bones and muscles 5 Flashcards
Parietal bones joined by ________________
Sagittal sutures
That connect to frontal bones by coronal sutures
Major Function and Characteristics of Bone
Mineral Components @ collagen fibers lend flexible strength.
Bone Cells are Categorized:
Osteoblasts
Osteocytes
Osteoclasts
Bones grow in size by ________________
Appositional Growth
The pontential shape and size of a bone and individuals final adult height are determined ____________________
Genetically
Factors such as nutrition and hormones can modify these genetic factors
___________are important to bone growth.
Vitamins
Vitamin D is important for
Absorption of Calcium
Vitamin C is necessary for
Collagen Synthesis
Hormones are important in bone_________
Growth
Sex____________also influence bone growth
Hormones
__________and___________stimulate ossification of the epiphyseal plate.
Estrogen and Testosterone
Females usually stop growing earlier than males because __________causes quicker closure of the epiphyseal plate.
Estrogen
Men have _________bones than women
Denser
Race affects bone_________
Mass
African Americans and Hispanic have higher bone masses than Caucasian and Asians
Most effective preventative measure against effects of aging on the skeletal system is
Increase in physical activity.
Taking dietary calcium and vitamin D supplements.
Intensive exercise can reverse loss of bone matrix.
With aging new osteons fail to completely fill in spaces produced when older_______ are removed
Osteons
Another name for skullcap
Calvaria
Muscles that move a structure
Agonists
Muscles that oppose movement of a structure
Antagonists
Muscles that stabalize structures
Synergists
What type of cartilage is associated with bone
Hyaline Cartilage
Precursor for most bones in the body
Bonej lengthening and bone repair often involve the production of ___________cartilage, followed by its replacement of bone
Hyaline
Facts about the Perichondrium
- It is a double layered connective tissue sheath covering most cartilage.
- The out layer is dense, irregular connective tissue containing fibroblasts. Blood vessels and nerves penetrate the outer layer of the perichondrium but do not enter the cartilage matrix.
- The inner layer-more delicate. Has fewer fibers and contains chondroblasts.
_______________cartilage has no pericardium blood vessels, or nerves.
Articular
Cartilage grows in 2 ways
- Appositional Growth
2. Interstitial Growth
Facts about bone
Bones consists of extracellular bone matrix @ bone cells.
The composition of the bone matrix is responsible for the characteristics of bone
By weight mature bone is about:
35% organic-Consists primarily of collagen, proteoglycans.
65% inorganic-Primarily of Calcium phosphate crystal called-HYDROXYAPATITE
Facts about Bone
The collagen and mineral components are responsible for the major functional characteristics of bone.
The collegen fibers lend flexible strength to the matrix.
The mineral components give the matrix weight-bearing strength
If you remove all the minerals from a long bone it becomes overly flexible.
It the collagen is removed from the bone it becomes very brittle.
Bone cells are categorized as:
- osteoblasts
- osteocytes
- osteoclasts
Body of Bone
The shaft (Diaphysis) composed primarily of compact bone, but can also contain spongy bone, with an outer layer of compact bone. Within joints, the end of a long bone is covered with hyaline cartilage called articular cartilage. The epiphysis is the part of a long bone that develops from a center of ossification. The epiphyseal plate separates the epiphysis from the diaphysis. The diaphysis of a long bone can have a large internal space called the medullary cavity. The periosteum is a connective tissue membrane that covers the outer surface of a bone. The endosteum is a single layer of cells that lines the internal surfaces of all cavities within bones.
When a bone stops growing in length, the epiphyseal plate becomes ossified and is called the ________________________
Epiphyseal Line
Facts about Vitamin D
Your body can synthesize or ingest it.
Your level of Vitamin D increases when exposed to sunlight
Insufficient Vitamin D in children causes rickets
Insufficient Vitamin D in adults-Osteomalacia
Facts about Vitamin C
Necessary for collagen synthesis.
In children a deficiency can retard their growth.
In children and adults can cause scurvy
Facts about Bones
- Bones play an important role in regulating blood ca2+ levels, which must be maintained within narrow limits for function such as muscle contractions and membrane potentials to occur normally.
- Bone is the major storage site form calcium in the body , and movement of Ca2+ into and out of bones.
- When blood Ca2+ levels are too low, osteoclast activity increases.
- If bloof Ca2+ levels are too high, osteoclst activity decreases.
- Calcium homeostasis is maintained by two hormones-Parathyroid Hormone (PTH) and Calcitonin
The major regulator of blood Ca2+ levels is
PTH (Parathyroid Hormone)
