Indiana Standard: 5
Osteocyte
The Muscular System
Functions of the 640 Muscles in our Body
• Move bones and joints
• Push substances such as food, fluid and
blood through the body
• Help regulate body temperature by
releasing heat when energy is used, and
by shivering when we are cold.
Osteocyte
The Muscular System
Three Types of Muscle
Smooth Muscle
Cardiac Muscle
Skeletal Muscle
Muscle Cells are Called Muscle Fibers
Osteocyte
The Muscular System
Smooth Muscle
• Involuntary muscle (doesn’t require
thought to move)
• Smooth without striations or stripes
• Lines many organs, examples:
• Moves food through digestive
system
• Empties the bladder
• Pushes baby out during birth
• Regulates width of blood vessels
Osteocyte
The Muscular System
Cardiac Muscle
• Involuntary muscle (doesn’t
require though to move)
• Striated or striped
• Makes up most of the heart
• Pumps blood through the body
• Cells are connected with
intercalated discs that allow
impulses to travel from cell to
cell triggering contractions
Osteocyte
The Muscular System
Skeletal Muscle
• Voluntary (requires thought to
move)
• Striated or striped
• Attached to joints with tendons at
points of origin (immovable end)
and insertion (moveable end)
• Made up of fast twitch and slow
twitch muscle fibers
Osteocyte
The Muscular System
Skeletal Muscle
Point of Origin
•Point of attachment that
does not move.
Point of Insertion
•Point of attachment that
moves.
The Muscular System
Skeletal Muscle
Fast Twitch Muscle Fibers
• Contribute to speed
• Anaerobic respiration
provides energy via
glycolysis
• Less mitochondria
The Muscular System
Skeletal Muscle
Slow Twitch Muscle Fibers
• Contribute to endurance
• Aerobic respiration
provides energy via the
citric acid cycle and
electron transport chain
which yield 36 ATP
• More mitochondria
The Muscular System
Skeletal Muscle Fiber
Muscle Fiber
• Muscle cell
The Muscular System
Skeletal Muscle Fiber
Myofibril
• Long strands of
protein within
muscle fibers
• Contain actin and
myosin filaments
The Muscular System
Skeletal Muscle Fiber
Sarcomere
• Section of a
myofibril
• Contain the actin
and myosin
needed to make
the muscle
contract
The Muscular System
Skeletal Muscle Fiber
Actin
• Thin protein fibers
• Attached to the ends of
the sarcomere which are
called Z lines
• Pulling on actin filaments
causes the sarcomere to
contract
The Muscular System
Skeletal Muscle Fiber
Myosin
• Thick protein fibers
• Attached to the center of
the sarcomere which is
called the M line
• Myosin fibers are
responsible for the pulling
action that causes the
sarcomere to contract
The Muscular System
Increase or Loss of Muscle Tissue
Hypertrophy
• Muscles grow when they are exposed to physical
stress causing microscopic damage
• The body releases cytokines to activating the
immune system to repair damage
• The repetitive process of damage and repair
eventually makes muscles bigger and stronger
• This increase in mass and strength is hypertrophy
The Muscular System
Increase or Loss of Muscle Tissue
Hypertrophy
• The body’s ability to repair muscle affected by:
• Diet
• Rest
• Genetics
Atrophy
• When muscles are not exposed to resistance or
physical stress they shrink
• This is known as atrophy
The Muscular System
Isotonic and Isometric Contractions
Isotonic Contractions
• There IS movement with isotonic exercise
• Isotonic exercise builds muscle
Isometric Contractions
• Isometric exercises are static exercise
• There is NO movement with isometric exercise
• Isometric exercise builds muscle
KAHOOT