Exam #2 Flashcards
AP2 (31 cards)
Pericardium
Outer covering of heart
2 serous membranes
2 layers: outer fibrous and inner visceral layer (epicardium)
Myocardium
Muscular tissue of heart walls
Endocardium
Connective tissue that lines heart chambers
Preload
Force that stretches ventricles from blood entering
Contractibility
Force contraction of our heart muscle
Afterload
Pressure ventricles need to overcome in large vessels to eject blood out (aorta and pulmonary trunk)
End diastolic volume
Amount of blood in ventricles after they are full (high pressure)
End systolic volume
Amount of blood in ventricle after contracting (low pressure)
Cardiac output
Amount of blood pumped out of blood in 1 minute
Plateau phase of contractile cell
K+ is closed in depolarization and plateau
K+ is open in repolarization
Na+ is closed in plateau and repolarization
Na+ is open in depolarization
Ca2+ is closed in depolarization and repolarization
Ca2+ is closed in plateau
What are the steps in the conduction system
- SA node depolarize from pacemaker cells
- A/V node pause in depolarization to allow atria to finish contracting
- A/V bundle link between atria and ventricle junction
- Bundle branches branch will split can become blocked
- Purkinje fibers branch throughout ventricular mascular wall
Where are the cardioinhibitory and cardioacceleratory centers located
Medulla oblongata
Parasympathetic
Slows heart rate synapses with S/A node, A/V node, and right atrium
Sympathetic
Increase heart rate synapse with S/A node, A/V node, and right and left atria and right and left ventricles
What happens during a heart block
Partial: conduction through A/V node is slowed or partially blocked
Complete: no impulses get through the A/V node
Ventricles beat at their own intrinsic rhythm
Circulation can not be maintained
An artificial pacemaker may be implanted
First heart sound
A/V valves closing
Isovolumetric contraction phase
High pressure in ventricles
(end diastolic volume measured)
Second heart sound
S/L valves closing
isovolumetric relaxation phase
HIgh pressure in large vessels
(end systolic volume measured)
What is required for cardiac fibers to contract?
Extracellular calcium activates the release of sarcoplasmic reticulum calcium to be released causes contractions
What happens to the cardiac cycle when exercising skeletal muscle?
The most important factor stretching cardiac muscle is venous return
What increases cardiac output?
Positive Inotropic
(increase body temp, preload, and norephrine)
What decreases cardiac output?
Negative Inotropic
What side of the heart pumps more blood then the other and why?
It pumps out the same amount because of different pressures left will be higher but it will be the same amount of blood
Hypokalemia
Decreases potassium and increased contractility
Does heart rate go down when you get older?
Yes
