Chapter 14 Human Locomotion

In humans, locomotion involves the interaction of: 1. Bones 2. Cartilage 3. Muscles 4. Tendons 5. Ligaments

(I) Bones Composed mainly of calcium Made up of living bone cells and connective fiber tissue

Bones provide: Support and protection of body organs Anchorage for muscles Leverage for muscles Bone marrow for the production of blood cells

Bone Marrow white blood cells platelets Found in hollow cavities of bone These hollow cavities are known as the Haversian canals Produce: red blood cells white blood cells platelets

Where bone meets bone in an organism Joints Where bone meets bone in an organism

Types of Joints Immovable joint Ball-and-socket joint Hinge joint Gliding joint

Immovable Joint Bones that are tightly fitted together

Ball-and-Socket Joint Can move in all directions

Hinge Joint Permits back and forth motion

Provides limited flexibility in all directions Gliding Joint Provides limited flexibility in all directions

(II) Cartilage Unlike bone, cartilage is flexible and elastic Found at joints, nose, and ear Absorbs shock

Ossification The process by which cartilage gradually changes into bone Ex: In humans, the skeleton of an embryo is made up of mostly cartilage. By adulthood, most of this cartilage changes into bone by the process of ossification

(III) Muscles Three types of muscle: Skeletal muscle Smooth muscle Cardiac muscle

Skeletal Muscle Voluntary (can be controlled) Involved in locomotion Attached to bone Striated in appearance (striped) Function as antagonistic pairs

Antagonistic Pairs Muscles work as opposites Ex: 1. Bicep contracts then triceps relaxes 2. Triceps contracts then the bicep relaxes http://www.innerbody.com/anim/arm.html

Summary When the bicep contracts, the arm bends upward (flexes) and therefore the bicep is known as a flexor When the triceps contracts, the arm extends outward and therefore the triceps is known as an extensor

Smooth Muscle Smooth are not striated in appearance Involuntary (cannot control movement) Found in: -walls of digestive organs -walls of arteries and veins -walls of internal organs

Cardiac Muscle Found only in the heart Striated in appearance Involuntary http://www.mco.edu/cci/movies/cardiacEM.mov

(IV) Attachments Ligaments- connect bone to bone Tendons- connect muscle to bone

(V) Disorders of Locomotion Arthritis- inflammation of the joints Tendonitis- inflammation of a tendon, usually where it is attached to the bone