Podcast
Questions and Answers
What happens to mean arterial blood pressure during exercise?
What happens to mean arterial blood pressure during exercise?
How do baroreceptors react when blood pressure increases?
How do baroreceptors react when blood pressure increases?
How does the body's vascular response differ between arm and leg exercise at similar workloads?
How does the body's vascular response differ between arm and leg exercise at similar workloads?
What anatomical locations are primarily associated with baroreceptors?
What anatomical locations are primarily associated with baroreceptors?
Signup and view all the answers
Which statement about baroreceptor function during rest and exercise is true?
Which statement about baroreceptor function during rest and exercise is true?
Signup and view all the answers
What occurs beyond 40% of VO2 max in terms of cardiovascular function?
What occurs beyond 40% of VO2 max in terms of cardiovascular function?
Signup and view all the answers
What effect does exercise have on stroke volume for males?
What effect does exercise have on stroke volume for males?
Signup and view all the answers
Which factor is NOT a contributor to increasing stroke volume with exercise?
Which factor is NOT a contributor to increasing stroke volume with exercise?
Signup and view all the answers
What defines preload in the context of cardiac function?
What defines preload in the context of cardiac function?
Signup and view all the answers
How does veno constriction assist in increasing preload during exercise?
How does veno constriction assist in increasing preload during exercise?
Signup and view all the answers
What happens to ventricular contractility during exercise?
What happens to ventricular contractility during exercise?
Signup and view all the answers
What role does afterload play in affecting stroke volume?
What role does afterload play in affecting stroke volume?
Signup and view all the answers
How does the respiratory pump facilitate venous return to the heart during exercise?
How does the respiratory pump facilitate venous return to the heart during exercise?
Signup and view all the answers
What is the primary equation for calculating cardiac output?
What is the primary equation for calculating cardiac output?
Signup and view all the answers
What is the average resting cardiac output for females?
What is the average resting cardiac output for females?
Signup and view all the answers
How does cardiac output change when moving from rest to exercise?
How does cardiac output change when moving from rest to exercise?
Signup and view all the answers
What is the average resting heart rate for an untrained individual?
What is the average resting heart rate for an untrained individual?
Signup and view all the answers
What physiological mechanisms contribute to an increase in heart rate during exercise?
What physiological mechanisms contribute to an increase in heart rate during exercise?
Signup and view all the answers
What occurs to stroke volume when an untrained individual begins exercising?
What occurs to stroke volume when an untrained individual begins exercising?
Signup and view all the answers
At what heart rate is the sympathetic nervous system primarily activated?
At what heart rate is the sympathetic nervous system primarily activated?
Signup and view all the answers
What is defined as the volume of blood ejected from the heart during one contraction?
What is defined as the volume of blood ejected from the heart during one contraction?
Signup and view all the answers
What happens to afterload during exercise?
What happens to afterload during exercise?
Signup and view all the answers
How does stroke volume change during prolonged exercise?
How does stroke volume change during prolonged exercise?
Signup and view all the answers
What is the composition of the endocardium?
What is the composition of the endocardium?
Signup and view all the answers
What impact does chronic endurance exercise training have on stroke volume?
What impact does chronic endurance exercise training have on stroke volume?
Signup and view all the answers
Which of the following statements about cardiac output during exercise is correct?
Which of the following statements about cardiac output during exercise is correct?
Signup and view all the answers
What adaptation is primarily responsible for increased stroke volume with endurance training?
What adaptation is primarily responsible for increased stroke volume with endurance training?
Signup and view all the answers
What role does plasma volume play during exercise?
What role does plasma volume play during exercise?
Signup and view all the answers
How do heart rate and stroke volume change during endurance training?
How do heart rate and stroke volume change during endurance training?
Signup and view all the answers
Which variable in the Hagen-Poiseuille equation is most influenced by exercise?
Which variable in the Hagen-Poiseuille equation is most influenced by exercise?
Signup and view all the answers
What role do arterioles play in regulating total peripheral resistance?
What role do arterioles play in regulating total peripheral resistance?
Signup and view all the answers
What happens to blood vessel length during exercise?
What happens to blood vessel length during exercise?
Signup and view all the answers
How does blood pressure regulate in response to high levels?
How does blood pressure regulate in response to high levels?
Signup and view all the answers
What determines total peripheral resistance in blood vessels?
What determines total peripheral resistance in blood vessels?
Signup and view all the answers
Why is calculating mean blood pressure not straightforward as (SBP + DBP) / 2 during exercise?
Why is calculating mean blood pressure not straightforward as (SBP + DBP) / 2 during exercise?
Signup and view all the answers
What physiological factor minimally affects blood viscosity during exercise?
What physiological factor minimally affects blood viscosity during exercise?
Signup and view all the answers
What are baroreceptors and where are they primarily located?
What are baroreceptors and where are they primarily located?
Signup and view all the answers
Study Notes
Blood Pressure & Exercise
- Systolic blood pressure increases during exercise.
- Diastolic blood pressure remains unchanged or slightly decreases during exercise.
- Mean arterial blood pressure increases during exercise.
- Baroreceptors do not decrease blood pressure during exercise because they reset to a higher limit, fighting to maintain the pressure.
Blood Pressure Response to Exercise
- Arm exercise results in higher blood pressure compared to leg exercise with similar workloads. This is because the body dilates only ⅓ of the body (arms) and constricts ⅔ of the lower body, leading to a higher resistance in the vascular system. Leg exercise dilates ½ of the body and constricts ½, resulting in lower resistance.
- Blood flow and oxygen usage are the same for both arm and leg exercise with similar workloads.
Baroreceptors
- Located in the carotid arteries and aortic arch.
- When stretched as a result of increased blood pressure, they increase parasympathetic nerve activity, decrease sympathetic nerve activity, and subsequently reduce blood pressure.
Cardiac Output
- Cardiac output (CO) is the amount of blood ejected from the heart per minute; CO = HR x SV.
- Resting cardiac output average: 4.5 L/min for females, 5 L/min for males.
- Cardiac output increases during exercise to meet the oxygen demands of working muscles.
- Heart rate (HR) increases linearly with increasing exercise intensity to deliver more oxygenated blood.
- Stroke volume (SV), the amount of blood ejected from the heart in one contraction, also increases during exercise.
Heart Rate Regulation
- Resting heart rate: 60-70 bpm for untrained individuals.
- Maximal heart rate: 220 - age
- Increase in heart rate is driven by the autonomic nervous system, primarily the sympathetic nervous system.
- Parasympathetic activity (vagus nerve) slows down heart rate.
- Sympathetic activity (cardiac accelerator nerve) increases heart rate, becoming more dominant at heart rates exceeding 100 bpm.
Stroke Volume Regulation
- Stroke volume increases during exercise, peaking and plateauing around 40% of VO2 max in untrained individuals.
-
Variables influencing stroke volume:
- Preload: The amount of blood in the ventricle prior to contraction, increased by venoconstriction, skeletal muscle pump, and respiratory pump.
- Contractility: The strength of the ventricular contraction, increased by sympathetic stimulation and circulating epinephrine.
- Afterload: Aortic blood pressure, which is the pressure against which the heart has to pump blood, decreases during exercise.
Cardiac Drift
- During prolonged exercise, heart rate increases, cardiac output remains the same, and stroke volume decreases. This is due to a decrease in plasma volume from sweating, leading to lower preload.
Effects of Endurance Training
- Cardiac output remains the same during exercise because trained individuals have a higher stroke volume.
-
Endurance training increases stroke volume by:
- Increasing left ventricle chamber size and wall thickness (hypertrophy).
- Increasing preload.
- Increasing contractility.
- Decreasing afterload.
Oxygen Consumption (VO2)
- VO2max (maximum oxygen consumption) is increased with endurance training due to increased cardiac output and a-vO2 difference (the difference in oxygen content between arterial and venous blood).
- VO2rest, VO2submax remain the same even with training, because cardiac output doesn't change at these intensities, and changes in a-vO2 difference compensate.
Total Peripheral Resistance (TPR)
- TPR is the resistance to blood flow in the peripheral circulation.
- Exercise affects TPR through changes in the radius (diameter) of blood vessels.
- Arterioles are the primary regulators of TPR.
- Exercise-induced changes in TPR depend on the type and intensity of exercise.
- Working skeletal muscles dilate, while non-working muscles constrict to redirect blood flow.
Blood Pressure Regulation
- Resting blood pressure: 120/80 mmHg.
- Blood pressure regulation during rest is primarily controlled by baroreceptors.
- Slow-acting mechanisms of blood pressure regulation: the kidney through the renin-angiotensin system.
- Fast-acting mechanisms of blood pressure regulation: baroreceptors.
-
When blood pressure is too high - Decrease sympathetic nerve activity, increase parasympathetic nerve activity.
- This results in a lower heart rate and vasodilation, lowering blood pressure.
Cardiac Muscle
- The endocardium is not comprised of cardiac muscle cells, but rather endothelial cells.
- The left ventricular wall is thicker than the right ventricular wall.
-
Cardiac myocytes are characterized by:
- Single nuclei.
- Branching fibers.
- A single fiber type.
- Cardiac myocytes do not contain multiple satellite cells.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the effects of exercise on blood pressure, including systolic and diastolic responses. This quiz covers key concepts like mean arterial pressure and the role of baroreceptors during physical activity.
