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)
Parathyroid hormone signals osteoclast to break down bone and release calcium into blood
(regulates low blood calcium levels)
Locations of Parathyroid gland
- Bone
- Kidney
- Intestines
What is the function of ‘Calcitonin’?
Decrease calcium production
____ is controled by calcitonin?
osteoblast
Which gland secretes calcitonin?
Thyroid gland
T/F
Calcitonin ‘REVERSE’ the effects from parathyroid hormone
TRUE
List 2 factors that increase and decrease osteoblast activity
Increase: Decrease:
- Exercise - lack vit D,C,K & calcium
- Testosterone - Inadequate exercise
- Intake of vit D,C,K & calcium
List 2 factors that increase and decrease osteoclast activity
Increase: Decrease:
- Parathyroid hormone - Estrogen
- Decrease in blood ca+ levels - Calcitonin
- Increase in blood Ca+ level
- What’s the effect of ‘Osteoporosis’?
- What causes this condition?
- Make bones weak & brittle
- Inadequate inorganic matrix
LIst 3 factors that affects osteoporosis
- Ca+ & Vit D
- Hormone factors
- Age (older ppl)
