What is the affect on the cardiovascular medullary centers when ...

[cnetterville]

What is the affect on the cardiovascular medullary centers when the cerebral carbon dioxide is low?
 
  a. Excitatory
  b. Inhibitory
  c. No affect
  d. Increased vascular tone

Question 2

Which of the following are true of the force against which the left ventricle must pump? 1. Referred to as left ventricular afterload. 2. Equivalent to systemic vascular resistance. 3. Helps to determine left ventricular stroke volume.
 
  a. 1 and 3 only
  b. 1 and 2 only
  c. 1, 2, and 3
  d. 2 and 3 only

[babybsemail]

Answer to Question 1

ANS: B
The cardiovascular centers are also affected by local chemical changes in the surrounding blood and cerebrospinal fluid. For example, decreased levels of carbon dioxide tend to inhibit the me-dullary centers.

Answer to Question 2

ANS: C
A major factor affecting stroke volume is the force against which the heart must pump. This is called afterload. In clinical practice, left ventricular afterload equals the SVR. In other words, the greater the resistance to blood flow, the greater is the afterload.