Kin 267 Cardiorespiratory System

Stimulation of sinoatrial node by sympathetic system nerves results in an increase of heart rate

• Positive chronotropic effect

• Positive inotropic effect

• Positive dromotropic effect

• Negative chronotropic effect:

• Negative inotropic effect

Stimulation of atria & ventricles by sympathetic nervous system causes an elevation in intracellular (Ca2+), increasing contractility

• Positive chronotropic effect

• Positive inotropic effect

• Positive dromotropic effect

• Negative chronotropic effect:

• Negative inotropic effect

Stimulation of sinoatrial & atrioventricular nodes by sympathetic nervous system enhances conductivity of electrical signal, such as increasing AV conduction velocity

• Positive chronotropic effect

• Positive inotropic effect

• Positive dromotropic effect

• Negative chronotropic effect:

• Negative inotropic effect

Stimulation of sinoatrial node by Vagus nerve lowers heart rate

• Negative dromotropic effect

• Positive inotropic effect

• Positive dromotropic effect

• Negative chronotropic effect:

• Negative inotropic effect

currently questionable since Vagus nerve does not directly innervate cardiomyocytes other than sinoatrial & atrioventricular nodes.

• Negative dromotropic effect

• Positive inotropic effect

• Positive dromotropic effect

• Negative chronotropic effect:

• Negative inotropic effect

Stimulation of sinoatrial & atrioventricular nodes by Vagus nerve inhibits conductivity of electrical signal, such as increasing AV conduction velocity

• Negative dromotropic effect

• Positive inotropic effect

• Positive dromotropic effect

• Negative chronotropic effect:

• Negative inotropic effect

are specialized, striated muscle cells that make up heart muscle (myocardium) & are responsible for its rhythmic contractions

• Cardiomyocytes

• Myofibrils

• Mitochondria

• Gap Junctions

• Contractile Cardiomyocytes

Cardiomyocytes contain ______ - rod like units within cell composed of chains of sarcomeres, basic contractile units of muscle

• Cardiomyocytes

• Myofibrils

• Mitochondria

• Gap Junctions

• Contractile Cardiomyocytes

cardiomyocytes contain numerous _____ to support high energy demands of cardiac muscle contraction

• Cardiomyocytes

• Myofibrils

• Mitochondria

• Gap Junctions

• Contractile Cardiomyocytes

Cardiomyocytes are connected by ________ - allow for rapid & coordinated electrical signals to pass between cells, ensuring synchronized heartbeats

• Cardiomyocytes

• Myofibrils

• Mitochondria

• Gap Junctions

• Contractile Cardiomyocytes