Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

PHYSIOLOGY II > Lecture 15: Calcium Balance > Flashcards

Lecture 15: Calcium Balance Flashcards

1
Q

T/F Ca is the most abundant element in the body

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

~99% of body Ca is found where

A

skeletal bone and teeth
0.9% is cytoplasmic (soft tissue)
0.1% in blood and exctracellular fluid (10mg/dl)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the second most abundant mineral in the body

A

Phosphate

0.1% in blood and ECF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

hydroxyapatite

A

biological apatite that makes bone (Ca+Phosphate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how can plasma ionized Ca be altered?

A
  • increases in plasma proteins increases total bound Ca w/ minimal changes to ionized Ca
  • increases in anions (phosphate) increase anion or complexed Ca and decrease ionized Ca
  • acid base fluxes: protons compete w/ calcium for albumin binding sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how can plasma ionized Ca be altered?

A
  • hormonally mediated exchange b/w intestine, bone, kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Ca+ balance in the body (b/w ECF/bone/intestine/kidney) is slow compared to Ca+ balance in the

A

ECF (B/w ECF + bone fluid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ca and phosphate levels in the blood are regulated by ______ and vitamin _____

A

Parathyroid Hormone (PTH) and Vit D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

calcitonin opposes …..

A

PTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What conditions stimulate PTH

A
  • low plasma Ca
  • high plasma phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the main regulator of Ca metabolism

A

PTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what conditions stimulate Vit D and what does it do

A
  • low plasma Ca
  • increases absorption of Ca from the inteestine
  • mainly balances Ca metabolsim via absorption in the gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

______ is not essential for the homeostasis or balance of Ca but does correct symptoms of hypercalcemia

A

Calcitonin
stimulates bone resorption of Ca

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

most domestic animals have how many pair of parathyroid glands

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the plasma half life of PTH

A

2-5 min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

PTH is a _____ hormone

A

peptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

high Ca levels inhibit the release of ….

A

PTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

majority cell type in the Parathyroid gland, they detect extra cellular Ca levels

A

Chief cells

*HUMORAL RESPONSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

bone is a living tissue composed of mineral components called the ______

A

matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

osteoblasts

A

bone builders
deposite the matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

osteocytes

A

former osteoblasts that are now internalized in the bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

osteoclasts

A

bone demolition
resorb the matrix
they are dervied from modified macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the 2 calcium pools

A

Labile pool:in bone fluid, allows for rapid exchange of Ca w/ blood
Stable pool: in bone matrix, allows for storage and slow exchange of Ca, site of bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

bone organization

A

osteon w/ central canal
lamellae canaliculi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
the osteoblast-osteocyte network is a pool of living tissue that has a ______ reserve of Ca+
labile
26
PTH activates membrane bound _____ in the osteobalsts and osteocytes to take in Ca
**Ca pumps** * Ca then transferred from these cells to the central cancal and into the blood * phosphate left behind
27
PTH receptors are located in....?
osteoblasts | NOT osteoclasts
28
In fast exchange, Ca is moved from the _____ pool in the bone fluid into the ____ by PTH-activated Ca+ pumps located inside the osteocytic-osteoblastic membrane
labile pool into the plasma
29
In slow exchange, Ca is moved from the _____ pool in the mineralized bone into the _____ through PTH induced dissolution of the bone by ______
stable pool to the plasma, osteoclasts
30
PTH inhibits the bone formation activity of _______
osteoblasts
31
Long term slow exchange of Ca+ causes a _______ in osteoblast activity and a ________ in osteoclast activity
decreased osteobalst activity increased osteoclast activity
32
osteoblasts release _______ (a ligand) that binds its receptor to cause macrophages to differentiate into osteoclasts
RANKL (binds to RANK)
33
Osteoclasts release ______ and _____ to dissolved the matrix and release Ca and phoshpate
Hcl and hydrolytic enzymes
34
what are the 2 direct effects of PTH in the kidney
* Conserves Calcium * Eliminates Phosphate
35
how do the kidneys conserve calcium when stimulated by PTH
* resorb more filtered Ca * increase Na/Ca cotransport in the DT * urine Ca decreases
36
how do the kidneys eliminate phosphate
* phosphate resobsorption decreases * inhibits Na/PO43- cotransport in the PCT * urine phosphate increases ** Phosphate elimination is necessary to avoid cation-anion complexes and apatite formation in blood**
37
how does PTH activate Vit D
by stimulating **1α hydroxylase** within the kidney, which converts vit D precursor into its active form
38
how is Vit D obtained
through diet or dervied from precursor in skin w/ UV light exposure
39
what are the 3 steps of VIT D synthesis
1. UV dependent proteolysis of 7-dehydrocholesterol to vitamin D3 (Can also come from diet) 2. Activation : in liver, CYP27A1 adds OH group to carbon 25 3. PTH dependent activation: in kidney, CYP27B1 adds OH group to Carbon 1
40
effects of Vit D in the kidney
promotes Ca reabsorption form the DT and promotes PT resorption of phosphate
41
in bone, Vit D synergizes w/ PTH to stimulate ________ and bone remodeling
resorption
42
osteomalacia in adult animals
* impaired ability to absorb Ca and Phosphate in the intestine * usually results from interstinal surgery that causes decreased Vit D absorption * malabsorption syndrome, malnutrition, renal failure, celiac disease * bones become demineralized and soft, fracture easily
43
Phosphate is regulated directly by _____ in the intestines
vit D
44
Phosphate is regulated indirectly by....
**the inverse relationship bw plasma phosphate and Ca** * a fall in phosphate increases Ca, resulting in decreased PTH * PTH decrease increases renal phosphate reabsorption
45
calcitonin is produced in _____ cells of the thyroid gland
Parafollicular C cells
46
hypercalcemia stimulates calcitonin release to decrease_________
**ECF Ca** * this decreases bone resportion by limiting the activity of osteoclasts via the cAMP pathway * inhibits Ca and phosphate reabsorption in kidney
47
calcitonin has no effects in the intestine or on ________
vit D
48
malignant cell clusters secrete _______ and bind to the PTH receptor
**PTH-related peptide** (PTH-r) an **antagnosit** to the PTH receptor
49
what is the effect of PTH-rp bindng to PTH receptor
* increases bone resorption * increases renal Ca reabsorption * inhibits renal phosphate reabsorption ** most common cause of hypercalcemia and dogs and is common in cats**
50
2 main effects of excessive PTH-rp secretion
* hypercalcemia * hypophosphatemia
51
clinical signs of hypercalcemia
* weakness, lethargy, difficulting getting up * hyporexia, nausea, V+, constipation * hypertension, arrythmia * polydipsia, polyuria, urolithiasis, UTIs
52
the main effects of Vit D occur where
**small intestine** * increases Ca and phosphate absorption by increasing the expression of Ca binding protein, **Calbindin**
53
Rickets in juveniles
insufficient Vit D, Ca and phosphate to mineralize bone * growth failure, skeletal abnormalities
54
primary hyperparathyroidism results in excess _______, and subsequently _______ and _______
PTH - hypercalcemia - hypophosphatemia
55
physiological effects of PTH Hypersecretion
* elevated urine levels of PO43- and Ca * increase in ca-containing kidney stone * impaired renal functioning * reduces the excitability of muscle and nerves * thinning of bone, increased risk for fracture * osteoporosis, osteomalacia | **commonly caused by PTH-secreting parathyroid adenoma**
56
horses lack _______ and thus don't form calcitriol
1α-hydroxylase
57
for horses, intstinal absorption of Ca is ________ of Vit D signaling
independent they absorb more Ca in the GI tract than any other species
58
main mechanism of removing excess dietary calcium (equine)
renal excretion
59
equine chronic failure may be indicated by ________ due to decreased excretion
**hypercalcemia** neoplasia, hyperparathyroidism and Vit D toxicity may also cause hypercalcemia
60
What causes equine hypervitaminosis D
latrogenic (Dr caused) or by ingetion of calcinogenic plants * hypercalcemia * hyperphosphatemia
61
physiological symptoms of hypoparathyroidism
* low PTH * hypocalcemia * hyperphosphatemia * increased neuromuscular excitability * cataracts * cognitive changes
62
what might cause hypoparathyroidsim
* damage from surgical thyroidectomies * treatment for cancers * Grave's disdease

PHYSIOLOGY II (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions