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Autonomic Innervation of heart
Heart Rate
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Heart rate
• Normal :- 60 – 80 beats / min.
• Both sm!. " !arasm!. #ut :- $00 / min.
• %a&al tone:- 'ee!s HR at (0 to 80 beats / min
• %a&otom:- HR becomes $60 to $(0 / min.• Restin&
sm!athetic tone - increase the HR
u! to $)0 beats/min
• *achcar+ia :- Increase in HR
• Bra+car+ia :- ,ecrease in HR
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actors affectin& HR
• A&e :- Inverse relation
• e :- ore in females +/t more sm!. *one
• 1ercise :- ,irect relation 2ith &ra+e of
eercise.
#auses – sm!. Activit3va&al tone3 bo+
tem!. catecholamines3 *4 " h!oia3
h!erca!nea3 aci+emia• Bo+ tem!erature:- 5 $0 beats for $
rise
• are7s a2:- Inverse relation 2ith B9
• ,ru&s:- 1!ine!hrine 3Nore!ine!hrine
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• 1motions:-1citement3 an&er 5;3shocinus Arrhthmia7 -
Ins!iration5;31!iration=;
• lee!:-=;
• eals:- 5;
• Athletes:-=; +ue to5 va&al tone
• ,iseases:- *hrotoicosis 5;3#ushin&7s
refle=;3 anemia 5;3 shoc< 5;
actors affectin& HR?..cont+
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Innervation @f Heart
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#ar+iac innervationm!athetic
•Heart
$;5 rhthmicit of AN i.e. HR ve chronotro!iceffect;
); 5 s!ee+ " force of contraction of mocar+iumve
ionotro!ic effect;
; 5 con+uctivit of tissue ve +romotro!ic effect;
4; 5 ecitabilit of heart ve bathmotro!ic effect;
• Bloo+ vessels – bin+s to C rece!tors
– %asoconstriction
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•1ffects:-
$; =rhthmicit of AN i.e. = HR -ve chronotro!ic
effect;
); = s!ee+ " force of contraction of mocar+ium -ve
ionotro!ic effect;
; = con+uctivit of tissue -ve +romotro!ic effect;
4; = ecitabilit of heart -ve bathmotro!ic effect;
#ar+iac innervation9arasm!athetic
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Autonomic control - sm!athetic
M e m b r a n e p o t e n t i a l ( m V
)
Sympathetic
stimulation
Resting
Threshold
Seconds
•Nore!ine!hrine acts on B a+rener&ic rece!tors of
heart•ore ve R9 +ue to 5 !ermeabilit for Na "
#a ions
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Autonomic control - !arasm!athetic
•Ach acts on muscarinic rece!tors
•H!er!olariDation +ue to 5 !ermeabilit for ' ions
M e m b r a n e
p o t e n t i a l ( m V
)
Resting
Parasympathetic
stimulation
Threshold
Seconds
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Heart Rate
A&e
e
1ercise
Bo+ *em!erature
,ru&s
,iseases
1motions
Res!iration
lee!
eals
Athletes
Nerves#ar+iac @ut!ut
Ehich factors #han&e *he Heart RateF
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Brain Areas Involve+ in #ontrol
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Re&ulation of HR
• ocal :- tretch3 *em!.3 BR3 *4-,irect effect
• Nervous :-
– Central – corte3 h!othalamus3 %#3va&al
centre
– Reflexes :- e.&. Barorece!tors3chemorece!tors3
Bainbri+&e refle
• Hormonal :- 1!ine!hrine3 noe!ine!hrine3 *4
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*han< Gou
