Osseous tissue and bone Flashcards
Endoskeleton
rigid internal skeleton to which muscles are attached and is composed of cartilage or bone
Skeletal system includes:
bones, cartilages, ligaments, and connective tissues
What are the 6 functions of the skeletal system?
support
storage of minerals
storage of lipids
blood cell production
protection
leverage (force of movement)
How many major bones in an ADULT skeleton?
206
Bones are identified by:
shape, internal tissue, and bone marking
What are the bone shapes?
long bones
flat bones
sutural bones
irregular bones
short bones
sesamoid bones
Long bones:
are found in arms, legs, hands, feet, fingers, and toes
long and thin bones used primarily for movement
Flat bones:
are found in the skull, sternum, ribs, and scapula
thin with parallel surfaces for protection
Sutural bones:
small, irregular bones found between the flat bones of the skull
Irregular bones:
have complex shapes
ex: spinal vertebrae and pelvic bones
Short bones:
small and thick bones such as ankle/wrist bones
Sesamoid bones:
small and flat bones that develop inside tendons near joints of knees, hands, and feet and are strapped in place with limited movement
Process (bone marking)
any projection or bump
Ramus (bone marking)
an extension of a bone making an angle with the rest of the structure
Trochanter (bone marking)
a large, rough projection
Tuberosity (bone marking)
smaller, rough projection
Tubercle (bone marking)
a small, rounded projection
Crest (bone marking)
a prominent ridge
Line (bone marking)
a low ridge
Spine (bone marking)
a pointed process
Head (bone marking)
the expanded articular end of an epiphysis, separated from the shaft by a neck
Neck (bone marking)
a narrow connection between the epiphysis and diaphysis
Condyle (bone marking)
a smooth, rounded articular process
Trochlea (bone marking)
a smooth, grooved articular process shaped like a pulley
Facet (bone marking)
a small, flat articulate surface
Fossa (bone marking)
a shallow depression
Sulcus (bone marking)
a narrow groove
Foreman (bone marking)
a rounded passageway for blood vessels or nerves
Canal (bone marking)
a passageway through the substance of a bone
Fissure (bone marking)
an elongated cleft
Sinus or antrum (bone marking)
a chamber within a bone that is normally filled with air
Diaphysis
aka the shaft
has a heavy wall of compact bone or dense bone with a central space called the marrow cavity
Epithysis
Wide part at each end of the bone that articulates with other bones
mostly spongy bone covered with compact bone
Metaphysis
where the diaphysis and epiphysis meet
Osseous tissue
a hard, mineralized connective tissue that gives bones strength and structure
Osteocytes
mature bone cells that maintain the bone matrix that live in the lacunae
Osteocyte funtion
maintain protein and mineral content of the matrix and repair broken bone
Osetoblasts
immature cells that create new bone and help heal and grow existing bones
Osetoclasts
cells that break down old bone tissue to make room for new bone growth and repair
Osteoprogenitor cells
stem cells (mesenchymal) in bone that are responsible for bone growth and repair. They are found in the bone marrow and are the precursors to more specialized bone cells, such as osteoblasts and osteocytes
Osteolysis
a progressive condition that causes bone tissue to be destroyed, softened, and weakened
Bone matrix
a composite material that gives bones their strength and structure
Bone matrix composition
Organic component: Made up of proteins like collagen, osteonectin, and osteocalcin, which contribute to the tensile strength and structural organization of bones
Inorganic component: Made up of calcium and phosphate, which form hydroxyapatite crystals that give bones their hardness and rigidity
Compact bone structure:
composed of cylindrical units called osteons, which consist of concentric rings of bone matrix (lamellae) surrounding a central canal (Haversian canal) containing blood vessels and nerves
Perforating canals
Microscopic channels in the compact bone that run perpendicular to canals. They carry blood vessels from the periosteum into the bone and connect the canals with each other and the periosteum
Circumferential lamellae
form lamellar rings that encompass the entire external circumference of the shaft of long bones
Periosteum
a fibrous sheath that covers bones. It contains the blood vessels and nerves that provide nourishment and sensation to the bone
Functions of the periosteum
-isolate bone from surrounding tissues
-provide a route for circulatory and nervous supply
-participate in bone growth and repair
Endosteum
A membrane lining the inner surface of the bony wall also identified as the lining membrane of the Bone marrow cavity
Spongy bone
a lightweight, supportive bone tissue that’s found in the ends of long bones and gives bones their strength while reducing their weight
no blood supply
Red bone marrow
has blood vessels, forms red blood cells, and supples nutrients to the osteocytes
Yellow Bone marrow
made mostly of fat and contains stem cells that can become cartilage, fat, or bone cells
Osteogenesis
bone formation
Ossification
the process of replacing other tissues with bone
Intramembranous ossification
a process that directly converts mesenchymal tissue into bone
1st step of intramembranous ossification
mesenchymal cells aggregate and differentiate into osteoblasts and begin ossification at ossification center
2nd step of intramembranous ossification
Blood vessels grow into the area to supple the osteoblasts and spicules connect trapping blood vessels inside bone
3rd step of intramembranous ossification
spongy bone develops and is remodeled into osteons of compact bone
Endochondral ossification
the process of bone formation in which cartilage scaffolds, arranged in zones, are gradually replaced by bone
1st step of endochondral ossification
mesenchymal cells differentiate chondodrytes
2nd step of endochondral ossification
the cartilage model of the future bony skeleton and the perichondrium form
3rd step of endochondral ossification
blood vessels enter the cartilage bringing fibroblasts that become osteoblasts and spongy bone develops at the primary ossification center
4th step of endochondral ossification
Remodeling creates a marrow cavity and bone replaces cartilage at the metaphyses
5th step of endochondral ossification
Capillaries and osteoblasts enter the epiphyses creating secondary ossification centers
6th step of endochondral ossification
Epiphyses fill with spongy bone
Epiphyseal lines
a ridge on the surface of a mature bone that marks the point where the epiphysis and diaphysis of a bone fuse together
What are the 3 sets of vessels that make up the blood supply to mature bones?
-nutrient artery and vein
-metaphyseal vessels
-periosteal vessels
Bone remodeling
a continuous process that replaces old or damaged bone tissue with new bone tissue
Vitamin C (effects on bone)
required for collagen synthesis and stimulates osteoblast differentiation
Vitamin A (effects on bone)
stimulates osteoblast activity
Vitamins K and B12 (effects on bone)
help synthesize bone proteins
Calcitrol
a hormone that’s the active form of vitamin D and is produced in the kidneys
What is the most abundant mineral in the body?
Calcium
Calcium ions are vital to:
membranes, neurons, muscle cells and are closely monitored by homeostasis
PTH (parathyroid hormone)
increases calcium ion levels by stimulating osteoclasts increasing intestinal absorption of calcium that decreased calcium excretion in the kidneys
Calcitonin
secreted by C cells in the thyroid
decreases calcium ion levels by inhibiting osteoclast activity thus increasing calcium excretion in the kidneys
