cardiac output regulation
What is cardiac output?
the amount of blood the heart pumps in one minute
What is local autoregulation?
the intrinsic ability of tissues to maintain a relatively constant blood flow despite changes in systemic blood pressure
What is blood pressure?
Blood pressure is the force of blood pushing through your arteries
What is the action potential?
electrical signal that travels along the axon of a neuron
Describe the factors affecting stroke volume.
End-diastolic volume (EDV) (preload)
Myocardium Contractility
Mean arterial pressure (afterload)
Describe the role of metabolites in local blood flow regulation
Metabolites (Adenosine, NO, K+, H+) are produced my muscle activity and triggers various signaling cascade to induce vasodilation
when blood pressure is measured in someone what are the 2 numbers representing?
systolic (High #) and diastolic (low #) pressure
Describe the phases of the cardiac action potential. You can draw
PQRST
Explain the role of heart rate in cardiac output
CO = HR x SV
How do endothelial cells contribute to local blood flow?
EC possess mechano-sensors triggered shear stress, which activate signaling cascade (NO) that leads to smooth muscle relaxation
Explain how baroreceptors function in blood pressure regulation.
they monitor the stretch of the arterial walls (carotid/aorta). when stretched increase PNS activity (decrease SNS)
Conversely, with low blood pressure decrease PNS activity (increase SNS)
What is the role of the sinoatrial node?
main pacemaker
How does the Frank-Starling law affect cardiac output?
increased venous return and EDV increases myocardium contractility
what are the main sites of vasodilation
feed arteries and arterioles
How do the kidneys regulate blood pressure?
via the control of blood volume
How does the electrical conduction system of the heart work?
SA node > AV Node > Bundle branches > Purkinje Fibers
What are the effects of sympathetic and parasympathetic stimulation on cardiac output?
SNS: increases HR and stroke volume (contractility), which increases CO
ParaS: Decreases HR, which decreases CO
cite 5 mechanisms that control blood flow
-sympathetic vasoconstriction, vasoconstrictors (ET, ANG)
- Flow induced vasodilation, erythrocyte release of vasodilators, conducted vasodilations, functional sympatholysis, muscle released vasodilators
Explain the exercise pressor reflex
Peripheral neural drive originating in skeletal muscle that activates brainstem cardiovascular control areas during physical activity to change HR and BP
Mediated by type III and IV afferents
Explain the significance of the electrocardiogram (ECG) in monitoring heart activity.
Detecting Arrhythmias, diagnosing myocardial infarction, monitor training adaptations
HRV to track health and performance