The Heart Flashcards
learn anatomy of the heart
Where is the heart?
The heart is in the mediastinum.
What is the heart covered by?
The heart is covered by pericardium.
How many chambers does the heart have?
The heart has 4 chambers. Right & left atrias (auricles are off the atrias) and Right and left ventricles. Atrias are thinner walled.
Where is the apex of the heart?
The apex of the heart is located in the left ventricle.
How many valves in the heart and what do they do?
There are 4 valves, 2 atrial-ventricular valves, and 2 semilunar valves.
What are the atrial-ventricular valves?
Mitral (bicuspid)–is the left atrial-ventricular valve and the tricuspid is the right. They are connected with the chordae tendinae to papillary muscles.
What are the semilunar valves?
The semilunar valves are pulmonary and aortic.
How does the blood flow in the heart?
The right ventricle pumps it to the lungs, the left ventricle pumps blood to systemic.
What is systemic blood?
The blood goes from superior & inferior vena cava & coronary sinus to the right atrium to the right ventricle to pulmonary circulation.
What is pulmonary circulation?
Pulmonary circulation starts with the right and left pulmonary artery, the blood then goes to the lungs, then to the right and left pulmonary veins, then to the left atrium then to the left vent then back to systemic via the aorta.
How does fetal circulation work?
The umbilical vein has oxygenated blood (from placenta to fetus), then it goes to the ductus venosus bypasses (mostly) fetal liver (to heart), which forms ligamentum venosum after birth.
Why are fetal lungs bypassed?
Fetal lungs are not oxygenating blood so they are bypassed by ductus arteriosus (connects pulmonary trunk with aorta), ligamentum arteriosum is remnant, foramen ovale is a hole (connects right and left atria), forms fossa ovale after birth.
What is corornary circulation?
It is the blood supply to the muscle of the heart (myocardium), aorta; to the right & left corornary arteries, to the myocardium, to cardiac veins, to coronary sinus to the right atrium.
What are some pathologies related to coronary blood supply?
Ischemia, angina pectoris, and myocardial infarction.
What is ischemia?
Ischemia is reduced blood flow, usually leads to hypoxia.
What is angina pectroris?
Angina pectoris is also know as strangled chest, it causes pain due to myocardial ischemia, caused by an enlarged heart or reduced blood supply.
Why is myocardial infarction?
Myocardial infarction is death of heart tissue due to lack of blood flow, due to or may cause heart block. Heart block is blocking conduction system of heart and causes ventricular fibrillation.
What makes the heartbeat?
The heartbeat is a pacemaker within the heart (Sino-atrial node), it initiates the signal (impulse) for each heartbeat, the heart rate is determined by other factors, and the signal to beat goes via conduction system.
What is the SA node? (Sino-atrial node)
Starts with the AV node, Bundle of His, Purkinje fibers, and ends with the wall of ventricles. Each impulse travels via gap junctions (intercalated disks and the conduction system. 1st the aortia contracts (systole), then ventricles, the atria relaxes (diastole) as ventricles contract. Impulse travels to ventricles via bundle of His, to right and left branches, impulse goes to Purkinje fibers to walls of ventricles (apex first) to papillary muscles, the impulse stimulates contractile fibers.
What is an electrocardiogram?
It’s an impulse conduction through the heart generates electrical currents that can be measured at the body surface. A recording of this type of the heartbeat is an EKG, it consists of a P wave, QRS complex, and T wave. P wave-atrial depolarization, spread of impulses from SA node. QRS ventricular depolarization spread of impulse through ventricles. Ventricles contract right after QRS. T wave-ventricular repolarization is slower than depolarization. S-T segment time at which ventricles are fully depolarized.
