skeletal/muscular system

• hydrostatic skeleton: fluid in muscular cavity
• exoskeleton: chiton with a waxy coating
• endoskeleton: internal support structure
• human bones - 206
• axial skeleton: skull, rib cage, spinal column (80 bones)
• appendicular: girdles and limbs (126 bones)
• sarcolemma: muscle cell membrane
• sarcoplasm: muscle cell cytoplasm
• myofibrils: protein fibers in muscle cells

  • myofilaments: thin actin and thick myosin
• sarcomere: striations
• sarcomere reticulum: muscle cell endoplasmic reticulum
• transverse tubules: membrane channel into muscle cell, signal to contract reaches area at same time
• Contractioon

  • motor neuron releases the neurotransmitter (acetylcholine)
  • sodium ions diffuse across sarcolemma and through transverse tubules
• Contraction (2)

  • triggers sarcoplasmic reticulum to release calcium ions
  • myosin attached to actin and pulls them toward each other using ATP
  • muscle fiber shortens
  • continues as long as acetylcholine is released by motor neuron
• Relaxation

  • motor neuron ceases stimulation of muscle fiber
  • acetylocholinesterase breaks up remaining acetylcholine
  • calcium ions transported back to sarcoplasmic reticulum
  • myosin lets go of actin filament and muscle fiber relaxes
• facial bones

  • 2 zygomatic: cheek
  • 2 maxillae: upper jaw
  • 2 inferior nasal conchae: inner nasal
  • 2 nasal: bridge of nose
• facial bones

  • 2 palatine: hard palate
  • 2 lacrimal: tear duct
  • 1 vomer: nasal septum
  • 1 mandible: lower jaw
• cranium

  • 1 frontal: forehead
  • 1 occipital: back and bottom
  • 2 temporal: lower sides
• cranium

  • 2 parietal: top and upper sides
  • 1 ethmoid: between nose and eyes
  • 1 sphenoid: center, connects all other cranial bones
• rib cage

  • 1 sternum: breast plate
  • 7 pairs of true ribs: attached directly to sternum
  • 3 pairs of false ribs: attached indirectly to sternum
  • 2 pairs of floating ribs: do not attach to sternum
• vertebral column

  • 7 cervical: neck
  • 12 thoracic: chest
  • 5 lumbar: lower back
• vertebral column

  • 1 sacrum: back of pelvis
  • 1 coccyx: tail bone
• appendicular: girdles and limps (126 bones)
• pectoral girdle

  • 2 scapula: shoulder bone
  • 2 clavicle: collar bone
• arm

  • humerus: upper arm
  • radius: lateral forearm
  • ulna: medial forearm
• hand

  • carpals: wrist
  • scaphoid
  • lunate
  • triquetrum
  • pisiform
  • trapezium
  • trapezoid
  • capitate
  • hamate
• hand

  • metacarpals: palm
  • phalanges: 3 bones per finger, 2 per thumb
• pelvic girdle

  • 2 coxal
  • ilium: top
  • ischium: bottom
  • pubis: front
• leg

  • femur: thigh
  • tibia: medial shin
  • fibula: lateral shin
  • patella: kneecap
• foot

  • tarsals: ankle and heel
  • talus: ankle
  • calcaneus: heel
  • navicular
• foot

  • cuboid
  • 3 cuneiform: medial, intermediate, and lateral
  • metatarsal: sole
  • phalanges: 3 bones per toe, 2 per big toe