Lec 17: Skeletal physiology, articulation Flashcards
What causes bones to lengthen longitudinal?
Growth of chondrocytes
(Location: epiphyseal plate)
T/F
The epiphyseal plate is composed of hyaline cartilage that did not ossify?
TRUE
List the 5 different zones of cells within epiphyseal plate?
O-C-H&M-P-R
[Diaphyseal side]TOP
- Zone of ossification
- Zone of calcification
- Zone of hypertrophy & maturation
- Zone of proliferation
- Zone of reserve cartilage
[Epiphyseal side]BOTTOM
“Chondrocytes” starts to divide (mitosis stage) in which zone?
Zone of proliferation
In which zone does chondrocytes enlarge/mature?
Hypertrophy & maturation
What happens to chondrocytes in the zone of Calcification?
They die»_space; Their matrix calcifies
What happens in th zone of ossification?
Calcified cartilage becomes bone
T/F
Zone of reserved cartilage is involved in bone growth
FALSE - It’s not included
What is the direction of bone growth?
Upward/longitudinal
What component drives the calcified cartilage to become bone?
Osteoclast (resorbtion)
Longitudinal continues as long as ____ occurs in zone of proliferation?
Mitosis (cell division)
Around what age does mitosis ‘slow’ down?
12-15 years of age
At what age does the zone of proliferation ossifies completely? (leaving epipphyseal line)
18-21 years of age
(Bone stops growing)
Bone growth in width is know as______?
Appositional growth
What happen during appositional growth?
- Forms new circumferential lamellae > (new layer of bone)
- New osteon forms
- Bone gets thicker/wider
What is the most important hormone as it relates to bone development?
Growth Hormones
Function of Growth Hormone
_Increase protein synthesis
_Increase cell division in all tissue
_Increase rate of mitosis in Chondrocytes > epiphyseal plate
_Increase osteogenic cell activity
_Cause osteoblast to react > increase bone width growth
What causes appositional growth?
Osteoblast in periosteum build new bone layer
Whats the medical term for ‘bone loss’?
Osteoporosis
Name the 2 main factors that’s necessary for bone remodeling?
Osteoblast - Bone deposition
&
Osteoclast - Bone resorption
List 2 other factors that affect bone remodeling?
(Dietary factors) IMPORTANT!
- Calcium intake
[too much>build up>kidney stone] [too little>brittle bone>break easily] - Vit D intake [increase Ca absorption>increase bone deposition]
- Vit C intake [helps to produce collagen fiber]
Whats the function of the ‘Parathyroid gland’?
Detects low calcium level - Increase low calcium level
(Calcium Homeostasis)
T/F
Parathyroid gland controls ‘osteoclast’?
TRUE
The parathyroid gland releases which hormone into the blood?
Parathyroid hormone (PTH)
