Skeletal, Muscular and
Integumentary Systems
Chapter 36
Skeleton

Endoskeleton
Purpose(s):
1.support
2.protection
3.movement
4.Mineral “bank”
5.Blood cell formation
Structure
Osteon
Ossification of cartilage
Fixed/immovable/suture joints
Detail of movable joint such as
hinge at knee
Muscles

Over 600
 40% mass of human
body
 Greater percent of
men’s body weight
than women’s
 Three different types:
1. cardiac
2. skeletal
3. smooth
Detail of Muscle structure:
Motor Units
Animated Contraction
muscles move
1. Action Potential reaches NMJ
causing release of Acetycholine
2. Ach attaches to receptor on muscle
fiber causing transmission of signal
throughout sarcoplasmic reticulum
3. Calcium gets released from SR
4. Ca attaches to troponin moving
tropomyosin out of active site on actin
5. The myosin head is now able to
attach to actin forming a “crossbridge”
6. The myosin head pivots causing
contraction
7. ATP is used to release the myosing
head and the process begins again
Skeletal muscle function
Skeletal Muscles work in pairs:
Integumentary System
Purpose(s) of Skin:
1. Barrier
2. Body temperature
3. Removes waste
4. Protects against
U.V. radiation