Bone and Calcium Homeostasis

Question 1

_____is the most abundant mineral in bone

Answer 1

Calcium

Question 2

____is the most abundant mineral in the human body.

Answer 2

calcium

Question 3

Calcium ions are needed not only for bone mineralization but for tooth health, regulation of the heart rate and strength of contraction, blood coagulation, contraction of smooth and skeletal muscle cells, and regulation of nerve impulse conduction.

Ise read it and say T/F

Answer 3

Ttttttt

Question 4

The normal level of calcium in the blood is about ____.

Answer 4

10 mg/dL

Question 5

When the body cannot maintain a normal level of calcium , a person will experience ___ or ____

Answer 5

hypo- or hypercalcemia.

Question 6

Calcium metabolism or calcium homeostasis is the mechanism by which the body _____calcium levels.

Answer 6

maintains adequate

Question 7

Derangements of calcium metabolism lead to ____ or _____, both of which can have important consequences for health.

Answer 7

hypercalcemia or hypocalcemia

Question 8

calcium flow to and from the bone is neutral

T/F

Answer 8

T

Question 9

about ___ mmol of calcium from bone is turned over a day.

Answer 9

five

Question 10

Bone serves as an important storage point for calcium, as it contains ___% of the total body calcium.

Answer 10

99

Question 11

Calcium release from bone is regulated by _____ hormone.

Answer 11

parathyroid

Question 12

_____stimulates incorporation of calcium in bone.

Answer 12

Calcitonin

Question 13

Hypocalcemia
-A condition characterized by abnormally ___ levels of calcium

-it can have an adverse effect on a number of different body systems including circulation, muscles, nerves, and bone.
T/F

Answer 13

low

T

Question 14

Without adequate calcium, blood (has difficulty coagulating or over coagulates?) , the heart may ___ or _____ altogether, muscles may have difficulty _____, nerves may have difficulty functioning, and bones may become ____.

Answer 14

has difficulty coagulating

skip beats or stop beating

contracting

brittle

Question 15

The causes of hypocalcemia can range from ____ to____

Answer 15

hormonal imbalances

an improper diet.

Question 16

Treatments for hypocalcemia are constant irrespective of the cause
T/F

Answer 16

F

vary according to the cause

Question 17

prognosis for hypocalcemia are generally (good or bad?)

Answer 17

Good

Question 18

when calcium level reduces below normal, ____ glands release ____ that increases the activity of osteo___ to ____ calcium from ___, __reased calcium reabsorption from kidneys and calcium’s absorption in the ____increases with__ synthesis

Answer 18

parathyroid; PTH

clasts

release ; bone

inc

small intestine ; vitD

Question 19

Hypercalcemia

• a condition characterized by abnormally —- levels of calcium
• the nervous system is (overactive or underactive?) , which results in ___,___ reflexes, constipation and ___ of appetite, confusion, and in severe cases,___.

Answer 19

high

Underactive

lethargy

sluggish

loss

coma

Question 20

calcium homeostasis is critical.

T/F

Answer 20

T

Question 21

The ___,____, and____ systems play a role in this, but the kidneys do, too.
-These body systems work together to maintain a normal calcium level in the blood

Answer 21

skeletal

endocrine

digestive

Question 22

when calcium level rises above normal, ____ gland releases____ that ____ osteoclasts activity and____ calcium’s rate of reabsorption in the kidney and calcium level decreases back to normal

Answer 22

thyroid

calcitonin

inhibits

reduces

Question 23

The body deposits calcium in the bones when blood levels get too___, and it releases calcium when blood levels drop too___.
-This process is regulated by____,____, and____.

Answer 23

high

low

PTH

vitamin D

calcitonin

Question 24

Calcium is a chemical element that can be produced by some biological processes.

T/F

Answer 24

F

Can’t be produced by any

Question 25

The only way calcium can enter the body is through the ____

Answer 25

diet.

Question 26

The ___ act as a storage site for calcium

Answer 26

bones

Question 27

Cells of the parathyroid gland do not have plasma membrane receptors for calcium. T/F

Answer 27

F They do

Question 28

When calcium is not binding to parathyroid gland membrane receptors, the cells release___, which stimulates osteo__ proliferation and ____ of bone by osteo___. -This demineralization process ___ calcium into the blood.

Answer 28

PTH clast; resorption;clasts releases

Question 29

PTH promotes ___ of calcium from the urine by the kidneys, so that the calcium ___ to the blood. -Finally, PTH stimulates the synthesis of____, which in turn, stimulates calcium absorption from any_____ in the______.

Answer 29

reabsorption returns vitamin D digested food small intestine

Question 30

When blood levels of calcium get too high, the ____ gland is stimulated to release____, which ____ osteoclast activity and ___ calcium uptake by the bones, but also ____ reabsorption of calcium by the kidneys. -All of these actions ___ blood levels of calcium.

Answer 30

thyroid calcitonin inhibits stimulates decreases lower

Question 31

High calcium intake may be a risk factor in the development of osteoporosis. T/F

Answer 31

F Low calcium levels

Question 32

With a better bone balance, the risk of osteoporosis is lowered. T/F

Answer 32

T

Question 33

Supplementation with _____ and _____ slightly improves bone mineral density.

Answer 33

vitamin D calcium

Question 34

Vitamin D and Calcium Homeostasis - Vitamin D is converted to____(also called _____) in the liver. - Part of it is converted by the ___ to ____, the biologically active form of vitamin D. - It circulates as a hormone in the blood, regulating the concentration of____ and____ in the bloodstream and promoting the healthy growth and remodeling of bone.

Answer 34

calcidiol calcifediol kidneys calcitriol calcium; phosphate

Question 35

Responses to Blood Calcium Changes * When blood calcium concentration rises - the ______ cells of the thyroid gland increase calcitonin secretion into the blood. - At the same time, the parathyroid glands (increase or reduce?) parathyroid hormone secretion into the blood. - The resulting high levels of calcitonin in the blood stimulate the bone to remove calcium from the___ and deposit it as____. - Removal of calcium from the bone is also (facilitated or inhibited?)

Answer 35

parafollicular Reduce blood plasma bone Inhibited

Question 36

When the blood calcium level is too low -calcitonin secretion is ____ and PTH secretion is _____. -This results in the ___ of calcium from the___ to correct blood calcium levels.  

Answer 36

inhibited stimulated removal; bone

Question 37

calcitriol: The active metabolite—_________—that is involved in the_____ of calcium.

Answer 37

1,25-dihydroxycholecalciferol absorption

Question 38

calcidiol: A  ______ that is produced in the ___ by the____ of vitamin D3 (____) by the enzyme ____________

Answer 38

prehormone liver hydroxylation cholecalciferol cholecalciferol 25-hydroxylase.