Cardiovascular and Lymphatic Systems Overview

The heart is located in the mediastinum, anterior to the descending aorta, esophagus, and major bronchi, from T5 to T8. It's roughly two-thirds of the way to the left of the midline and projects anterior, superior, and to the left.

The heart has four valves: Aortic, Pulmonary, Mitral, and Tricuspid. Each valve is located in a specific area of the heart, ideal for auscultation.

The cardiac cycle consists of five phases: atrial systole/ventricular diastole, isovolumetric ventricular systole, ventricular ejection, isovolumetric ventricular relaxation, and passive ventricular filling.

A phase of the cardiac cycle where all four valves are closed, and the ventricles are contracting but not yet changing the volume of blood.

During this phase, the semilunar valves (aortic and pulmonary valves) open, and blood is forcefully ejected from the ventricles.

The phase after ventricular contraction, where all valves are closed, and the ventricles begin to relax.

The atria contract in this phase of the cardiac cycle to further fill the ventricles with blood.

The mean pressure in the right atrium is around 4 mmHg, ranging from 0 to 8 mmHg.

Protective membrane preventing overdistension and protecting the heart; attached to the diaphragm and fused to great vessel connective tissue.

Delicate layer with a visceral (epicardium) and parietal layer that reduces friction during heart beat via a thin fluid layer called pericardial fluid.

Outermost layer of the heart wall.

The heart muscle layer composed of atrial, ventricular, and conductive muscles with different properties.

Contractile muscle of the atria, relatively thin.

Contractile muscle of the ventricles; thicker than atrial muscle, responsible for pumping blood.

Left ventricle (LV) muscle is significantly thicker than right ventricle (RV) muscle, adapting to higher pressure demands of systemic circulation.

Innermost layer of the heart wall, connected by connective tissue to the myocardium, and lining the chambers, valves, and great vessels.

Optimal pressure for perfusing the smallest coronary vessels crucial for heart function.

Heart valves (tricuspid and mitral) that prevent blood flowing back into the atria from the ventricles.

Heart valves (pulmonary and aortic) preventing backflow from arteries into ventricles.

Reduces heart rate (chronotropy), conduction speed (dromotropy), and contraction strength (inotropy). Also causes coronary vasodilation.

Pressure receptors (carotid and aortic) that regulate blood pressure by affecting the cardio inhibitory centers.

Reflex triggered by increased right atrial volume and stretch increasing heart rate.

Cranial nerve carrying afferent signals from carotid baroreceptors.

Cranial nerve carrying afferent signals from aortic baroreceptors and parasympathetic signals to the heart.

Forcibly exhaling against a closed glottis, increasing intrathoracic pressure and decreasing venous return.

Rapid depolarization (Na+ in), phase 1 initial repolarization (K+ out, Cl- in) , plateau phase (Ca+ in, K+ out), rapid repolarization (K+ out), and resting potential (maintaining balance with Na/K pump).

Spontaneous depolarization (Na+, Ca+ leak-in), followed by depolarization (Ca+ in) and repolarization (K+ out, maintaining resting membrane potential).

Functional unit of muscle contraction, located between two Z-discs, composed of actin and myosin filaments.

Light band in the sarcomere containing only actin filaments.

Dark band in the sarcomere where actin and myosin filaments overlap.

Light area within the A band, containing only myosin tails.

Process where myosin heads bind to actin, detach, and repeat, causing muscle shortening.

The amount of blood pumped out of the left ventricle during a heartbeat.

The percentage of blood in the ventricle that's pumped out during contraction.

The blood flow pattern in a fetus, bypassing the lungs.

An opening between the atria in a fetus, allowing blood to bypass the lungs.

A fetal blood vessel connecting the pulmonary artery and aorta, bypassing the lungs.

A fetal vessel connecting the umbilical vein to the inferior vena cava, bypassing the liver.

An ejection fraction above the average range (70-80%). Indicative of a healthy heart or an artificial state.

Physiological responses (hormonal and nervous) to the failing heart, such as increased catecholamines, angiotensin II, and ADH.

The closing of the ductus venosus, foramen ovale, and ductus arteriosus after birth, redirecting blood flow to match the postnatal circulatory system.

Changes in the heart's position and size (right ventricle), decreased pulmonary vascular resistance (PVR), and increased systemic vascular resistance (SVR) occur after birth, strengthening the left ventricle.

Birth defects in the heart structure that result in either increased or decreased pulmonary blood flow or obstructed outflow.

Congenital heart defects causing the shunting of blood from the high-pressure left side to the low-pressure right side, leading to pulmonary congestion and cyanosis.

A condition where increased pulmonary vascular resistance (PVR) equals or exceeds systemic vascular resistance, reversing the shunt direction in congenital heart defects.

Congenital heart defects causing hypoxemia (low blood oxygen levels) and cyanosis (bluish discoloration of the skin) due to desaturated blood mixing.

Congenital heart defects causing obstruction of blood flow to the left or right side of the heart, mostly due to narrowed vessels, without shunting.

Congenital heart defects that reduce blood flow to the lungs, usually leading to a right-to-left shunt, and cyanosis.