Ch 18 Heart
_(nervous system) dominates the autonomic stimulation, _(what do to heart rate) heart rate and causing _(term for this)
PNS dominates the autonomic stimulation, slowing heart rate and causing vagal tone
acronym to remember order of waves in ECG?
PeQue eReS Travieso P wave->QRS complex->T wave
what is the function of pulmonary circuit?
Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated (oxygen-rich) blood back to the heart.
The endocardium houses _ fibers
Purkinje
the second heart sound is associated with the closing of which valve?
Semilunar valve
using Frank-Starling Law of the Heart state two activities that would increase stroke volume
Slow heartbeat (allows for more time for ventricular filling) and exercise (increase volume in blood) increase venous return to the heart, increasing Stroke Volume
Sympathetic nervous system (SNS) stimulation to the heart is activated by_(4 activities)
Sympathetic nervous system (SNS) stimulation is activated by stress, anxiety, excitement, or exercise
what is the function of systemic circuit?
Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart.
The cardiovascular system consists of the _(5)
The cardiovascular system consists of the heart, and vessels, arteries, capillaries and veins.
what two hormones increase heart rate?
The hormones epinephrine and thyroxine (increases metabolic rate and body heat) increase heart rate
How the wall of right ventricle compares with the wall of left ventricle? explain why
The right ventricle has a thinner wall than does the left ventricle because it must pump blood only as far as the lungs, compared to the left ventricle pumping to the entire body. (greater friction or resistance to blood flow)
what is different in cardiac muscle vs skeletal muscle regarding the use of calcium ions_
What is different is that calcium ions are involved in action potential
Which of the following is not part of the conduction system of the heart? a. AV valve b. bundle of His c. AV node d. SA node
a. AV valve
state which aspect of stroke volume (EDV vs ESV) these affect: a. preload b. contractility c. afterload
a. prelaod affecs EDV (end diastolic volume) b. contractility affects ESV (end systolic volume) c. afterload affects ESV (end systolic volume)
Isovolumetric contraction ________. a. refers to the short period during ventricular systole when the ventricles are completely closed chambers b. occurs only in people with heart valve defects c. occurs while the AV valves are open d. occurs immediately after the aortic and pulmonary valves close
a. refers to the short period during ventricular systole when the ventricles are completely closed chambers
describe the electrical event in the heart that occurs during each of the following: a) the QRS wave of the ECG b) the T wave of the ECG c) the P-R interval of the ECG
a. ventricular depolarization b. ventricular repolarization c. atrial depolarization and the conduction of the action potential through the rest of the instrinsic conduction system
what kind of respiration the heart uses?
aerobic respiration
cardiac output
amount of blood pumped by each ventricle in one minute
thachycardia
an abnormally fast heart rate
bradycardia
an abnormally slow heart rate
left ventricle ejects blood through_
aorta (largest artery)
where contraction begins in the heart?
apex
contraction of cardiac muscle is what shape?
as a wave
where oxygen and carbon dioxide exchange happens?
at capillaries (capillary beds)
P wave leads to_(what happening in the heart)
atrial contraction
Which of the events below does not occur when the semilunar valves are open? a. AV valves are closed. b. Ventricles are in diastole. c. Ventricles are in systole. d. Blood enters pulmonary arteries and the aorta.
b. Ventricles are in diastole.
During the period of ventricular filling ________. a. pressure in the heart is at its peak b. blood flows mostly passively through the atria and the open AV valves into the ventricles c. the atria remain in diastole d .it is represented by the P wave on the ECG
b. blood flows mostly passively through the atria and the open AV valves into the ventricles
Which vessel(s) of the heart receive(s) blood during right ventricular systole? a. aorta b. pulmonary trunk c. venae cavae d. pulmonary veins
b. pulmonary trunk
what is the transport medium of the body?
blood
ischemic
blood deprived
how blood moves with respect to pressure?
blood moves from greater pressure to less pressure places
what is the definition of a vein?
blood vessels that return blood toward the heart from the circulation
what coronary arteries do?
bring blood to the heart (supply blood to heart for its own use)
what is another name of atrioventricular bundle?
bundle of His
The tricuspid valve is closed ________. Check all that apply. a.while the atrium is contracting b. while the ventricle is in diastole c. when the ventricle is in systole d .by the movement of blood from atrium to ventricle
c. when the ventricle is in systole
Path of Blood through the Heart is also known as_
cardiac cycle
for the following, state whether it applies to skeletal muscle, cardiac muscle, or both: AP exhibits a plateau phase
cardiac muscle
for the following, state whether it applies to skeletal muscle, cardiac muscle, or both: refractory period is almost as long as the contraction
cardiac muscle
after passing through the capillary beds of the myocardium, the venous blood is collected by the_
cardiac veins
what happens to myocardial cells in myocardial infraction?
cells die
disease related to inadequate circulation
coronary artery disease (CAD)
Select the correct statement about cardiac output. a. Decreased venous return will result in increased end diastolic volume. b. If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased. c. Stroke volume increases if end diastolic volume decreases. d. A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.
d. A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________. a. sends blood through a smaller valve b. pumps a greater volume of blood c. expands the thoracic cage d. pumps blood against a greater resistance
d. pumps blood against a greater resistance
cardiac reserve
differences between resting and maximal cardiac output
SL valves open and close in response to_
differences in pressure
what is the function of purkinje fibers?
estimulates heart cells
true or false: the left ventricle pumps more blood with each beat than the right ventricle
false
the interatrial septum bears a shallow depression called_
fossa ovalis
what is another name for myocardial infraction? (common name)
heart attack
vagal tone
heart rate at rest under both autonomic divisions signaling
Is the blood in the pulmonary vein low or high in oxygen?
high in oxygen
electrocardiogram
is a graphic record of heart activity
An electrocardiogram
is a recording of the electrical changes that occur during a cardiac cycle.
cardiac reserve (how determined mathematically)
is the difference between resting and maximal CO
cardiac output is the result of_(mathematical equation to get it)
is the product of heart rate (HR) and stroke volume (SV) untis: ml/min
where the sinoatrial node is found within the heart?
it is found in the right atrial wall, just inferior to the entrance of the superior vena cava
the ability of cardiac muscle to depolarize and contract is intrinsic. what this means?
it is the property of the heart muscle and does not depend on the nervous system
approximately, 2/3 of the heart mass lies to_(right vs left) of the midsternal line
left
Is the blood in the pulmonary artery low or high in oxygen?
low in oxygen
slow depolarization step in pacemaker action potential is called_
membrane potential
what is another name for the bicuspid valve?
mitral valve
The AV node conducts impulses more_(rate) than other parts of the system
more slowly
the real danger of an inadequate blood supply to the myocardium is what?
not lack of nutrients, but lack of oxygen
in heart, action potentials are initiated by_
pacemaker cells
what is an important structure of the heart in its intrinsic nervous system?
pacemaker cells
Another name for the subenodcardial conducting network?
pikinje fibers
what kind of feedback is found in cardiac muscle stimulation?
positive feedback cycle
what is the function of semilunar valves?
prevent backflow of blood into ventricle
diastole
relaxation of heart muscle
the coronary arteries deliver blood when they are _
relaxed
T wave leads to what happening in the heart?
repolarization of ventricle
The heart has four internal chambers: two on top and two below. A _____________ divides the chambers on each side.
septum
deep the fibrous pericardium is the _
serious pericardium
fossa ovalis
shallow depression found in the interatrial septum that marks the spot where an opening, the foramen ovale, existed in the fetal heart
what is the pacemaker of the heart?
sinoatrial (SA) node
for the following, state whether it applies to skeletal muscle, cardiac muscle, or both: has triads
skeletal muscle
for the following, state whether it applies to skeletal muscle, cardiac muscle, or both: source of Ca2+ for contraction is only SR
skeletal muscle
repolarization is_than depolarizaiton
slower
cardiac cycle is marked by _(2 things that need to happen to keep blood moving) in the heart
succession of pressure and blood volume changes
after 0.1 s of P wave begin, what happens?
the atria contract
in which direction does the depolarization wave travel across the ventricle?
the depolarzation wave travels upward from the apex toward the atria, and from endocardoum to epicardium
from inside to outside, list the layers of the heart wall and the coverings of the heart
the layers of the heart wall are endocardium, myocardium, and epicardium. The epicardium is also called the visceral layer of the serous pericardium. This is surrounded by the parietal layer of the serous pericardium and the fibrous pericardium
what ventricle forms the apex?
the left ventricle
apex
the lower pointy part of the hearth
mediastum
the medial cavity of the thorax that holds the heart
the heart is in the mediastinum. what is the mediastinum?
the mediastinum is the medial cavity of the thorax within which the heart, great vessels, and trachea are found
which of the two autonomic nervous systems that act on the heart is constantly acting on it? what it does?
the parasympathetic is constantly acting on it to slow it down to resting heart rate
which side of the heart acts as pulmonary pump? systemic pump?
the right side of the heart acts as the pulmonary pump, whereas the left acts as the systemic pump
which part of the intrinsic conduction system directly excites ventricular myocardial cells?
the subendocardial connecting network (pukinje fibers)
how the contraction is? (way of motion and where starts)
the wringing motion of contraction begins at the heart apex and moves toward the atria, following the direction of excitation wave through the ventricle walls
what direction do arteries carry blood with respect to the heart?
they always carry blood away from the heart -Artery=Away
what direction do veins carry blood with respect to the heart?
they always carry blood toward the heart
how does the heart get nourishment? (circulation name)
through the coronary circulation
complete blockage of coronary arteries leads to_
tissue death and hear attack
the heart is a _(role)
transport system pump
true or false: the left ventricle pumps blood at a higher pressure than the right ventricle
true
true or false: the left ventricle wall is thicker than the right ventricle wall
true
the cardioinhibitory center sends impulses to the _nerve
vagus nerve
stroke volume correlates with _(structure of heart force)
ventricular contraction
what follows the ventricular depolarization wave?
ventricular contraction almost immediately follows
if the mitral valves were insufficient, would you expect to hear the murmur (blood flowing through the valve that should be closed) during ventricular systole or diastole?
ventricular systole
electrocardiogram measures _
voltage differences
when AV valves are forced to be open?
when blood pressure on the atrial side of the AV valves exceeds that in ventricles
list and describe the 3 parts of the action potential of pacemakers (3)
1. pacemaker potential: the pacemaker potential is due to special properties of the ion channels in the sarcolemma. In these cells, hyperpolarization at the end of an action potential both closes K+ channels and opens slow Na+ channels. The Na+ influx alters the balance between K+ loss and Na+ entry, and the membrane interior becomes less and less negative (more positive). 2. Depolariztion: Ultimately at threshold, Ca2+ channels open, allowing explosively entry of Ca2+ from the extracellular space. As a result, in pacemaker cells, it is the influx of Ca2+ (rather than Na+) that produces the rising phase of the action potential and reverses membrane potentials 3. Repolarization: As in other excitable cells, the falling phase of the action potential and repolarization reflect opening of K+ channels and K+ efflux form the cell
describe ventricular systole (atria in diastole) in cardiac cycle
-as the atria relax, the ventricles begin contracting, causing rise in ventricular pressure, closing AV valves. This results in isovolumetric contraction phase. -Ventricular pressure continues to rise. When it finally exceeds the pressure in the large arteries issuing from the ventricles, the isovolumetric stage ends as the SL valves are forced open and blood rushes from the ventricles into the aorta and pulmonary trunk
where are located the two atrioventricular (AV) valves?
-at each atrial-ventricular junction
what is the state of the atria during ventricular systole?
-atria have been in diastole -they have been filling with blood and the intra-atrial pressure has been rising
The A-V node rapidly sends a signal down the __________ bundle and into the interventricular septum.
-atriovenricular (AV)
from the AV node, the impulse sweep to_
-atrioventricular bundle
list the 2 classification of valves and their corresponding valves (4 in total)
-atroventricular valves: tricuspid and bicuspid (mitral) -semilunar valves: pulomary and aortic
what can alter the normal behavior of the heart?
-autonomic nerve fibers can alter its basic rhythm
the_system regulates the cardiac conduction system to meet the needs of the body
-autonomic nervous system
cardiac pacemaker cells (other name, found in what system, what kind of membrane potential has, name of membrane potentials, what do)
-autorythmic cells -making up the intrinsic conduction system have an unstable resting potential that constantly depolarizes, drifting slowly toward threshold. These spontaneously changing membrane potentials, called pacemaker potentials or prepotentials, initiate the action potentials that spread throughout the heart to trigger its rhytmic contractions
both left and right coronary arteries arise from the _and encircle the heart in the_
-base of the aorta -coronary sulcus
because of gap junctions, how the myocardium work?
-because gap junctions electrically couple cardiac cells, the myocardium behaves like a single coordinated unit, or functional synctium
why a sustained contraction results in heart contraction? why this is needed?
-because of the plateau, sustained contraction develops because it is needed to eject blood from the heart
why atria are thin walled chambers?
-because they need to contract only minimally to push blood "downstairs" into the ventricles -they contribute little to the propulsive pumping activity of the heart
causes of reduced blood flow? (3)
-blood clots -fatty artheroslerotic plaques -Muscle spasm
ischemia
-blood deprivation
what is the definition of an artery?
-blood vessels that conduct blood away from the heart into circulation
what kind of energy molecules heart uses?
-both skeletal and cardiac muscles use multiple fuel molecules, including glucose and fatty acids, but cardiac is more adaptable and readily switches metabolic pathways to use whatever nutrients are available, including lactic acid
as with skeletal muscles, cardiac muscle contraction is triggered by_
-by action potentials that sweep across cell membranes
when SV drops, how heart maintains constant cardiac output? (2)
-by increasing heart rate and contractility
cardiac muscle cannot go to tetany. why?
-cardiac muscle cannot go into tetany because the absolute refractory period is almost as long as the contraction
T wave
-caused by ventricular repolarization
myocardial infraction (what it is, what causes it, and commonly called as_)
-condition characterized by dead tissue areas in the myocardium -caused by interruption of blood supply to the area -commonly called heart attacks
intrinsic cardiac conduction system (what it consists of, what do)
-consists of non contractile cardiac cells specialized to initiate and distribute impulses throughout the heart, so that it depolarizes and contracts in an orderly, sequential manner
During the cardiac cycle, pressure within the heart chambers rises and falls with the ________________ and ____________________ of atria and ventricles.
-contraction and relaxation
systole
-contraction of heart muscle -way to remember: "Si contraction"
what two grooves visible on heart surface indicate the boundaries of its four chambers? what they carry?
-coronary sulcus (or atrioventicular groove)= encircles the junction of the atria and ventricles like a crown -anterior interventricular sulcus, which continues as the posterior interventricular sulcus (mark the position of the septum separating the ventricles) -they carry the blood vessels that supply the myocardium
a typical ECG has 3 almost immediately distinguishedable waves or _: (list them)
-deflections -P wave, the QRS complex, T wave
what are the two things that intercalated discs contain? describe each (function)
-desomosomes prevent adjacent cells from separating during contraction -gap junctions allow ions to pass from cell to cell, transmitting current across the entire heart
electrocardiograph
-device that detects the electrical currents generated in and transmitter through the heart, which spread throughout the body
pericardium
-double-walled sac that encloses the heart
S-T segment (what special thing includes and what happens to heart)
-during this segment, the action potential of the ventricular myocytes are in their plateau phases, the entire ventricular myocardium is depolarized
isovolumetric contraction phase
-during ventricular systole (atrial diastole) step of cardiac cycle -The split second period when the ventricles are completely closed chambers and the blood volume in the chambers remains constant as the ventricles contract -happens when there is enough pressure to close AV valves (bicuspid or mitral and tricuspid), but not enough to open SL valves (pulmonary and aortic valve)
describe the fundamental difference between heart muscle and skeletal muscle: means of stimulation
-each skeletal muscle fiber must be stimulated to contract by a nerve ending, but some cardiac muscle cells are self-excitable -these cells can initiate own depolarization, but that of the rest of the heart as well, in a spontaneous and rhythmic way. This property is called automaticity or autorhythmicity
auricles
-ear shaped -outer portion of atrium
the atrioventricular bundle is the only_between ventricles and atria
-electrical connection
how can we determine stroke volume?
-end diastolic volume (amount of blood in ventricle at end of relaxation) minus end systolic volume (the amount of blood that remains at the end of contraction of ventricles) SV=end diastolic volume (EDV) minus end systolic volume (ESV)
The inner ____________________is smooth and is made of connective tissue and epithelium. It is continuous with the endothelium of major vessels joining the heart.
-endocardium
cardiac veins come together into_
-enlarged vessel called coronary sinus
The outermost layer, the _______________________, is made up of connective tissue and epithelium, and contains blood and lymph capillaries along with ______________ arteries. It is the same as the _ pericardium.
-epicardium -coronary arteries -visceral
what hormones are released from the postsynaptic junctions of the parasympathetic and sympathetic? which kind of reaction they cause?
-epinephrine and norepinephrine -fly and flight response vs relaxation response
which ventricle pumps greater volume?
-equal volumes of blood are pumped to the pulmonary and systemic circuits at any moment, but the two ventricles have very unequal workloads -left ventricle can generate much more pressure than the right and is more powerful, but both pump the same volume
After running to catch a bus, Josh noticed that his heart was beating faster than normally and was pounding forcefully in his chest. How did his increased heart rate and stroke volume come about?
-exercise activates the sympathetic nervous system, Sympathetic nervous system activity increases heart rate. It also directly increases ventricular contractility, thereby increasing Josh's stroke volume
contractility (what affects, what it is, and how increases)
-factor affecting stroke volume -cardiac cell contractile force due to factors other than EDV -it increases when more Ca2+ enters the cytoplasm from extreacellular fluid and the SR
afterload
-factor affecting stroke volume -back pressure exerted by blood in the large arteries leaving the heart -pressure that the ventricles must overcome to eject blood
preload
-factor that affects stroke volume -amount ventricles are stretched by contained blood
what parts of the heart does the parasympathetic postganglionic fibers innervate?
-fibers project most heavily to the SA and AV node
what are the layers of the pericardium? (from superficial to deep)
-fibrous -parietal -visceral (epicardium)
It [the pericardium] is made of a tough outer bag that surrounds a double-layered sac. This tough, outer layer is composed of dense connective tissue and is called the _____________ pericardium.
-fibrous pericardium
the loosely fitting superficial part of the pericardium sac is called_, which is made of_(tissue)
-fibrous pericardium -dense connective tissue
list from most external to most internal all the layers of heart
-fibrous pericardium -parietal layer of serous pericardium -pericardial cavity (with serous fluid) -epicardium (visceral layer of serous pericardium and part of heart wall) -myocardium (part of heart wall) -endocardium (part of heart wall) -heart chamber
describe isovolumetric relaxation, early diastole phase of cardiac cycle
-following T wave, the ventricles relax -because the blood remaining in their chambers, referred to end systolic volume (ESV), is no longer compressed, ventricular pressure drops rapidly and blood in the aorta and pulmonary trunk flows back toward the heart, closing the SL valves -closure of the aortic valve raises aortic pressure briefly as backflowing blood rebounds off the closed valve cusps, an event beginning at the dicrotic notch, shown on the pressure graph -once again ventricles are closed chambers
blood flow (within the heart in a simplified version)
-from atria to ventricles and out the great arteries
From the SA node, the depolarization wave spreads via _throughout the atria and via the_pathway to the_
-gap junctions -internodal pathway -atrioventricular (AV) node
When the atria fill, pressure in the atria is ________________________ than that of the ventricles, which forces the ________________ valves open. Pressure inside atria rises further as they _, _(purpose of previous action)
-greater -atrioventricular valves (AV valves) -contract -forcing the remaining blood into the ventricles.
how contractibility affects stroke volume?
-greater contractibility, more blood is ejected from the heart (greater SV), hence lower end systolic volume (ESV)
list the steps (briefly) of the pacemaker and its action potentials
1. pacemaker potential: this slow depolarization is due to both opening of Na+ channels and closing of K+ channels. Notice that the membrane potential is never a flat line 2. Depolarzation: The action potential begins with the pacemaker potential reaches threshold. Depolarization is due to Ca2+ influx through Ca2+ channels 3. Repolarizatiomn is due to Ca2+ channels inactivating and K+ channels opening. This allows K+ efflux, which brings the membrane potential back to its most negative voltage
can you list the components of the conduction system? (5)
1. sinoatrial node (SA) 2. atrioventricualr node (AV) 3. AV Bundle of His 4. R and L bundle branches 5. Purkinje fibers
illustrate the path of blood through the heart (14)
1. superior and inferior vena cava 2. right atrium 3. tricuspid valve 4. right ventricle 5. pulmonary valve 6. pulmonary arteries 7. lungs 8. pulmonary veins 9. left atrium 10. bicuspid (mitral) valve 11. left ventricle 12. aortic valve 13. aorta 14. body
list in a simplified way the conduction system pathway within the heart
1. the sinoatral (SA) node (pacemaker) generates impulses 2. the impulses pause at the atrioventricular (AV) node 3. The atrioventricular (AV) bundle connects the atria to the ventricles 4. the bundle branches conduct the impulses through the interventricular septum 5. the subendocardial conducting networks (pukinje fibers) depolarize contractile cells of both ventricles
describe ventricular filling in cardiac cycle (2 steps, include pressures, when valves are open vs close, and ECG waves)
1. ventricular filling: pressure in heart is low, blood flows passively through the atria and open AV valves into ventricles. aortic and pulmonary valves are closed 2. atrial systole: following depolarization (P wave), the atria contract, compressing the blood in their chambers. This causes a sudden slight rise in atrial pressure, which propels residual blood out of the atria into the ventricles -At this point, the ventricles are in the last part of their diastole and have the maximum volume of blood they will contain in the cycle -Then the atria relax and the ventricles depolarize (QRS complex). Atrial diastole persists through the rest of the cycle
when measuring pressure, how it is formatted? (what over what?)
120/80 contraction/relaxation systolic/diastolic
the heart is composed of how many pumps?
2
what is the average heart rate?
75 beats per minute
what regulates heart rate?
Autonomic Nervous System (parasympathetic and sympathetic)
average hear rate
Average heart rate: 75 beats/min
using Frank-Starling Law of the Heart state two activities that would decrease stroke volume
Blood loss and extremely rapid heartbeat decrease SV
describe the fundamental difference between heart muscle and skeletal muscle: organ vs motor unit contrction
-in skeletal muscles, the impulses are not spread from cell to cell. Only muscle fibers that are individually stimulated by nerve fibers contract. Skeletal muscle contracts with some of the muscle's motor units activated -Cardiac muscle either all fibers in the heart contract as a unit or the heart does not contract at all. This is coordinated action occurs because gap junctions electrically tie all cardiac muscle cells together into a single contractile unit. Consequently, the depolarization wave travels across the heart from cell to cell via ion passage through the gap junctions
end diastolic volume (EDV)
-in ventricular filling, maximum amount of blood the ventricles will contain in the cycle -they results after the atrium propels residual blood out of hte atria into the ventricles
When ventricles contract, pressure inside them ________________________ sharply, causing ______ valves to close and the __________________ and ________________________ valves to open.
-increase -AV valves -aortic and pulmonary valves
how the symphatetic affect the heart? (2)
-increases both rate and the forces of heartbeat
the apex points _(direction)
-inferiorly toward the left hip
endocardium (location, made out of what tissue, located where, and what does)
-innermost layer of heart wall -made out of endothelium -Located on the inner myocardial surface -it lines the heart chambers and covers the fibrous skeleton of the valves
what are the two types of septum and what separate? (2)
-interatrial septum=separates the two upper atria -terventricular septum= separates the ventricles
trabeculae carnae (how look, what are them, and what do)
-irregular ridges of muscle that mark the internal walls of the ventricular chambers
angina pectoris
-is thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium
what are the two conditions resultant of coronary artery disease?
-ischemia -hypoxia
when a region of the heart is oxygen starved, _cells begin to _
-ischemic cells -metabolize anaerobically, producing lactic acid
what is the main function of the cardiac conduction system?
-it coordinates and synchronizes heart activity
what coronary sinus does?
-it empties deoxygenated blood from myocardium (cardiac veins) into the right atrium
how preload affects stroke volume?
-it is directly proportional: the higher the preload, the higher the stroke volume -More blood that comes in to heart, the more blood it can pump out because cardiac muscle tissue, the more stretches, the greatest contracts
Describe the location of aortic semilunar valve
-it is found between left ventricle and aorta leading to body
where atrioventricular bundle is found?
-it is found in the superior part of the interventricular septum
Coronary artery disease (CAD)
-it is the block of the coronary arteries that prevent blood from arriving to the heart
The parietal layer of the serous pericardium lines_
-it lines the internal surface of the fibrous pericardium
what is the function of the cardiovascular system?
-it provides the transport system "hardware" that keeps blood continuously circulating to fulfill the critical homeostatic need (transport of nutrients and oxygen and prevents buildup of wastes)
what is the function of the SA node?
-it sets the pace of the heart as whole because no other region of the conduction system or the myocardium has a faster depolarization rate
where does the cardiac cycle start?
-it starts when the heart is in total relaxation, when the ventricles are being filled
how pressure works with respect to molecules?
-it works with the amount of molecules in relation with space -if take same amount of molecules in: -small area: lot pressure -large area: less pressure
what happens if vagal nerves did not innervated the heart?
-it would not send inhibitory impulses to SA node -the same effect as if the parasympathetic nervous system did not work -increase in heart rate since PNS make the heart rate to be slower than it would be if the vagal nerves were not innervating it
anastosomes (what are them, where found, what provide, what happens when blocked)
-junctions among the coronary arterial branches -these fusing networks provide additional collateral routes for blood delivery to the heart muscle, but are not robust enough to supply adequate nutrition when a coronary artery is suddenly occluded (blocked)
hypoxia
-lack of oxygen in blood
what quantity of mitochondria do cardiac cells contain? what ability this gives to cardiac cells?
-large quantity of mitochondria -they are highly fatigue resistant
action potential and contractile phase last_in cardiac muscle than in skeletal muscle
-lasts much longer
QRS complex leads to what happening in the heart?
-leads to ventricular contraction
relaxation results in_pressure, contraction results in_pressure
-less pressure -more pressure
where is the atrioventricular (AV) node located?
-located in the inferior portion of the interatrial septum immediately above the tricuspid valve
intracellular spaces between cardiac cells are filled with_. This is connected to _, which acts both as _(2)
-loose connective tissue matrix (endomysium) containing numerous capillaries -fibrous cardiac skeleton - tendon and as an insertion
The first sound (_ (sound)) occurs as _ (what happens) and _ are closing. The second sound (_(sound)) occurs as _(what happens) and _ valves are closing.
-lub -ventricles contract -AV valves -dup -ventricles relax -aortic and pulmonary valves (SL vavles)
Heart sounds (_)(sound effect) are associated with _
-lub-dup -closing of heart valves
what Q wave says?
-marks the beginning of ventricular excitation
End diastolic volume (EDV)
-maximum volume of blood -At ventricular filling, the ventricles are in the last part of their diastole and have the maximum volume of blood they will contain in the cycle
list the 3 fundamental differences between heart muscle and skeletal muscle
-means of stimulation -organ vs motor unit contraction -length of absolute refractory period
The heart lies in the __________________(cavity) under the sternum; its apex extends to the ________ (#) intercostal space.
-mediastum -fifth
myocardium (location, what it is, what it means, composed of what kind of tissue, function)
-middle layer of heart wall -means muscle heart -composed of cardiac muscle and forms the bulk of the heart -this is the layer that contracts
epicardium (location, what it is, and other name)
-most superficial wall of heart also known as visceral layer
pectinate muscles (what are them, were found)
-muscle bundles found internally in the right atrium on the wall -they are found in the auricle of the left atrium wall
papillary muscles (what are them, what do, and where found)
-muscle bundles that play a role in valve function -project into the ventricular cavity
how muscle tension is found within the plateau period?
-muscle tension develops during the plateau and peaks just after the plateau ends
The middle layer called ________________consists of cardiac muscle and is the thickest layer of the heart wall
-myocardium
coronary arteries provide an intermittent, pulsating blood flow to_and are found_(layer of wall)
-myocardium -on epicardium
besides mitochondria, what else occupies the volume of cardiac cells?
-myofibrils composed of typical sarcomeres -sarcomeres contain Z discs, A bands, and I bands that reflect the arrangement of the thick (myosin) and thin (actin) filaments composing them
An ECG is a composite of all the action potentials generated by_(2)at a given time
-nodal and contractile cells
what are the 3 things that blood carries?
-oxygen -nutrients -wastes
the right side of the heart receives _(oxygen content) blood from _(where) and then pumps blood to_(where) to _(do what in this place). This circuit is called_
-oxygen-poor blood -body tissue -to lungs -pick up oxygen and dispel carbon dioxide -pulmonary circuit
the left side of the heart receives _(oxygen content) blood from _(where) and then pumps blood to_(where) to _(do what in this place). This circuit is called_
-oxygenated blood -lungs -throughout the body -supply oxygen and nutrients to body tissues -systemic circuit
As the ventricles contract, _______________ muscles contract, pulling on ____________________ and preventing the backflow of blood through the A-V valves.
-papillary muscles -chordae tendinae
list the 3 heart walls from most superficial to deepest
-pericardium -myocardium -endocardium
quiescent period
-period of time for heart relaxation
what are the 3 factors that affect stroke volume?
-preload -contractility -afterload
blood flow through the heart is controlled by _changes. explain
-pressure changes -blood flows down a pressure gradient through any available opening
what atrioventricular valves do?
-prevent backflow of blood into trai when the ventricles contracts
what can lead to myocardial infraction?
-prolonged coronary blockage
what are the functions of the fibrous pericardium? (3)
-protects heart -anchors it to surrounding structures -prevents overfilling of the heart with blood
These impulses rapidly spread through ____________ fibers into the walls of the ventricles and cause the ventricles to contract.
-pukinje fibers
right ventricle pumps blood into_, which routes blood to_(where and what happens here)
-pulmonary trunk -lungs where gas exchange occurs
Function of heart. How it achieves it?
-pump blood -by changing pressure by contracting (increase pressure in area, so blood wants to go to low pressure away from area) and relaxing (decreases pressure in area, so blood wants to go to that area)
cardiac cycle refers to what?
-refers to all events associated with blood flow through the heart -includes all events associated with the blood flow through the heart during one complete heartbeat
atrium_happens at the same time as ventricle_
-relaxation -contraction
the AV bundle splits into_, which course along the_toward_
-right and left bundle branches -interventricular septum -heart apex
tricupsid valve
-right atrioventricular valve -has 3 flexible cusps
pacemaker cells are found in which areas? (4)
-sinoatrial node -atrioventricular node -atrioventricular bundle -right and left bundle branches -subendocardial conducting network (pukinje fibers)
the characteristic rhythm of SA node is called_and determines_
-sinus rhythm -heart rate
How skeletal muscle fibers differ in function to cardiac muscle cells?
-skeletal muscle fibers are independent of one another both structurally and functionally -By contrast, the plasma membranes of adjacent cardiac cells interlock like the ribs of two sheets of corrugated cardboard at dark-staining junctions called intercalated discs
how cardiac muscle is different to skeletal muscle? (3) (5)
-skeletal muscle: long, cylindrical, multinucleate -cardiac: short, fat, branched, and interconnected. Each fiber has one or two large, pale centrally located nuclei
how the prasympathetic nervous system affects the heart?
-slows the heart
intercalated discs
-specialized connections between myocardial cells containing gap junctions and desmosomes -it connects one cardiac muscle cell to another cardiac muscle cell
what are the two systems involved in Extrinsic Innervation of the Heart and how affect heart?
-stimulated by the sympathetic cardioacceleratory center -inhibited by the parasympathetic cardioinhibitory center
blood enters the right atrium via 3 veins (list them and from where they return the blood)
-superior vena cava: returns blood from body regions superior to the diaphragm (deoxygenated blood) -inferior vena cava: returns blood from body areas below the diaphragm (deoxygenated blood) -coronary sinus collects blood draining from the myocardium (deoxygenated)
exercise affects heart rate through_nervous system
-sympathetic
what are the two main terms in cardiac cycle?
-systole -diastole
pulmonary circuit
-the blood vessels that carry blood to and form the lungs
systemic circuit
-the blood vessels that carry blood to and from all body tissues
In the myocardium, how the cardiac muscle cells are arranged?
-the branching cardiac muscle cells are tethered to one another by crisscrossing connective tissue fibers and arranged in spiral or circular bundles, effectively linking all parts of the heart together
explain what is the function of chordae tendinae along with papillary muscles?
-the chordae tendinae and the papillary muscles serve as guy-wires that anchor the valve flaps in their closed position -When AV valves close, the papillary muscles contract and chordae tendinae tighten, preventing valve flaps from everting into atria
cardiac skeleton (what it is comoposed of, what forms, what does)
-the connective tissue fibers form a dense network, the fibrous cardiac skeleton, that reinforces the myocardium internally and anchors the cardiac muscle fibers -prevents stretching of vessels and valves and limits the spread of action potentials to specific pathways of the heart
The visceral layer of the serous pericardium lines_
-the external heart surface
P-Q interval
-the interval in which it marks the beginning of ventricular excitation
what kind of relationship within the cardiac cells the Frank-Starling Law of the Heart takes into account? explain it
-the length-tension relationship -resting cardiac cells are shorter than optimal length, as a result, stretching cardiac cells can produce dramatic increases in contractile force -the most important factor stretching cardiac muscle is venous return, the amount of blood returning to the heart and distending the ventricles
in angina pectoris, what happens to myocardial cells?
-the myocardial cells are weakened by the temporary lack of oxygen but do not die
Q-T interval
-the period from the beginning of ventricular depolarization through ventricular repolarization
what allow the hearts to hold the contraction for a longer period of time?
-the plateau phase, in which calcium ions influx -calcium is a positive charged ion and maintains that lesser positive charge
base
-the posterior flat surface of the heart
the independent, but coordinated, activity of the heart is a function of what structures? (2)
-the presence of gap junctions -the activity of the heart's in-house conduction system, which is called the intrinsic cardiac conduction system
the right coronary artery courses to the right side of the heart, where it also gives rise to two branches:
-the right marginal artery serves the myocardium of the lateral right side of the heart -the posterior interventricular artery runs to the heart apex and supplies the posterior ventricular walls. near the apex of the heart, this artery merges (anastomoses) with the anterior interventricular artery -together the branches of the right coronary artery supply the right atrium and nearly all the right ventricle
what is the function of the serous fluid found in the pericardial cavity of the serous pericardium?
-the serous membranes, lubricated by the fluid, glide smoothly past one another, allowing the mobile heart to work in relatively friction free environment -decrease friction caused by the movement of the layers against one another
how the system to deliver calcium ions different in cardiac cells?
-the system for delivering Ca2+ is less elaborated in cardiac muscle cells -The T tubules are wider and fewer than in skeletal muscle and they enter the cell once pro sarcomere at Z discs (in skeletal muscle T tubules enter twice per sarcomere, at the A band-I band junction) -the cardiac sarcoplasmic reticulum is simpler and lacks terminal cisterns (Do not have triads)
P-R interval is _(what happens in the heart during it)
-the time from the beginning of atrial excitation (including contraction) to the beginning of ventricular excitation
what is the "autorhytmic" characteristic of cardiac cells?
-they are able to depolarize spontaneously and this pace the heart
how afterload affects stroke volume?
-they are inversely related -high afterload reduces the ability of ventricles to eject blood. Consequently, more blood remains in the heart after systole, increasing ESV, and reducing stroke volume
what the pukinje fibers do? (location, and what do)
-they complete the pathway through the interventricular septum, penetrate the heart apex, and then turn superiority into the ventricular walls -the bulk of the depolarization depends on the large fibers of eh conducting networks or pukinje fibers
the sympathetic postganglionic fibers innervate what parts of the heart? (4)
-they innervate the SA (make it fire more rapidly) and AV node, heart muscles (cardiac muscle cells themselves to have stronger muscle contraction), and coronary arteries
what is attached to the AV valve flaps? what do?
-tiny collage cords called chordae tendinae (heart strings), which anchor the cusps to the papillary muscles protruding from the ventricular walls
The right A-V valve is called the ________________ valve. The left A-V valve is called the __________ valve or mitral valve.
-tricuspid -bicuspid
in which veins there are no valves?
-vena cavae (inferior and superior) -pulmonary veins -three of them go into atria
Double-layered sac. The innermost layer of this sac immediately surrounds the heart and is called the ____________________ pericardium (also called _______________). At the base of the heart, this inner layer folds back on itself to become the ________________ pericardium. Between the layers of this sac is a potential space called the ______________ cavity and it is filled with _________ fluid.
-visceral pericardium -epicardium -parietal pericardium -pericardial cavity -serous fluid
what is different between left and right? (volume vs pressure)
-volume of blood pumped is the same in both side -pressure is different. The left side has greater pressure than the right side because it must overcome high resistance since it pumps blood through the body
when AV valves are open vs close?
-when the heart is completely relaxed, the AV valve flaps hang limply into the ventricular chambers below and blood flows into the atria and then through the open AV valves into the ventricles -when the ventricles contract, compressing the blood in their chambers, the intraventricular pressure rises, forcing the blood superiorly against the valve flaps. As a result, the flap edges meet, closing the valve
when the semilunar valves are open vs close?
-when the ventricles contract and intraventricular pressure rises above the pressure in the aorta or pulmonary trunk, the SL valves are forced open and their cusps flatten against the arterial walls as blood rushes past them -when the ventricles relax, and the blood (no longer propelled forward by ventricular contraction) flows backward toward the heart, it fills the cusps and closes the valves
If SA node is not working properly, can you live? explain
-yes, you can live -SA node does not active always, have some that disappear: have, have, no have, have have, no have, no have, etc -Still AV will work, but it will weaker
what are the 3 main events during cardiac cycle? Include their subevents within them
1. Ventricular filling (mid to late diastole): ventricular filling and atrial contraction 2. Ventricular systole (atria in diastole): Isovolumetric contraction phase and ventricular ejection phase 3. Early diastole: Isovolumetric relaxation
for the following, state whether it applies to skeletal muscle, cardiac muscle, or both: as troponin
Both
inadequate circulation results due to what disease?
Coronary artery disease (CAD)
end diastolic volume
EDV = amount of blood collected in a ventricle during diastole
end systolic volume
ESV = amount of blood remaining in a ventricle after contraction
what formula rules the flow of blood?
F=Pressure/resistance
bicuspid valve
-also called mitral valve -left atrioventricular valve -has 2 flexible cusps
conditions resulting from ischemia? (2)
-angina pectoris -myocardial infraction (MI)
_(2) semiluar valves guard the bases of the _and _(what do)
-aotric and pulmonary valves -large arteries issuing from the ventricles (aorta and pulmonary trunk respectively) -prevent backflow into the associated ventricles
Upper chambers of the heart are called ___________ and they _(what do). Below them, the thick-muscled ________________________ (name and what do).
-artrium -receive blood returning to the heart -ventricles -pump blood to the body and lungs
In an electrocardiogram, the first wave, the_ wave, corresponds to the _. The _ complex corresponds to the _ (2) The _waves ends the ECG pattern and corresponds to _
- P -depolarization of the atria -QRS -depolarization of ventricles and hides the repolarization of atria. -T -ventricular repolarization
the left coronary artery runs toward the left side of the heart and then divides into two major branches: (where they run and what parts supply blood)
- the anterior interventricular artery follows the anterior interventricular sulcus and supplies blood to the interventricular septum and anterior walls of both ventricles -circumflex artery supplies the left atrium and the posterior walls of the left ventricle
how cardiac muscle is similar to skeletal muscle? (2)
--striated -contract by sliding filament mechanism
what the calcium surge across the sarcolemma cause? what this appear as in the action potential tracing? what this prevents?
--what the calcium surge across the sarcolemma prolongs the depolarization potential briefly, producing a plateau in the action potential tracing -at the same time, few K+ channels are open, which also prolong the plateau and prevent rapid repolarization -As long Ca2+ is entering the cell, the cells continue to contract
gap junctions allow_, which make the heart to depolarize faster
-allow calcium ions to move from one cell to another
why at the AV node, the impulse is delayed? (function)
-allows atria to respond and complete their contraction before the ventricles contract
how calcium ions are used differently in cardiac muscle contraction?
-10-20 percent of calcium ions needed for the calcium pulse that triggers contraction enters the cardiac cells from extracellular space -Once inside, it simulates the SR to release other 80 percent of calcium ions needed -calcium ions are barred from entering nostimulating cardiac fibers, but when Na+-dependent membrane depolarization occurs, the voltage change also opens channels that allow calcium ions to enter from the extracellular space -These channels are called slow Ca2+ channels because their opening is delayed a bit -the local influenxes of calcium ions through the channels trigger opening of nearby calcium ions-sensitive channels in the SR tubules, which liberates bursts of calcium ions (calcium sparks) that dramatically increase the intracellular calcium ions concentration
P wave (what it is, how long it lasts, what happens in heart that causes it)
-1st small wave of ECG -lasts about 0.08 s -results from movement of depolarization wave from the SA node through the atria
heart has _(#) receiving chambers. how they are named?
-2 -right atrium and left atrium
the heart has_(#) pumping chambers. how they are named?
-2 -right ventricle and left ventricle
QRS complex (what it is, what happens in heart that causes it, precedes what action, why has this shape)
-2nd wave of ECG -results from ventricular depolarization and precedes ventricular contraction -it has complicated shape because of the paths of the depolarization wave through ventricular walls, producing corresponding changes in current direction
how many cusps semilunar valves have?
-3 pocketlike cusps
blood enters the left atrium via veins, list them
-4 pulmonary veins enter the left atrium with oxygenated blood from lungs
what ensures the one way traffic of blood within heart? how they do that?
-4 valves -they open and close in responses to differences in blood pressure
how coronary arteries receive their blood (physiology description)?
-At base of aorta, right above aorta semilunar valves, there is two holes -when blood goes through aorta, then heart relax and blood goes back -blood go through the holes, which are called coronary arteries and are part of the coronary circulation, gives the heart its blood -Heart gets blood when it relaxes its left ventricle
what causes blood to move?
-Blood is moved due to changes in pressure -increase pressure in one area, the blood will move to an area with less pressure
what they refer: conduction system vs contraction system?
-Conduction system: impulses, nerves, bringing info and stimulating the heart -Contraction system: the heart contracting
electrocardiogram abbreviations? (2)
-ECG -EKG
what are the two variables that help to determine cardiac output?
-Heart rate is the number of heart beats per minute (beats/min) -Stroke volume (ml/beat) is the amount of blood pumped out by a (1) ventricle with each beat
List three main characteristics of the contraction of cardiac muscle contraction (how sitmulated, how contracts, and duration)
-Is stimulated by nerves and is self-excitable (automaticity) -Contracts as a unit -Has a long (250 ms) absolute refractory period
Describe the location of pulmonary semilunar valve
-It is found between right ventricle and pulmonary trunk leading to lungs
describe what each of the 2 heart sounds are made by
-Lub: First sound occurs as AV valves close and signifies beginning of systole -Dup: Second sound occurs when SL valves close at the beginning of ventricular diastole
Bruce Theory of the heart
-Normal heart takes 75 beats per min -if can low resting beats, you will get more heart beats, you will live longer because have extra heart beats
list the interval and segments found in the electrocardiogram (4)
-P-R interval -P-Q interval -S-T segment -Q-T interval
The heart is located in _cavity within the _ area within the _(greater cavity) cavity
-Paracardial -mediastum -thoraxic
Frank-Starling Law of the Heart
-Preload, or degree of stretch, of cardiac muscle cells before they contract is the critical factor controlling stroke volume
A self-exciting mass of specialized cardiac muscle called the __________________ node (or pacemaker) is located on the _ and generates the impulses for heart contraction. This node_(what does)
-Sinoatrial (SA) node -posterior right atrium - initiates impulses that spread throughout the myocardium and is self-exciting (-it does not require a signal from the nervous system).
List the steps of cardiac cycle in simplified manner (not in order) (3)
-The cardiac cycle consists of (1) the atria beating in unison (atrial systole), (2) the contraction of both ventricles, (ventricular systole), and (3) the entire heart relaxes for a brief moment (diastole).
serous pericardium
-a thin, slippery, two-layered serous membrane that forms a closed sac around the heart
describe the fundamental difference between heart muscle and skeletal muscle: length of absolute refractory period
-absolute refractory period is the inexcitable period when Na+ channels are still open or inactivated -in skeletal muscle fibers, contracts last 15-100ms with brief refractory periods -cardiac muscle cells, in which absolute refractory periods last over 200 ms, nearly as long as the contraction. The long cardiac refractory period normally prevents tetanic contractions, which would stop the heart's pumping action
Parasympathetic nervous system (PNS) stimulation is mediated by _(agent) and _(relation with other autonomic nervous system)
-acetylcholine -opposes the SNS
end systolic volume (ESV)
-after ventricular contraction and when ventricles start to relax after T wave, the remaining blood in their chambers
list the 7 detailed steps of cardiac cycle
1. Blood low in oxygen returns to the right atrium via the venae cavae (superior and inferior) and coronary sinus. 2. The right atrium contracts, forcing blood through the tricuspid valve into the right ventricle. 3. The right ventricle contracts, closing the tricuspid valve, and forcing blood through the pulmonary valve into the pulmonary trunk and arteries. 4. The pulmonary arteries carry blood to the lungs where it can rid itself of excess carbon dioxide and pick up a new supply of oxygen. 5. Freshly oxygenated blood is returned to the left atrium of the heart through the 4 pulmonary veins. 6. The left atrium contracts, forcing blood through the left bicuspid valve (mitral valve) into the left ventricle. 7. The left ventricle contracts, closing the bicuspid valve (mitral valve) and forcing open the aortic valve as blood enters the aorta for distribution to the body.
List the steps of the action potential of contractile cardiac muscle cells (3)
1. Depolarization is due to Na+ influx through fast voltage-gated Na+ channels. A positive feedback cycle rapidly opens many Na+ channels, reversing the membrane potential. Channel inactivation ends this phase. 2. Plateau phase is due to Ca2+ influx through slow Ca2+ channels. This keeps the cell depolarized because few K+ channels are open. 3. Repolarization is due to Ca2+ channels inactivating and K+ channels opening. This allows K+ efflux, which brings the membrane potential back to its resting voltage.
state the steps in the sequence of depolarization and repolarization of the heart related to the deflection waves in the ECG tracing (6)
1. P wave: atrial depolarization, initiated by the SA node 2. with atrial depolarization complete, the impulse is delayed at the AV node [point between P and Q] 3. ventricular depolarization begins at apex, causing the QRS complex. Atrial repolarization occurs 4. Ventricular depolarization is complete [between S and T] 5. Ventricular repolarization begins at apex, causing the T wave 6. Ventricular repolarization is complete [after T wave]
rate cardiac pacemaker cells of spontaneous depolarization from fastest to slowest
1. SA node 2. AV node 3. AV bundle
List the detailed steps of Blood Supply to the Heart pathway (4)
1. The first branches off of the aorta, which carry freshly oxygenated blood, are the right and left coronary arteries that feed the heart muscle itself. 2. Branches of the coronary arteries feed many capillaries of the myocardium. 3. The heart muscle requires a continuous supply of freshly oxygenated blood, so smaller branches of arteries often have anastomoses as alternate pathways for blood, should one pathway become blocked. 4. Cardiac veins drain blood from the heart muscle and carry it to the coronary sinus, which empties into the right atrium. (deoxygenated blood)
the relationship between preload and stroke volume is described by the following law_
Frank-Starling Law of the Heart
when the heart gets blood?
Heart gets blood when it relaxes its left ventricle
_concentrations must be maintained for normal heart function
Intra- and extracellular ion concentrations must be maintained for normal heart function
During the cardiac cycle, there are two periods when all four valves are closed. Name the two periods
Isovolumetric contraction Isovolumetric relaxation
The P wave of a normal electrocardiogram indicates ________.
atrial depolarization
Impulses from the S-A node quickly spread throughout the atria and cause them to contract. Impulses also spread to the ______________ node.
atrioventricular node (AV)
