QuestionSBA
QuestionChoice
This is incorrect as skeletal muscle contraction squeezes the blood through the veins back to the heart, increasing venous return, and hence increasing the end diastolic volume. Due to Starling's law, this will also increase the stroke volume.
10026262
c
Decreased end diastolic volume and decreased systolic volume
QuestionChoice
Skeletal muscle contraction squeezes the blood through the veins back to the heart, increasing venous return, and hence increasing the end diastolic volume. Due to Starling's law, an increased end diastolic volume will stretch the myocardium, resulting in a greater force of contraction and hence larger stroke volume.
10026260
a
Increased end diastolic volume and increased systolic volume
QuestionChoice
Whilst this will indeed result in an increased end diastolic volume, this answer is incorrect as the systolic volume should also increase. Due to Starling's law, an increased end diastolic volume will stretch the myocardium, resulting in a greater force of contraction and hence larger stroke volume.
10026261
b
Increased end diastolic volume but no change in systolic volume
QuestionChoice
This answer is wrong for two reasons. Firstly, skeletal muscle contraction squeezes the blood through the veins back to the heart, increasing venous return, and hence increasing the end diastolic volume. Secondly, Startling's law states that an increased end diastolic volume will increase the systolic volume, and vice versa. Therefore, if the end diastolic volume were to decrease, it would also result in a decreased systolic volume. In this question, however, the correct answer was an increased end diastolic and systolic volume.
10026264
e
Decreased end diastolic volume and increased systolic volume
QuestionChoice
This answer is incorrect. Whilst there is a limit to Starling's law whereby such a large increase in end diastolic volume will start to decrease ventricular contraction, this will not be reached by skeletal muscle contraction alone. Therefore, both the end diastolic and systolic volumes will be increased.
10026263
d
Increased end diastolic volume and decreased systolic volume
Concept
Chapter
2693
3892
The Frank-Starling curve
Topic
159
Cardiovascular physiology
17650
What effect will repetitive skeletal muscle contraction have on the end diastolic volume and stroke volume of the heart?
a