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Stroke volume - preload, sarcomere length and Frank -Starling law

By: HWC, Views: 6316

• Sarcomere length affects muscle tension and the force of contraction. • Increased muscle stretch (increased sarcomere length) at the beginning of contraction increases tension produced during the contraction. • A more forceful contraction ejects more blood, thus increasing stroke volu...

Cardiac Cycle (Part 2 of 4)

By: Administrator, Views: 9703

Prior to atrial systole, blood has been flowing passively from the atrium into the ventricle through the open AV valve. During atrial systole the atrium contracts and tops off the volume in the ventricle with only a small amount of blood. Atrial contraction is complete before the ventricle begins...

Factors that influence muscle tension - Sarcomere length and force, understretched and overstretched

By: HWC, Views: 6678

• Muscle tension generated through the contraction of muscle cells provides the force necessary for the muscular system to function. • The amount of tension produced depends on several factors: • Sarcomere length Frequency of stimulation • Motor unit size • Recruitment of moto...

Cardiac Cycle (Part 3 of 4)

By: Administrator, Views: 9275

Ventricular contraction

Definitions of stroke volume, preload definition & Factors influencing stroke volume

By: HWC, Views: 6483

• Stroke volume is directly correlated with cardiac output-the greater the stroke volume the greater the cardiac output. • Stroke volume represents the difference in the amount of blood between: • the volume in the ventricles at the end of diastole (end-diastolic volume EDV); • the ...

Hormonal regulation of pregnancy - week 1

By: HWC, Views: 6988

• During pregnancy, hormones play a significant role in triggering changes in the mother and fetus. • Ormones : • Maintain the lining of the uterus and prevent menstruation. Prepare the mammary glands for lactation. • Increase flexibility of the pubic symphysis. • Affect the mot...

Isovolumetric VC, Ventricular ejection, Isovolumetric & Passive ventricular filling

By: HWC, Views: 6643

• Isovolumetric means that blood volume does not change. • Ventricular blood volume and cell length remain constant. • With valves closed and contraction continuing, ventricular pressure continues to rise. • Ventricular pressure rises above arterial pressure. • Increased ventr...

Requirements for nervous signals

By: HWC, Views: 6642

• The function of neurons is to allow communication between cells, thereby maintaining homeostasis. • Electrical signals, called membrane potentials, travel along the membranes of the neurons. • Voltage variability and distance traveled determine the type of nervous signal. 1. Graded...

Structures that affect circulation - heart and systolic/diastolic BP

By: HWC, Views: 6607

• Heart generates blood pressure. • Arterioles produce resistance thereby regulating blood flow to tissues. • Veins store blood; kidneys regulate blood volume; both affect venous return and cardiac output. ■ Contractions of the ventricles determine blood pressure, which drives th...