MODULE 02
GETTING THE SKELETONS OUT OF THE
CLOSET:
THE SKELETAL SYSTEM
SECTION 01: SKELETAL SYSTEM INTRODUCTION
· It is composed of bones, cartilages, joints, and ligaments.
· It accounts for approximately 20% of body mass.
· It includes 206 named bones. THE TYPES OF BONES
· It is divided into two divisions - the axial and appendicular
skeletons There are four types of bones. Remember, regardless of the
type, all bones are composed of an outer layer of
Video: Take notes compact bone and an inner layer of spongy bone.
Short Bones – as wide as they are tall, provide stability and
FUNCTIONS OF SKELETAL SYSTEM some movement
Example: Bones of the ankle and wrist
Support
The large bones of the lower limbs act as pillars for the Long Bones: Elongated cylindrical shaft – longer than wide,
body trunk and the ribs anchor the thoracic wall. The most are found in appendicular skeleton
skeleton provides framework that anchors all soft organs. Example: Femur
Protection Irregular Bones
The rib cage encloses the thoracic cavity and the skull, and Example: Vertebra
the vertebrae surround the soft tissue of the nervous system.
Flat Bones – with large surface area for muscle
Blood cell formation attachments and protection of organs
Hematopoiesis occurs within the marrow cavities of the Example: Bones of the skull
bones.
Sesmoid Bone – embedded in tendon
Storage Example: Patella (knee cap)
Fat is found in the interior of the bones, along with the bone
matrix, which serves as a reserve for various minerals.
Movement STRUCTURE OF LONG BONES
Skeletal muscles use the bones as levers.
As their name suggests, long bones have a greater length
Hematopoeisis than width, and an elongated shaft. They are the most
Production of blood cells – occurs within the marrow common bone type found in the body. Long bones can be
cavitites of the bones as large as the femur and tibia, or as small as the bones of
the fingers and toes.
EPIPHYSIS
SECTION 02: BONE AND CARTILAGE Knobby, enlarged regions at the end, form joints, and serve
as attachment sites for tendons and ligaments.
BASIC COMPOSITION OF BONE
METAPHYSIS
Every bone is composed of two layers: Region between the diaphysis and epiphysis.
Outer layer: made up of compact bone, which is hard and DIAPHYSIS
strong. Elongated cylindrical shaft.
Inner layer: made up of spongy bone, which appears
porous and sponge-like.
You can think of any type of bone as a sandwich of spongy
bone, with compact bone on either side of spongy bone in
the middle.
Blood cells are produced by the bone marrow, found
within medullary cavity, which is the inner cavity of the
bone.
, ADDITIONAL FEATURES OF LONG BONES SECTION 03: AXIAL SKELETON
In addition to the three main structural features of long
AXIAL SKELETON REVIEW
bones, there are some additional characteristics.
As you may recall from Module 01, the axial skeleton
1. Articular Cartilage: Articular cartilage covers the
consists of the skull, vertebral column, ribs, and sternum.
epiphysis, reduces friction between joints, and absorbs
shock in movable joints. Based on your knowledge of the
SKULL
types of cartilage from Module 01, answer the question.
BONES OF THE SKULL
What type of cartilage is articular cartilage?
The skull has 22 bones in total, but only the more prominent
Feedback:
bones will be discussed in this module. Two sets of bones
Hyaline because it lines the joint surface.
make up the skull: the cranial and facial bones.
2. Periosteum: A tough sheath of dense irregular
a. Cranial Bones
connective tissue that covers the surface of bone, except
for areas covered by articular cartilage. The periosteum
protects the bone, and contains blood vessels and nerves
that supply the bone. It also has cells that are responsible
for forming new bone tissue.
3. Medullary Cavity: Based on your knowledge of the
medullary cavity, answer the question.
There are 8 bones that make up the cranium, providing
protection for the brain. In this course, you will be
What is the function of the inner cavity of the long bone, or
responsible for knowing 7 of these bones that form a roof
medullary cavity?
(cranial vault) and floor (cranial base), enclosing the brain
Feedback:
in a space called the cranial cavity.
Blood cell production occurs in the bone marrow within the
medullary cavity.
• Frontal (1)
Single bone
· Forms the forehead and roof of the orbits (eye
sockets)
• Parietal (2)
Paired
· Form superior and lateral surfaces of skull
• Temporal (2)
The temporal bones are paired and form the
lateral and inferior walls of the skull.
Review the features of the temporal bone on the diagram.
· Zygomatic process
· External auditory (acoustic) meatus (ear hole)
· Mastoid process
GETTING THE SKELETONS OUT OF THE
CLOSET:
THE SKELETAL SYSTEM
SECTION 01: SKELETAL SYSTEM INTRODUCTION
· It is composed of bones, cartilages, joints, and ligaments.
· It accounts for approximately 20% of body mass.
· It includes 206 named bones. THE TYPES OF BONES
· It is divided into two divisions - the axial and appendicular
skeletons There are four types of bones. Remember, regardless of the
type, all bones are composed of an outer layer of
Video: Take notes compact bone and an inner layer of spongy bone.
Short Bones – as wide as they are tall, provide stability and
FUNCTIONS OF SKELETAL SYSTEM some movement
Example: Bones of the ankle and wrist
Support
The large bones of the lower limbs act as pillars for the Long Bones: Elongated cylindrical shaft – longer than wide,
body trunk and the ribs anchor the thoracic wall. The most are found in appendicular skeleton
skeleton provides framework that anchors all soft organs. Example: Femur
Protection Irregular Bones
The rib cage encloses the thoracic cavity and the skull, and Example: Vertebra
the vertebrae surround the soft tissue of the nervous system.
Flat Bones – with large surface area for muscle
Blood cell formation attachments and protection of organs
Hematopoiesis occurs within the marrow cavities of the Example: Bones of the skull
bones.
Sesmoid Bone – embedded in tendon
Storage Example: Patella (knee cap)
Fat is found in the interior of the bones, along with the bone
matrix, which serves as a reserve for various minerals.
Movement STRUCTURE OF LONG BONES
Skeletal muscles use the bones as levers.
As their name suggests, long bones have a greater length
Hematopoeisis than width, and an elongated shaft. They are the most
Production of blood cells – occurs within the marrow common bone type found in the body. Long bones can be
cavitites of the bones as large as the femur and tibia, or as small as the bones of
the fingers and toes.
EPIPHYSIS
SECTION 02: BONE AND CARTILAGE Knobby, enlarged regions at the end, form joints, and serve
as attachment sites for tendons and ligaments.
BASIC COMPOSITION OF BONE
METAPHYSIS
Every bone is composed of two layers: Region between the diaphysis and epiphysis.
Outer layer: made up of compact bone, which is hard and DIAPHYSIS
strong. Elongated cylindrical shaft.
Inner layer: made up of spongy bone, which appears
porous and sponge-like.
You can think of any type of bone as a sandwich of spongy
bone, with compact bone on either side of spongy bone in
the middle.
Blood cells are produced by the bone marrow, found
within medullary cavity, which is the inner cavity of the
bone.
, ADDITIONAL FEATURES OF LONG BONES SECTION 03: AXIAL SKELETON
In addition to the three main structural features of long
AXIAL SKELETON REVIEW
bones, there are some additional characteristics.
As you may recall from Module 01, the axial skeleton
1. Articular Cartilage: Articular cartilage covers the
consists of the skull, vertebral column, ribs, and sternum.
epiphysis, reduces friction between joints, and absorbs
shock in movable joints. Based on your knowledge of the
SKULL
types of cartilage from Module 01, answer the question.
BONES OF THE SKULL
What type of cartilage is articular cartilage?
The skull has 22 bones in total, but only the more prominent
Feedback:
bones will be discussed in this module. Two sets of bones
Hyaline because it lines the joint surface.
make up the skull: the cranial and facial bones.
2. Periosteum: A tough sheath of dense irregular
a. Cranial Bones
connective tissue that covers the surface of bone, except
for areas covered by articular cartilage. The periosteum
protects the bone, and contains blood vessels and nerves
that supply the bone. It also has cells that are responsible
for forming new bone tissue.
3. Medullary Cavity: Based on your knowledge of the
medullary cavity, answer the question.
There are 8 bones that make up the cranium, providing
protection for the brain. In this course, you will be
What is the function of the inner cavity of the long bone, or
responsible for knowing 7 of these bones that form a roof
medullary cavity?
(cranial vault) and floor (cranial base), enclosing the brain
Feedback:
in a space called the cranial cavity.
Blood cell production occurs in the bone marrow within the
medullary cavity.
• Frontal (1)
Single bone
· Forms the forehead and roof of the orbits (eye
sockets)
• Parietal (2)
Paired
· Form superior and lateral surfaces of skull
• Temporal (2)
The temporal bones are paired and form the
lateral and inferior walls of the skull.
Review the features of the temporal bone on the diagram.
· Zygomatic process
· External auditory (acoustic) meatus (ear hole)
· Mastoid process
