GROSS ANATOMY

GROSS ANATOMY

HEART MEDIASTINUM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Factors that affect end systolic volume are?
A
End diastolic volume
B
Temperature
C
Afterload
D
Contractility
Explanation: 

Detailed explanation-1: -End-systolic volume depends on two factors: contractility and afterload. Contractility describes the forcefulness of the heart’s contraction. Increasing contractility reduces end-systolic volume, which results in a greater stroke volume and thus greater cardiac output.

Detailed explanation-2: -ESV can be affected by 4 factors; preload, afterload, contractility, and Heart rate, and EDV also depends on 3 factors; venous return, Heart rate, and compliance. Preload (ie, the EDV):The more cardiac muscle is stretched, the harder it contracts (Frank & Starling’s law).

Detailed explanation-3: -Changes in ventricular inotropy (contractility) alter the rate of ventricular pressure development, affecting ESV and SV. For example, an increase in inotropy (e.g., produced by sympathetic activation of the heart) increases SV and decreases ESV.

Detailed explanation-4: -Contractility refers to the pumping ability of a ventricle. With increased contractility, there is a more complete emptying of the ventricle during systole and therefore a decreased end-systolic volume.

Detailed explanation-5: -In the normal heart, exercise leads to both increased contractility and afterload, resulting in a normal physiologic decrease in ESV.

There is 1 question to complete.