1. Skeletal System The skeleton has six major functions:
support
movement
protection
production of blood cells
storage of calcium
endocrine regulation
The skeletal system has 4 major components:
Bones – hard stuff that protects your organs and your muscle attach to
Cartilage – floppy stuff your ear is made of
Tendons – tissue that attached bones to muscles
Ligaments – tissue that attaches bones to bones

2. Functions of Skeleton Support Movement Protection
-- The skeleton provides a place for our muscle’s ligaments to attach to. It also helps us keep our shape. Without it we would be gelatinous lumps of flesh.
Movement
-- The skeleton provides a supporting structure for our muscle’s ligaments to attach to and contract (pull) against, thus creating movement with the help of joints.
Protection
-- Our bones protect our most fragile organs. The skull protects our brain, our vertebrae protect our spinal chord, and our ribcage, spine, and sternum protects our the lungs, heart, major blood vessels, liver, and spleen.
Production of blood cells
-- Red (allow us to eat, breath, and live) and white (protect us from infections) blood cells are made in the bone marrow located inside of our bones. Our bone marrow produces about 500 billion blood cells per day.
Storage of minerals
-- Bones matrix (the hard part of our bones) stores and metabolizes (uses) calcium. Bone marrow (the gooey stuff at the center of bones) stores and metabolizes (uses) iron.
Endocrine regulation
-- Bone cells release a hormone called osteocalcin, which helps your body maintain normal blood sugar (glucose) and body fat levels. Osteocalcin also increases the body's insulin secretion and insulin sensitivity.

3. Muscular System Three Major functions Three types of muscles:
Movement food through the digestive system (peristalsis)
Movement of blood through the circulatory system
Movement of the body by attaching to the skeletal system.
Three types of muscles:
smooth muscles (involuntary, control movement of blood vessels, aorta, arteries, veins, bladder, uterus, reproductive tracts, gastrointestinal tract, respiratory tract, and iris of the eye
cardiac muscle (the heart) (involuntary, pumps blood by stimulations from the sinoatrial node)
Skeletal muscles (voluntary muscles attached to bones by bundles of collagen fibers known as tendons)

4. Functions of the Muscular System
Food (glucose)
Movement
-- Walking, lifting, pushing, pulling, eye movement, heart pumping, swallowing, breathing, urination, contractions of digestive tract (peristalsis), bowel movement, etc.
-- In order to move, muscle cells need food for energy (chemical). Cell food is glucose (sugar) which gets turned into ATP. ATP is the “energy currency” of the body.
Maintain Position
-- Standing still (not collapsing)
Circulate blood
-- The heart is a muscle that pumps blood to all cells throughout the body. This blood is rich in oxygen, glucose, and other substances the body's cells need to live.
Muscle Movement
Oxygen
(energy currency of the body)