simple notes

What is the function of the pericardium?

It is a tough membranous sac that surrounds the entire heart.

What is myocardium?

The muscle tissue around the heart.

What are myocardial cells?

Cardiac muscle cells.

What are intercalated disks?

Specialized cell junctions in the myocardium where one muscle connects to the next.

Which blood vessels supply the heart with blood?

Coronary blood vessels.

What is intrinsic control of the heart rate?

It is the rate of depolarization set by cells in the upper right atrium.

What is spontaneous rhythmicity?

The ability of cardiac muscle to generate its own electrical signal without external stimulation.

What is the intrinsic heart rate?

100 bpm.

List the components of the cardiac conduction system.

SA node, AV node, AV bundle, Purkinje fibers.

What role does the sympathetic nervous system play in heart rate?

It increases depolarization of the SA node and increases heart rate.

What is the function of the vagus nerve?

It connects the brain to the heart and carries impulses to the SA and AV nodes, releasing ACh.

What is the impact of ACh on heart rate?

It decreases heart rate.

What hormones increase heart rate and contractility of the heart?

Norepinephrine and epinephrine.

What is the cardiac cycle?

All mechanical and electrical events during one heartbeat.

Differentiate between diastole and systole.

Diastole is the filling phase and systole is the contraction phase.

What is the P wave in an ECG?

It represents atrial depolarization.

What does the QRS complex indicate?

Ventricular depolarization.

What occurs during atrial systole?

The SA node activates an action potential and the atria contract, pushing blood into the ventricles.

What is end diastolic volume?

Total volume of blood in the ventricles at the end of diastole.

What happens during ventricular systole?

Electrical contraction travels from the AV node down the Purkinje fibers, leading to a high pressure in ventricles.

What are the heart sounds associated with AV valve and SL valve closures?

First sound: Lubb (AV valve closes); Second sound: Dupp (SL valves close).

What is cardiac output?

The total volume of blood pumped by the ventricle per minute, calculated as HR x SV.

What factors affect stroke volume?

Preload, afterload, and contractility.

What is preload?

The stretch of the ventricle from blood filling; high preload results from high venous return.

Define afterload.

The force that the ventricle has to overcome to eject blood.

What does the Frank-Starling mechanism explain?

The relationship between preload and contractility, which is linear.

What is ejection fraction?

The fraction of blood pumped out of the left ventricle in relation to the amount of blood that was in the ventricle before contraction.

What is the tunica interna?

The thin single layer of blood vessels.

What do arterioles do?

They are the smallest of arteries that lead to capillaries and provide the greatest control of circulation.

What is the definition of blood pressure?

Pressure exerted by blood on arterial walls.

What is the significance of MAP (Mean Arterial Pressure)?

It is the average pressure exerted by blood as it travels through arteries.

What is functional sympatholysis?

The process by which blood flow is shunted to active muscles during exercise due to local vasodilation.

What triggers the respiratory control center in the brain?

Initial neural response to the need for increased ventilation during exercise.

What causes dyspnea?

Shortness of breath due to the buildup of CO2 and H+.

What is VO2 max?

The maximum amount of oxygen that can be utilized during maximum intensity exercise.

How does the body regulate acid-base balance during exercise?

Through chemical buffers in blood, pulmonary ventilation, and kidney function.

What does spirometry measure?

The volume of air in the lungs.

What is the role of myoglobin?

To transport oxygen to mitochondria.

What does Henry's Law state?

Gases dissolve in liquids in proportion to their partial pressure.

What is the role of chemoreceptors in respiratory regulation?

They are sensitive to changes in PO2, PCO2, and H+ in the blood.

What is the effect of increased temperature on oxygen unloading?

Increased temperature leads to more oxygen being unloaded.

What does Fick's Law relate to?

The rate of diffusion depends on the ratio of surface area and the difference in partial pressures.

What characterizes exercise-induced asthma?

Lower airway obstruction causing bronchospasm.

What does the ventilatory equivalent for oxygen measure?

The ratio between the volume of air ventilated and the amount of oxygen consumed by tissues.

What happens during the Valsalva maneuver?

It increases intrathoracic pressure and restricts venous return.

What are the primary components responsible for blood's oxygen-carrying capacity?

Hemoglobin and its binding to oxygen.

What happens to blood lactate during active recovery?

It is removed quicker because it keeps blood flow elevated and enhances lactate diffusion.

What does the term erythrocytes refer to?

Red blood cells (RBCs).

What initiates the contraction of the heart?

The electrical signal generated by the SA node.

What happens to blood flow during exercise?

Increases to the skeletal muscles and decreases to other organs.

What is the significance of residual volume?

The amount of air remaining in the lungs after max expiration.

What role does pH play in oxygen unloading?

More acidic pH during exercise results in more oxygen being unloaded.

Define total lung capacity.

The maximum volume of air in the lungs after maximum inspiration.

What does the cardiac output increase from resting to exercise?

It can increase linearly from 5.0 to 20-40 L/min.

What is the significance of inspiratory capacity?

It is the sum of tidal volume (TV) and inspiratory reserve volume (IRV).