HOMEOSTASIS OF CALCIUM ROLE OF Ca**
■ Nerve function
- Enzymatic reactions
• e\eitation-contraction. coupling
• excitation-secretion coupling
• Blood clotting mechanism, coagulation - taking blood (first hyp oc alec mie tetany)
« cAMP dependent functions (activity of adenylcyclascXllEd messengers
■ permeability of membranes
• Growth and development___
Stabilisation of membrane potential bypocalcemic TETANY
-go o mv
CONTENT OF CALCIUM IN
THE BODY
2% of body weight - 5. element in the body, 99% in hones
Ca balance Intestine plasma
Lin iliiriiiH ladaliun_ I
Calcium in plasma
TOTAL 2.3. - 2.7 mmol /1 (9.2-10,8mg%) stabile M, i-1 exchangeable
nond if fusible t eliliissible
hound to proteins   Ca>+, completed to anioiis(cptra(e)
I
lunkjtioit fit' pro(('irrs+
ntdjtp&f'^ djAtadtagrfC**-*1
HYPKRVKNTH-ATION -* ^ otnc.lt» -> tendency to TETANY
_
PHOSPHATE
85-90% in skeleton
ATP, tAMP, phwphurylatcd proteins, iinsr&anic phosphate
TOTAL in plasma
(t2mg%)
2/3 organic Compounds JJ3 inorganic anions
Plasma concentration of Ca++ and phosphate
Blood is nearly saturated solution
CONST, product: Ca++ x phosphate P in plasma 0.8 - 1.4 mmol/1
Example: infusion of phosphate „,. Ca into bones -> hypocalcaemia
1
BONES
dynamic balance between formation and reabsorption
- OSTEOBLASTS Secrrfv COLLAGEN -» MATRIX Alkalir phosphatase
hydrolysis of enteric p Iii'.hIliit sol u hi lit y ofC*++ nn<& p is evcreded
precipitation
1 mU<H<iM. sth
- iwadnnMK rtl n
In oldvr people ostMpoiwi
OSTEOCLASTS Polynuclcar cells erode by Acidic phosphatase (HvdroxyprDLiri itdcucd)
H par»1 hurmi'ii
PARATHYROID HORMON -PTH
4 glands embedded i" Th. G. during STEUMECfOMlt" minimally IP. G.
CHIW CELLS fl*TH) clicn""*ceplor and effector
-fk'vcl cif Ca++ in plasma
...-T- secretion of pre-pru-honiione
... .proteolysis
... hinl effective peptide 34 AMA (KIA determines all Iog£<hi-r>
1,1). flXYphylte {feel)
PTH increases ealcaemia intestine plasma
vitD TBsuipLiimoi'Ca
Iresnrplion ofiraki pexcrction of hy ~ - i kidney phw|iliiinili
Resurption -P, +' ^Syrttof cnkitriul
HYPOPARATHYROIDISM
- PTH essential for life
1. after parahyradcrtomy (during thyroid surgery -1 Parath. gL)
- lyiaptaaw after 2-3 d»yt (or later)
2. Idiopathic - exceptionally
TETANY
1. Chrostck's sign - tapping over the facial nerve
2. Troussea's sign - spasm of upper extremity after occluding the circulation for some min.
DEATH LARYNGOSPASM
HYPERPARATHYROIDISM
l. PRIMARY = hypcrcalcaetnic adenoma
Dmmjmi ■hulhin affcaaM - multiplf tjrrti - piwtciiw cystica gwwrmBwhf* - RK< kl .INGHA1 sf:N s DISEASE
EJrokvn bane*, m-pbi tililhiasis
Call-aomi* D**t 4 nnrmJ/1
,.ctilctmk' death" = snip nl'ihe heal I in systole l»e- *r v-xcvctioH of indro\ypvoliii In ntiM 1, SEC. = norimicalcemic hyperplasia and
hypcrfunction -during 4- takitrk-U nephropathy
(compensation of loss of calcium)
Vitamin D- synthesis of D hormone
IIV itglll
Ili lllf dltl Vllamln li , g|-f r[<KalelftT°l
1 ■mfcjjJ""'1
mth.rrft      1 ' ii.|TiyVj]r |i li.*Mg
AJu> In Lit Id* iv ■ . ... ■
D hormone - l,25-(OH2) chotecalciferol
Stimulates expression of genes involved in synthesis and transport proteins
xyprolinii
kt es tine
vresorptiiiii Ca, P
. — -;>
•^Resorption Ci
'I'Rtsorpliiin P
Deficiency ■ children lietabUnnHH Vii.n<insu(Ticieiit mineralisation, weakness aid bCWJAR   w*gh! bemne brat),      I vkD-wWnl I U-« 1(J*OT^«, & CukMnoi WW I) M-     ■•     • : ' Irewfl«?     eaiáliid <rar^ reaslent to th adulP       J i..::-i-:==! dem-"-"'™*™! _
Calcitonin
Secretion - paiafolikukr cells in Th. GL Plasma ievel is bw, role is uncertain bones -I resorption ofCa++ kidney - T excretion of Ca and Pti Secretion is activated by CCK ■ protect against postprandial hypercalcaemia ..decreased talccmia supports resorption of Ca I K,. may be in young skelet development