AMA 177 - Anatomy &
Physiology/Medical
Terminology/Pathology 8
Musculoskeletal System
Function:
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Made up of bones, muscles and joints.
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Bones are the framework that protect and support
internal organs.
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Bones manufacture red blood cells in the marrow and
store minerals necessary for growth.
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Muscles are responsible for the movement of the
body.
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Joints are the places where bones come together; the
type of joint depends on the need for more or less
movement.
Structure of the
Musculoskeletal System: Bones
Bones: composed of connective tissue (osseous
tissue) as well as blood vessels and nerves.
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Bones need calcium and phosphorus to grow.
Bone cells called osteoblasts and osteoclasts
work together to build bones and breakdown
excess bone tissue; bones are living tissues
that constantly rebuild and renew as a
response to the mechanical stress of
movement.
Bones:
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There are 206 bones in the body.
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Long bones, such as the femur, are every strong and have large
surface areas for muscles to attach.
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Short bones, such as the carpals in the hand, are grouped
together to help provide movement.
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Flat bones, such as the ribs, cover and protect soft body parts.
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Sesamoid bones, such as the kneecap, are small and rounded;
they are found near joints to increase the efficiency of the
muscles near that joint.
Study all the different types of bones and their locations and
function in the body.
Parts of the bone:
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Diaphysis: middle region of long bones
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Epiphysis: each end of the long bones
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Epiphyseal plate: cartilage tissue that is constantly
replaced as bone grows; disappears when bone is fully
grown, very obvious in children
Metaphysis: flared portion of bone between
diaphysis and epiphysis
Periosteum: strong, fibrous, vascular covering of long
bones; has extensive nerve supply
Parts of the bone continued:
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Articular cartilage: ends of long bones and surface of any bone
that meets another to form a joint; cushions the joint, allowing
fluid movement
Compact bone: layer of hard dense bone under the periosteum;
contains canals of blood vessels that nourish the bone and
remove waste products
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Haversian canals: channels in compact bone that contain blood
vessels
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Medullary cavity: central shaft of long bones that contains
yellow bone marrow that is made up of mostly fat cells
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Cancellous bone: spongy, porous bone tissue in the center of
bones that contain spaces that contain red bone marrow; this is
where red blood cells are made.
Bone processes:
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Enlarged areas that extend out from bones that
function as attachments for muscles and tendons
Bones also contain openings and hollow areas that help
join bones together and serve as passages for blood
vessels and nerves:
Fossa: shallow cavity in a bone
Foramen: opening in a bone for blood vessels and
nerves
Fissure: deep, narrow slit in a bone
Sinus: hollow cavity in a bone
Structure of the Musculoskeletal System:
Muscles
Three types of muscles:
 Striated: made up of voluntary or skeletal muscles that move all
bones, facial expressions and eye movement; we control these
muscles. Muscle fibers are arranged in bundles. There are more
than 600 muscles in the body. Muscles attached to bones
contract and relax in groups to cause movement; tendons
connect the muscles to the bones
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Smooth: involuntary or visceral muscles that move internal
organs, such as the digestive tract; we do not control these.
Muscle fibers are arranged in sheets that wrap around vessels
Cardiac: heart muscles; we do not control these. Arranged in
branching fibers
Study all the different types of muscles and their locations and
function in the body as well as the types of movements they
create.