A&P I Lecture 7: Skeletal System Anatomy, Bone Growth, and Fractures

55 flashcards

How many bones are in the adult human skeleton?: 206 bones
What are the two major divisions of the skeleton?: Axial Skeleton and Appendicular Skeleton
How many bones are in the Axial Skeleton?: 80 bones
What bones are included in the Axial Skeleton?: Skull (22 bones), vertebral column (26), thoracic cage (25), auditory ossicles (6), hyoid (1)
What is the primary function of the Axial Skeleton?: Supports and protects the brain, spinal cord, and thoracic organs
How many bones are in the Appendicular Skeleton?: 126 bones
What does the Appendicular Skeleton include?: Upper and lower limbs, pectoral girdle, and pelvic girdle
What type of tissue are bones classified as?: Osseous tissue (rigid connective tissue)
What is the role of cartilage in the skeletal system?: Provides flexibility at joints
What are ligaments?: Dense regular connective tissue connecting bones to each other
What is the epiphysis of a long bone?: The proximal and distal ends containing spongy bone and covered with articular cartilage
What is the diaphysis of a long bone?: The shaft composed of dense compact bone enclosing the medullary cavity
What is the function of the medullary cavity?: Contains red marrow for hematopoiesis in children and yellow marrow for fat storage in adults
What is the role of osteocytes?: Mature bone cells that maintain mineral content of the matrix
What do osteoblasts do?: Bone-forming cells that secrete osteoid and initiate calcification
What is osteolysis?: The process performed by osteoclasts to break down the matrix and release calcium
What is the composition of the organic portion of bone matrix?: Mainly collagen fibers providing tensile strength and flexibility
What is hydroxyapatite?: The inorganic portion of bone matrix primarily made of calcium phosphate and hydroxide
What is the function of the periosteum?: Protects bone, provides routes for blood vessels/nerves, and is essential for growth and repair
What is appositional bone growth?: Growth in diameter at the outer surface of existing bone
What is endochondral ossification?: The process where hyaline cartilage is gradually replaced by bone
What role does parathyroid hormone (PTH) play in calcium regulation?: Increases blood calcium levels by stimulating osteoclasts and enhancing intestinal absorption
What is the function of calcitonin?: Lowers blood calcium levels by inhibiting osteoclasts and increasing calcium excretion by kidneys
What is the role of the nutrient artery and vein in bone?: They enter the bone through nutrient foramen and nourish osteons and marrow
What is articular cartilage?: A thin layer of hyaline cartilage at joint surfaces that reduces friction
What is the significance of the medullary cavity?: It is involved in hematopoiesis in children and fat storage in adults
What is the primary mineral stored in bone?: Calcium ( H 99% of body's Ca²⁺)
What is the role of osteoprogenitor cells?: Stem cells that differentiate into osteoblasts for growth and repair
What hormonal influences stimulate bone growth during puberty?: Estrogen and testosterone stimulate bone growth and speed up ossification.
What happens to epiphyseal cartilage during puberty?: Epiphyseal cartilage narrows and is replaced by bone, resulting in an epiphyseal line in adults.
What is intramembranous ossification?: It is the process where mesenchymal cells differentiate into osteoblasts and produce dermal bones.
What types of bones are produced through intramembranous ossification?: Dermal (membrane) bones such as the skull, mandible, clavicle, and sesamoid bones.
What is the first step in intramembranous ossification?: Mesenchymal cells secrete osteoid matrix and differentiate into osteoblasts.
When does ossification begin during embryonic development?: Ossification begins around the 8th week of embryonic development.
What is pituitary growth failure?: It is caused by inadequate growth hormone, leading to reduced epiphyseal cartilage activity and shorter bones.
What is achondroplasia?: It is caused by abnormal epiphyseal cartilage growth, resulting in short long bones and dwarfism.
What is Marfan syndrome?: It is caused by excess cartilage at epiphyseal plates, leading to long limbs and connective tissue defects.
What causes gigantism?: Overproduction of growth hormone before epiphyseal closure results in excessive height and long bones.
What is acromegaly?: It is caused by growth hormone overproduction after epiphyseal closure, leading to bone thickening in the face, jaw, and hands.
What is fibrodysplasia ossificans progressiva (FOP)?: It is a genetic mutation causing ectopic bone formation in muscles and connective tissue, leading to irreversible disability.
What are fractures?: Fractures are breaks in bone continuity due to trauma or pathology.
What are the phases of fracture healing?: The phases include hematoma formation, fibrocartilaginous callus, bony callus, and bone remodeling.
What is a closed fracture?: A closed or simple fracture is completely internal and only visible on x-rays.
What is an open fracture?: An open or compound fracture projects through the skin and is more dangerous due to infection and uncontrolled bleeding.
What is a transverse fracture?: A transverse fracture breaks the shaft across the long axis of the bone.
What is a spiral fracture?: A spiral fracture is produced by twisting stresses and spreads along the length of the bone.
What is a compression fracture?: A compression fracture occurs in vertebrae subjected to extreme stresses.
What characterizes a greenstick fracture?: A greenstick fracture involves one side of the shaft broken and the other side bent, typically occurring in children.
What is an epiphyseal fracture?: An epiphyseal fracture occurs where the bone matrix is calcifying and can stop growth if not monitored.
What is a Pott fracture?: A Pott fracture occurs at the ankle and affects both leg bones.
What is a Colles fracture?: A Colles fracture is a break in the distal radius.
What are the two parts of the skeletal system?: The skeletal system consists of the axial skeleton (skull, vertebral column, ribs/sternum) and the appendicular skeleton (appendages and pelvic girdle).
What are the three regions of the skull?: The skull has three regions: cranial, facial, and mandible.
What bones make up the vertebral column?: The vertebral column consists of cervical, thoracic, lumbar, sacral, and caudal regions.
What is the function of the ribs?: The ribs encase the thoracic cavity and join the vertebrae on one end and the sternum on the other.