msk Flashcards
(115 cards)
what does the msk system consist of
bones, joints, ligaments, muscles, tendons, and connective tissues that support and bind tissues and organs together
ligaments vs tendons
Ligaments bind bones together at joints
ligaments = Connective tissue that attaches bone to bone at a joint; stabilizes joint and prevents movement beyond intended range of motion
Tendons attach muscles to bones
tendons = Connective tissue that attaches muscle to bone; tendon acts on bone when the muscle contracts to cause movement
skeletal bone provides
form, support, protection, stability, and movement to the body
Shape to the body
Physical support
Protection of organs
Stores minerals – calcium; and lipids
Responsible for blood cell formation
Muscle attachment sites – to facilitate movement
muscles
keep skeleton upright and facilitate body’s physical movement
attach to the bones of the skeletal system
- each muscle is a discrete organ composed of skeletal muscle tissue, blood vessels, tendons, nerves
- muscle tissue found in the heart, digestives organs, blood vessels
- ~ 700 muscles that account for half person’s body weight
how many bones in human body
206
-bones are formed from osseous tissue-provides structure and function to the body
nerves
- control the contraction of skeletal muscles
- interpret sensory information
- coordinate the activities of the body’s organ systems
osseous tissue composed of
composed of calcified connective tissue
Ground substance and 90-95% collagen fibers (ossein) create the bone matrix
Calcium and phosphorus stored in matrix adding strength and density
Osteocytes are contained in the matrix
cartilage
semi-rigid connective tissue deposited in areas where the bones need to move such as ribcage and joints
Soft connective tissue found between joints; shock absorber to reduce friction
structure of bone
Periosteum
Outermost layer of bone; protective sheath; thin tough membrane of fibrous tissue; provides support for tendons
Completely covers all bones except at joints where there is a layer of cartilage
Two layers: inner cellular osteogenic layer that forms new bone tissues and outer fibrous connective tissue layer for blood and nerve supply to bone
Osteogenic layer decreases in older bones
compact bone
under periosteum
hard outer layers of the bone; no spaces between lamellae
cancellous/spongy bone
under compact bone
lighter, softer, weaker, more porous but with greater surface area; spaces between lamellae; more vascular; “honeycomb appearance”
medulla
hollow cavity containing marrow within cancellous bone
bone development
Cartilage is the major component of skeleton when very young –provides greater flexibility and resiliency
Cartilage becomes harder with deposition of calcium phosphate in it
Some cartilage cells break loose and channels develop in the shaft of the bones
Blood vessels enter these channels and carry other connective tissue cells – some develop into osteoblasts and osteoclasts
Osteoblasts enter cartilage and form the layers of bone
Osteoclasts tear down old and excessive bone structures, allowing osteoblasts to rebuild with new bone – continuous process which slows down with age
osteoblasts
bone forming cells which secrete collage and substances to form the ground substance of bone
osteocytes
most common cell in mature bone
Responsible for bone growth and density
osteoclasts
cells that reabsorb bone tissue
lamellae
circular layers of bone matrix around the Haversian canal (osteon – functional unit of compact bone)
trabeculae
functional unit of cancellous bone; contain osteocytes but no osteons; receive nutrition from marrow tissue
bone marrow
Fills inner core of bones - the medullary cavity
Soft, gelatinous tissue – myeloid tissue
Red bone marrow for hematopoiesis OR yellow bone marrow filled with adipose tissue (or both)
red marrow
Primarily in central bones of adults – skull, vertebrae, sternum, ribs, pelvis, and upper thirds of long bones (humerus and femur)
In all bones until age seven – when need is high for new blood formation
yellow marrow
Primarily a storehouse for fats
Can be converted to red marrow under certain conditions (severe blood loss, fever)
Fill the cavities of other bones without red marrow
types of bone
endochondral and intramembranous long short flat sesamoid irregular
endochondral and intramembranous bones
Endochondral/intra-cartilaginous - ossification from centers arising in cartilage
Intramembranous – direct formation of bone on the mesenchyme (embryonic connective tissue) for formation of flat bones
ossification: formation of bone
Conversion of connective tissues into bone
Initiated at centers of ossification – points at which bone formation is started by osteoblasts through laying down of lamellae
Centers of ossification – primary or secondary