Biology - Chapter 11.6: Skeletal System Flashcards
1
Q
Long bones
A
- Compact and spongy bone
- Includes: epiphysis, diaphysis, medullary cavity, metaphysis, epiphyseal plate
2
Q
Short bone
A
- .g. parts of the wrist
- support
3
Q
Flat bone
A
- e.g. skull
- protection
4
Q
Sesamoid bone
A
- e.g. kneecap
- found within tendons to help muscle pull
5
Q
Irregular bones
A
- e.g. pelvis
- look irregular
6
Q
Bone Remodeling
A
Constant back and forth between ossification (bone formation) and resorption (bone loss)
7
Q
Osteoprogenitors
A
Immature precursor cells that differentiate into osteoblasts
8
Q
Osteoblasts
A
- Build bone by secreting proteins and utilizing blood calcium
- Differentiate into osteocytes once trapped
9
Q
Osteocytes
A
-Live in lacunae of osteons to maintain bone
10
Q
Osteoclasts
A
- Resorb bone, bringing calcium back into the blood
- Derived from monocytes
11
Q
Parathyroid hormone
A
- secreted by parathyroid gland
- increases blood calcium levels
- stimulates osteoclasts
- depress osteoblasts
12
Q
Calcitonin
A
- secreted by thyroid gland
- decreases blood calcium levels
- depresses osteoclasts
- stimulates osteoblasts
13
Q
Material of Bones
A
Organic: osteoid
Inorganic: hydroxapatite
14
Q
Intramembrous ossification
A
- Mainly for flat bones
- Bone is created directly within fibrous membrane
- Osteoblasts start by secreting osteoid, which hardens and houses osteocytes
- Cortical bone is then created
15
Q
Endochondral ossification
A
- Bone is created indirectly through a cartilage model, mainly for long bones
- Cartilage model calcifies during fetal development, creating ossification centers (primary & secondary) that help form the features of long bone
