Sunday, September 25, 2016

ch. 5 | the skeletal system

functions of skeletal system:
  1. support- provides framework to support soft tissues
  2. protection- protects internal organs from injury
  3. movement- muscles provide force while bones serve as levers 
  4. mineral homeostasis- bone tissue stores calcium & phosphorus 
  5. blood cell protection- red bone marrow goes through hemopoiesis (blood cell production)
  6. triglyceride storage- yellow bone marrow is made of adipose cells which stores triglycerides
  • the adult skeletal system is made of 206 different bones
4 types of bones:
  1. long- longer than they are wide, knobby ends, curved structure (arms, legs, fingers, toes)
  2. short- equal in width & length (wrists, ankles)
  3. flat- thin, provide protection & surfaces for muscle attachments (skull, sternum, ribs)
  4. irregular- complex shapes (face, vertebral column)
parts of a long bone:
  • diaphysis: middle of long bone, hollow
has a hollow chamber called medullary cavity 
contains yellow marrow which stores fat 
  • epiphysis: end of long bone, solid
contains red marrow which produces red blood cells
covered by articular cartilage
  • periosteum: tough membrane covering the bone 
  • osteoblasts: build extracellular matrix; when entrapped in matrix--> becomes osteocytes
  • osteoclasts: digest & reabsorb proteins & minerals from matrix
axial skeleton: 80 bones
  • foramen: holes in a bone for passage of vessels or nerves
cranial bones:
  • suture: immovable joint that joins most of the skull bones
  • fontanels: soft spots on a baby's head- allow the bones of skull to compress as baby is born & provide room for brain to grow 
  • hyoid bone: located in the neck, suspended from styloid process; supports tongue, stabilizes airways, provides attachment points for tongue/neck/pharyngeal muscles 

vertebral column: 26 vertebrae

  • types of vertebrae:
-cervical: (7) has 3 openings, neck region
-thoracic: (12) posterior to chest, attachment points for ribs
-lumbar: (5) form lower back
-sacrum: (5 fused into 1) posterior wall of pelvis
-coccyx: (4 fused into 1) tailbone 
  • parts of a vertebrae:

appendicular skeleton: 126 bones
  • clavicle & scapula:

  • humerus:
  • radius & ulna:
  • hand:
  • pelvic girdle:
  • femur:
  • knee:
  • fibula & tibia:
  • foot:

types of joints:
  • hinge joint:
  • pivot joint:
  • plane joint:
  •  ball-and-socket:

  • dorsiflexion: instep of foot moved toward shin
  • plantar flexion: toes pointed downward
  •  flexion: decreases angle btwn bones
  • extension: increases angle btwn bones
  • elevation: upward
  • depression: downward
  • lateral rotation: turn away from midline (horizontally)
  • medial rotation: turn towards midline (horizontally)
  • abduction: move away from midline (vertically)
  • adduction: move towards midline (vertically)

joints classified structurally:
  • fibrous: no movement

  • cartilaginous: 

  • synovial: freely movable

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