Drew's+heart+hw

(1) In which direction does the heart tilt? It is tilted so that the apex is oriented to the left.

(2) What is the approximate size of the heart? It is the size of the fist.

(3) Describe the mycoardium. The major portion of the heart and consists largely of cardiac tissue

(4) Why do you think a heart attack is sometimes called a mycocardial infarction p. 97? It is sometimes called a mycocardial infarction because it relates to the mycocardium

(5) Describe the pericardium. Thick, membranous sac that supports and protects the heart.

(6) Describe the septum. The wall that seperates the heart into a right side and left side.

(7) Where are the atria? Describe their walls. The atria is located in the upper chamber of the heart.

(8) Where are the ventricles? Describe their walls. They are in the lower chambers of the heart. They have thick walls

(9) Where are the atroventricular valves? Describe their shape (number of flaps) and various names. They lie between the atria and the ventricles.

(10) What are the chordae tendinae? Strong fiborous strings the are supporting the valves.

(11) Where are the semilunar valves? Why do they have that name? They lie between the ventricles and the attatched vessles. They have the name because of their shape.

(12) List the path of blood through the heart. 1.The superior vena cava enter the right atrium 2. The right atrium sends blood through an atrioventricular valve. 3. The right ventricle sends blood through the pulmonary semilunr valve. 4. 4 pulmonary veins enter the left atrium 5. The left atrium sends blood through an atrioventricular valve. 6. The left ventricle sends blood through the aortic semilunar valve into the aorta to the body proper.

(13) Where does blood go when it leaves the right side of the heart? Into the left atrium

(14) Where does blood go when it leaves the left side of the heart? The aortic semilunar valve

(15) Which side of the heart is stronger? Why? The left side because it has the harder job.

(16) Why is the heart a double pump? Because the right ventricle of the heart sends blood throughout the body.

(17) Define systole. The working phase that refers to the contractions of the chambers.

(18) Define diastole The resting phase that refers to te relaxation of the chambers

(19) How many times does the heart normally contract in a minute? 70 times a minute

(20) What causes the "lub" and "dup" of the heart sounds? The ventricles cause the sounds

(21) What is the sinoatrial node? What does it do? Why is called the pacemaker? The SA is the node located in the upper dorsal wall of the right atrium. It is called the pacemaker because it initiates the heartbeat and sends the signals.

(22) What is the atrioventricular bundle? Why is the delay important between the SA node and AV bundle? It is the two branches of the AV node. The delay allows electrical current to flow in between cells.

(23) What does in ECG measure? It measures the electrical changes that occur in the myocardium during a cardiac cycle.

(24) What triggers the P wave? When the SA node triggers an impulse

(25) What triggers the QRS wave? The electrical signals