Flashcards in Chapter 18 (Heart) Deck (104):
How big is your heart?
App. the size of your fist
What is the pericardium?
a double-walled sac around the heart composed of several layers
What is the function of the fibrous pericardium?
Protection, anchoring, prevents overfilling of heart with blood
What does the parietal layer of the heart line?
The internal surface of the fibrous pericardium
What does the viseral layer (aka epicardium) line?
The surface of the heart
What seperates the parietal and viceral layers of the heart?
Fluid filled pericardial cavity
What is the function of serous fluid?
It helps provide a friction free enviroment
What is the epicardium?
Visceral layer of the serous pericardium
What is the myocardium?
Cardiac muscle layer forming the bulk of the heart
What is the endocardium?
The endotheilial layer of the inner myocardial surface
What does the prefix myo- usually represent?
When you think of coronary which organ do you usually think of?
The atria are the what of the heart?
The recieving chambers
Arteries take things _________ from the heart.
Veins take things __________ the heart.
Each atrium has a protruding___________?
______________ mark atrial walls.
Where does the blood enter the right atria?
From the superior and inferior venae cavae and coronary sinus.
Where does the blood enter the left atria from?
The pulmonary veins
The ventricles are the _____ of the heart.
Which two muscles mark ventricular walls?
Papillary and trabeculae carnae muscles
The right ventricle pumps blood into ____?
The left ventricle pumps blood into the _____ ?
Heart valves ensure ______ blood flow through the heart.
_______ valves lie between the atria and the ventricles
_____ valves prevent backflow into the atria when ventricles contract.
_________anchor AV valves to papillary muscles
________valve lies between the left ventricle and the aorta
________valve lies between the right ventricle and pulmonary trunk
Semilunar valves prevent ____ of blood into the ventricles.
Semilunar valves prevent ____ of blood into the ventricles.
What are some of the things that you will see when you look at a cardiac muscle?
The cardiac muscle is short, branched, fat, and interconnected
______ anchor cardiac cells together
The mitochondria in the heart make it ___?
Where are autorhythmic cells located?
Sinoatrial node (SA node)
What do autorythmic cells do to action potentials?
They initiate them
What do autorythmic cells use for rising phase of the action potential
At what rate does the (SA Sinoatrial node) generate impulses?
About 75 times a minute
At what rate does the Atrioventicular (av node) delay the impulse?
App. 0.1 second
Impulse passes from the atria to ventricles via _____?
Atrioventricular bundle (bundle of his).
Av bundle branches carrty the impulse ___ the apex of the heart
Purkinje fibers carry the impulse ___ heart apex and ventricular walls
The heart is ______ by the sympathetic cardiovasular center
stimulated (speed up)
The heart is ______ by the parasympathetic cardioinhibitory center
inhibited (slow down)
The P wave corresponds to ____ of SA node
QRS complex corresponds to ventricular _____
T wave corresponds to ventricular ______
The atrial repolarization record is masked by the larger _____ complex.
Heart sounds (lub-dub) are associated with ____ of heart sounds
The 'lub' first heart sound occurs as AV valves close and signifies _____ of systole
The dub the second heart sound occurs when the SL valves____ at the beginning of ventricular diastole
Cardiac cycle refers to all events associated with blood flow _____ the heart
What is systole?
Contraction of the heart
What is diastole?
Relaxation of the heart
What is the first stage of the cardiac cycle?
When does ventricular filling occur?
During ventricular filling Heart blood pressure is low as blood enters the ____ and flows into the ventricles
During ventricular filling AV valves are open, then ______ occurs
What is the second stage of the cardiac cycle?
What does the atria do during ventricular systole?
In the second stage of the cardiac cycle rising ventricular pressure results in ___ of the av valves
When referencing diastole what should you always think of ?
What is the 3rd stage of the cardiac cycle?
The ventricular ejection phase
What is cardiac output?
It's the amount of blood pumped by each ventricle in one minute
CO is the produve of _____ and _____.
Heart rate and stroke volume
What is heart rate?
The number of heart beats per minute
What is SV?
Stroke volume the amound of blood pumped out by a ventricle with each beat
What is cardiac reserve?
Its the difference between resting and maximal CO
What is the preload?
the amount venticles are stretched by contained blood
Anything that increases _____ increases edv and thus SV
Blood loss and extremely rapid heartbeat ___ SV
What is afterload?
Afterload is the back pressure exerted by blood in the large arteries leaving the heart
When is afterload an issue?
Individuals with hypertension
What does hypertension reduce the ability to do?
reduces the ability of the ventricles to eject blood
What is contractility?
its the increase in contractile strength, independent of stretch and EDV
What does contractililty result in?
It results in greater amount of blood being pumped
What are some things that increase SV?
increased sympathetic stimuli, certain hormones, calcium and some drugs
What are some things that decrease Sv?
Acidosis, increased extracellular potassium, and calcium channel blockers
When you think of chrono what should you always think of?
What are positive chronotropic factors?
Factors that increase the heart rate
What are negative chronotropic factors?
factors that decrease the heart rate
What are some of things that stimulate the sympathetic nervous system?
stress, anxiety, excitement, or excersise
What are some of the things that mediate the parasympathetic nervous system?
What opposes the SNS?
Which of the nervous symptoms dominates autonomic stimulation
Pns dominates the autonomis stimulation, slowing heart rate and causing _____?
What is the atrial (Bainbridge) reflux?
a sympatheic reflux initiated by increased blood in the atria (venous return)
How does the atrial reflex increase heart rate and force of contraction by____?
causing stimulation of the SA node, stimulating baroreceptors in the atria, causing increased sns stimulation
What are two hormones that increase heart rate?
Epinephrine and thyroxine
What does hypocalcemia do to the heart?
depresses heart rate
What does hypercalcemia do to the heart?
causes erratic heart rates
What does hypernatremia do to the heart?
blocks heart contraction
What does hyperkalemia do to the heart?
lowers resting membrane potential (may lead to heart block and cardiac arrest)
What does hypokalemia do to the heart?
heart beats feeble and arrhythmically
When a baby is born and the umbilical cord is cut, what structures change in the heart to dicontinue the bypass system?
The foramen ovale connets the two atria and the ductus arteriosus connects the pumonary trunk and the aorta
Name the 3 bullet points on the Ventricular filling
diastole, av valves are open, and the semi-lunar is closed, atrial systole
Name the 2 bullet points on the isovolumetric contractoin
all valves are closed systole
Name the 2 bullet points on the ventricular ejection
systole, semilunar valves are open and the av valves are closed
name the 2 bullet points on the isocolumetric relaxation
all valves are closed, diastole
What does the acyromym LAB RAT stand for?
Left atrium bicuspid, and right atrium tricuspid
What are the two types of cardiac muscle cells?
normal cardiac muscle and automatic/autorythmic cells
What are normal cardiac muscles stimulated by?
Influx of calcium
How do automatic/autorythmic cells work?
They use a calcium influx rather than sodium for the rising phase of the ap
The SA node is known as what?