Skeletal System Flashcards
What are the 6 major functions of the skeletal system?
Support, protection, movement, mineral storage, site of hematopoiesis, and triglyceride storage.
What are the 5 classes of bone?
Long bone, sesamoid, short bone, flat, irregular
Give an example of a long bone.
Humerus or femur.
Give an example of a sesamoid bone.
Patella.
Give an example of a short bone.
Trapezoid, carpals.
Give an example of a flat bone.
Sternum, ribs, scapula.
Give an example of an irregular bone.
Vertebrae, ethmoid.
Define diaphysis.
The shaft of a long bone.
What is the metaphysis?
The area where the ends of a long bone attach to the shaft, open as a juvenile but fuse in adulthood.
What is the epiphysis?
The ends of a long bone that are detached in juveniles but become fused in adulthood.
Where does hematopoiesis occur?
In red bone marrow of the pelvis, ribs, sternum, vertebrae, skull, and in the ends of the humeri and femurs.
What does an osteogenic cell do?
They develop into osteoblasts.
What do osteoblasts do?
They form the bone matrix. OsteoBlasts Build.
What do osteocytes do?
They maintain bone tissue.
What do osteoclasts do?
They function in resorption and break down the bone matrix.
What is a haversian system?
AKA an osteon; a group of concentric lamellae surrounding blood vessels and lymphatic vessels.
What are the two basic types of bone tissue?
Compact bone and spongy bone.
What special feature of compact bone allows it to have a structural function?
The concentric ring arrangement of the lamellae allow the bone to be dense and strong but still have vessels feeding the tissue.
What are other names for spongy bone?
Cancellous or trabecular bone.
What percent of bone is water?
20%
What cells provide the framework of bone?
A matrix of collagen fibres.
What inorganic compounds can be found in bone?
Salts deposited in collagen matrix where they ossify, calcium phosphate and calcium carbonate which form hydroxyapatite crystals.
What are the two kinds of bone development.
Intramembranous ossification and endochondral ossification.
Describe the steps of intramembranous ossification.
An ossification center develops in the tissue, then the ossification center begins to calcify; next the trabeculae (spongy bone) forms, and lastly the periosteum (vascular connective tissue around the bone) forms.
Describe the steps of endochondral ossification.
A cartilage model forms and grows first, next a primary ossification center forms in the middle of the bone, then the medullary (marrow) cavity forms. A secondary ossification center forms in the epiphysis, and lastly articular cartilage and the epiphyseal plate form.
When does osteogenesis occur in fetuses?
Begins around 6-7 weeks
What is the function of pituitary growth hormone?
Stimulates growth, especially on long bones by stimulating insulin-like growth factors.
What is the function of thyroid hormones in bone development?
They stimulate growth.
What is the function of androgens and estrogens in bone development?
They are responsible for pre-pubertal growth spurts and estrogen promotes closure of epiphyseal growth plates.
Which vitamins and minerals are found in bone.
Vitamins: D, A, B, C
Minerals: calcium, phosphorous, and magnesium.
Where is parathyroid hormone produced?
In the parathyroid gland.
When is parathyroid hormone released?
When blood calcium levels are low.
What does parathyroid hormone do?
Stimulates osteoclasts to increase bone resorption (osteoclasts break down bone to release calcium into the blood).
Where is calcitonin produced?
In the parafollicular cells of the thyroid gland.
When is calcitonin released?
When the blood calcium levels are high.
What does calcitonin do?
Stimulates osteoblasts to increase bone formation and lower blood calcium levels (calcitonIN INto bone)
Why do we need both parathyroid hormone and calcitonin?
They work together to maintain appropriate calcium levels for nerve and muscle cell activity.
What is osteoporosis?
When there is more bone resorption than bone formation, causing weak and brittle bones.
What is the most common form of dwarfism?
Achondroplasia which is a defect in long bone development.
What are the functional classifications of joints?
Synarthrosis, amphiarthrosis, and diarthrosis.
Define synarthrosis.
Immovable joints, such as the sutures of the skull.
Define amphiarthrosis.
Slightly movable joints, such as intervertebral joints.
Define diarthrosis.
Freely moveable joints.
What are the structural classifications of joints?
Fibrous, cartilaginous, and synovial.
Define fibrous joints.
Held together with fibrous tissue. Ex. sutures of skull or syndesmosis between tibia and fibula.
Define cartilaginous joints.
Held together with cartilage. Ex. Pubic symphysis.
Define synovial joint.
When there is a cavity between two articulating bones and the joint is fully moveable, such as between humerus and radius/ulna.
What is a bursa?
A fluid filled sac that cushions a gliding surface between tissues.
