Cardiovascular System Overview

The heart is located in the mediastinum, tilted slightly to the left, and anterior to the descending aorta, esophagus, and major bronchi, from T5-T8.

Aortic, Pulmonary, Mitral, and Tricuspid valves ensure one-way blood flow through the heart.

Specific locations on the chest to listen to heart valve sounds (using a stethoscope).

Atrial systole (contraction) and ventricular diastole (relaxation). Rapid and slow filling of ventricles.

All four heart valves are closed, but the ventricles are contracting, increasing pressure.

During this phase, the semilunar valves open, and blood is pushed out of the ventricles.

All heart valves are closed, and the ventricles are relaxing, while preparing to fill with blood again.

Normal pressure in the right atrium is approximately 4 mmHg.

Reduced blood flow to the heart muscle due to narrowed blood vessels.

Blood pressure in the aorta during relaxation of the heart's ventricles.

Heart valves between atria and ventricles preventing backflow.

Heart valves between ventricles and major arteries preventing backflow.

Size of the opening of the tricuspid valve in cm^2, typically 7–10.

Size of the opening of the mitral valve in cm^2, typically 2–6.

Slows HR, reduces contraction force, and constricts coronary vessels.

Pressure receptors in the carotid and aortic arches that respond to blood pressure changes.

Heavy connective tissue that surrounds the heart, fused to the great vessels. Prevents over-expansion and protects the heart.

Thin, delicate sac forming a double layer (parietal and visceral) around the heart; reduces friction with fluid. Visceral layer is the epicardium.

Outermost layer of the heart wall; part of the serous pericardium (visceral layer)

The muscular middle layer of the heart wall, composed of atrial, ventricular and conductive muscle.

Thick ventricular muscle (especially in the left Ventricle), crucial for generating sufficient force to pump blood. Thicker in the left side of the heart

Left ventricular wall 3 times thicker than the RV wall.

Innermost layer of the heart wall, smooth lining of the chambers, continuous with blood vessels.

Connective tissue that forms structural support for the heart valves and separates the atria and ventricles, important for electrical insulation

The amount of blood ejected from the left ventricle during one heartbeat.

The percentage of blood in the ventricle at the end of diastole that's pumped out during systole.

Ejection fraction of 70-80% indicates a healthy heart pumping effectively.

Blood flow in the developing fetus, characterized by bypassing the lungs via the foramen ovale, ductus arteriosus, and ductus venosus.

An opening between the atria in the fetal heart.

Connects the pulmonary artery to the aorta in fetal circulation.

Connects the inferior vena cava to the umbilical vein in fetal circulation.

Changes in blood flow that happen after birth as the baby's circulatory system adapts to breathing independently.

Myosin heads bind to actin filaments, pulling them closer together to cause muscle contraction.

A protein complex on actin filaments that regulates muscle contraction by blocking the myosin-binding site.

The process that links nerve signals to muscle contraction, involving T-tubules and sarcoplasmic reticulum.

The volume of blood inside the ventricle at the end of diastole, affecting the force of contraction.

The resistance the ventricle must overcome to eject blood during systole, influencing the contraction strength.

The volume of blood pumped by one ventricle per minute (Heart rate x Stroke volume).

Calcium channels in heart cells that are blocked by drugs to reduce contraction strength.

Calcium channels in heart cells with a transient effect.

Ductus venosus, foramen ovale, and ductus arteriosus close after birth, redirecting blood flow.

Heart position shifts; right ventricle decreases, left ventricle thickens; heart rate adjusts (100-180 bpm); blood flow follows adult pattern.

Birth defects that affect heart structure or function.

Defects that allow excessive blood flow to the lungs (high pressure to low pressure).

A complex congenital heart defect that decreases pulmonary blood flow and causes cyanosis. (complex, decreased pulmonary blood flow, cyanosis).

Increased pulmonary vascular resistance (PVR) reverses blood flow shunting.

Conditions like rubella, diabetes, and alcohol abuse during pregnancy increase congenital heart defect risk. (during pregnancy).

Congenital disorders preventing blood flow from the heart; no shunting.