1. Unit 3 Test Review

2. Calcium Homeostasis

3. Ca++ Online Help:
eText – Section 6.8
Smart Video – Hormone Regulation
MP3 Tutor – Calcium Regulation
IP Animation – Bone
This is a feed back mechanism
Stimulus
Receptor
Control Center
Effector
Response

4. Low Calcium Ion Level in Blood
Factors That Increase Blood Calcium Ion Level
These responses are triggered
when blood calcium ion level
decreases below 8.5 mg/dL.
Low Calcium Ion Level in Blood
(below 8.5 mg/dL)
Parathyroid Gland Response
Low calcium level causes the
parathyroid glands to secrete
parathyroid hormone (PTH).
PTH
Bone Response
Intestinal Response
Kidney Response
Osteoclasts stimulated to
release stored calcium ions
from bone
Intestinal
absorption
of calcium
increases
Kidneys
absorb
calcium ions
Osteoclast
more
Bone
calcitriol
Calcium released
Calcium absorbed
Calcium conserved
Ca2+
level in
blood
increases
Decreased calcium
loss in urine
© 2018 Pearson Education, Inc.

5. High Calcium Ion Level in Blood
Factors That Decrease Blood Calcium Ion Level
Intestinal and kidney
responses are triggered when
blood calcium ion level rises
above 11 mg/dL.
High Calcium Ion Level in Blood
(above 11 mg/dL)
Thyroid Gland Response
C cells in the thyroid
gland secrete calcitonin.
Calcitonin
Bone Response
Intestinal Response
Kidney Response
Osteoclast activity
decreases; osteoblast
activity unaffected
Intestinal
absorption
of calcium
decreases
Kidneys
excrete
calcium ions
less
Osteoclast
calcitriol
Bone
Calcium release slowed
Calcium absorbed slowly
Calcium excreted
Ca2+
level in
blood
decreases
Increased calcium
loss in urine
© 2018 Pearson Education, Inc.

6. Endosteum vs. Periosteum

8. Types of Cells

9. Figure 6–5 Types of Bone Cells.
Endosteum
Osteoblast
Osteogenic
cell
Osteoid
Medullary
cavity
Matrix a
Osteogenic cell: Stem
cell whose divisions
produce osteoblasts b
Osteoblast: Immature
bone cell that secretes
organic components of
matrix
Medullary
cavity
Matrix
Ruffled
border
Osteocyte
Osteoclast
Canaliculi
Matrix c
Osteocyte: Mature bone
cell that maintains the bone
matrix d
Osteoclast: Multinucleate
cell that secretes acids and
enzymes to dissolve bone
matrix
© 2018 Pearson Education, Inc.

10. Types of Fractures

12. Types of Fractures
Fig. 61-4

13. Refer to page 203 in your eText for a quick review
Bone Healing

16. Bone Growth

18. Bone Remodeling