Lecture test #1- chapter 20 Flashcards
how do atrium contract?
from top down
what are the great vessels?
blood vessels that are connected to one of the heart’s chambers
what extrinsic regulation?
organ is controlled by another organ system
what do people say about autorhythmic cardiac muscle that isn’t true?
that they “spontaneously depolarize” and are an “unstable cell membrane”
the amount of stretching in ventricle wall before contraction (systole)
preload
what does loose sr-t-tubule cause?
a slower action potential than skeletal muscle
what is the second thing that cardiac muscle has that skeletal muscle doesn’t
loose SR-t-tubule connections
what is the second step of the cardiac cycle?
ventricular systole (period of isovolumetric contraction)
what is the average mass of the human heart?
250g in females and 300g in males
what do you see with a ventricular fibrilation?
no P, QRS or T waves
contraction of a chamber
systole
when blood is flowing out of the left ventricle what is happening with the aortic semilunar valve/
it is open and the cups of the valve are pushed by the blood toward the aorta
how does the heart regulate blood supply?
the rate and force of heart contractions change to meet metabolic needs of the tissue
where can the 3rd heart sound be detected?
near the end of the first one-third of diastole during passive ventricular filling
what is happening with a heart murmur?
the mitrovalve snaps shut and flutters
what is a hypothesis as to why trabeculae and pectinate muscles are there?
to form lines to help direct flow of blood or to create turbulance in blood to regulate BP
what happens third during the conducting system?
AV bundle divides into right and left bundle branches and action potentials descend to the apex of each ventricle along the bundle branches
what is normal to have right under the epidcardium?
a little connective tissue
when blood is flowing out of the left ventricle what is happening with the bicuspid vavle?
it is closed and the cups of the valve overlap as they are pushed by the blood toward the left atrium
what is another name for the triscuspid valve?
right atrioventricular valve (AV)
how long does it take to go from the start at the SA node down the middle of the AV node?
.13 seconds
what do you see on a ECG with a premature ventricular contraction?
no P waves precede PVCs
what is the 3rd step of the cardiac cycle?
ventricular systole (period of ejection)
how much of cardiac muscle do autorhythmic cardiac muscle take up?
about 1%
which layer of the pericardium does the blood go into the heart?
in the endocardium
which valves separate the atrium from the ventricles?
triscupid and mitral valves
what does the anterior side of the heart lie up against?
the sternum
what do you see with an atrial fibrilation?
no clear P waves and rapid QRS complexes
what is the white valves on the heart model?
collagen
when is the heart generally larger?
in phyisically active males
which cardiac muscle determine when all muscles depolarize?
the 1st one (SA node) (pacemaker)
where does the serous membrane, visceral layer lie?
up against teh organ
what do we call an extra or abnormal heart sound?
a heart murmur
how much blood came out a ventricle
stroke volume (SV)
what happens second during the conducting system?
they pass through AV node along the AV bundle
where is the pericardial layer, the parietal layer located?
furthest away from the organ
what are the chordae tendineae?
collagen tendon chords
what does the metabolic needs of the tissue of the heart depend on?
conditions such as rest, exercise and changes in body position
what does ACh do?
make HR go down
what does the T wave represent?
ventricular repolarization
what do you see on an ECG with a bundle branch block?
prolonged QRS complexes
what is happening during a fibrulation?
cardiac cells are contracting independently (heart shakes, not pumping)
what does the p wave represent?
depolorization of atrium (atrial depolarization)
electrically speaking how does cardiac muscle behave?
as a single unit (all for one and one for all)
what type of gated ion are gap junctions?
non gated (open all the time)
what is the first sound you hear when listening to the heart?
the AV valve closing
what is the 4th step of the cardiac cycle?
ventricular diastole (period of isovolumetric relaxation)
where does the first sound of the heart occur?
at the beginning of ventricular systole
what is an influence for preload?
more blood= more stretching (EDV)
what generates blood pressure?
contractions of the heart
why is pericarditis very problematic?
reduces the ability to avoid friction between the heart and the sternum
where are pectinate muscles found?
in the atrium, usually the right atrium
the volume of blood in each ventricle at the end of diastole (normal value=125ml)
EDV (end diastolic volume)
where is the heart located?
right behind the sternum in the inferior mediastinum
the force of pressure that must be overcome for blood to leave the ventricle
afterload
what is the first heart sound caused by?
vibration of the AV valves and surrounding fluid as the valves close
what happens last during the conducting system?
they are carried by purkinje fibers from bundle branches to ventricular walls and papillary muscles
what is occuring during ventricular systole (period of isovolumetric conraction)? (4) (ABVS)
1) atria are relaxed
2) blood flows into atria from the veins
3) ventricular contraction causes ventricular pressure to increase and causes AV vavlve to close
4) semilunar valves remain closed
how does the heart route blood?
it separates the pulmonary and systemic circulations
what does the semilunar valves not have?
chords or papillary muscles
what are 2 example of extrinsic regulation of the heart?
1) nervous system
2) endocrine system
where does the posterior side of the heart rest on?
the vertebral bodies
what does the Frank-starling law represent?
more in=more out
what do you see on an ECG with a complete heart block (third degree AV node block)?
p waves and QRS complex are not coordinated
where is the in inferior mediastinum?
in the thoracic cavity, behind the sternal attachment of ribs 2-6
what is the 3rd heart sound caused by?
blood flowing in a turbulant fashion into the ventricles
what happens first during the conducting system?
action potential originate in SA node and travel across the wall of the atrium from SA node to AV node
what causes the second heart sound?
closure of the aortic and pulmonary semilunar valves.
what stops a fibrulation?
a defibrulator
what is the 5th step of the cardiac cycle?
ventricular diastole (passive ventricular filling_
how much of the heart is made up of myocardium?
95%
what is the first sound of the heart heard?
a low pitched-sound described as “lubb”
what does instrinsic mean?
the heart will run at SA pace more than 80 bpm
what do valves prevent?
backflow
what happens at the SA node that allows everyone to follow?
the shortest time interval and depolarizes close to 100 times/minute and sets pace for entire myocardium
what is occuring during atrial systole? (3) (AIC)
1) atria contract
2) increasing atria pressure
3) completing ventricular filling while ventricles are relaxed
which myocardial wall is thicker the ventricle or atrium?
ventricle
what doe we call the parietal layer?
the fibrous pericardium
what does the endocardium have?
a bunch of modifications
relaxation of a chamber
diastole
why will a channels depolarize at a given time?
because of leak channels
what is the function of the serous fluid?
to hold the organ in place and reduce friction between neighboring organs
what are 2 more endocardial modifications?
1) pectinate muscles (musculi pectanati)
2) trabeculae
how does calcium differ between cardiac and skeletal muscle?
for skeletal muscle almost all calcium involved comes from the sarcoplasmic reticulum and in cardiac muscle about 20% comes from outside the cell and 80% from the sarcoplasmic reticulum
what sets the pace?
the SA node (pacemaker)
what are 2 changes that occur with stroke volume?
preload and afterload
what does the QRS complex represent?
ventricular depolarization
what is pericarditis?
infection or inflammation of the pericardium
how do ventricles contract?
from bottom up
what does the connective tissue do for the epicardium?
holds the coronary vessels in place
what does the separation of the pulmonary and systemic circulations ensure?
better oxygenation of the blood flowing to the tissues
where is the base of the heart?
the widest space on top with the greatest vessels gong in and out (superior to the mediastinum)
what does the presence of collagen in the coronary sulcus cause?
it can’t carry an action potential
what are valves known as?
endocardial modifications
what is the second sound of the heart heard?
a higher-pitched sound often described as “dupp”
what does cardiac muscle have that skeletal muscle doesn’t have?
intercalated discs
what sound do we hear when listening to the heart?
closing of the valves
when blood is flowing into the left ventricle what is happening with the biscupid valve?
it is open and the cusps of the valve are pushed by the blood into the ventricle
what is the order of blood flow?
1) superior and inferior vena cava
2) right atrium
3) tricuspid valve
4) right ventricle
5) pulminary semilunar valves
6) pulmonary trunk
7) pulmonary arteries
8) lungs
9) pulmonary veins
10) left atrium
11) bicuspid (mitral valve)
12) left ventricle
13) aortic semilunar valve
14) aorta
15) whole body
what is a possible cause of a Atrial fibrilation?
Ectopic action potentials in the atria
what is a possible cause of a premature ventricular contraction? (5) (ELTIO)
1) ectopic foci in ventricles
2) lack of sleep
3) too much caffeine
4) irritability
5) occasionally occurs with coronary thrombosis
what is a valve for?
they allow something to pass through and in almost all circumstances in ONE direction
what does the parietal layer have?
a bunch of collagen fibers
where are papillary muscles?
at the bottom of the chordae tendineae
when blood is flowing into the left ventricle what is happening with the aortic semilunar valve?
it is closed and the cups over lap as they are pushed by the blood in the aorta toward the ventricle
what affects cardiac output?
changes in HR and stroke volume
what 2 other endocardial modifications allow blood to leave the heart?
1) chordae tendineae
2) papillary muscles
what is occuring during ventricular systole (period of ejection) (3) (CCC)
1) continued ventricular contraction
2) causes a greater increase in ventricular pressure which pushes blood out of the ventricles
3) causes semilunar valve to open
what is the second sound you hear when listening to the heart?
the semilunar valve snapping closed
what is ocurring during ventricular diastole (period of isovolumetric relaxation)? (2) (AA)
1) as the ventricles begin to relax, blood flowing back from the aorta and pulmonary trunk toward the relaxing ventricles causes the semilunar valves to close
2) AV valves are closed
what is the epicardium also know as?
the visceral pericardium
where does the second sound of the heart occur?
at the beginning of ventricular diastole
what is the 3rd heart sound heard?
a faint sound heard in some normal people particularly the thin and young
what are pectinate muscles and trabeculae?
ridges and irregularities
what is occuring during ventricular diastole (passive ventricular filling)? (2) (AB)
1) as ventricular relaxation continues, the AV valves open
2) blood flows from the atria into relaxing ventricle accounting for most of the ventricular filling.
which 2 layers of the pericardium are simple squamous epithelium?
epicardium and endocardium
what is a possible cause of a complete heart block?
ischemia of AV nodal fibers or compression of AV bundle
after the AV node what happens?
it pauses for about .1 seconds
where is the apex of the heart?
the bottom, rests on diaphragm
what is the shape and size of the adult heart?
it’s shaped like a blunt cone and approximately the size of a closed fist
what is a possible cause of a ventricular fibrilation?
ectopic action potentials in the ventricles
what is another name for the bicuspid valve?
mitral or left atrioventricular valve (AV)
which ventricular myocardial wall is thicker?
left
what is blood pressure responsible for?
moving blood through blood vessels
what are the intercalated disks made up of?
desmosomes and gap junctions
what is the mediastinum?
the space between the 2 lungs
if you wait long enough what will happen to cardiac muscle?
it will contract
what is the myocardium made up of?
cardiac muscle cells
where are trabeculae found?
hills and vallies when in ventricles
what are the functions of the heart? (4) (GRER)
1) generating blood pressure
2) routing blood
3) ensuring one-way blood flow
4) regulating blood supply
when does the heart generally decrease in size?
after approximately age 65, especially if not physically active
what is a gap junction?
ion channel between 2 neighboring cells
why is the QRS complex bigger?
because it has more cardiac muscle cells
where does atrial repolarization occur?
in the middle of the QRS complex (not supposed to be seen on ECG)
why do the semilunar valves not need chords and papillary muscles?
because there’s only a pump on one side rather than 2
through gap junctions what happens next?
sweeps through myocardium to AV node
how fast does it go from SA node to AV node?
.03 seconds
what is the first step of the cardiac cycle?
atrial systole (active ventricular filling)
what is other sound you hear when listening to the heart?
blood turbulence
what does the pericardium help with?
friction of the heart
what is intrinsic regulation?
when the organ controls itself
volume of blood ejected from ventricle in one minute
cardiac output (CO)
volume of blood in ventricle at the end of systole (normal value=55 ml)
ESV (end systolic volume)
what sounds do muscle fibers make of the heart?
no sound
how is blood supplied to the myocardium?
by the coronary arteries
what is the function of the coronary vessels? (3) (BFS)
1) bring oxygen and nutrients
2) feed the myocardium
3) supply the heart with its blood supply
what is the structure of muscle cells? (4) (SB1I)
1) striated
2) branched (maybe)
3) 1-2 nuclei
4) intercalated disks
what provides energy for cardiac muscle cell?
ATP
what does ATP production depend on?
oxygen availability
