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A&P. Chapter 5 Notes The skeletal system. SECTION 1. Bones: an overview. SKELETON. GREEK – “DRIED UP BODY” STRONG & LIGHT ADAPTED FOR FUNCTIONS OF PROTECTION & MOTION ABLE TO STAND UPRIGHT W/ BALANCE SYSTEM INCLUDES: JOINTS, CARTILAGES, LIGAMENTS. 2 SKELETAL SUBDIVISIONS. AXIAL
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A&P Chapter 5 Notes The skeletal system
SECTION 1 Bones: an overview
SKELETON • GREEK – “DRIED UP BODY” • STRONG & LIGHT • ADAPTED FOR FUNCTIONS OF PROTECTION & MOTION • ABLE TO STAND UPRIGHT W/ BALANCE • SYSTEM INCLUDES: • JOINTS, CARTILAGES, LIGAMENTS
2 SKELETAL SUBDIVISIONS • AXIAL • FORM THE LONGITUDINAL AXIS • SKULL, VERTEBRAL COLUMN • BONY THORAX
SKELETAL SUBDIVISIONS • APPENDICULAR • BONES OF THE LIMBS & GIRDLES • 126 BONES OF THE LIMBS • PECTORAL GIRDLE FOR • PELVIC GIRDLE ATTACHMENT
FUNCTIONS OF BONES SUPPORT PROTECTION MOVEMENT STORAGE (fat, Ca, P…) BLOOD CELL FORMATION
CLASSIFICATION OF BONES • 206 BONES (in adult) • 2 TYPES • COMPACT-dense, looks smooth • SPONGY-small pieces, open space
SHAPES & SIZES OF BONE • LONG BONES • MORE LONG THAN WIDE; LIMBS • SHORT BONES • MOSTLY SPONGY BONE; WRIST/ANKLE • FLAT BONES • SKULL, RIBS, STERNUM • IRREGULAR BONES • VERTEBRAE, HIPS
LONG BONE STRUCTURE • DIAPHYSIS • SHAFT; COMPACT BONE • PERIOSTEUM • COVERS THE ENDS OF DIAPHYSIS; FIBROUS CONNECTIVE TISSUE; SHARPEY’S FIBERS (CT fibers) • EPIPHYSIS • ENDS OF THE LONG BONE
LONG BONE STRUCTURE • ARTICULAR CARTILAGE • HYALINE CARTILAGE; DECREASE FRICTION • EPIPHYSEAL LINE • REMNANT OF EPIPHYSEAL PLATE • YELLOW MARROW • CAVITY OF SHAFT; FAT STORAGE
LONG BONE STRUCTURE • RED MARROW • FOUND IN SHAFT IN INFANTS • ADULTS-SPONGY BONE OF FLAT BONES OR EPIPHYSES OF LONG BONES 10. BONE MARKINGS • TABLE 5.1 PG 119 • SITES WHERE ATTACHMENTS TAKE PLACE
BONE MARKINGS • PROJECTIONS/PROCESSES • GROW OUT FROM BONE SURFACE • DEPRESSIONS/CAVITIES • INDENTATIONS IN THE BONE
MICROSCOPIC ANATOMY PASSAGEWAY FOR: nutrients & wastes OSTEOCYTES- mature bone cells LACUNAE-matrix which house osteocytes LAMELLAE-concentric circles of lacunae
MICROSCOPIC ANATOMY HAVERSIAN CANAL-lamellae arranged around OSTEON-each complex of a central canal & matrix rings (HAVERSIAN SYSTEM) CANALICULI-tiny canals that radiate outward to all lacunae
MICROSCOPIC ANATOMY NOURISHMENT-bc of elaborate system of canals, bone cells are well nourished VOLKMANN’S CANAL-communication pathway from outside of bone to inside; at right angles to the shaft
MICROSCOPIC ANATOMY • WEIGHT vs. PROTECTION-one of the hardest materials in the body • Light in weight; resists tension; support system w/o giving up mobility • CALCIUM SALTS-in matrix; give bone its hardness • ORGANIC PARTS-collagen fibers; provide bone’s flexibility & strength
BONE FORMATION • SKELETON IS FORMED BY: • CARTILAGE & BONE • 2 OF STRONGEST, MOST SUPPORTIVE TISSUES IN THE BODY • EMBRYONIC: • HYALINE CARTILAGE REPLACED BY BONE • CARTILAGE: • REMAINS IN ISOLATED AREAS (NOSE, RIBS, JOINTS)
OSSIFICATION • 2 MAJOR PHASES: • HYALINE MODEL IS COVERED W/ BONE MATRIX BY BONE FORMING CELLS-OSTEOBLASTS • HYALINE CARTILAGE MODEL IS “DIGESTED” AWAY; MEDULLARY CAVITY OPENS W/IN NEWLY FORMED BONE
CARTILAGE • BY BIRTH MOST HYALINE CARTILAGE HAS BEEN CONVERTED TO BONE EXCEPT: • ARTICULAR CARTILAGE (ENDS OF BONES) • EPIPHYSEAL PLATES (COVER ENDS OF BONES)
BONE GROWTH • BONES MUST WIDEN AS THEY LENGTHEN -> HOW?(pg. 122) • APPOSITIONAL GROWTH • CONTROLLED BY HORMONES
BONE REMODELING • IN RESPONSE TO 2 FACTORS: • CALCIUM LEVELS IN BLOOD • PULL OF GRAVITY & MUSCLES ON THE SKELETON
BONE REMODELING ESSENTIAL IF BONES ARE TO RETAIN NORMAL PROPORTIONS & STRENGTH … …ASSOCIATED WITH Ca LEVELS IN THE BLOOD AND PARATHYROID HORMONE (INCREASE OR DECREASE Ca ions IN THE BLOOD) SEE/READ PG. 122
BONE FRACTURES • BREAKS IN THE BONE RESULTING FROM EXCEPTIONAL TRAUMA THAT TWISTS/SMASHES THE BONES • CLOSED (SIMPLE)-break does not penetrate the skin • OPEN (COMPOUND)-broken bone ends penetrate the skin
BONE FRACTURES • REDUCTION-realignment of the broken bone ends • CLOSED-bone ends are “coaxed” back into position by a Dr. • OPEN-surgery is performed
BONE FRACTURES 4 MAJOR EVENTS TO REPAIR A BONE FRACTURE pg. 124 A HEMATOMA IS FORMED BREAK IS SPLINTED BY A FIBROCARTILAGE CALLUS BONY CALLUS IS FORMED PERMANENT “PATCH” AT FRACTURE SITE
SECTION 2 Axial skeleton
AXIAL SKELETON • FORMS LONGITUDINAL AXIS • 3 PARTS: • SKULL • VERTEBRAL COLUMN • BONY THORAX
AXIAL SKELETON SKULL VERTEBRAL COLUMN BONY THORAX
SKULL FORMED BY 2 SETS OF BONES CRANIUM - Protects the brain FACIAL BONES - Hold the eyes in anterior position/allow facial muscles to function SUTURES – interlocking, immovable joints
CRANIUM • COMPOSED OF 8 LARGE, FLAT BONES • ALL SINGLE BONES, EXCEPT FOR 2 (PARIETAL & TEMPORAL ARE PAIRED) • FRONTAL BONE-forms forehead, projection below eyebrow, superior eye orbital • PARIETAL BONE-superior & lateral walls of the cranium
CRANIUM • TEMPORAL BONES – lie inferior to parietal bones; markings: • External auditory meatus • Styloid process pg • Zygomatic process 126 • Mastoid process • Jugular foramen • Carotid canal
CRANIUM • OCCIPITAL BONES-most posterior bone; forms the floor & back wall • FORAMEN MAGNUM-allows spinal cord to connect to the brain
CRANIUM 5. SPHENOID BONE-spans the width of the skull/forms part of the floor of the cranial cavity 6. ETHMOID BONE-forms the roof of the nasal cavity & part of the orbits
FACIAL BONES 14 BONES; 12 PAIRED; MANDIBLE & VOMER ARE SINGLE • MAXILLAE (paired) • PALATINE BONES (paired) • ZYGOMATIC BONES (paired) • LACRIMAL BONES (paired) • NASAL BONES (paired)
FACIAL BONES 6. VOMER (single bone) 7. INFERIOR CONCHAE (paired) 8. MANDIBLE (single bone)
HYOID BONE NOT A PART OF THE SKULL ONLY BONE THAT DOES NOT ARTICULATE W/ ANOTHER BONE SUSPENDED MID-NECK SERVES AS A MOVABLE BASE FOR THE TONGUE & ATTACHMENT POINT FOR NECK MUSCLES
FETAL SKULL ¼ OF BODY LENGTH (ADULT 1/8) BONES ARE NOT FORMED – HYALINE CARTILAGE FONTANELS-FIBROUS MEMBRANES THAT CONNECT CRANIAL BONES (SOFT SPOTS) 22-24 mos. = BONE
VERTEBRAL COLUMN AXIAL SUPPORT OF THE BODY EXTENDS FROM THE SKULL TO PELVIS BODY WT. IS TRANSMITTED TO LOWER LIMBS 26 IRREGULAR BONES/REINFORCED W/ LIGAMENTS SPINAL CORDS RUNS THROUGH CENTRAL CAVITY
VERTEBRAL COLUMN • PRE-BIRTH=33 SEPARATE VERTEBRAE • 2 FUSED FORM SACRUM & COCCYX • ADULT=24 VERTEBRAE • 7 CERVICAL (NECK) • 12 THORACIC (MIDDLE) • 5 LUMBAR (LOWER BACK)
VERTEBRAL COLUMN • INTEVERTEBRAL DISCS– SEPARATE EACH VERTEBRAE; CUSHION/SHOCK ABSORB • AGING OF DISCS: • YOUNG = 90% WATER/SPONGY/COMPRESSIBLE • OLDER= WATER CONTENT , BECOME HARDER/LESS COMPRESSIBLE
VERTEBRAL COLUMN • HERNIATED DISCS: • DRYING OF DISCS • WEAKENING OF LIGAMENTS • PROTRUDING DISC PRESSES ON SPINAL NERVES->PAIN/NUMBNESS
VERTEBRAL COLUMN • CURVATURES: • PRIMARY-THORACIC & SACRAL REGIONS/ PRESENT @ BIRTH • SECONDARY: OCCUR WHEN WE: • CERVICAL – BABY RAISES H/HER HEAD • LUMBAR – BEGIN TO WALK
VERTEBRAL COLUMN • ABNORMAL SPINAL CURVATURES: • SCOLIOSIS • KYPHOSIS PAGE 132 • LORDOSIS MAY BE CONGENITAL OR RESULT FROM POOR POSTURE, DISEASE, UNEQUAL MUSCLE TONE/PULL