Homeo Hom eostasis stasis an and d fe feedb edback ack me - - PowerPoint PPT Presentation
Homeo Hom eostasis stasis an and d fe feedb edback ack me mech chanism anism Ass. s.Le Lec. . Inas S. Mohammed med Biomedi Bi medical Engineering cal Engineering Un University sity of of Techno nolo logy 1 6 January 6
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Ass. s.Le Lec. . Inas S. Mohammed med Bi Biomedi medical Engineering cal Engineering Un University sity of
nolo logy
Hom Homeo eostasis stasis an and d fe feedb edback ack me mech chanism anism
De Definition inition of Ho Home meostas
is
tasis is: : The he tendenc tendency of
an or
ganism m or
cell to to regula gulate te its its inter internal nal en envir ironm
ent and and ma mainta intain in equ equilibriu ilibrium, m, us usual ually by by a a system tem of
eedbac back k con contr trols
, so
as to s to sta tabiliz bilize health and f e health and functioning. unctioning.
ery or
gan in in the the body body contributes contributes to to homeos homeostas tasis is. . A A comple complex x set et of
hemical, ther thermal, mal, and and neur neural al factor actors inter interact act in in comple complex x way ays, , both both helping helping and and hindering hindering the the body body w while it w hile it wor
ks to maintain homeos to maintain homeostas tasis is. .
tasis is can be cons can be consider idered in ed in regar gards ds to to a cell, a cell, tis tissue, ue, or
gan, biological system, tem,
envir ironmental
tem.
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cells
1- Vasoconstriction of damaged blood vessels. 2- Platelet plug forming. 3- Coagulation or blood clotting.
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Defin init ition ion of Homeostas
is
TYPES PES OF FEED EEDBACK BACK ME MECHANISM CHANISM
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The here e ar are tw e two
types es of
eedb dbac ack k mec mecha hanism: nism:-
1-Nega gativ tive e feedbac eedback mec k mechanis hanism. m. 2- Positive feedback mechanism.
Negative ative feedbac back k mechanism ism
Nega gativ tive e feedbac eedback k : : Is the primar the primary mec mechanis hanism m thr through
hich h your endocrine s
tem maintains “ homeostasis “.
*Example :-
The control of blood sugar (glucose) by insulin is another good example of a negative feedback mechanism. When blood sugar rises, receptors in the body sense a change . In turn, the control center (pancreas) secretes insulin into the blood effectively lowering blood sugar levels. Once blood sugar levels reach homeostasis, the pancreas stops releasing insulin.
PO POSITIV TIVE E FE FEED EDBACK BACK ME MECH CHANI ANISM
Pos
itive e feedbac eedback mec k mechanis hanism: m: Incr ncreas ease e in f in function unction in r in res espons ponse e to a s to a stimulus timulus
*Example mple :
A- A A good e good example xample of
a pos positiv itive e feedbac eedback s k system tem is is child hild bir birth.
During la labor bor, , a a is is releas eleased tha ed that intens t intensif ifies ies and s and speeds peeds up up contr contractions actions. .
xytocin tocin hor hormone mone called called to to be r be releas eleased and the c ed and the cycle le
xytocin tocin The he incr increas ease in e in contr contractions actions caus causes es mor more e goes goes on until
the baby by is is bor
itive e feedbac eedback k mec mechanis hanism. m. B- Another good e Another good example xample of
a positiv itive e feedbac eedback mec k mechanis hanism m is is blood blood clotting.
nce a ves essel el is is dama damaged, ged, pla platelets telets star tart to c t to cling ling to to the injur the injured ed site ite and r and releas elease e chemicals hemicals tha that a t attr ttract mor act more e pla platelets telets. . The pla he platelets telets continue to pile continue to pile up and up and releas elease e chemicals hemicals until until a c a clot lot is is for
med.
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PO POSI SITIVE TIVE & NE NEGATIVE ATIVE FEEDBAC EEDBACK K ME MECHANISM ANISM
*No Note te :-
Just remember that positive feedback mechanisms enhance the
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FEEDBACK DBACK MECH CHANI ANISM SM
A feedback mechanism is a process that uses the conditions of one component to regulate the function of the other. It is done to either increase or dampen the change in the system. When the process tends to increase the change in the system, the mechanism is known as positive feedback. Negative feedback is when the process seeks to counter the change and maintain equilibrium.
*Ho Home meost stasis asis is the tendency ency to resist t change e in order r to ma maintai ain n a stable, le, relatively ively constan ant t internal rnal enviro ronment nment.
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