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

By: HWC, Views: 6885

• 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 - afterload definition & hypertension

By: HWC, Views: 6166

• Pressure (or other resisting force) that ventricles must overcome to push open semilunar valves and eject blood. ▪ Normally, the left ventricle blood pressure must overcome arterial pressure in the aorta. ▪ Abnormally high blood pressure, or hypertension, increases aortic pressure w...

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

By: HWC, Views: 6313

• 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...

Stroke volume

By: HWC, Views: 6662

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: 6606

• 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...

Frequency of stimulation and force (Recruitment of motor units and force)

By: HWC, Views: 7007

• Muscle tension depends on the frequency of stimulation. • Muscle twitch: First stimulus. • Wave summation: When a second stimulus excites a partially relaxed muscle, producing a stronger contraction. • Unfused tetanus: Successive stimulations at the same frequency, producing a se...

Electrocardiogram Examination

By: Administrator, Views: 9527

An electrocardiogram (ECG or EKG) is a test that checks how your heart is functioning by measuring the electrical activity of the heart. With each heartbeat, an electrical impulse (or wave) travels through your heart. This wave causes the muscle to squeeze and pump blood from the heart. Sinoat...

Haustral churning, Gastrocolic reflex and mass peristalsis & Defecation

By: HWC, Views: 6793

• As the cecum becomes filled and distends, a local reflex causes: • Closure of the ileocecal valve. • Activation of haustral churning. • Haustral churning mixes the chyme, which helps absorption of water, salts, and vitamins. • Haustral churning propels the contents of the colo...

Interview with Person who has Panic Attacks

By: Administrator, Views: 9692

Panic attacks are sudden periods of intense fear that may include palpitations, sweating, shaking, shortness of breath, numbness, or a feeling that something bad is going to happen. The maximum degree of symptoms occurs within minutes. Typically they last for about 30 minutes but the duration can...