Chapter 11 Bones Quiz Monday April 13 2015 Bones are living organs that contain several tissues including two types of bone tissue Bone health is achieved through complex interactions among nutrients hormones and cartilage and connective tissue environmental factors Factors that may affect the strength of bone peak bone density o Working out exercising o Intake of minerals phosphorus calcium fluoride sodium and magnesium o Genetics o Hormones estrogen levels o Smoking The composition of bone provides strength and flexibility There are two bone types o 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 in the body o Trabecular spongy bone a porous bone tissue that makes up only 20 of the skeleton About 65 of bone tissue is made up of an assortment of minerals mostly calcium and phosphorus that provide harness but the remaining 35 is a mixture of organic substances that provide strength durability and flexibility The most important of these is collagen o Collagen is a protein that forms strong fibers in bone and connective tissue Trabecular bone has a faster turnover rate than cortical how quickly the bone tissue is broken down remodeling Bones develop through a series of 3 processes bone growth bone modeling and bone Bone remodeling maintains a balance between breakdown and repair o Bone is broken down through a process called resorption where osteoclasts break down bone creating bone loss See more osteoclasts activity in older adults o Osteoblasts is bone building where the cells work to synthesize a new bone matrix by laying down the collagen containing organic component of bone Red blood cells are produced in the bone marrow Peak bone density Is when bone is at its strongest The machine most accurate for measuring bone density is the DXA o There is one located down stairs in the Sandals Building Calcium is the most recognized nutrient associated with bone health however Vitamin D and K phosphorous magnesium and fluoride are also essential for strong bones o Calcium The active transport of calcium is dependent on the active form of Vitamin D 1 25 dihydroxyvitamin D most of the absorption of calcium at low to moderate intake levels is accounted for by this Vitamin D active transport Function to provide structure to the bones and teeth When blood calcium is low HYPOCALCEMIA the parathyroid glands are stimulated PTH Together PTH and Vitamin D stimulate the kidneys to reabsorb calcium from the bloodstream They also stimulate osteoclasts to break down bone to release calcium When blood calcium levels are too high HYPERCALCEMIA the thyroid gland secretes a hormone called calcitonin o Vitamin D Can be synthesized in the body from exposure to UV rays from the sun The process of converting sunlight into Vitamin D UV rays react with 7 dehydrocholesterol it is converted to cholecalciferol inactive Vitamin D which is converted to calcidiol in the liver which travels to the kidneys where it is converted to Calcitriol active form of Vitamin D Function regulates blood calcium levels If do not consume enough can have loss of bone mass from fat Rickets in children and Malabsorption in adults o Vitamin K Small amount can be synthesized in large intestine by the bacteria Function Responsible for blood coagulation the clotting of blood If do not consume enough can have excessive bleeding Babies are injected with Vitamin K at birth to prevent hemorrhagic newborn disease because they do not have a lot of bacteria in the intestine to synthesize Vitamin K Function critical in bone formation 85 of bone required for proper fluid balance component of ATP DNA membranes Good sources in soft drinks and high in protein containing foods o Phosphorus o Magnesium Kidneys regulate blood magnesium levels Functions influences hormones that influence bone supports Vitamin D metabolism Hypermagnesemia high levels of magnesium in blood occurs in individuals with impaired kidney function Hypomagnesaemia low levels of magnesium in blood resulting in hypocalcemia o Fluoride Stored in teeth and bones Function helps build growth of teeth help rebuild minerals in teeth and protects against cavities If consume too much fluoride can cause teeth to become porous stained and pitted Osteoporosis a disease characterized by low bone mass deterioration of bone tissue fragile bones decreased height and disfigured shortening and hunching of spine o Kyphosis Dowager s hump Risk factors for osteoporosis age gender smoking poor nutrition physical inactivity Modifiable factors is something you can do something about vs Non modifiable risk factors
View Full Document
Unlocking...