Heart Rate and Arrhythmias

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Which of the following scenarios would typically result in the lowest heart rate?

A female jogging.
A male athlete sleeping. (correct)
A 6-year-old child watching television.
A female doing yoga.

The basal level of heart rate under normal resting conditions is typically in which range?

30-40 beats/min
70-80 beats/min (correct)
50-60 beats/min
90-100 beats/min

A doctor measures a patient's resting heart rate at 95 beats per minute. Which of the following could explain this elevated heart rate?

The patient is an adult male.
The patient is a young child. (correct)
The patient is sleeping.
The patient is a male athlete.

Which of the following factors generally contributes to a lower heart rate?

Being an adult male (D) Signup and view all the answers

Which factor will cause an increase in the heart rate?

Exercise (C) Signup and view all the answers

Why is ventricular fibrillation considered a rapidly fatal condition?

Due to the extremely high and irregular ventricular contractions preventing effective blood pumping. (B) Signup and view all the answers

What ventricular contraction rate is typically associated with ventricular fibrillation?

Between 350-500 beats/min. (C) Signup and view all the answers

In the context of heart function, what is the primary consequence of ventricular fibrillation?

Loss of effective pumping action by the ventricles. (D) Signup and view all the answers

Which physiological process is most directly disrupted by atrioventricular block?

The conduction of electrical signals between the atria and ventricles. (C) Signup and view all the answers

What is a key difference between ventricular fibrillation and atrioventricular block in terms of their primary effect on heart function?

Ventricular fibrillation directly impairs the heart's pumping ability, while atrioventricular block disrupts the coordination of atrial and ventricular contractions. (C) Signup and view all the answers

What is the most likely effect of hypercalcemia on the heart's function?

Prolonged systole potentially leading to spastic contraction. (D) Signup and view all the answers

A patient's blood test reveals hyperkalemia. Which of the following is the most likely consequence regarding heart function?

Prolonged period of diastole, leading to a dilated and flaccid heart. (A) Signup and view all the answers

Which of the following best illustrates a positive inotropic effect on the heart?

An increase in the heart's force of contraction due to sympathetic stimulation. (C) Signup and view all the answers

If a patient is administered digitalis, what change in cardiac function would be expected, and why?

Increased force of contraction as digitalis is a positive inotropic agent. (C) Signup and view all the answers

A patient with a known heart condition experiences a sudden increase in blood calcium levels. Which intervention would be MOST appropriate given the effects of hypercalcemia?

Monitoring heart function closely to detect and manage potential spastic contractions. (B) Signup and view all the answers

If total peripheral resistance remains constant, which of the following changes would directly lead to an increase in arterial blood pressure (ABP)?

Increase in cardiac output (COP) (D) Signup and view all the answers

A patient's arterial blood pressure (ABP) increases significantly. Assuming no changes in total peripheral resistance, what change in cardiac output (COP) is most likely responsible for this increase in ABP?

A significant increase in COP due to increased sympathetic activity. (C) Signup and view all the answers

In a scenario where a patient's cardiac output (COP) is reduced by 20% due to a sudden heart condition, what compensatory mechanism involving total peripheral resistance would help maintain arterial blood pressure (ABP)?

A 20% increase in total peripheral resistance. (C) Signup and view all the answers

A doctor administers a drug that doubles a patient's cardiac output (COP) but observes only a slight increase in arterial blood pressure (ABP). Which of the following is the most likely explanation for this?

The drug simultaneously and proportionally decreased total peripheral resistance. (A) Signup and view all the answers

During intense exercise, both cardiac output (COP) and total peripheral resistance change. If COP increases significantly, what change in total peripheral resistance is most likely to occur and why?

Total peripheral resistance decreases due to vasodilation in active muscles. (C) Signup and view all the answers

What is the primary relationship between arterial blood pressure (ABP) and coronary blood flow?

Coronary blood flow is directly proportional to ABP, especially diastolic BP. (B) Signup and view all the answers

How does sympathetic stimulation affect coronary blood vessels?

It causes coronary dilatation. (A) Signup and view all the answers

Which of the following best describes the effect of parasympathetic stimulation on coronary blood vessels?

Vasoconstriction, decreasing blood flow. (B) Signup and view all the answers

If a patient's diastolic blood pressure decreases significantly, what direct effect would this have on coronary blood flow, assuming other factors remain constant?

A significant decrease in coronary blood flow. (A) Signup and view all the answers

A medication that blocks sympathetic nervous system activity is administered. What change in the coronary blood vessels would be expected as a direct result?

Vasoconstriction, due to reduced sympathetic influence. (B) Signup and view all the answers

How does increased sympathetic nerve activity contribute to physiological changes in individuals with increased adipose tissue?

It is stimulated by leptin, released from adipose tissue, influencing energy expenditure and cardiovascular function. (B) Signup and view all the answers

What is the combined effect of increased aldosterone and angiotensin II levels on blood pressure in obese individuals?

Increased blood pressure due to vasoconstriction and increased sodium retention. (C) Signup and view all the answers

How does leptin, released from adipose tissue, influence sympathetic nerve activity?

Leptin stimulates sympathetic nerve activity, increasing energy expenditure and potentially affecting cardiovascular function. (A) Signup and view all the answers

Why might increased levels of aldosterone and angiotensin II be observed in obese individuals?

As a compensatory mechanism to maintain blood pressure and fluid balance in response to physiological changes associated with obesity. (D) Signup and view all the answers

What is the likely long-term effect of chronically increased sympathetic nerve activity, aldosterone, and angiotensin II levels in an individual with obesity?

Increased risk of hypertension, cardiovascular disease, and metabolic dysfunction due to sustained elevated blood pressure and altered metabolic processes. (C) Signup and view all the answers

Hypercalcemia effect on heart

High blood calcium levels, leading to prolonged systole and potential spastic contraction (calcium rigor).

Hyperkalemia effect on heart

High blood potassium levels, leading to prolonged diastole, causing a dilated and flaccid heart.