Anatomy and Physiology Unit 2.1
(Chapter 7)pgs 227-235
Physiology of Osseous Tissue
227: Bone remains a metabolically active___________________through out life and has many roles to play.
It is involved in its own _________________, growth,_________________, and continues to exchange______
_______ with the surrounding tissues and fluids.
One important function of bone is that this organ keeps the ___________________________________
Within the body which keeps the other organ systems functioning.
Mineral Deposition
Mineralization is a ______________________ in which Calcium and Phosphate and other ions are taken from
_________________ and deposited in the bone tissue. _______________________ cells begin by laying
down __________________ in a helical pattern along the _____________. Calcium Phosphate hardens the
matrix by first forming seed_____________ (Hydroxyapitite). These crystals attract and promote the growth
and hardening of more hydroxyapatite.
Is this an example of POSITIVE or NEGATIVE feedback?????
Trouble: this osseous tissue can unfortunately form in other organs!!
Abnormal Calcification can lead to _________________________
(hardening of the arteries)
pg 228
Mineral Resorbtion
This is the process of _______________ bone tissue, and functions to release minerals into
the___________________.
_________________________cells carry this out. The space between ________________cells and bone
becomes filled with ___________(hydrochloric acid), and this dissolves the minerals in bones, especially the
calcium and phosphates. Additionally, Osteoclasts release______________________, that digests collagen
as well.
How do Bones Help Keep Ca2+ and P04 in Balance??
P04 groups are important in the formation of _____________, ________________, _______________, and
phospholipids and they also help in correcting __________________ imbalances.
Calcium plays roles in _______________communication, __________________contraction, formation of
_____________________, exocytosis, cell signaling, and is also an important _____________________ for
Enzyme function.
Normal [Ca2+] in blood plasma is ____________________
~45% is ionized Ca2+ that can diffuse through__________________________ and affect neighboring cells.
~55% is bound to blood plasma proteins which is not_________________________ but serves as a reserve.
Normal [H2P04- ] and [HP042-]is found in concentrations of about 500-800g, almost all in the bone.
Changes in the conc. of phosphates have little effect on the body.
Changes in the conc. of calcium have SERIOUS effects on the body.
Examples:
HYPOCALCEMIA: Calcium conc. is too LOW
Effects: excessive_______________ stimulation
___________________ spasms
__________________ muscles can’t relax
At about 4mg/dL muscles in larynx contract can lead to____________________.
Hypocalcemia can result from
1. Vitamin _______________deficiency
2. _______________________________
3. _______________________________
4.________________________________
HYPERCALCEMIA: Calcium conc. is too HIGH
Effects: Calcium binds to ____________________ inhibiting the Na channels from functioning
Reduced or _________________nervous system
Emotional ___________________________
This is
Sluggish_________________________
RARE!!!
Muscle___________________________, even cardiac arrest!
Calcium and Phosphate homeostasis depends on a balance of_____________________, ______________and
___________________________ and exchanges with Osseous Tissue.
This homeostasis is regulated by three hormones:
1.___________________
2.________________________
3._________________________
A) Calcitriol is the active form of ____________________________.
It is a hormone that is a _____________________________from organ to another.
Functions: To ____________________blood Calcium. How does it do this??
1. It stimulates the increased absorption of Calcium in the ____________________________.
2. Increases resorption of CA in bone by binding to ______________________which stimulate stem cells to
_______________________into more ____________________________. These then liberate ___________
And _________________from bone.
3. It promotes reabsorption of calcium by the kidneys so _______________is excreted.
B) Calcitonin is released by C cells of the ________________________.
Functions : to _____________________blood calcium. How does it do this???
1. It is secreted when blood Ca is too high and this reduces ________________________ activity.
(Osteoclast inhibition)
2. This increases the numbers of _______________________ which deposit Calcium into the bone.
(Osteoblast Stimulation)
Very important in children.
C) Parathyroid Hormone (PTH) is secreted by the parathyroid gland.
Functions: To Raise blood _____________levels.
How does it do this???
1. PTH binds to ____________________on Osteoclasts, promoting resorption, __________________Ca
Into the blood stream.
2. PTH promotes kidneys to reabsorb Calcium so less is excreted.
3. Promotes last step in ______________synthesis so you have high conc. of ___________________
4. Inhibits the formation of ____________________ thus inhibiting bone deposition.
Additionally there are some 20 plus other hormones that play a small role in the homeostasis of calcium and
phosphate concentrations in bone and blood. YIKES!!!
BONE FRACTURES
BASICALLY 2 TYPES:
Pg 232
1. Stress Fracture________________________________________
2. Pathological Fracture____________________________________
Bone breaks are categorized by:
1. direction of fracture
2._________________________
3.________________________________
know the types of fractures listed in 7.19
Pg 233 Stages of Healing
1. 0-48 hrs Hematoma and Granulation Tissue:____________________________________________
_______________________________________________________________________________________
2.
Formation of Soft Callus_______________________________________________________
_______________________________________________________________________________________
3. 4-6 wks
Conversion to Hard Callus_______________________________________________________
________________________________________________________________________________________
4. 3-4 mo.
Remodeling___________________________________________________________________
_________________________________________________________________________________________
Medical Treatment of setting Fractures:
Describe Closed Reduction:________________________________________________________________
Describe Open Reduction: __________________________________________________________________
Bone Disorders:
Describe what happens when Osteoporosis occurs:_____________________________________________
__________________________________________________________________________________________
________________________________________________________________________________________
What can one do to prevent this from occurring? What age is it best to start prevention measures?
_________________________________________________________________________________________
__________________________________________________________________________________________
Pick one other bone disease and explain:_______________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Illustrate the NEGATIVE Feedback loops for
a. correction of hypercalcemia
b. correction of hypocalcemia