organs of thehead, neck, and trunk.
1. Skull2. Hyoid Bone 3. Vertebral Column4. Thoracic Cage
Figure 6.1 The Axial Skeleton
• Anteriorview of theskeleton,highlightingcomponentsof the axialskeleton.
Organization Of The Skeleton
II. Appendicular Skeleton
1. Pectoral Girdle (scapula and clavicle)2. Upper Limbs (humerus, radius-outside, ulna-inside, carpals, metacarpals, phalanges)3. Pelvic Girdle (coxal bones) 4. Lower Limbs (femur, tibia-inside, fibula-outside, patella, tarsals metatarsals, phalanges)
Skull Consists of 22 bones held together by sutures
Skull
A. Cranium - surrounds and protects the brain, provides sites for muscles attachment (8 bones)
1. Frontal bone 2. Parietal bone (2)3. Occipital bone 4. Temporal bone (2) 5. Sphenoid bone 6. Ethmoid bone
Facial Bones
1. Maxillae 2. Palatine 3. Zygomatic bones 4. Lacrimal bones 5. Nasal bones 6. Vomer 7. Inferior nasal conchae 8. Mandible
Figure 6.2 Cranial and Facial Subdivisions of the Skull
• The skull canbe dividedinto thecranial andthe facialdivisions.
Figure 6.2 Cranial and Facial Subdivisionsof the Skull
Sutures
*Immovable joints*Form boundaries between skull bones
5 Sutures -Coronal (between frontal and parietal bones)
-Sagittal (between parietal bones)
-Lambdoid (between occipital and parietal bones)
-Squamous (between parietal and temporal bones)
-Frontonasal (between frontal and nasal bones)
Figure 6.3a/b The Adult Skull (posterior/superior)
Infantile Skull
Fontanels – fibrous membranes or soft spots that permit movement as skull develops and also helps pass during delivery.
Vertebral Column
-Vertebrae extend from the skull to the pelvis and areseparated by intervertebral disks.
3. Pedicle : 2 short stalks5. Laminae : 2 plates 6. Spinous process : the laminae fuse together4. Transverse process: between the pedicles and
laminae2. Transverse foramen :
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Cervical Vertebrae
•Bony axis of the neck •C1-C7
•The smallest and lightest vertebrae
Cervical Vertebrae
Thoracic Vertebrae
•12 Vertebrae •T1 – T12
•All articulate with ribs
Lumbar Vertebrae
•Large strong bodies to support weight•L1-L5 •Makes up the small of your back •Receives the most stress
Lumbar Vertebrae
Sacrum
•A curved, triangular structure, that shapes the posteriorwall of the pelvis•S1-S5 : fused
Coccyx
•Tailbone, small and triangular•Normally consists of 4 fused bones (sometimes 3 or 5)•Besides giving the pelvic organs little support it is almostuseless
Thoracic Cage -The chest and its bony framework
*Ribs •True ribs (1-7)•False ribs (8-12)•Floating ribs (11-12)
Sternum
1. Manubrium2. Body 3. Xiphoid process
Pectoral Girdle
-Shoulder girdle: consists of the clavicles, and the scapulas
1. Clavicles – collarbones2. Scapulae – shoulder bladea) acromion process – “apex of shoulder”b) coracoid process – “beak-like”c) glenoid cavity – “pit-shaped”
Upper Limbs
-humerous, radius, ulna, carpals, metacarpals, phalanges
Humerous
Radius-outside (lateral bone) of forearm, or thumb side of the forearm-thin at its proximal end and widened at its distal end
Ulna
-inside (medial bone) of forearm, or little finger side of forearm-proximal end is a coronoid process,olecranon process, and trochlear notch - grips the humerus like a pliers
Hand -carpals: (8) wrist -metacarpals: palm-phalanges: fingers
-proximal -middle -distal
Gliding joints
Synovial joints
Skeletal SystemDon’t forget…….
Always wear your…….
HELMET!!!