Quizlet Heart Flashcards
The cardiac cycle is regulated by what?
the medulla oblongata
Tension in the chordae tendineae and papillary muscles during ventricular systole prevent what?
eversion of the AV valves
The closing of the semilunar valves produces what?
the second heart sound
Veins in the myocardium drain into what?
the coronary sinus
The left ventricle refills with blood in preparation for initiation of the next cardiac cycle during what?
ventricular diastole
The first heart sound is associated with both atrioventricular valves closing during what?
ventricular systole
Nerve impulses that reach the heart by means of the vagus nerve are parasympathetic and cause what?
Decreased heart rate
The atrioventricular node is located where?
in the interatrial septum
The cardiac impulse spreads into the mass of the ventricular muscle tissue from what?
the purkinje fibers
Within the heart, there is a delay in impulse transmission at the AV node in order to allow time for what?
ventricular filling
The outer layer of the heart, called the epicardium, is also the inner visceral layer of what?
the pericardium
During exercise, increased muscle contraction helps return more blood to the heart. This would lead to what?
increased stroke volume
True or false: Within limits, the more the heart is stretched as it fills during systole, the greater
the force of contraction during diastole.
False
What muscle fibers are connected by intercalated discs?
Cardiac muscle fibers
What muscle fibers have longer contraction and refractory periods than skeletal muscle fibers?
Cardiac muscle fibers
What muscle fibers conduct action potentials through gap junctions?
Cardiac muscle fibers
What muscles of the heart help prevent the atrioventricular valve from protruding into the atria when the ventricles contract?
the chordae tendineae and papillary muscles
The two atria contract together and then the two ventricles contract together during what?
Normal heart action
Heart sounds are produced by what?
Closure of heart valves
Heart rate and strength of contraction are controlled by what?
the cardiovascular center
Ventricles exceeding the pressure in the aorta and pulmonary trunk cause what?
the opening of the semilunar valves
What is the blood supply to the myocardium called?
coronary circulation
What law of the heart is important in maintaining equal blood output from both ventricles?
the frank-starling law
The frank-starling law of the heart is important in maintaining equal blood output from what?
Both ventricles
True or false: The semilunar valves are open in the cardiac cycle during ventricular filling.
False
What equals stroke volume (SV) X heart rate (HR)?
Cardiac output
True or false: A drop in blood pressure would cause baroreceptors to stimulate the cardiovascular center to increase parasympathetic impulses.
False
Would a sympathetic stimulation of the sinoatrial (SA) node would cause the heart rate to speed up or slow down?
Speed up
Would a decrease in blood pressure would cause the heart rate to speed up or slow down?
Speed up
Would a parasympathetic stimulation of the hearts conduction system cause the heart rate to speed up or slow down?
Slow down
Would a stimulation of the vagus (CN X/10) nerve cause the heart rate to speed up or slow down?
Slow down
A valve disorder may cause what?
Heart murmur
Cardiac tamponade is another name for what?
Heart compression
A decrease in the blood supply to a bodily organ, tissue, or part caused by constriction or obstruction of the blood vessels is called what?
ischemia
What is the medical term for a heart attack?
myocardial infarction
What is the medical term for heart chamber relaxation
Diastole
The visceral layer of the serous pericardium is also part of what?
Epicardium
What is the only electrical connection between the atria and the ventricles?
the atrioventricular (AV) bundle
What causes contraction of the atria?
atrial depolorization
This marks the boundary between the ventricles
Anterior interventricular sulcus and posterior interventricular sulcus
This network of specialized cardiac muscle fibers that provide a path for each cycle of cardiac excitation to progress through the heart
Conduction system
This layer of the artery is composed mainly of elastic and collagen fibers
Outer layer
This artery supplies blood to the cardiac muscle
Coronary artery
An increase in which of the following results in increased filtration from capillaries to the interstitial space?
Capillary hydrostatic pressure
Venous return to the heart is enhanced by all the following except
Vasodilation
AV node times/min
40-60 times/min
In ventricle times/min
20-35 times/min
Cardiac cycle total seconds
0.8 sec
The usual rhythm of heartbeats, established by the SA node, is called
Normal sinus rhythm
Atrial systole
0.1 sec, atria contract at the same time as ventricles
Ventricular systole
0.3 sec, ventricles contract while atria relax
Relaxation period
0.4 sec, atria and ventricles relaxed
When ventricular pressure drops below atrial pressure, AV valves open, what begins ?
Ventricular filling
Volume of blood ejected per minute from the left ventricle is?
Cardiac output (CO)
If increase in blood pressure baroreceptors send nerve impulses to nerve (IX) and (X). Sending out what type of neurons?
Parasympathetic
Detect blood levels of chemicals such as O2, CO2 and H+
Chemoreceptors
Fluttering of heart or abnormal rate of rhythm of the heart?
Palpitation
Cessation of an effective heartbeat, heart completely stops
Cardiac arrest
Rings of smooth muscle where capillaries branch from arterioles
Precapillary sphincters
When blood volume falls or blood flow to the kidneys decrease what is released ?
Renin
Dehydration or decreased blood volume what is released?
(ADH)
Lowers blood pressure by causing vasodilation and promoting the loss of salt and water in urine.
Atrial natriuretic peptide (ANP)
The alternate expansion and elastic recoil of an artery after each contraction and relaxation of the left ventricle is called a ..
Pulse
