Download Lesson 1 the skeletal system

Lesson
1
The Skeletal System
How is it possible for you to perform motions such as
stretching and rolling your shoulders?
The interaction of bones and
muscles allows you to perform
these motions.
Lesson
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Lesson Objectives
In this lesson, you will learn to:
• Describe the functions of the skeletal system
• Identify the main divisions and types of bones
of the skeletal system
Lesson
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Functions of the Skeletal System
What Does Your Skeletal System Do?
• Your skeletal system protects your internal tissues and
organs from trauma.
• The skull, vertebrae, and ribs create protective cavities for
the brain, the spinal cord, and the heart and lungs,
respectively.
• Bones store minerals such as calcium and phosphorus,
which are important to the health and strength of the
skeleton and to various essential processes in your body.
• Bone marrow, a connective tissue within bones, produces
new red blood cells and white blood cells.
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Structure of the Skeleton
The Axial and Appendicular Skeletons
Your skeletal system consists of 206 bones that can be
classified in two main groups:
1. Axial skeleton
2. Appendicular skeleton
Lesson
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The Skeletal System
Structure of the Skeleton
Lesson
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Structure of the Skeleton
Types of Bones
All bones are covered with an outer layer of hard, densely
packed, compact bone, beneath which is spongy bone filled
with red bone marrow.
Almost every bone in the body can be categorized by shape:
• Long bones
• Short bones
• Flat bones
• Irregular bones
Lesson
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Structure of the Skeleton
Long Bones
• The humerus is the bone in your upper
arm.
• The diaphysis, or main column of a
long bone, is composed of compact
bone.
• Within the diaphysis is a narrow cavity
that contains yellow bone marrow.
• The end of a long bone is called the
epiphysis.
Humerus
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Structure of the Skeleton
Short Bones
Short bones are almost equal in length and width.
Wrist
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Structure of the Skeleton
Flat Bones
• Flat bones are somewhat thinner
and much flatter than other bones.
• Flat bones, such as those in the
skull, protect organs.
Rib
Irregular Bones
• Irregularly shaped bones have unusual shapes and do not
fit into the other categories.
Lesson
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Structure of the Skeleton
Cartilage
• In some joints, such as the knee, cartilage acts as a
cushion, reducing friction and allowing smooth motion.
• An embryo’s skeleton consists mostly of cartilage that
serves as a template from which bones will form.
• Early in embryonic development, the cartilage hardens,
which is called ossification.
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Structure of the Skeleton
Joints
• Some joints, such as those between the bones of the skull,
do not move.
• Others, including the joints between vertebrae, have limited
movement.
• Ligaments help stabilize the movements of bones at a joint.
• Movement is produced because muscles are attached to
bones by tendons and ligaments.
Lesson
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Classification of Flexible Joints
Structure of the Skeleton
Hip (ball-and-socket joint)
• Ball-and-socket joints allow the
widest range of movement in all
directions.
• Hinge joints allow a joint to bend
and straighten, promoting rotation.
• Pivot joints allow limited rotation or
turning of the head.
• Ellipsoidal joints allow bones to
slide over one another.
Knee (hinge joint)
Lesson
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Quick Review
Choose the appropriate option.
Q. _______ is a strong,
flexible connective tissue.
1. Cartilage
2. A ligament
3. An axial skeleton
4. A tendon
Lesson
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Quick Review - Answer
A. 1. cartilage
Cartilage is a strong, flexible connective tissue.
Click Next to attempt another question.
Lesson
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Quick Review
Q. Which of the following is NOT a function of the
skeletal system?
1. To support the upper body and head
2. To provide a strong, stable, and mobile framework on
which muscles can act
3. To connect the eyes and the brain with the heart and
the lungs
4. To protect the internal tissues and organs from
trauma
Lesson
A.
1
Quick Review - Answer
3. To connect the eyes and the brain with the heart
and the lungs
The skeletal system does not connect the eyes and the
brain with the heart and the lungs.
Click Next to attempt another question.
Lesson
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Quick Review
Q. Which of the following is NOT a type of joint?
1. Ball-and-socket joints: e.g., hip or shoulder joints
2. Roller joints: e.g., inner shoulder joints that connect
the joint to a muscle
3. Hinge joint: e.g., elbow, knee, ankle, and finger joints
4. Pivot joints: e.g., top two vertebrae
Lesson
A.
1
Quick Review - Answer
2. roller joints
The following is NOT a type of joint: roller joints, e.g.,
inner shoulder joints that connect the joint to a
muscle.
Click Next to attempt another question.
Lesson
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Quick Review
Choose the appropriate option.
Q. The ligament that holds the
bones in your forearm together
and helps form the pivot joint
affects your ability to move your
hand and arm.
True
False
Lesson
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Quick Review - Answer
A. True. The ligament that holds the bones in your
forearm together and helps form the pivot joint affects
your ability to move your hand and arm.
Click Next to attempt another question.
Lesson
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End of Lesson 1
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Lesson
1
Structure of the Skeleton
The Axial and Appendicular Skeletons
Your skeletal system consists of 206 bones that can be
classified in two main groups:
The axial skeleton
consists of the 80
1. Axial skeleton
bones of the skull,
2. Appendicular skeleton
spine, ribs, vertebrae,
and sternum, or
breastbone.
Lesson
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Structure of the Skeleton
The Axial and Appendicular Skeletons
Your skeletal system consists of 206 bones that can be
classified in two main groups:
1. Axial skeleton
2. Appendicular skeleton
The appendicular
skeleton is composed
of 126 bones of the
upper and lower
limbs, shoulders, and
hips.
Lesson
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Structure of the Skeleton
Cartilage
• In some joints, such as the knee, cartilage acts as a
cushion, reducing friction and allowing smooth motion.
• An embryo’s skeleton consists mostly of cartilage that
Cartilage is
serves as a template from which bones will form.
a strong, flexible
connective
• Early in embryonic development, the cartilage hardens,
tissue.
which is called ossification.
Lesson
1
Structure of the Skeleton
Cartilage
• In some joints, such as the knee, cartilage acts as a
cushion, reducing friction and allowing smooth motion.
• An embryo’s skeleton consists mostly of cartilage that
serves as a template from which bones will form.
Ossification is
• Early in embryonic development, the cartilage hardens,
the process by
which is called ossification.
which bone is
formed, renewed,
and repaired.
Lesson
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Structure of the Skeleton
Joints
A ligament is a
• Some joints, such as those between the bones of the skull,
band of fibrous,
do not move.
slightly elastic
connective
tissue
• Others, including
the joints
between vertebrae, have limited
movement. that attaches bone
to bone.
• Ligaments help stabilize the movements of bones at a joint.
• Movement is produced because muscles are attached to
bones by tendons and ligaments.
Lesson
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Structure of the Skeleton
Joints
• Some joints, such as those between the bones of the skull,
do not move.
A tendon is
• Others, including the
joints cord
between vertebrae, have limited
a fibrous
movement.
that attaches
muscle to the
• Ligaments help stabilize
bone. the movements of bones at a joint.
• Movement is produced because muscles are attached to
bones by tendons and ligaments.
Lesson
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Quick Review - Answer
A. Correct! Cartilage is a strong, flexible connective tissue.
Click Next to attempt another question.
Lesson
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Quick Review - Answer
You have answered the question incorrectly. Go back to try
again, or click Next to view the correct answer.
Lesson
1
Quick Review - Answer
A. Correct! The skeletal system does NOT function: to
connect the eyes and the brain with the heart and
the lungs.
Click Next to attempt another question.
Lesson
1
Quick Review - Answer
You have answered the question incorrectly. Go back to try
again, or click Next to view the correct answer.
Lesson
1
Quick Review - Answer
A. Correct! The following is NOT a type of joint: roller
joints, e.g., inner shoulder joints that connect the
joint to a muscle.
Click Next to attempt another question.
Lesson
1
Quick Review - Answer
You have answered the question incorrectly. Go back to try
again, or click Next to view the correct answer.
Lesson
1
Quick Review - Answer
A. Correct! The ligament that holds the bones in your
forearm together and helps form the pivot joint affects
your ability to move your hand and arm.
Click Next to attempt another question.
Lesson
1
Quick Review - Answer
You have answered the question incorrectly. Go back to try
again, or click Next to view the correct answer.