WEEK 1: INTRODUCTION TO BONE, JOINTS AND MUSCLES Flashcards
What makes up the skeletal system?
Made of bones and cartilage
Has 2 functional parts. Outline them.
1.Axial skeleton
*Skull, neck, and trunk (ribs, sternum, vertebral column, and sacrum]
2.Appendicular skeleton
limbs – upper and lower limbs, scapula, clavicle, and pelvis
What is a bone?
Living, hard, specialized connective tissue.
State the functions of bone.
*Supports body and vital cavities
*Protects vital structures
*Provides mechanical structure/framework for movement
*Supplies new blood cells to the body via marrow in medullary cavities
*Stores salt
The bone is covered by periosteum – thick, fibrous connective tissue.
State its function.
Interface for tendon and ligament attachments
Nourishes external bone
Assists in new bone deposition (e.g. fracture healing)
Has rich supply of pain fibers
Ste the functions of the inorganic components of bone.
Makes bone considerably rigid
Withstands compressive forces
State the function of collagen in the bone matrix.
Its flexibility makes bone flexible.
Bone thus withstands tensile forces.
Different classes of bone based on shape.
State the 5 classes of bones.
Give an example under each.
1.long – tubular (e.g., femur)
2.short – cuboidal (carpals and tarsals only)
3.Flat – skull
4.Irregular – e.g., facial bones
5.Sesamoid
- Generally, in oval and located in tendons
-Protects joint and provides a more effective lever for muscle activity (changes angle of pull)
-Protects knee from wear and tear during joint motion -(patella)
-May serve weight-bearing function (e.g., 2 in planter lig. of gr8 toe)
What are the functions of thinner compact + more trabeculae at ends of long bones and in short bones?
Thinner compact + more trabeculae at ends of long bones and in short bones -both absorbs & cushions forces across joints.
*The trabecular network of spongy bone reduces bone weight and density and transfers force from the articular surface of cortical bone
Why are compact bones thicker in the shafts (diaphysis) of long bones?
Provides strength for weight bearing.
.
Why do bones have larger epiphyses and articular surfaces?
To disperse forces/unit area across joints which helps reduce wear & tear of articular cartilage.
What does orientation of compact and trabeculae reflects?
Orientation of compact and trabeculae reflects direction and number of stresses to which bone subjected.
Describe the 3 types of cartilage.
1.Hyaline
*Most prevalent
*Covers articular surfaces (synovial joints); also forms costal cartilage, and in bronchi, part larynx, etc.
*Withstands compressive and shear forces at joints
*Has large amts of proteoglycans – provide stiffness
*Collagen fibers parallel to directions of shear
2.Fibrocartilage
*Withstands large tensile stresses
*Withstands some compression
*Found in intervertebral disks, intra-articular disks, symphyses
3.Elastic (in cartilage of larynx, external ear, & auditory tube)
*Large elastic fibers and can regain shape after deformation.
How are collagen fibers arranged in respect to directions of shear?
*Collagen fibers parallel to directions of shear
State the 3 basic types of joints/ articulations.
Fibrous (synarthroses, syndesmoses)
Cartilaginous
Synovial
