Cardiac Physiology and Function Quiz

A graphical representation showing the relationship between pressure and volume changes within the heart chambers over one cardiac cycle.

A functional network of interconnected cells that behave as a single unit, like a muscle fiber. In the heart, it refers to the way cardiac muscle cells are connected by intercalated discs.

Specialized junctions found between adjacent cardiac muscle cells, containing desmosomes for strong connection and gap junctions for rapid electrical signal transmission.

Strong, anchoring junctions that hold cardiac muscle cells together, preventing them from pulling apart during contractions.

Channels that allow rapid passage of electrical signals, such as action potentials, between cardiac muscle cells, ensuring synchronized contraction.

The inherent ability of cardiac muscle cells to spontaneously depolarize and generate their own action potentials, leading to rhythmic heartbeats.

The gradual depolarization of a cardiac muscle cell's membrane potential, leading to the creation of an action potential and initiating a heartbeat.

Insulating tissue that separates the atria from the ventricles, preventing electrical signals from spreading between them. This allows for coordinated pumping of blood by the two chambers.

The volume of blood in the ventricles at the end of diastole (relaxation).

The volume of blood remaining in the ventricles at the end of systole (contraction).

The amount of blood ejected from the ventricle in one heartbeat.

The volume of blood pumped by the heart per minute.

The extent of stretch on the heart muscle before contraction.

Ion channels are proteins embedded in cell membranes that open and close in response to changes in the transmembrane potential (TMP). They control the flow of specific ions (e.g., sodium, potassium) into and out of the cell. This controlled ion movement is crucial for generating electrical signals in cells, including heart muscle cells.

Time-dependence refers to the ability of some ion channels to close automatically after a certain period of time, even if the TMP remains favorable for their opening. This is essential for preventing excessive ion influx and ensuring proper repolarization of the cell, as seen with fast Na+ channels in heart muscle cells.

The SAN is the natural pacemaker of the heart. Its cells spontaneously depolarise over time, generating an action potential that spreads throughout the heart, initiating each heartbeat. The rate at which this occurs determines the heart rate.

The sympathetic nervous system increases heart rate by stimulating the SAN to generate action potentials more frequently. The parasympathetic nervous system decreases heart rate by slowing down the SAN's spontaneous depolarization.

Excitation-contraction coupling is the process that links an electrical signal (action potential) to a mechanical response (muscle contraction) in heart cells. This is achieved through the action of calcium ions, which act as a crucial messenger to trigger the contraction of muscle proteins.

An imaginary triangle spanning the trunk of the body, used to understand the direction of electrical activity in the heart. It helps determine which lead will best show certain electrical activity.

An electrical trace that reflects the action potentials, electrical impulses, traveling through the heart muscle fibers.

A rapid change in the electrical potential across a cell membrane. It's the electrical signal that travels through the heart muscle, causing contraction.

The process where the inside of a heart muscle cell becomes more positive, triggering muscle contraction.

The process where the heart muscle cell returns to its resting, negatively charged state, after depolarization.

The direction and strength of the electrical current generated by the heart during depolarization or repolarization.

The ECG trace changes based on the direction of the electrical impulse, whether the cells are depolarizing or repolarizing, and the strength of the electrical signal.

A process where increased levels of calcium in the cell trigger even more calcium release from intracellular stores, ultimately leading to muscle contraction.

Blood pressure (BP) is determined by cardiac output (CO) and systemic vascular resistance (SVR). It's the force blood exerts on the walls of arteries.

Heart rate (HR) is a component of cardiac output (CO), which directly influences blood pressure. A higher HR means more blood is pumped per minute, leading to a higher BP.

Stroke volume (SV) is the amount of blood ejected by the heart with each beat. A larger SV means more blood is pumped per beat, leading to a higher BP.

The aorta stretches to accommodate the blood ejected by the heart. A more elastic aorta can handle a larger SV, leading to a lower BP.

Diastolic blood pressure is the pressure in arteries when the heart is relaxed between beats. It's maintained by the elastic recoil of the arteries.

The Windkessel effect refers to the continuous blood flow in the aorta despite the intermittent pumping of the heart. It's due to the elasticity of the arteries.

Baroreceptors in the arteries detect changes in blood pressure. They send signals to the brain, which adjusts heart rate and blood vessel diameter to maintain normal BP.

This mechanism regulates long-term blood pressure by influencing vasoconstriction and fluid retention.

High blood pressure caused by narrowing or blockage of the renal arteries, which carry blood to the kidneys.

A tumor in the adrenal glands that produces excessive hormones, particularly adrenaline and noradrenaline, leading to high blood pressure.

Coarctation is a narrowing of the aorta, the main artery that carries blood from the heart. The narrowing creates resistance to blood flow, leading to high pressure in the upper body.

The heart muscle becomes thickened and stiff in response to high pressure, making it harder for the heart to pump efficiently, leading to heart failure.

High blood pressure puts extra strain on artery walls, leading to weakening and damage, contributing to atherosclerosis (plaque buildup).

A disease where plaque builds up inside arteries, narrowing them and reducing blood flow, leading to heart disease, stroke, and other problems.

High blood pressure caused by narrowing or blockage of the renal arteries (arteries supplying the kidneys), hindering blood flow and increasing pressure.

Conditions affecting the outer layer of the adrenal glands, which can disrupt hormone production, leading to various symptoms including hypertension.

A tumor in the adrenal glands that releases excessive amounts of adrenaline and noradrenaline, causing high blood pressure.

A narrowing or constriction of the aorta, the main artery carrying blood from the heart, leading to increased pressure in the upper body.

Enlargement and thickening of the left ventricle, the heart's main pumping chamber, caused by long-term high blood pressure, leading to reduced pumping efficiency.

Hardening and narrowing of arteries due to buildup of plaque, reducing blood flow and increasing the risk of heart disease, stroke and other problems.

The idea that injury to the artery lining triggers an inflammatory response, causing plaque buildup and atherosclerosis.

An early stage of atherosclerosis characterized by lipid deposits under the artery lining, marking the beginning of plaque formation.