the skeletal and muscular systems. the skeletal system the bones of the body make up the skeletal...
TRANSCRIPT
The Skeletal System
• The bones of the body make up the skeletal system (206 bones in adults)
• FUNCTION: Bones provide protection for internal organs and work with muscles to enable movement
Structure of Bones• There are two layers of bone
– 1st LAYER: The outer compact bone-dense connective tissue with a calcium salt matrix (hard)• Bone cells release calcium in rings
forming tubes called Haversian canals
– 2nd LAYER: The inner layer of spongy bone with many cavities… • (bone marrow makes blood cells and
platelets some bone marrow stores fats for energy)
– Covering-tough exterior membrane called the periosteum
Joints
• The place where two bones meet are called joints
• A tough connective tissue called cartilage cushions the bones at the joints
• Bands of connective tissue called ligaments hold bones together
anterior cruciate ligament
cartilage
Types of Joints
• Ball-and-socket joints: allow the widest range of motion – backward, forward, sideways, and in a circle– Hips and shoulders
• Pivot joints: allow a rotation movement– Vertebrae in the neck
• Hinge joints: allow bending and straightening– Knees and knuckles
More Joint Types
• Gliding joints: allow a sliding motion– Wrists and ankles
• Saddle joint: allows rotation and bending– At the base of the thumb
Muscular System
• Although bones allow for movement, they couldn’t do so without the muscular system
• Your body has over 600 muscles
• All muscles are specialized for contraction
"It eats meat. We're meat!” -From Zathura
Types of Muscles
• Smooth muscle – found in organs and blood vessels…under involuntary control
• Cardiac muscle – found only in the heart…under involuntary control
• Skeletal muscle – attached to bones by strips of connective tissue called tendons
How they work…
• Muscles receive a nerve impulse with causes them to contract…
• They are attached to bones in opposing pairs– Flexor muscles cause a joint to bend– Extensor muscles cause a joint to straighten
• Connective tissues called tendons connect the muscles to the bones