Transcript Introduction to Anatomy

Bone Tissue
A.
B.
C.
D.
Physiology: functions of bone
Anatomy: structure of bone
Histology of bone
Bone homeostasis
1. Remodeling
2. Bone's role in calcium
homeostasis
Physiology: Functions of Bone
1.
2.
3.
4.
5.
6.
support
protection
movement
mineral homeostasis
blood cell production (hematopoiesis)
energy storage
Shapes of Bones
1.
2.
3.
4.
long
short
flat
irregular
Types of Bone
1. compact (dense)
2. spongy
(cancellous)
Long Bone Anatomy
1. diaphysis
2. epiphysis
3. metaphysis
4. epiphyseal plate
(Read bone dvp. pg. 220-227)
5. articular cartilage
6. articular surfaces
7. periosteum
a. fibrous
b. osteogenic
8. medullary cavity
9. endosteum
Bone Cell Types
1.
2.
3.
4.
osteoprogenitor cells
osteoblasts -- (osteogenesis)
osteocytes– (strain sensors)
osteoclasts -- (bone resorption/osteolysis)
Bone Matrix
1. ground substance (25%)
2. collagen (25%)
3. mineral salts (50%)
-- tricalcium phosphate (hydroxyapatite)
-- ossification
Bone Histology
1. Haversian system
(osteon)
2. Haversian canal
3. lacuna
4. lamella
5. canaliculus
Bone and Calcium Homeostasis
1. remodeling
2. serves to:
a. resist mechanical stress
b. remove worn bone
c. store calcium
(1) parathyroid hormone and vitamin D
(2) calcitonin
Less kidney reabsorption
(more calcium excretion)
(osteogenesis)
> 10.5 mg/dL
(osteolysis)
(Intestinal absorption too)
< 9.5mg/dL
CALCITONIN and BLOOD CALCIUM REGULATION
CONTROLLED CONDITION
Normocalcemia
(blood calcium = 9.5-10.5mg%)
A stress or stimulus causes an increase in
blood calcium
negative
feedback
RETURN TO HOMEOSTASIS
Increased bone formation results in
increased calcium deposition in bone –
Return to normocalcemia
RECEPTOR
Parafollicular cells of thyroid gland
recognize hypercalcemia
EFFECTORS
(blood calcium >10.5 mg%
Reduced osteoclast activity
Increased osteoblast activity
CONTROL CENTER
Parafollicular cells secrete calcitonin
PTH and BLOOD CALCIUM REGULATION
CONTROLLED CONDITION
Normocalcemia
(blood calcium = 9.5-10.5mg%)
A stress or stimulus causes a decrease in
blood calcium
negative
feedback
RETURN TO HOMEOSTASIS
Increased bone breakdown results in
increased calcium release to blood –
Return to normocalcemia
RECEPTOR
EFFECTORS
Chief cells of parathythyroid glands
recognize hypocalcemia
Increased osteoclast activity
(blood calcium <9.5 mg%
Decreased osteoblast activity
Increased urine phosphate output
Decreased urine calcium output
CONTROL CENTER
Chief cells secrete PTH
end
Bone Growth, Stress and
Osteoporosis