Transcript MUSCULAR SYSTEM I

MUSCULAR SYSTEM
pp. 917-920
FUNCTION
• Support, movement, and protection
TYPES
• skeletal – muscles that move bones
(voluntary)
• smooth – involuntary muscles that protect
organs
• cardiac – involuntary muscles found only in
heart
MUSCLE STRUCTURE (external)
• Tendons connect
muscle to bone
• When the muscle
moves, the bones move,
and the joint bends
MUSCULAR MOVEMENT
•
Muscles arranged in opposing pairs and
while one relaxes the other contracts
flexor: contraction bends the joint
extensor: contraction straightens the
joint
MUSCLE STRUCTURE (internal)
myofibril muscle cell (fiber)fascicle muscle
• Two types of proteins (actin and myosin)
involved
• actin + myosin  myofibril
• myofibril attaches to Z line
• sarcomere: functional unit from Z line to Z
line
MUSCLE CONTRACTION
• contraction: shortening of sarcomere
between Z –lines
• myosin “heads” walk along the actin
• this requires ATP to walk and to release the
myosin after walking
ENERGY and FATIGUE
•
•
Aerobic respiration: breaking down
organic compounds to release energy to be
used by the body
Fatigue is the inability to contract (and
release) the muscle due to the lack of ATP
SKELETAL SYSTEM
pp 911-916
FUNCTION
•
•
•
Bones supports and
protects organs
Gives shape and
structure to the body
Produce red and
white blood cells
SKELETON
• Axial –the skull, face, vertebral column, and
rib cage.
• Appendicular –the arms and legs, pelvis,
scapula, collar bone, etc
• Includes bones and their associated tissues
(cartilage and ligaments)
BONE STRUCTURE
• Porous and made of proteins and minerals and
contains:
a) Osteocytes –cells that make bone
b) Bone marrow – soft bone tissue that
produces platelets and blood cells
BONE DEVELOPMENT
• Bones develop from cartilage hardening
(ossification)
JOINTS
• Place where two
bones meet
• Fixed: no movement between bones (ex.
skull).
• Semimovable: limited movement (i.e. rib
cage and vertebrae)
• Movable: see your coloring
JOINT STRUCTURE
• Cartilage between joints for cushion
• Ligaments connect joints