Mineral Homeostasis Flashcards
- __% of the Calcium in our bodies is found in our ____
- ____% of total adult bone mass turnover occurs annually due to bone ______
- During growth the rate of bone ______ exceeds _____ leading to the skeletal mass to ________
- _______ growth occurs at the _____ plates
- Increase in bone width occurs at the ______
- Rate of _______ & ______ are equal until ~30 where the rate of ________ begins to exceed the rate of _______ and bone mass _______
- 99%; bones
- 10%; remodeling
- Formation; resorption; increase
- Linear; epiphyseal
- Periosteum
- Formation; degradation; degradation; formation; decreases
- 20% of adult bone is _____/_____ bone
- 80% of adult bone _____/_____ bone. Is ___, ____, and solid bone that forms the _____: the outer shell of most bones. Provides _____ and ______ to the bone
- Trabecular; Spongy
- Cortical; Compact
- Dense; stiff;
- Cortex; strength; protection
-Active _______ synthesize and extrude
collagen
-Collagen fibrils form arrays of an organic matrix
called the ____
-______ ______ is deposited in the osteoid and
becomes mineralized
-Dependent on _______
-______ ______ and ______ play roles in
bone formation and their plasma levels are indicators of _____ activity
- Osteoblasts
- Osteoid
- Calcium Phosphate
- Vitamin D
- Alkaline Phosphatases; Osteocalcin; Osteoblast
-Interior ________ remain connected to surface
cells via transfer of ________ from enormous
surface area of the interior to extracellular fluid.
-Osteocytes; Calcium
Bone Resorption of Calcium by 2 Mechanisms:
1) ______ _____: Is a rapid and transient effect
2) _____ ______: Is slow and sustained
-Bone formation and resorption are mainly
regulated by _____ ____(___) and
Vitamin ____.
1) Osteocytic Osteolysis
2) Osteoclasitic resorption
- Parathyroid Hormone (PTH); VitaminD
Osteocytic Osteolysis -Transfer of \_\_\_\_\_\_\_\_ from canaliculi to extracellular fluid via activity of \_\_\_\_\_\_, by removing \_\_\_\_\_\_\_ from most recently formed crystals -\_\_\_\_\_\_ decrease in bone mass -Very \_\_\_\_\_\_ process
- Calcium; Osteocytes; Calcium
- NO
- Fast
Osteoclastic Resorption
-Does not merely extract ______, it _______
entire matrix of bone and ________ bone mass
-Cell responsible for resorption is the ________
- Calcium; destroys; diminishes
- Osteoclast
Mineral Homeostasis
-______ and ________ ions can combine to form
insoluble ______, the concentrations of these ions in
cells and body fluids is precisely regulated to
prevent inappropriate _______
-Mineral balance is achieved by ______ control
of ______ & ______ transport into and out of ______, ______, & _____
- Calcium and phosphate; salts; precipitations
- Hormonal; Calcium & Phosphate; Intestines; Kidneys; Bone
Importance of Calcium
-In bone provides structural ________ of the skeleton
-Most abundant ______ in the body
-Amount of Calcium is balanced among ______, ____, and _______, which is controlled via Calcium transfer from the 3 organs
Calcium in Extracellular and Cellular Fluids:
-__________ excitability and signal ______
-Blood ______
-________ secretion
-________ regulation
-________ excitation
- Integrity
- Mineral
- Intestines, kidney, bone
- Neurmuscular; transduction
- Coagulation
- Hormonal
- Enzymatic
- Neuron
Calcium in the Body
-~______ of Ca is ingested per day, and absorption occurs in the ____ _______, and
requires ________
-An adult human contains ~ _________g of Calcium
-Extracellular [Calcium] is ~_____ mg/dL, and [Calcium] in the cytosol is ~ ______M
- 1000mg; small intestines; Vitamin D
- 1,000g
- ~10mg/dL
- ~10-7 M
Regulation of Intracellular Calcium
- Stored in the ______ and ____
- ______ transport systems control intracellular [Calcium], where it gets pumped into storage site in _______ to avoid forming _______ pools
- Mitochondria; ER
- “Pump-leak”; organelles; cytosolic
Extracellular Calcium
- Normally ranges from _____ mg/dL in the
_____
3 forms of Calcium in serum:
1) _______ calcium makes up ____% of the total and is biologically ______
2) _______ calcium makes up ___%, where 90% is bound to _____ and the rest is bound to globulins
3) Calcium complexed to serum ________ (_____ & phosphate) make up 10%
- 8.5-10 mg/dL; blood
1) Ionized; 50%
2) Protein-bound; 40%; albumin
3) Constituents; Citrate
Daily Calcium Turnover
- Intake of ~____mg of ____ Calcium
- ~___mg of unabsorbed dietary Calcium and ~____mg of fecal Calcium are excreted
- The _____ filters ~______ mg/day and ~200mg get excreted in the _____, 98% of the _____ Calcium is exchanged back into the _____
- ~350mg gets absorbed into the ____ from the intestine, ~_____ mg goes back into the intestines, and bone _____ results in ~____mg being absorbed back into and from the bone with the _____.
- Bone contains ~______ mg of Calcium
- 1,000mg; dietary
- 650mg; 150mg
- Kidney; 10,000 mg/day; urine; filtered; blood
- blood; 150mg; remodeling; 500mg; blood
- 1 million mg
- ~_____ mg of phosphate is ingested per day
-Phosphate is absorbed in the _____ ____,
stored in the ______ and excreted by the ______
- 1,000
- Small Intestines; Skeleton; Kidneys
Storage of Phosphate
-An adult human contains approximately _____g of
phosphorus
-~ ____% of this is present in crystalline form in the
______
- ~___% is present in the _________ fluids, and the concentration in cells is ~___mM
-Phosphate concentrations are ____ rigidly maintained than that of ______
- 700mg
- 85%; skeleton
- 15%; extracellular; 5mM
- Less; Calcium
Phosphorous in Blood and Bone
-PO4 normal plasma concentration is _____ mg/dL.
87% is ______, with 35% complexed to
different ____ and 52% ionized.
-13% is in a non-diffusible _____ ____ state. 85-90% is found in ___
- The rest is in ____, ____, & ______
- 3.0-4.5 mg/dL; diffusable; ions
- protein bound; bone
- ATP; cAMP; & proteins
Regulation of Pi homeostasis
- Cells require adequate Pi for ____ metabolism and ____ ___ synthesis
- Cells take up Pi from the ____ using _______, a form of active transport
- Absorption and reabsorption of Pi occurs primarily in the ______ and the _____
- Pi is regulated by ____, _____, and _____
- Energy; nucleic acid
- blood; Na+/Pi co-transporters
- Intestines; kidneys
- PTH; Vitamin D; FGF23
Hormonal Control of Calcium
Major Hormones:
-__________: Acts on the intestines, kidneys, and bones
-______ ______(___): Acts on the kidneys and bones
-__________: Acts on the kidneys and bones
-Both ______ & _____ increase blood calcium, while _____ decreases it
- 1,25(OH)2 Vitamin D3
- Parathyroid Hormone (PTH)
- Calcitonin
- Vitamin D & PTH; Calcitonin
Vitamin D
-Is the precursor of the hormone __________, which increases absorption in the ______ and reabsorption in the _______
2 Natural Forms of Vitamin D:
1)______/______: Derived from the plant steroid ergosterol
2)______/______: Derived from cholesterol
-Both must be _______ to be in the active form, this occurs in the ______, and the rate is determined by ____
-Dietary Vitamin D is usually ____
- 1,25 (OH)2 Vitamin D3; small intestine; kidney
- Vitamin D2/Ergocalciferol
- Vitamin D3/Cholecalciferol
- Hydroxylated; kidney; PTH
- Vitamin D2
Health Problems Associated with Vitamin D Deficiency
Causes:
-Lack of ____ exposure
-__________ & supplements
-_________ related diseases like Crohn’s, Whipple’s, Cystic fibrosis, Coeliac, or liver disease
-______ & _______ failure
-_________
Consequences:
-Mental problems like ________ & _______
-Higher rate of _______
-______ disease
-__________ diseases like Type 1 diabetes & Rheumatoid arthritis
-Many different ________
-Bone diseases: ______, ________, & _______ (children only)
Causes: -Sun -Medications -Malabsortption -Renal & hepatic -Obesity Consequences: -Schizophrenia & depression -Autoimmune -Cancers -Osteoporosis; Osteomalacia; Ricketts
Mechanism of Vitamin D Action
-______ _______(___): Belongs to the steroid/thyroid hormone receptor superfamily. Binds cooperatively to ____ ____ ____(___) as a heterodimer with the Retinoid X Receptor (RXR)
-Vitamin D Receptor (VDR); Vitamin D response elements (VDREs)
- Calcium is dependent on ___________ for absorption by inducing the production of _____ _____ _____ that sequesters Calcium allowing it to be absorbed ______ the gradient
- In the small intestines is greatest in the _____>____>____
- _______ is better at low pH, with peak absorption at the beginning of the ______
- Vitamin D; Calcium Binding Proteins; Against
- Duodenum; Jejunum; Ileum
- Absorption; duodenum
Vitamin D Actions on Bones
- _______ have Vitamin D receptors and ______ do not
- Absence of _____ results in excess ______ accumulation, repressing Osteoblastic _____ synthesis
- ________ stimulates Osteoblast to produce a ______ signal to activate ______ to resorb Calcium from the matrix
- ________ also stimulates the process _______ _______
- Osteoblasts; Osteoclasts
- 1,25 (OH)2 Vitamin D3; Osteoid; Collagen
- 1,25 (OH)2 Vitamin D3; paracrine; Osteoclasts
- 1,25 (OH)2 Vitamin D3; Osteocytic Osteolysis
Regulation of Vitamin D
- _____ increases 1-hydroxylase activity, increasing production of active form. This ______ absorption in the intestines; _____ release from the bone; and _______ loss in the kidneys
- ____ is regulated via negative feedback inhibition
- Low [_____] increases 1-hydroxylase activity increasing production of the active form and ________ reabsorption from the urine
- PTH; increases; increases; decreases
- PTH
- [Phosphate], phosphate
