L18 Heart Rate Regulation

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Which part of the nervous system is primarily responsible for regulating heart rate under resting conditions?

Posterior hypothalamus

Cerebral cortex

Respiratory center

Vagal tone (correct)

Which of the following reflexes is responsible for the increase in heart rate due to increased venous return?

Carotid sinus syndrome

Bainbridge reflex (correct)

McDowal's reflex

Marey's Law

According to Marey's Law, what is the relationship between heart rate and arterial blood pressure?

Heart rate is exponentially related to arterial blood pressure

Heart rate is independent of arterial blood pressure

Heart rate is directly proportional to arterial blood pressure

Heart rate is inversely proportional to arterial blood pressure (correct)

Which of the following is the correct pathway for the Bainbridge reflex?

Increased venous return → increased right atrial pressure → stimulation of atrial stretch receptors → increased cardiac filling → increased heart rate Signup and view all the answers

Which part of the hypothalamus is responsible for stimulating the Cardiac Acceleratory Center (CAC) and increasing heart rate?

Posterior hypothalamus Signup and view all the answers

What is the effect of deep inspiration on heart rate according to the text?

Deep inspiration increases heart rate Signup and view all the answers

What is the mechanism by which stimulation of the carotid sinus baroreceptors can lead to bradycardia?

Stimulation of the Cardiac Inhibitory Center (CIC) Signup and view all the answers

Which of the following is a direct mechanism by which the respiratory center can influence heart rate?

Respiratory sinus arrhythmia Signup and view all the answers

What is the effect of sympathetic stimulation on the heart?

Increases the heart rate Signup and view all the answers

Which of the following statements about heart rate is true?

The average heart rate for adults is around 70 beats per minute Signup and view all the answers

Which factor does NOT contribute to physiological variations in heart rate?

Body mass index (BMI) Signup and view all the answers

Which of the following statements about the regulation of heart rate is true?

The parasympathetic nervous system decreases the SA nodal discharge and heart rate Signup and view all the answers

Which of the following heart rates would be considered bradycardia?

50 beats per minute Signup and view all the answers

What is the typical heart rate for an infant?

Around 120 beats per minute Signup and view all the answers

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

Their heart is stronger and more efficient Signup and view all the answers

What is the primary mechanism by which the autonomic nervous system regulates heart rate?

By controlling the SA nodal discharge Signup and view all the answers

What is the effect of voluntary contraction of skeletal muscles on heart rate?

Tachycardia Signup and view all the answers

Which of the following accurately describes the effect of hypoxia (low oxygen) on heart rate?

Mild to moderate hypoxia causes tachycardia, while severe hypoxia causes bradycardia Signup and view all the answers

Which hormone is associated with an increase in heart rate?

All of the above Signup and view all the answers

What is the effect of applying pressure on the eyeball (oculo-cardiac reflex) on heart rate?

Bradycardia Signup and view all the answers

How does moderate hypercapnia (increased carbon dioxide) affect heart rate?

Causes tachycardia Signup and view all the answers

Which of the following substances causes bradycardia (decreased heart rate)?

Morphine Signup and view all the answers

What is the approximate increase in heart rate for every 1°C rise in body temperature?

10-13 beats per minute Signup and view all the answers

Which of the following is NOT a factor that regulates heart rate?

Dietary habits Signup and view all the answers