34 terms

Heart 11.2 Quiz (Schermerhorn)

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Blood enters the right atrium via...
coronary sinus
angina pectoris
chest pain because myocardium is deprives of oxygen
Infarct
area of dead, deteriorating tissue resulting from a lack of blood supply
myocardial infarction
condition characterized by dead tissue areas in the myocardium caused by interruption of blood supply to that area (HEART ATTACK)
Atrial cells beat ___ times per min.
60
Ventricular cells beat ____ times per min.
20-40
The intrinsic conduction system is also known as
nodal system
What two systems regulate heart activity?
autonomic nervous system and intrinsic conduction system
Describe the intrinsic conduction system
sets heart rhythm; composed of nervous tissue that is similar to muscle; directs heart depolarization in one direction
How many BPM does the intrinsic system force?
75
sinoatrial node
pacemaker of the heart; located in the right atrium (starts each heart beat)
the atrioventricular node is at
the junction of the atria and ventricles
AV bundle (bindle of His) is...
in the interventricular septum
Purkinje fibers
spread within the ventricle wall muscles
After the SA node starts the beat and the impulse is spread through the atria to the AV node... what happens?
The atria contract; the AV node delays impulse so atria can finish contracting; the impulse goes through AV bundle, bundle branches and purkinje fibers - "wringing contraction of ventricles"; ventricles then contract
Electrocardiogram (ECG)
detects electrical currents generated throughout the body
What indicates a problem with the nodal system?
abnormalities in the shape of the waves and changes in their timing
Damage to the SA node results in...
a slower heart rate
Ischemia
lack of adequate blood supply to the heart can lead to fibrillation
fibrillation
uncontrolled quivering or twitching of the heart muscle; heart can't pump any blood
Tachycardia
fast heart rate; over 100 bpm
Bradycardia
slow heart rate; less than 60 bpm
cardiac cycle
A complete heartbeat consisting of contraction and relaxation of atria and ventricles
Systole
contraction
Diastole
relaxation
What is the average heart rate?
75 BPM
How long is the cardiac cycle?
0.8 seconds
Artial distole (think basics)
heart is relaxed; low pressure; AV valves are open; blood flows into atria and ventricles; semilunar valves are closed
Atrial systole
ventricles remain in diastole (relaxation); atria contract; blood is forced into the ventricles to complete filling
isovolumetric contraction
refers to the short period during ventricular systole when the ventricles are completely closed chambers
ventricle systole
Ventricles continue to contract; semilunar valves open and blood is ejected from ventricles; atria are relaxed and filling w/ blood
isovolumetric relaxation
Ventricles relax (diastole); semilunar valves close; when atrial pressure increases above intraventricular pressure, AV valves open
lub
closing of AV valves
dup
closing of semilunar valves