Lecture 1 CVS: the heart Flashcards
what is the approximate size and wieght of the heart
around the size of a fist, and less than one pound
what is the location of the heart
-within the mediastinum, between the 2nd and 5th intercostal spaces
-superior surface of the diaphragm
-2/3s tilted towards the left midsternal line
-anterior to vertebral column; posterior to the sternum
what are the contents of the mediastinum
great vessels (aorta, pulmonary trunk, SVC, & IVC), thymus, esophagus, and trachea
how much does the heart pump and beat each day
-beats ~100,000 times each day
-pumps ~8000L of blood /day
what are the base and apex of the heart
Base (superior portion)- posterior to the sternum; connection of great vessels
Apex (inferior tip)- pointed tip
what does the heart sit between
sits between two pleural cavities in mediastinum
where do you find the apical pulse
palpated betweeen 5th and 6th ribs, just at the tip
what is the pericardium of the heart
membranous sac covering the heart
what does the pericardium consist of
1) superficial Fibrous Pericardium: protects and anchors the heart, and prevents overfilling
2) Deep Two-layered Serous Pericardium:
-Outer Parietal Layer: lines internal surface of fibrous pericardium
-Inner Visceral Layer: epicardium- on external surface of the heart
what does the pericardial cavity do
it is fluid filled and decreases friction
what are the three layers of the heart
Epicardium, Myocardium, and Endocardium
what is the epicardium
visceral layer of serous pericardium (outermost); covers surface of the heart
what is the myocardium
middle layer, thick layer of cardiac muscle cells and connective tissue, electrical signals flow within cells
what is the endocardium
the innermost layer, continuous with endothelium of blood vessels, simple squamous epithelium and areolar tissue
what are the chambers of the heart
right atrium (RA), right ventricle (RV), left atrium (LA), and left ventricle (LV)
what does the right atrium do
receives blood from the SVC (superior vena cava) and the IVC (inferior vena cava) with is the systemic circuit, & the coronary sinus (which supplies heart tissues themselves with blood and nutrients)
what does the right ventricle do
receives blood from RA; pumps to lungs through pulmonary trunk (pulmonary circuit)
what does the left atrium do
receives blood from lungs through pulmonary veins
what does the left ventricle do
receives blood from LA; pumps blood through aortic valve into systemic circuit
what are sulci in the heart
grooves containing fat and blood vessels
what is the coronary sulcus
marks border between atria and ventricles
what is the anterior interventricular/posterior interventricular sulci
mark boundary between left and right ventricles
difference between atria and auricles
the atria are the two upper chambers of the heart while the auricles are muscular pouches extending from the atria
what is a septa
muscular partitions separating heart chambers
what is the interatrial septum
separates the atria
what is the interventricular septum
separates ventricles; much thicker than interatrial septum
what do the heart valves do
ensure unidirectional blood flow through heart, and open & close in response to pressure changes
what are the two major types of valves in the heart
the atrioventricular valves (AV) and the semilunar valves
what do the atrioventricular valves do
-they are between the atria and ventricles; tricuspid (righht side) and mitral valves/bicuspid valves (left side)
-permit bloodflow from: RA to RV and from LA to LV
what do the semilunar valves do
-they are between ventricles and major arteries
-each consists of three cusps that roughly resemble a half moon
-prevent backflow of blood into the ventricles
where is the pulmonary semilunar valve and what does it do
-between trhe right ventricle and pulmonary trunk
-prevents backflow of blood from the pulmonary trunk into the right ventrical
where is the aortic semilunar valve and what does it do
-between the left ventricle and aorta
-prevents backflow of blood from the aorta into the left ventricle