Lecture 15 - Control Regulation of Cardiac Output Flashcards
Negative feedback systems
response to a disturbance in the opposite direction of the disturbance
ex: blood pressure, insulin
Positive feedback systems
response to a disturbance in the same direction of the disturbance
ex: blood clotting, parturition
what controls cardiac output
heart rate and stroke volume
arterial blood pressure is controlled by
arteriole diameter
blood volume is controlled by
receptors in the kidney, brain, and heart
what is the set point of cardiac output
150 mL/kg/min
what is the set point for stroke volume
1.5 mL/kg
what is the set point for blood volume
80 mL/kg of body weight
what happens to flow if:
pressure between two points increases
increases
what happens to flow if:
radius increases
increases
what happens to flow if:
viscosity increases
decreases
what happens to flow if:
length of vasculature increases
decreases
radius of vasculature is controlled by
smooth muscle cells
where does the largest drop in pressure occur in the systemic flow of blood
at arterioles
T/F: velocity is inversely proportional to cross-sectional area of vasculature
TRUE
Acetylcholine is a ______ inotrope and chronotrope
negative or positive
negative
describe the job of:
Alpha 1 adrenergic receptor
- vasoconstriction
- increase peripheral resistance and BP
describe the job of:
Alpha 2 adrenergic receptor
- inhibits norepinephrine, acetylcholine, and insulin release
describe the job of:
Beta 1 adrenergic receptors
- increases heart rate, lipolysis, contractility, and renin
describe the job of:
Beta 2 adrenergic receptors
- vasodilation
- decreases peripheral resistance
T/F: Beta 1 adrenergic receptors increase the calcium in the cell
TRUE
what nerves are afferent to the CNS from the heart
CN 10 and 11
what nerves are efferent to the CNS for the heart
CN 10 and sympathetic trunk
what senses blood pressure changes
aortic and carotid sinus baroreceptors
an increase in baroreceptor stretch and vagal response has what effect of HR and BP
decreases
loss of blood volume will result in what on ECG
sinus tachycardia (increased HR)
parasympathetic stimulation will result in what on ECG
sinus bradycardia
T/F: aortic baroreceptors have a greater interval of pressure they can detect than carotid baroreceptors
FALSE
T/F: the minimum perfusion pressure is 50-60 mmHg
TRUE
how does the juxtaglomerular sense blood volume change, and what is the action?
senses sodium delivery and stretch and activates RAAS
T/F: RAAS activation must have a healthy heart to be efficient
TRUE
T/F: ACE inhibitors decrease coughing
FALSE
what senses changes to blood volume
- juxtaglomerular apparatus
- atrial stretch receptors
what is the action of atrial stretch receptors
ANP/BNP release to act as a diuretic
what are 3 things that control blood pressure and volume at the local level
- pH
- oxygenation
- endothelin/nitric oxide
what determines stroke volume
- preload
- afterload
- contractility
what are qualitative indicators of preload
- pulmonary vein size
- caval size
- ventricular stretch
what are quantitative indicators of preload
- diastolic wall tension and ventricular pressure
- left atrial, pulmonary capillary wedge, and central venous pressure
what are qualitative indicators of afterload
- resistance
- body response to disease
what are quantitative indicators of afterload
- peak systolic wall tension
- systemic/pulmonary vascular resistance/impedance
what are qualitative indicators of contractility
body response to disease
what are quantitative indicators of contractility
- LV ejection fraction
- LV peak pressure
