BIO 132 – Anatomy and
Physiology II
Study Outline
16.1. Determinants of Cardiac Output:
a. Cardiac output (CO) is computed from the product of ____________________________ and _____________________________.
b. At rest, cardiac output is typically on the order of ______________________, but can increase to about _____________________________ during extreme exercise.
c. A general term for the ratio between a person’s maximum CO and their CO at rest is called the _________________________________ which is typically on the order of about __________________________________.
16.2. The Fick Principle:
a. Cardiac output can be determined using a method called the __________________________________.
b. In this technique, the quantity of O2 that leaves the lungs in the pulmonary veins must be equal to the quantity of O2 in the ________________________ plus the quantity of O2 that enters ___________________________________.
c. The quantity of O2 present in the pulmonary artery or pulmonary vein is equal to the O2 concentration in that vessel multiplied by ___________________________________, which in this case is equal to ___________________________________.
d. In its final form, the formula used in the Fick principle states that cardiac output is equal to the ratio of _________________________________ and the difference between the O2 concentration in the ________________________ minus the __________________________________.
16.3. Regulation of Stroke Volume:
a. The _____________________________________ of a given cardiac cycle represents the amount of blood that leaves the ventricle each beat.
b. Stroke volume (SV) is determined by the difference between the ______________________________ and the ________________________.
c. The ________________________________ is the amount of blood left in the ventricle after ventricular ejection.
d. The three most important factors which affect stroke volume are _________________________________, __________________________, and _________________________________.
e. The __________________________________ refers to the amount that the ventricles are stretched just before contraction. According to the Frank-Starling Law of the Heart, SV increases as the _________________________ increases.
f. Preload can be indicated as either ___________________________ or by _______________________________________. In general a curve which relates some measure of ventricular performance with some index of cardiac muscle fiber length is called a __________________________________.
g. Preload will increase when heart rate ___________________________ or during exercise because contracting muscles increase _______________________________. By contrast excessive heart rate will ________________________ ventricular filling and thus ________________.
h. The Frank-Starling Law of the Heart ensures that the _____________________ and ______________________________ remain equal.
i. A shift in the ventricular function curve to the left indicates an increase in __________________________________. Any agent that causes such a change is called a ________________________________.
j. Enhanced contractility results in a more complete ejection of blood per beat, thus reducing _________________________________.
k. An increase in contractility is a direct result of an increase in intracellular ______________________________ levels. This occurs in the presence of ___________________________, and _______________________________, and the hormones __________________________, ____________________, and ____________________________________.
l. Any agent that results in a shift in the ventricular function curve to the right is called a __________________________________, one example being _______________________________________.
m. _________________________________ refers to the pressure that must be overcome for the ventricles to eject blood from the heart. In the case of the left ventricle, afterload refers to the _______________________________. Afterload can become significant in patients suffering from _______________________________, which will reduce stroke volume due to an increase in ____________________________________.
16.4. Regulation of Heart Rate:
a. Although ___________________________ cells are able to generate and maintain a basic rate of heart beat, the activity of these cells is influenced by the _____________________________________ system consisting of ____________________________ and ______________________ divisions.
b. The __________________________ system acts to increase heart rate, which is called a ______________________________ effect. Conversely the _____________________________ system acts to decrease heart rate, which is called a ______________________________ effect.
c. Both divisions of the autonomic nervous system are controlled by ________________________________ centers located in the medulla.
d. While sympathetic nerves distribute to the SA node, AV node, atrial and ventricular muscle, parasympathetic nerves distribute primarily to the _____________________________ and _____________________________.
e. Increased parasympathetic input to the SA node results in a _______________ in the slope of the pacemaker potential and a reduction in ________________. Sympathetic input to the SA node results in a _______________________ in the slope of the pacemaker potential.
f. While a denervated heart will beat at rate of about _____________________, under the influence of parasympathetic nerves, the rate falls to about ____________________________. The term which describes how heart rate is under the dominant influence of the parasympathetic system is called _________________________________.
16.5. The Baroreceptor and Bainbridge Reflexes:
a. An elevation in blood pressure results in a __________________________ in heart rate, mediated by _______________________________ nerves. This is called the ___________________________ reflex.
b. When blood pressure is low, heart rate _____________________________, mediated by _____________________________ nerves.
c. An increase in blood volume will result in increased atrial stretch, which in turn will lead to ___________________________ in heart rate. This is called the _____________________________ reflex.
d. Increased atrial stretch will also stimulate the release of ______________________________ which stimulates the kidney to increase ________________________ and __________________________ excretion.
16.6. Summary of Factors that Regulate Cardiac Output:
a. Stroke volume will be increased when ___________________________ is increased due to increased venous return during exercise or with increased ________________________________.
b. Stroke volume will be decreased when ___________________________ is decreased due a fall in ___________________ or ____________________.
c. An increase in afterload will increase _________________________ which will __________________ stroke volume.
d. Heart rate is increased in response to sympathetic nerves which in turn are stimulated by ___________________________, _____________________, _____________________________, or ____________________________.
e. Heart rate is decreased in response to parasympathetic nerves in response to an increase in _____________________________.