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Heart sounds

By: HWC, Views: 7785

During a normal, healthy heartbeat, or what we call a cardiac cycle, the top two chambers of the heart, called the atria, contract simultaneously. Then, as they relax, the bottom two chambers, called the ventricles, contract. This explains what happens during a cardiac cycle, but what it doesn't ...

Structures that affect circulation - heart and MABP

By: HWC, Views: 7445

■ BP is defined as the systolic BP over the diastolic BP. ■ MABP = diastolic BP + 1/3 (systolic BP - diastolic BP). ■ MABP accounts for diastole lasting longer than systole; mean is not equidistant between the two pressures.

The primary factors that affect circulation - MABP, CO and SVR

By: HWC, Views: 8225

Introduction Blood flow is determined by the relative intensities of factors that drive and resist moving blood. • Cardiac output (CO) equals the mean arterial blood pressure (MABP, a driving force) divided by systemic vascular resistance (SVR, a resisting force). • Hormones and the cen...

ADH and the arterioles, kidneys, sweat glands and the Atrial natriuretic peptide (ANP)

By: HWC, Views: 7971

• ADH is also known as vasopressin. • Produced by hypothalmus and secreted by neurosecretory cells in posterior pituitary gland. • Responds to high blood osmotic pressure representing low amounts of water in the blood. • Binds to smooth muscle cells in walls of arterioles, stimulate...

Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 8078

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

Stroke volume

By: HWC, Views: 7870

Preload definition • Preload is the degree of stretch of cardiac muscles cells prior to contraction. • The amount of stretch is related to the end-diastolic volume[EDV]. • Increased return blood flow from the veins increases end-diastolic volume. Cardiac muscle sarcomeres stretch and ...

Structures that affect circulation - heart and systolic/diastolic BP

By: HWC, Views: 7826

• 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...