Connective Tissue Flashcards
4 examples of connective tissue
- loose connective tissue
- tendons
- bone
- blood
3 types of bone cells
- osteoblasts
- osteoclasts
- osteocytes
Function of osteoblasts
produce the organic matrix, move into the cavity, and secrete the osteoid to fill in the hole
Function of osteoclasts
resorb bone to form a cavity
Function of osteocytes
produce the factors that regulate the start of both bone formation and resorption
How is growth in bone thickness achieved?
by adding new bone on top of the outer surface of already existing bone
How is growth in bone length achieved?
through the action of chondrocytes in the proliferative and hypertrophic zones of the growth plate
5 main parts in the structure of a long bone
- articular cartilage
- bone of epiphysis
- epiphyseal plate
- bone of diaphysis
- marrow cavity
When do osteoblasts retire?
When they become osteocytes in mature non-growing bones
When osteoblasts retire(osteocytes) what are they involved in?
the hormonally-regulated exchange of calcium between bone and blood
What promotes the growth of bone in bone length and thickness?
Growth hormone and IGF-1
What stimulates the proliferation of epiphyseal cartilage?
Growth hormones via IGF-1
What can growth hormones promote?
lengthening of long bones as the epiphyseal plate remains cartiliganinuous
Effects that abnormal growth hormone secretion can have on growth?
Can cause gigantism or acromegaly
Key functions of the skeleton
- supports the body
- facilitates movement
- protects internal organs
- produces blood cells
- stores and releases minerals and fat
Should plasma Ca2+ be closely regulated?
Yes
How much of ECF Ca2+ is free?
less than 0.1%
Name some activities in the free fraction of ECF Ca2+ play a role in
- neuromuscular activity
- stimulus-secretion coupling
- maintenance of tight junctions between cells
- clotting of blood
Is bone dynamic?
Yes, it continuously undergoes remodeling
Parathyroid hormone(PTH) raises what when it starts to fall?
plasma Ca2+
What is osteoporosis?
a decrease in bone density caused by lack of Ca2+, resulting in reduced deposition of the bone’s organic matrix
2 ways to help prevent osteoporosis
- physical activity throughout life
- a large reservoir of bone midlife