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Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 6524

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

Baroreceptor Reflex

By: HWC, Views: 6020

Baroreceptors located In the carotid sinus and the arch of the aorta respond to increases in blood pressure. Increased blood pressure stretches the carotid arteries and aorta causing the baroreceptors to increase their basal rate of action potential generation. Action potentials are conduct...

Epinephrine/NE (heart rate, altered blood flow, glycogenolysis & bronchodilation)

By: HWC, Views: 6566

• Stressors trigger increased sympathetic stimulation from the hypothalamus to the chromaffin cells of the adrenal medulla. • This causes the immediate release of epinephrine and norepinephrine (NE). • Epinephrine/NE binds to the cardiac muscles of the heart. • Cardiac muscle cells ...

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...

Exercise and cardiac output & Definition of stroke volume

By: HWC, Views: 6628

▪ Cardiac output: • Maintains blood flow throughout the body. • Measure of blood volume ejected from the heart over a given time. • Determined by multiplying heart rate by stroke volume (CO = SV x HR). • Heart rate: Number of beats/min. • Stroke volume: Amount of blood eject...

Cardiac conductile cells

By: HWC, Views: 6904

• In order for the heart to function properly, all of its cells must contract in a specific sequence. This sequence is determined by a pathway known as the conduction system. • Cardiac muscle cells have two attributes that enable the conduction system to work: • Connective. Action pot...

Negative Feedback Regulation of Blood Pressure

By: HWC, Views: 6659

stimulus • Blood pressure determines the flow of blood to and from capillaries. • Low blood pressure results in reduced blood flow. • High blood pressure can cause blood vessels to break. Baroreceptors • The aortic arch carries blood to the body. • The common carotids ca...

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...

Types of Shock (Part 2 of 2)

By: Administrator, Views: 9318

Shock is a life-threatening condition in which delivery of oxygen to the organs is low, causing organ damage and sometimes death. Blood pressure is usually low.