Skeletal System Notes
Name:___________
I. SKELETAL SYSTEM
A. Made up of all the bones in our body, it is the framework of the body
1. each bone in your body is a living organ, made of different tissues
a) cells in bones take in food and use energy
B. 5 Functions of Skeletal System
1. Framework gives shape & support to body
2. Bones protect the internal organs
3. Major muscles of body are attached to the bones
4. Blood cells are formed in red marrow of some bones
5. Skeleton is a place where major quantities of calcium and phosphorus
compounds are stored
II. BONES
A. Adult skeleton has 206 bones (baby has 270)
B. Classification: according to shape
1. Long (femur), short (carpals), flat (scapula), or irregular (vertebrae)
2. Shapes are genetically controlled
3. Shapes are modified by work of muscles attached to them
C. Internal & External Characteristics
1. Surface: covered with tough, tight fitting membrane called periosteum
a) Blood vessels carry nutrients into the bone
b) Important in the growth and repair of bone
2. Compact bone: under the periosteum
a) Contains bone cells, blood vessels, minerals and elastic fibers
b) Elastic fibers keep bone flexible
c) 2 diseases that result from a lack of mineral in bone: rickets, osteoporosis
3. Spongy bone: found towards the end of the bone
a) Less compact
b) Has many small open spaces that make the bone light weight
4. Marrow: a fatty tissue that fills the cavities, or spaces, in bones
a) Produces red blood cells—2-3 billion per second
b) Produces white blood cells
5. Cartilage: thick smooth layer of tissue that covers the ends of the bones
a) Flexible, important at the joints because it absorbs shock and makes
movement easier
III. BONE DEVELOPMENT
A. Embryo—Fetus
1. Skeleton made of cartilage
2. Cartilage gradually broken down and replaced with osteoblasts
a) Bone-forming cells
b) they deposit calcium and phosphorus that make bone tissue hard
3. Healthy bone tissue is always being formed and reformed by cells
a) Osteoclasts: break down bone tissue
b) They break down bone and release calcium and phosphorus
IV. FRACTURES
A. Break in the bone
1. Simple: bone is broken, but the broken ends do not break through the skin
2. Compound: broken ends of bone stick out through skin
B. To Heal a Fracture: broken ends are brought into contact with each other
1. Periosteum makes new bone cells
2. Thick band of new bone forms around the break
3. Band of bone disappears over time as the bone is reshaped with osteoclasts
V. JOINTS
A. Any place where 2 or more bones meet
B. Ligaments: tough bands of tissue that hold bones together at the joints
C. Classification of Joints
1. Immovable: allows little or no movement
a) Skull, pelvis
2. Movable: allows body to make a wide range of movements
a) Pivot: 1 rotates in the ring of another (arm, head)
b) Ball and socket: 1 bone has a rounded end that fits into a cup-like cavity on
another bone (shoulder, hip)
c) Hinge: has a back and forth movement (elbow, knee, fingers)
d) Gliding: 1 part of the bone glides over another bone (wrist, ankle)
Skeletal System Notes
Name:___________
I. SKELETAL SYSTEM
A. Made up of all the ______ in our body, it is the __________ of the body
1. each bone in your body is a living ______, made of different ________
a) _____ in bones take in _____ and use _______
B. 5 Functions of Skeletal System
1. Framework gives ______ & ________ to body
2. Bones ________ the _________ organs
3. Major ________ of body are _________ to the bones
4. ______ cells are formed in ____ _______ of some bones
5. Skeleton is a place where major quantities of ________ and ___________
compounds are _______
II. BONES
A. ______ skeleton has ____ bones (_____ has ____)
B. _______________: according to ______
1. _____ (femur), ______ (carpals), _____ (scapula), or ________ (vertebrae)
2. Shapes are ____________ controlled
3. Shapes are __________ by work of ________ attached to them
C. Internal & External _________________
1. ________: covered with tough, tight fitting _________ called __________
a) Blood ________ carry __________ into the bone
b) Important in the _______ and _______ of bone
2. ________ bone: under the ___________
a) Contains bone ______, blood vessels, minerals and ________ fibers
b) Elastic fibers keep bone _________
c) 2 diseases that result from a lack of _______ in bone: rickets, __________
3. _______ bone: found towards the ____ of the bone
a) Less ________
b) Has many small _____ spaces that make the bone ______ _______
4. _______: a ______ tissue that fills the cavities, or _______, in bones
a) Produces ____ blood cells—2-3 ________ per second
b) Produces ______ blood cells
5. _________: thick _______ layer of tissue that ______ the ____ of the bones
a) Flexible, important at the _______ because it absorbs ______ and makes
movement easier
III. BONE DEVELOPMENT
A. Embryo—_______
1. Skeleton made of __________
2. Cartilage gradually broken down and replaced with ________
a) _____-________ cells
b) they deposit ________ and ___________ that make bone tissue hard
3. ________ bone tissue is always being formed and _________ by cells
a) ____________: break _____ bone tissue
b) They break down bone and _________ calcium and phosphorus
IV. FRACTURES
A. _______ in the bone
1. _______: bone is _______, but the broken ends do ___ break through the ___
2. _________: broken ends of bone stick ____ through _____
B. To _____ a Fracture: broken ends are brought into _______ with each other
1. ___________ makes new bone ______
2. Thick _____ of new bone forms ________ the break
3. Band of bone _________ over time as the bone is _______ with _________
V. JOINTS
A. Any place where __ or more bones _____
B. __________: tough bands of _______ that hold ______ __________ at the joints
C. ______________ of Joints
1. __________: allows little or ___ movement
a) ______, _______
2. ________: allows body to make a wide range of __________
a) ______: 1 ________ in the ring of another (____, _____)
b) _________________: 1 bone has a ________ end that fits into a
____-_____ cavity on another bone (_________, ____)
c) ______: has a back and ______ movement (______, _____, _______)
d) ________: 1 part of the bone glides over _______ bone (______, _____)