Bone Physiology Flashcards
Osteocytes are?
Bone cells, make the framework
Osteoblasts are?
Construction, adds to bone
Osteoclasts are?
Demo crew, dissolves and reshapes bone
What is intramembranous ossification?
the process of bone development from fibrous membranes. It is involved in the formation of the flat bones of the skull, the mandible, and the clavicles
What is endochondral ossification?
the process of bone development from hyaline cartilage. All of the bones of the body, except for the flat bones of the skull, mandible, and clavicles
What is the ossification center?
sites in bones where calcification begins and bone replaces fibrous connective tissue or cartilage
What is the epiphyseal plate?
a thin layer of cartilage that lies between the epiphyses and metaphyses, and is where the growth of long bones takes place
What are the zones of the epiphyseal plate?
Real People Have Career Options Resting Proliferating Hypertrophic Calcified Ossification Zone
What does the zone of resting cartilage do?
anchors growth plate to bone
What does the zone of proliferating cartilage do?
rapid cell division
What does the zone of hypertrophic cartilage do?
cells enlarge and remain in columns
What does the zone of calcified cartilage do?
thin zone, mostly dead cells that have calcified
Osteo cells complete the bone growth `process
How long does longitudinal growth continue?
as long as epiphyseal plates are open
What does Vitamin D do for bones?
Necessary to absorb calcium
Deficiency leads to rickets and osteomalacia
Where do you get Vitamin D?
Eggs, dairy
UV light converted by liver and kidneys
What does Vitamin A do for bones?
necessary for osteoblast/clast
deficiency inhibits bone development
Where do you get Vitamin A?
Cheese, eggs, fish, fruits and veggies,
What does Vitamin C do for bones?
required for collagen synthesis 90% of bone
deficiency inhibits bone development
Where do you get Vitamin C?
Citrus fruits and peppers are major sources, other fruits and veggies as well
Where is growth hormone produced?
Anterior pituitary
What does growth hormone do?
stimulates cell division
What is pituitary dwarfism?
lacking GH
What is pituitary gigantism?
excess GH before growth plate closes
What is acromegaly?
Excess GH, abnormally large hands, feet, jaw
Which hormone lowers blood calcium but increases the amount of osteoblast activity in bones?
Calcitonin
What does PTH do?
Increases blood calcium
Increases osteoclast number and activity
Why do we have calcium in our blood?
Blood clotting
Cell signaling
Stimulus for muscle contraction in response to electrical excitation
Proper membrane permeability
What do the sex hormones do to bone growth?
Testosterone and estrogen promote bone cell formation, estrogen has a stronger effect
When are nearly all bones ossified by?
23 - females
25 - males
What is Wolff’s Law?
a bone grows or remodels in response to the forces or demands placed on it
What happens to calcium and bones during pregnancy?
Pregnant women absorb calcium better, produce more estrogen, all to protect bones
Not applicable for teen pregnancies
What happens to bones during breastfeeding?
3-5% bone mass lost
Baby steals calcium from mother
Mom producing less estrogen
Restored in 6 months
What is the order of BMD racially?
Black
Hispanic
Caucasian
Asian
What happens to trabecular bone with aging?
density decreases with aging in 30s, hip, vertebrae, and femur
What happens to compact bone with aging?
half the rate as trabecular, in 40s
What is osteomalacia?
refers to a marked softening of your bones, most often caused by severe vitamin D deficiency
What is osteopenia?
when your bones are weaker than normal but not so far gone that they break easily, which is the hallmark of osteoporosis.
What is osteoporosis?
A condition in which bones become weak and brittle.
What foods to eat to prevent and treat bone loss?
Fish, dairy, fruits and veggies
What lifestyle choices can prevent and treat bone loss?
have a healthy and varied diet with plenty of fresh fruit, vegetables and whole grains.
eat calcium-rich foods.
absorb enough vitamin D.
avoid smoking.
limit alcohol consumption.
limit caffeine.
do regular weight-bearing and strength-training activities.
What is epidermolysis bullosa?
he name for a group of rare inherited skin disorders that cause the skin to become very fragile
Which protein is missing or dysfunctional in children who are born with epidermolysis bullosa?
collagen
