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10 terms

USI Summer Session Chapter 18 A&P - The Heart part 7

Factors that Influence Heart Rate
STUDY
PLAY
Epinephrine
from adrenal medulla enhances heart rate and contractility
Thyroxine
Increases heart rate and enhances the effects of norepinephrine and epinephrine
Factors that Influence Heart Rate
•Age
•Gender
•Exercise
•Body temperature
Tachycardia
abnormally fast heart rate (>100 bpm)

If persistent, may lead to fibrillation
Bradycardia
heart rate slower than 60 bpm

May result in grossly inadequate blood circulation

May be desirable result of endurance training
Congestive Heart Failure (CHF)
Progressive condition where the CO is so low that blood circulation is inadequate to meet tissue needs
Embryonic heart chambers
Sinus venous
Atrium
Bulbus cordis
Ventricle
Foramen ovale
connects the two atria in a fetal heart
Ductus arteriosus
connects the pulmonary trunk and the aorta
Congenital heart defects
Lead to mixing of systemic and pulmonary blood

Involve narrowed valves or vessels that increase the workload on the heart