Nutrition chapter 11
Hypercalcemia
A condition characterized by an abnormally high concentration fo calcium in the blood.
Hypocalcemia
A condition characterized by an abnormally low concentration of calcium in the blood.
Hypomagnesemia
A condition characterized by an abnormally low concentration of magnesium in the blood.
Calcium tentany
A condition in which muscles experience twitching and spasms due to inadequate blood calcium levels.
Hypermagnesemia
A condition marked by an abnormally high concentration of magnesium in the blood.
Cortical bone (compact bone)
A dense bone tissue that makes up the outer surface of all bones, as well as the entirety of most small bones of the body.
Osteroporosis
A disease characterized by low bone mass and deterioration of bone tissue, leading to increased bone fragility and fracture risk.
Calcium rigor
A failure of muscles to relax, which leads to a hardening or stiffening of the muscles; caused by high levels of blood calcium.
Parathyroid hormone (PTH)
A hormone secreted by the parathyroid gland when blood calcium levels fall. It is also known as parathormone, and it increases blood calcium levels by stimulating the activation of vitamin D, increasing reabsorption of calcium from the kidneys, and stimulating osteoclasts to break down bone, which releases more calcium into the bloodstream.
Calcitonin
A hormone secreted by the thyroid gland when blood calcium levels are too high. Calcitonin inhibits the actions of vitamin D, preventing reabsorption of calcium in the kidneys, limiting calcium absorption in the intestines, and inhibiting the osteroclasts for breaking down bone.
T-score
A numerical score comparing an individuals bone density to the average peak bone density of a 30 year old healthy adult to determine the risk for osteoporosis.
Trabecular bone (spongy bone)
A porous bone tissue that makes up only 20% of the skeleton and is found within the ends of the long bones, inside the spinal vertebrae, inside the flat bones (sternum, ribs, and most bones of the skull), and inside the bones of the pelvis.
Female athlete triad
A potentially serious condition characterized by coexistence of three disorders: low energy availability, menstrual dysfunction, and low bone density.
Collagen
A protein that forms strong fibers in bone and connective tissue.
Rickets
A vitamin D- deficiency disease in children. Symptoms include deformities of the skeleton, such as bowed legs and knocked knees.
Osteomalacia
A vitamin D-deficiency disease in adults, in which bones become weak and prone to fractures.
Matrix Gla protein
A vitamin K-dependent protein located in the protein matrix of bone in cartilage, blood vessel walls, and other soft tissues.
Osteocalcin
A vitamin K-dependent protein that is secreted by osteroblasts and is associated with bone turnover.
Osteoclasts
Cells that erode the surface of bones by secreting enzymes and acids that dig grooves into the bone matrix.
Osteoblasts
Cells that prompt the formation of new bone matrix by laying down the collagen-containing component of bone, which is then mineralized.
Dual energy x-ray absorptiometry (DXA,DEXA)
Currently the most accurate tool for measuring bone density.
Bone density
The degree of compactness of bone tissue reflecting the strength of the bones. Peak bone density is the point at which a bone is strongest.
Bioavalability
The degree to which the body can absorb and use any given nutrient.
Phylloquinone
The form of vitamin K found in plants.
Menaquinone
The form of vitamin K produced by bacteria in tthe large intestine.
Calcitriol
The primary active form of vitamin D in the body.
Resorption
The process by which the surface of bone is broken down by cells called osteoclasts.
Remodeling
The two-step process by which bone tissue is recycled; includes the breakdown of existing bone and the formation of new bone.
Ergocalciferol
Vitamin D2, a form of vitamin D found exclusively in plant foods.
Cholecaciferol
Vitamin D3, a form of vitamin D found in animal foods and the form we synthesize from the sun.