Skeletal & Calcium Flashcards
the cells that form bone, they secrete the matrix of bone and then supply minerals necessary to harden it
osteoblasts
bone cells that become trapped in the ossified matrix; can revert back to previous state if injury occurs
osteocytes
instead of forming new bone, these eat it away; they are necessary for remodeling to take place by removing bone where it is not needed
osteoclasts
these bone cells allow the body to withdraw calcium from the bones when it is needed to raise the calcium level in the blood
osteoclasts
when the bone matrix is infiltrated with calcium and phosphate in the form of hydroxyapatite crystals
ossification
the sparse population of bone cells embedded in a hard intercellular substance; initially soft and composed of collagen fibers in protein and polysaccharides
bone matrix
cave-like spaces in the ossified matrix that trap osteoblasts
lacunae
tiny channels through the matrix of bone that allow threadlike projections from osteocytes communicate with each other and also with blood vessels
canaliculi
give bone its characteristic hardness
hydroxyapatite crystals
calcium’s roles in body functions
- muscle contraction
- blood clotting
- milk secretion
- skeletal formation and maintenance
two hormones responsible for calcium
calcitonin and parathyroid hormone
calcium level that is too high
hypercalcemia; calcitonin prevents
calcium level that is too low
hypocalcemia; parathyroid hormone prevents
thyroid gland produces:
calcitonin
parathyroid glands produces:
parathyroid hormone
regulation of calcium levels in the body
calcitropic
hardest and most rigid type of connective tissue; aka bone
osseous connective tissue
blood cell formation
hematopoiesis
hormone that is essential for blood clotting and bone/tooth formation
vitamin d
bone minerals
calcium and phosphorus are the most abundant minerals with magnesium salts
light, spongy bone with tiny spicules containing bone marrow randomly arranged
cancellous bone
heavy, dense bone; shafts of long bones and the outside layer or all bones
compact bone
tiny, tightly compacted cylinders of bone that runs lengthwise containing layers of ossified bone matrix
haversian systems
contains blood and lymph vessels and nerves
haversian canal
membrane that covers outer surfaces of bones
periosteum
composed of fibrous tissue
outer layer of periosteum
enables bones to increase in diameter by containing osteoblasts
inner layer of periosteum
two types of bone formation
endochondral and intramembranous
bone is formed either by growing or by replacing a cartilage model
endochondral bone formation
bone develops from fibrous tissue membrane; only occurs in skull bones
intramembranous bone formation
primary growth center
diaphysis of cartilage rod
secondary growth center
epiphysis
allow for lengthening of the bone
epiphyseal plates
what are the two calcitropic hormones involved in calcium homeostasis?
calcium and parathyroid hormone
what inhibits bone reabsorption by osteoclasts?
calcitonin
during bone formation, osteoblasts replace cartilage where?
the diaphyseal aspect of the growth plate
where are the secondary growth centers of bones located?
the epiphysis of the cartilage rod
what is an example of a spheroidal joint?
the hip
channels through bone matrix that contain blood vessels; join at right angles other canals
volkmann’s canals
large bone vessels that carry blood into and out of bone marrow
nutrient foramina
bone marrow
fills the space between bones
forms blood cells, most prominent in younger animals
red bone marrow
primarily adipose connective tissue, can convert back to original marrow if needed
yellow bone marrow
number of pairs equals number of thoracic vertebrae
ribs
ventral ends of the ribs; join together
costal cartilage
end in the thoracic wall muscles
floating ribs
area where cartilage meets bony rib
costochondral junction
manubrium is most cranial, xiphoid process most caudal; forms floor of the thorax
sternum
joints
- fibrous or immovable
- cartilaginous or slightly movable
- synovial or freely moving
fibrous; immovable
synarthroses; skull sutures and splint bones of metacarpus/metatarsus
cartilaginous; slightly movable
amphiarthroses; intervertebral joints and pelvic/mandibular symphyses
synovial; freely movable
diarthroses; shoulder and stifle joint
types of synovial joints
- spheroidal - ball and socket
- trochoid - pivot
- arthrodial - gliding/rocking
- ginglymus - hinge
hinge joint; one joint surface swivels around another
ginglymus; elbow joint and atlanto-ocipital joint
gliding joint; rocking joints
arthrodial; carpus
pivot joint; one bone pivots or rotates on another
trochoid; atlanto-axial joint
ball and socket joint; allows the most extensive movement of all joint types
spheroidal; shoulder and hip joints
