HEART LOCATED AT THE APPROXIMATELY AT THE LEVEL OF THE ______________, ___________

3 LAYERS OF THE HEART

LAYERS OF THE HEART - the actual contracting muscle of the heart

LAYERS OF THE HEART - lines the inner chambers and heart valves

COVERINGS OF THE HEART ____________ - a double-walled sac - prevents heart from over expanding when blood volume increases - Limits heart motion - Reduces friction between the heart and surrounding tissues - Protects the heart against infection

4 CHAMBERS OF HEART

4 CHAMBERS OF HEART - receiving chambers - assist with filling the ventricles - blood enters under low pressure

PART IN 4 CHAMBERS OF HEART - discharging chambers - thick-walled pumps of the heart - during contraction, blood is propelled into circulation

valves between atria and ventricles

- allow blood to flow in only one direction to prevent backflow - open and close in response to pressure changes in the heart

bicuspid (mitral) valve

tricuspid valve

FUNCTION OF AV VALVES - anchored the cusps in place by chordae tendineae to the walls of the ventricles - _____ during heart relaxation, when blood passively fills the chambers - _____ during ventricular contraction

OPERATION OF THE AV VALVES

valves between ventricle and artery

FUNCTION OF SEMILUNAR VALVES - prevent blood from flowing back into the ventricles during relaxation - ________ during heart relaxation - ________ during ventricular contraction

OPERATION OF THE SEMILUNAR VALVES

blood in the heart does not nourish the _____

CARDIAC CIRCULATION - branch from the aorta to supply the heart muscle with oxygenated blood

CARDIAC CIRCULATION - drain the myocardium of blood

CARDIAC CIRCULATION - a large vein on the posterior of the heart; receives blood from cardiac veins - blood empties into the right atrium via ______

CORONARY ARTERIES ➢ right atrium and ventricle ➢ inferior portion of the left ventricle ➢ posterior septal wall ➢ sinoatrial and atrioventricular nodes.

CORONARY ARTERIES - consists of two major branches, ➢ the left anterior descending ➢ circumflex arteries.

LEFT MAIN CORONARY ATERY ➢ supplies blood to the anterior wall of the left ventricle ➢ anterior ventricular septum ➢ apex of the left ventricle.

LEFT MAIN CORONARY ARTERY ➢ supplies blood to the left atrium lateral and posterior surfaces of the left ventricle. ➢ The coronary arteries supply the capillaries of the myocardium with blood. ➢ If blockage occurs in these arteries, the client is at risk for myocardial infarction.

Intrinsic conduction system of the heart ➢ Located in the right atrium ➢ Serves as the heart’s pacemaker

Intrinsic conduction system of the heart ➢ at the junction of the atria and ventricles

Intrinsic conduction system of the heart ➢ are in the interventricular septum

Intrinsic conduction system of the heart ➢ spread within the ventricle wall muscles

Intrinsic conduction system of the heart pathway ➢ The ______ starts each heartbeat ➢ Impulse spreads through the _____ to the AV node ➢ Atria contract ➢ At the _______, the impulse is delayed briefly ➢ Impulse travels through the AV bundle, bundle branches, and Purkinje fibers ➢ Ventricles contract; blood is ejected from the heart

- Located in the lower aspect of the atrial septum - Receives electrical impulses from the sinoatrial node - With 100ms delay to let the atria finish contracting - If the sinoatrial node fails, the atrioventricular node can initiate - sustain a heart rate of 40 to 60 beats/min. - QRS complex - Atrial repolarization and relaxation

• A continuation of the AV node • located at the interventricular septum • It branches into the right bundle branch • extends down the right side of the interventricular septum • left bundle branch, which extends into the left ventricle. • The right and left bundle branches terminate into Purkinje fibers.

- Diffuse network of conducting strands located beneath the ventricular Endocardium - These fibers spread the wave of depolarization through the ventricles - _______ can act as the pacemaker - Rate between 20 and 40 beats/min when higher pacemakers (such as the sinoatrial nerve) fail.

Homeostatic Imbalance • damage to AV node causes ventricles to beat at their own rate, which is much slower, some or all of the time • artificial pacemakers can be installed if damage to SA node

Homeostatic Imbalance • lack or adequate blood supply to the heart muscles

Homeostatic Imbalance • rapid, uncoordinated quivering of the ventricles; makes the heart unable

Homeostatic Imbalance • rapid heart rate, over 100 beats per minute

Homeostatic Imbalance slow heart rate, less than 60 beats per minutes

• due to the closure of the AV valves • heard loudest at the apex of the heart

• due to the closure of the semilunar valves • heard loudest at the base of the heart.

• may be heard if ventricular wall compliance is decreased and structures in the ventricular wall vibrate; this can occur in conditions such as congestive heart failure or valvular regurgitation

• this is an abnormal finding, and the causes include cardiac hypertrophy, disease, or injury to the ventricular wall. • may be heard on atrial systole

➢ sounds during heartbeat cycle (whooshing or swishing) made by turbulent blood in or near your heart ➢ Not a disease but may/can indicate an underlying heart problem

The normal sinus heart rate is __ to __ beats/min.

➢ Also called pressoreceptors ➢ Located in the walls of the aortic arch and carotid sinuses. ➢ Specialized nerve endings affected by changes in the arterial BP. ➢ Increases in arterial pressure stimulate ________, and the heart rate and arterial pressure decrease. ➢ Decreases in arterial pressure reduce stimulation of the baroreceptors and vasoconstriction occurs, as does an increase in heart rate.

➢ Located in the vena cava and the right atrium, respond to pressure changes that affect circulatory blood volume.

__________ in blood volume result in: ➢ decreased antidiuretic hormone release – increasing diuresis ➢ decreasing blood volume ➢ thus decreasing BP

_________ in blood volume result in: ➢ increased antidiuretic hormone release ➢ this promotes an increase in blood volume and therefore BP

➢ potent vasoconstrictor ➢ causes the BP to increase.

The ________ is the contraction phase

The _______ is the relaxation phase

• ____/___ mm Hg • _____ systolic • _____ diastolic

- Amount of blood pumped by each side (ventricle) of the heart in 1 minute - Stroke volume multiplied by the number of heart beat in a minute (heart rate)

- Volume of blood pumped by each ventricle in one contraction (each heartbeat) - About 70 ml of blood is pumped out of the left ventricle with each heartbeat

- The degree of stretching of the heart muscle when it is filled-up with blood

- The resistance to which the heart must pump to eject the blood