40 Questions
What is the primary function of the P wave in an electrocardiogram?
Indicates depolarization of the atria
What is the result of the parasympathetic division releasing acetylcholine on heart rate?
Decreases heart rate
What is the name of the node that acts as the heart's built-in pacemaker?
SA node
What occurs during the diastole phase of the cardiac cycle?
Relaxation of the ventricles
What is the function of the QRS complex in an electrocardiogram?
Represents the contraction of the ventricles
What is the effect of norepinephrine and epinephrine on heart rate?
Increases heart rate
What is the primary function of the T wave in an electrocardiogram?
Represents the repolarization of the ventricles
What is the purpose of measuring changes in blood volume in the finger in this lab?
To observe changes in blood flow
What is the term for the recording of electrical changes in the cardiac muscle during the cardiac cycle?
Electrocardiogram
What is the division of the autonomic nervous system that increases heart rate?
Sympathetic division
What is the primary method of measuring blood volume in plethysmography?
Shining a beam of light through the skin to measure reflected light
What is the result of vasoconstriction on blood flow to a particular area?
Decreased blood flow
What is the role of the sympathetic division in regulating blood flow?
Causing vasoconstriction in the viscera
What is the effect of cold temperatures on local blood vessels?
Vasoconstriction to retain core body temperature
What is the primary function of vasodilation in active skeletal muscle during exercise?
To transport wastes away and replenish oxygen and nutrients
What is the effect of metabolites and blood pH on local blood vessels?
Vasodilation to increase blood flow
What is the role of aldosterone in regulating blood vessel diameter?
Regulating blood vessel diameter
What is the result of vasodilation on blood flow to a particular area?
Increased blood flow
What is the purpose of measuring pulse amplitude in plethysmography?
To measure the change in blood volume
What is the role of the smooth muscle in arteriole walls in regulating blood vessel diameter?
Causing vasoconstriction through contraction
The SA node is responsible for slowing down the heart rate.
False
The P wave indicates the depolarization of the ventricles.
False
Acetylcholine increases the rate of depolarization at the SA node.
False
The QRS complex represents the repolarization of the ventricles.
False
The ECG measures changes in blood volume in the finger.
False
The T wave represents the depolarization of the atria.
False
Norepinephrine and epinephrine decrease heart rate.
False
The autonomic division has no influence on heart rate.
False
The heart has its own built-in pacemaker node.
True
Measuring changes in blood flow to the finger is not a part of this lab.
False
The pulse transducer shines a beam of light through the skin in the finger and measures the light reflected by the oxygen in the blood.
False
Vasoconstriction occurs when the smooth muscle in the arteriole walls relax.
False
The sympathetic division causes vasodilation of arterioles leading into the viscera and skin.
False
During exercise, local vasoconstriction occurs in active skeletal muscle to reduce blood flow.
False
The primary function of plethysmography is to measure the electrical changes in the cardiac muscle during the cardiac cycle.
False
The diameter of the arterioles has no effect on the amount of blood flowing to a particular body part.
False
Aldosterone is a hormone that causes vasodilation of arterioles.
False
Plethysmography involves measuring the changes in blood volume in the heart.
False
The pulse amplitude is a direct measurement of the change in blood volume in the finger.
False
Cold temperatures cause local vasodilation to increase blood flow to the skin or extremities.
False
Study Notes
The ECG and the Heart
- The heart's mechanical activity (contraction and relaxation) is controlled by electrical activity (depolarization and repolarization events).
- An electrocardiogram (ECG) records electrical changes in cardiac muscle during the cardiac cycle.
- The P wave indicates depolarization of the atria, which leads to their contraction.
- The QRS complex indicates depolarization of the ventricles right before they contract to pump blood out of the heart.
- The T wave represents repolarization of the ventricles as they relax, allowing the heart to refill with blood.
Regulation of Heart Rate
- The heart has its own built-in pacemaker, the SA node.
- The autonomic division and hormones can influence the rate of depolarization at the SA node.
- Norepinephrine and epinephrine increase the rate of depolarization at the SA node, increasing heart rate under stress.
- Acetylcholine slows down the rate of depolarization at the SA node, resulting in a drop in heart rate.
Measuring Changes in Blood Volume
- Plethysmography records volume changes in the body.
- The volume of blood in tissues changes with the cardiac cycle, creating a pulse.
- A pulse transducer measures changes in blood volume in a body part, such as the finger.
- The pulse transducer shines a beam of light through the skin and measures the light reflected by the heme pigment in the blood.
Regulation of Blood Flow
- The amount of blood flowing to a particular body part depends on the diameter of the arterioles leading into that tissue.
- Vasoconstriction and vasodilation occur when the smooth muscle in the arteriole walls contracts and relaxes, respectively.
- External factors, such as the sympathetic division, and local factors, such as temperature and changes in metabolites, influence the smooth muscle of the arteries.
- Vasoconstriction and vasodilation can be influenced by various hormones, such as vasopressin (ADH) and aldosterone.
- Local factors, such as cold temperatures, can cause vasoconstriction to divert blood away from the cold skin or extremities.
- During exercise, local factors, such as carbon dioxide and metabolic acids, can cause vasodilation in active skeletal muscle.
The ECG and the Heart
- The heart's mechanical activity (contraction and relaxation) is controlled by electrical activity (depolarization and repolarization events).
- An electrocardiogram (ECG) records electrical changes in cardiac muscle during the cardiac cycle.
- The P wave indicates depolarization of the atria, which leads to their contraction.
- The QRS complex indicates depolarization of the ventricles right before they contract to pump blood out of the heart.
- The T wave represents repolarization of the ventricles as they relax, allowing the heart to refill with blood.
Regulation of Heart Rate
- The heart has its own built-in pacemaker, the SA node.
- The autonomic division and hormones can influence the rate of depolarization at the SA node.
- Norepinephrine and epinephrine increase the rate of depolarization at the SA node, increasing heart rate under stress.
- Acetylcholine slows down the rate of depolarization at the SA node, resulting in a drop in heart rate.
Measuring Changes in Blood Volume
- Plethysmography records volume changes in the body.
- The volume of blood in tissues changes with the cardiac cycle, creating a pulse.
- A pulse transducer measures changes in blood volume in a body part, such as the finger.
- The pulse transducer shines a beam of light through the skin and measures the light reflected by the heme pigment in the blood.
Regulation of Blood Flow
- The amount of blood flowing to a particular body part depends on the diameter of the arterioles leading into that tissue.
- Vasoconstriction and vasodilation occur when the smooth muscle in the arteriole walls contracts and relaxes, respectively.
- External factors, such as the sympathetic division, and local factors, such as temperature and changes in metabolites, influence the smooth muscle of the arteries.
- Vasoconstriction and vasodilation can be influenced by various hormones, such as vasopressin (ADH) and aldosterone.
- Local factors, such as cold temperatures, can cause vasoconstriction to divert blood away from the cold skin or extremities.
- During exercise, local factors, such as carbon dioxide and metabolic acids, can cause vasodilation in active skeletal muscle.
This quiz covers the mechanical activity of the heart, including contraction and relaxation, and how it is controlled by electrical activity. It also explores the electrocardiogram (ECG) and its relation to the cardiac cycle.
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