Heart Parameters

These flashcards cover key terms and concepts related to the heart and cardiovascular system, emphasizing structure, function, and physiological processes.

Cardiovascular System

Composed of three main components: heart, vessels, and blood, primarily functioning to deliver nutrients and remove wastes.

Closed Circulatory System

Found in humans, where blood circulates within vessels and capillaries are sites of exchange.

Open Circulatory System

Found in arthropods and mollusks, where circulatory fluid bathes organs directly.

Atria

The two upper chambers of the heart that receive blood; include right atrium (RA) and left atrium (LA).

Ventricles

The two lower chambers of the heart that pump blood out; include right ventricle (RV) and left ventricle (LV).

Systole

The contraction phase of the heart cycle, where the heart muscles pump blood out.

Diastole

The relaxation phase of the heart cycle, where the heart fills with blood.

Gap Junctions

Protein channels that connect adjacent cardiac muscle cells for the direct transmission of electrical signals.

Syncytium

A network of interconnected cardiac muscle cells that coordinate contraction.

Autorhythmic Cells

Cells that can spontaneously generate their own action potentials, such as nodes in the heart.

SA Node

Sinoatrial node, known as the pacemaker of the heart, setting the basic rhythm.

Bradycardia

A slower than normal heart rate, typically below 60 beats per minute.

Tachycardia

A faster than normal heart rate, typically above 100 beats per minute.

Electrocardiogram (ECG)

A test that measures the electrical activity of the heart, providing diagnostic information about heart rate and possible abnormalities.

P Wave

Represents atrial depolarization in the cardiac cycle.

QRS Complex

Represents ventricular depolarization and atrial repolarization in the cardiac cycle.

T Wave

Represents ventricular repolarization in the cardiac cycle.

End Diastolic Volume (EDV)

The volume of blood in a ventricle at the end of diastole.

End Systolic Volume (ESV)

The volume of blood remaining in a ventricle after contraction.

Late Ventricular Diastole (Atrial)

The phase when the atria contract, filling the ventricles with blood before systole. During this phase, the atrioventricular valves (mitral and tricuspid) are open, while the semilunar valves (aortic and pulmonary) are closed.

End Diastolic Volume (EDV)

The volume of blood in a ventricle at the end of diastole. Composed of:

• Passive flow
• Active flow
• Remainder from previous cycle
  Typically assumed to be 100 mL (usually higher, e.g., Luke Skywalker: 135 mL).

Atrial Systole

The phase of the cardiac cycle when the atria contract, pushing blood into the ventricles. This occurs just before the ventricles begin to contract.

End Diastolic Volume (EDV)

The volume of blood in a ventricle at the end of diastole. Composed of:

• Passive flow
• Active flow
• Remainder from previous cycle
  Typically assumed to be 100 mL (usually higher, e.g., Luke Skywalker: 135 mL

Isovolumic Ventricular Systole

The phase of the cardiac cycle during which the ventricles contract without any change in volume

Ventricular Ejection

The phase of the cardiac cycle during which the ventricles contract and pump blood into the aorta and pulmonary artery, following the opening of the semilunar valves

Isovolumic Ventricular Diastole

The phase of the cardiac cycle when the ventricles are relaxed, and the pressure in the ventricle is less than the pressure in the arteries (systolic). During this phase, the semilunar valves shut, producing the second heart sound (S2), and the pressure in the ventricle is greater than the pressure in the atria.

First Heart Sound (S1)

Occurs during the isovolumic ventricular contraction phase when the atrioventricular valves (mitral and tricuspid) close due to increasing pressure in the ventricles

Right Atrium Pressure

The pressure within the right atrium of the heart, which is typically lower than the pressure in the ventricles during diastole. It plays a crucial role in the filling of the ventricles and is affected by overall blood volume and venous return. It is typically 5/0 mmHg.

Left Atrium Pressure

The pressure within the left atrium of the heart, which is typically higher than the pressure in the right atrium and helps facilitate the flow of oxygenated blood from the lungs into the left ventricle during diastole. It is also typically 5/0 mmHg.

Normal Venous Pressure

The pressure within the veins, which is typically around 5-10 mmHg, playing an essential role in returning blood to the heart

Right Ventricle Pressure

The pressure within the right ventricle of the heart, which is typically 15/0 mmHg.

Left Ventricle Pressure

The pressure within the left ventricle of the heart, which is typically 120/0 mmHg.

Heart Composition

The heart is composed of 99% cardiac muscle, which is specialized for continuous and rhythmic contraction

Heart Blood Flow

The journey of blood through the heart starts when deoxygenated blood from the body returns to the right atrium via the superior and inferior vena cavae. From the right atrium, blood flows through the tricuspid valve into the right ventricle. When the right ventricle contracts, blood is pumped through the pulmonary valve into the pulmonary arteries, leading to the lungs for oxygenation. Oxygenated blood returns to the left atrium via the pulmonary veins. Next, blood flows through the mitral valve into the left ventricle. Finally, when the left ventricle contracts, blood is ejected through the aortic valve into the aorta, distributing oxygen-rich blood to the rest of the body

SA Node Function

1. SA node spontaneously depolarizes.
2. Depolarization spreads through atria to AV node.
3. Conduction slows through AV node.
4. Depolarization travels from AV -> bundle of His -> left/right bundle branches (L/RBB) -> apex.
5. Depolarization spreads upward from apex -> Purkinje fibers -> ventricular contraction.