Skeletal System
A. Functions:
1. Support for organs and other tissues
2. Movement-muscles need anchor to pull on to produce movement
3. Protection-of soft internal organs
4. Fat storage-yellow marrow in bones
5. Hematopoiesis-formation of red blood cells which carry oxygen. Making red blood
cells.
B. Components of Skeleton
1. Bones
a. Long Bones-femur, humerus, tibia
b. Short Bones-carpals, tarsals
c. Flat Bones-ribs, skull, os coxa, scapula
d. Irregular Bones-vertebrae
2. Bone marrow
a. Red marrow-making red blood
cells (hematopoeisis)
b. Yellow marrow-stores adipose (energy)
3. Bone Joints (articulation)
a. Fibrous Joints- fixed joints held together by dense CT---no appreciable
movement (sutures of the skull bones)
b. Cartilaginous Joints- hyaline or fibrous CT connects the bones forming the joint
(joints between the vertebrae, symphysis pubis)
c. Synovial Joints
1. Characteristics-Fully moveable joints, hyaline cartilage on articulating
surfaces. Dense CT capsule surrounding the joint, inner layer of capsule has
a layer of synovial membrane, which secretes synovial fluid.
2. Ball and socket joint- movement in many different planes. (shoulder and
hip)
3. Hinge joint- Allows flexion and extension muscle actions at a joint (knee
and elbow, phalanges)
4. Gliding or Plane Joint-Bones of the wrists and ankles (carpals and tarsals)
5. Saddle Joint-Thumb joint, movement in two planes, opposable thumb.
6. Pivot Joint-Rotation around a central axis
7. Condyloid or Ellipsoidal=Rotation around an axis, joint between the atlas
and axis vertebrae of the neck (1st and 2nd cervical vertebrae)