The Science of Human Movement

THE MUSCULOSKELETAL

SYSTEM

Video

IF WE HAD NO BONES

• The purpose of the skeleton is to

provide structure, support and

protection to the various organs

and systems necessary for life

• A typical adult human skeleton

contains 206 bones

THE HUMAN SKELETON

Do infants have more or fewer bones than

adults?

THE HUMAN SKELETON

Do infants have more or fewer bones than adults?

Answer: More! Many bones begin separated but fuse together as humans develop. For example, the bones of the skull begin separated to allow for brain growth and development.

(This is why babies’ heads are so vulnerable)

THE HUMAN SKELETON

The human skeleton consists of

three types of connective tissue:

• Bone Tissue

• Ligaments

• Cartilage

STRUCTURAL FEATURES

The Right Knee

• Rigid and dense material

which contains living cells and

non-living minerals (mostly

calcium and phosphorus).

• Canals in bones contain

nerves and blood vessels.

BONES

The Right Knee

• Due to the living cells, bone

can regenerate if injured.

• Only a small percentage of

bone tissue is actually living

BONES

The Right Knee

• Tough, elastic connective tissues

• Hold bones together, especially where extra support is necessary (ie. at joints)

• Made up of collagen fibres (non-living), so regeneration after an injury is more difficult

LIGAMENTS

The Right Knee

• Made of special cells, surrounded by collagen fibres. Limited regeneration following injury

• Strong and flexible, but they contain special proteins that decrease friction

• Located where bones contact each other

CARTILAGE

The Right Knee

In small groups, consider the following question:

What does your body do, in order for you move

from one place to another?

HOW DO WE MOVE?

The human body contains three different types of muscle:

• Cardiac Muscle is the muscle lining the walls of the heart.

• Smooth Muscle is the muscle lining the digestive system (peristalsis)

• The type specifically associated with movement is called Skeletal Muscle.

MUSCLE

(Bundle of

Muscle fibres)

A Skeletal Muscle is connected to one or more bones via Tendons, which are

like less elastic (but more stable) versions of ligaments.

Muscles exert a force on bones and cause them to move in response to signals from the nervous system.

Muscles can pull, but never push…

SO HOW DO WE MOVE?

• In order to return a bone to its original

position, an opposing muscle, or antagonist

muscle must pull it back

ANTAGONIST MUSCLES

• A bone disorder characterized by loss of calcium

• Affects people of all ages, women are more prone to

it

• Painless, but weaker bones make injuries more

common, especially in the elderly

• Consuming foods with lots of calcium and vitamin

D help lessen the risk

OSTEOPOROSIS

OSTEOPOROSIS

Since the skeleton is central to the human body’s

support and protection, it experiences many physical

impacts and stresses.

Severe impacts can tear ligaments, tendons, muscles and

fracture bones.

X-Rays are taken after a serious injury to determine if a

bone is fractured, and how to best treat the injury.

STICKS AND STONES…

Left Arm

Broken ulna (Transverse Fracture)

STICKS AND STONES…

All vertebrates have musculoskeletal systems similar to

ours, with muscles attached to bones beneath the skin.

IN OTHER NEWS…

Invertebrates (worms, jellyfish

etc.) have very different

systems, since they have no

rigid frame and can change

shape.

EXOSKELETONS

Insects and arthropods wear their skeleton outside

of their skin (called an exoskeleton).

Homework: pg 101 - #1-6

HOMEWORK