HS 20 - Weir
The Skeletal System
 The skeletal system and the muscular system work in combination with one
another
 Muscles and bones enable you to lift heavy objects, run, jump and write
 The Skeletal system consists of all the __________ in the body and the
____________ that connect the bones
 Bones are ________________________ by joints and __________________
by muscles
 Human infants are born with about _________ bones, some of which fuse together as the
body develops.
 The adult human skeletal system consists of _________ bones, as well as a network of
tendons, ligaments and cartilage that connects them

Most of these bones are contained in the hands and feet - Your hands and feet are capable of
the greatest diversity of movement
FUNCTION:
 _______________________
 Movement
 _____________________ (for internal organs)
 _____________________________________
 Stores minerals (ex. Calcium)
Types of Skeletons:
 Vertebrates (humans) have an ___________________________ – meaning the bones are
internal
 Some invertebrates (insects, crabs, etc.) have an ____________________________ –
bones are external
2 Divisions of the Skeletal System
1) __________________________________  central supporting part of the skeleton –
includes bones of the skull, backbone, ribs and breastbone
HS 20 - Weir
2) __________________________________  consists of bones of
the upper and lower limbs and their supporting structures
 The appendicular skeleton is attached to the axial skeleton via the:
 ________________ girdle (clavicle & scapula)
 ________________ girdle (2 hip bones)
4 Basic Shapes of Bones:
 ___________ bones – femur
 ___________ bones – wrist & ankle
 ___________ bones – skull & scapula
 ________________ bones – vertebrae
2 Types of Bone:
1) ___________________________  hard, dense, & strong (outer layer)
2) ___________________________ (Cancellous Bone)  lighter, less
dense (inner layer)
The bone is covered by a thin, tissue covering that contains blood vessels,
nerves and bone-forming cells – this tissue is called the
________________________.
Bone Development:
 In the embryo stage most of the skeleton is __________________ – there are special cells
called  _______________________ - Bone forming cells
**Note: “oste” means bone
 The cartilage eventually develops into bone
 This process is called ___________________________
 ________________ form within the bone called “Haversian Canals” – these canals
provide pathways for nerves and blood vessels
 Bone is a ____________________________ therefore oxygen and nutrients are essential
for its development.
 Eventually the Haversian canals grow together forming the _______________________.
HS 20 - Weir

Bone Marrow  The tissue located in the ______________________ cavity of the long bones
 It is the bone marrow that produces blood cells, and stores fat
Anatomy of the Skeletal System:
HS 20 - Weir
** Note: The femur is the __________________ bone in the body - Often referred to as the thigh
bone
Bone Anatomy:
 The main shaft is called the ______________________
 Each rounded end is the __________________________
Bone Composition:
 _______________ makes up ¼ of the weight of human bone
 Another ¼ consists of _________________ – connective tissue, type of protein
 The remaining ½ consists of calcium, phosphorus, and other minerals.
Growth of Bones:
 The _____________________________ secretes the growth hormone causing our bones
to grow in length
 This continues until about the age of 25.
 However the ________________________ and ___________________ of your bones
must be continually maintained by your body.
JOINTS:
 Joint  _________________________________________________________________
 Joints are made up of cartilage and ligaments
Types of Joints:
a) _________________________________  not capable of movement (ex. Skull)
 these joints have no gaps between the bone
b) _________________________________  have restrictive movement (ex.
Vertebral column)
 have small bands of _____________________ between the bones
HS 20 - Weir
c) ___________________________________  move freely (ex. joints in arms & legs)
** Note: Movable joints can be classified according to the type of movement the joint permits.
For Example:
 Ball-and-socket (shoulders)
 Hinge (elbow)
 Pivot (neck)
 Gliding
Ligaments ___________________________________________________________________
 Located in hands, feet, wrists ankles, but most obvious are
those in the knees.
Tendons  ___________________________________________
Teeth:
 Teeth are considered part of the skeletal system but they are not counted as bones.
 Teeth are made of dentin and _________________
 Enamel is the _______________________ substance in your body.
 Teeth also play a key role in the digestive system.
Illnesses of the Skeletal System:
a) _________________________________
 A medical condition in which the bones become brittle and fragile from
____________________________
 Increases bone fragility and risk of fractures
Causes:
 typically as a result of hormonal changes
 calcium or Vitamin D ________________________
HS 20 - Weir
 Women tend to have smaller, thinner bones than men.
 Estrogen, a hormone in women that protects bones, decreases sharply when women reach
menopause, which can cause bone loss.
 This is why the chance of developing osteoporosis increases as women reach menopause.
b)



_____________________________________
Inflammation of one or more of your _______________
Causes joint pain and stiffness
There are many variations of arthritis
Examples of Arthritis:
Osteoarthritis:
 caused by mechanical wear and tear on joints
 Probably the most common type of arthritis
Rheumatoid Arthritis
 An autoimmune disease in which the body's own immune system attacks the body's
joints.
Osteoarthritis
Rheumatoid Arthritis
HS 20 - Weir
c) _______________________
 an ______________________ of bone that occurs along the edges of a bone.
 Can form in any bone but are most commonly found in joints, where two or
more bones come together.
 Heels spurs are a common example
d) _______________________________

Uncommon

Can begin in any bone in the body, but it most commonly affects the long bones that make
up the arms and legs.
Signs & Symptoms may include…

_________ in a bone or joint - over time, the pain will become constant.

swelling or a lump that can be felt

changes in function or mobility of the affected area

a bone that breaks for no known reason
e) Scoliosis  _____________________________________________________________
Causes:

Can be present at birth

Result of abnormal muscles or nerves

Due to injury
f) ______________________________________

Held securely in place with a cast so bone can heal

The body forms a _________________________________ – a mass of new cartilage and
bone to hold the broken ends together

New bone gradually replaces the callus and ____________ the fracture