CALCIUM

Question 1

Fifth most common element
most prevalent cation in the human body
○ Na+ is prevalent in plasma since it maintains osmolality;
○ majority of calcium is stored in bones
■ not _____________ active
■ Not ________________

Answer 1

Calcium
physiologically
circulating

Question 2

Function of Calcium

Answer 2

• enzyme activity
• blood coagulation
• excitability of skeletal and cardiac muscle
• maintenance of blood pressure

Question 3

stored as hydroxyapatite

Answer 3

● skeletal mineralization

Question 4

involved in activities of platelets to stop
bleeding

Answer 4

● blood coagulation

Question 5

Ca2+ propagate signals down the
axons

Answer 5

● neural transmission

Question 6

Calcium
○ Involved in dumping of neurotransmitters, like
____________, into the synapsis

Answer 6

acetylcholine

Question 7

__________ is needed for acetylcholine to leave the terminal
end of the axon, enter the synaptic cleft, and bind to its
receptor in the adjacent cell neuron

Answer 7

○ Ca2

Question 8

CALCIUM DISTRIBUTION
_________ - bone
________ - blood + ECF
_________ - bound to anion (____, ______, ______)
_________ - bound to protein
__________ - free/ ionized calcium - active but hard to measure alone

Answer 8

99%
1%
15% - citrate, bicarbonate, lactate
40%
45%

Question 9

Almost all calcium is stored in __________

Answer 9

bones

Question 10

Decreased free calcium levels in blood can cause muscle spasms or uncontrolled muscle contractions called __________

Answer 10

tetany

Question 11

• Three hormones which regulate Ca++
  secretion

Answer 11

1. Parathyroid Hormone
2. Vitamin D
3. Calcitonin

Question 12

• I. Parathyroid Hormone (PTH)
• stimulated by decreased ionized Ca2+
  1. ______________
  2. ________________
  3. ________________
  4. ________________
  5. _________________

Answer 12

1. bone
2. bone resorption
3. kidneys
4. conserve ca2+
5. Renal production of Vit D

Question 13

• II. Vitamin D (1,25-Dihydroxycholecalciferol
  [1,25-(OH)2-D3])
• increases Ca2+ absorption in the __________
• enhances effect of _______ on bone resorption

Answer 13

intestine
PTH

Question 14

• A lipid soluble hormone that binds to a typical
  nuclear receptor, analogous to steroid hormones.
  Because it is lipid soluble, it travels in the blood
  bound to hydroxylated a-globulin.
• Extrarenal sites of the active form: _________, __________

Answer 14

Vitamin D
placenta,
granulomatous tissues

Question 15

EFFECTS OF VITAMIN D
* Promotes __________ absorption of calcium
* Causes synthesis of ____________ and
_________________
*Has slight effect to increase calcium re-absorption in
______________
* Works with PTH to cause calcium resorption from
bone (activates osteoblasts to activate osteoclasts to
resorb Ca++)

Answer 15

intestinal
calcium binding protein and related facilitated transport
kidneys

Question 16

VITAMIN D3 LAB METHODS
* better marker: _____________(longer halflife)
* ______________ versus ____________
* reference method: ______________
* values are influenced by ______________ and
____________

Answer 16

25-hydroxy vitamin D
2-3 weeks / 5-8 hours
dual mass spectrometry
sunlight exposure and Latitude

Question 17

• originates in the parafollicular C cells
• secreted when the concentration of Ca2+
  increases (hypercalcemia)

Answer 17

Calcitonin

Question 18

• inhibits the action of PTH and Vit. D

Answer 18

Calcitonin

Question 19

• ____________ acts to decrease plasma Ca++ levels
  While _________ and _________ act to increase plasma Ca++

Answer 19

Calcitonin
PTH and Vitamin D

Question 20

• ______________ is synthesized and secreted by the
  parafollicular cells of the thyroid gland

Answer 20

Calcitonin

Question 21

• The major stimulus of calcitonin secretion is a rise in
  _________________

Answer 21

plasma Ca++ levels

Question 22

• Chronic excess of calcitonin does not produce
  ______________ and removal of parafollicular cells
  does not cause _____________

Answer 22

hypocalcemia
hypercalcemia.

Question 23

CALCITONIN LAB METHODS
* _____________________
* IV administration (0.5 µg / kg body
weight) over____________
* Blood samples: baseline, ____________
minutes after the start of infusion

Answer 23

Pentagastrin (Pg) Stimulation Test
5 seconds
1, 2, 5, and 10

Question 24

Peak Calcitonin
10
30-50
50-100
100
basal or post pg CT increase 10

Answer 24

Normal 80% adult
5% of normal adult
Possible MTC
Probable MTC
C cell pathology

Question 25

 promotes leaching of Ca2+ frombones
 H+ displace calcium fromproteins

Answer 25

Acidosis

Question 26

causes plasma proteins to have greater negative
charge, binding ionized calcium

Answer 26

Alkalosis

Question 27

SIGNS AND SYMPTOMS
Hypocalcemia
Hypercalcemia

Answer 27

Neuromuscular irritability
Paresthesia
Muscular Cramps
Tetany
Seizures
Cardiac irregularities
Arrythmia
Heart Block

NPMTSCAH

Neurologic
Mild drowsiness / Weakness
Depression
Lethargy
Coma
GI
Constipation
Nausea
Vomiting
Anorexia
Peptic ulcer disease
Renal
Nephrolithiasis
Nephrocalcinosis

Question 28

Calcium ions released into the cell causing filaments in the muscle fiber

Answer 28

muscle contraction

Question 29

calcium ions pumped into storage allowing the muscle filaments to relax

Answer 29

muscle relaxation

Question 30

Hypocalcemia

Answer 30

• Primary
  hypoparathyroidism
• Hypomagnesemia
  &
  hypermagnesemia*
• Hypoalbuminemia
• Acute pancreatitis
• Renal disease
• Rhabdomyolysis
  Pseudohypoparathyroidism

Question 31

Hypercalcemia

Answer 31

• Primary
  hyperparathyroidism*
• Hyperthyroidism
• Benign familial
  hypocalciuria
• Malignancy
• Multiple myeloma
• Increase vitamin D
• Thiazide diuretics
• Prolonged immobilization