Cardiac Flashcards
what covering tissue has most nerves?
parietal layer
what kind of tissue makes up the endocardium?
simple squamous
where does SVC drain from?
above the diaphragm
where does IVC drain from?
below the diaphragm
where does the coronary sinus drain from?
the heart itself
what are the muscles in the ventricles called?
trabeculae carneae
what are the muscles in the atria called?
pectinate
what is the fibrous skeleton?
site for anchoring of cardiac muscle (base)
not electrically excitable
support for great vessels and valves
what is endocardial cushion defect?
cardiac muscle doesn’t form properly and the fetus has mixed blood heart pumping
what is the purpose of the auricles of the atria?
blood reservoir
what is an interatrial septum?
fuses together after birth
what is cristae terminales?
c-shaped ridge that separates the atria
what is the fossa ovalis?
where the foramen ovale used to be (in between atria)
what is the pressure in the RV?
25 mmHg
what is the pressure in the RA and LA?
8 mmHg
what is the most common congentical defect?
ventricular septal defect (VSD)
how does a VSD pt present?
high pitched murmur
bad peripheral tissue perfusion
congestive heart failure (the system gets disrupted)
when do coronary arteries fill?
diastole
leaflets of aortic valve cover up the coronary arteries in systole
what is the biggest cerebral artery?
middle cerebral
what does coarctation mean?
narrowing
what is tetralogy of fallot?
large VSD, stenosed pulmonary valve, aorta emerges from both ventricles, right ventricle hypertrophy due to stenosed pulmonary valve
what is transposition of great vessels?
RV is connected to aorta and LV is connected to pulmonary trunk
where do coronary arteries branch off?
ascending aorta
where is AV node located?
above tricuspid valve in RA
what is the resting potential for a myocardial cell?
-90 mV
what inflows to myocardial cell when it plateaus?
K outflow and Ca inflow
what is the third phase of myocardial cells excitation?
Ca channels close and K outflow continues
why is the refractory period important in the heart?
you don’t want the heart cells to fire at will (it lasts almost as long as the cardiac cell cycle)
does the SA node have a resting phase?
no, it goes to -60 and then depolarizes again
what type of junctions do cardiac cells have?
desmosomes and gap junctions
what are imbedded in the plasma membrane?
Ca ion channels
what is functional syncytia?
cardiac muscles contract as a unit or not at all
-gap junctions facilitate this
what happens when myocardial tissue is infarcted?
troponin levels rise
how much of the Ca comes from EC space?
20%
-opening of channels is triggered by opening of Na channels
what sources of energy can the heart use to produce ATP?
glucose, fatty acids and lactic acid
the rising phase of the action potential in the SA node is due to what?
the rapid entry of Calcium (NOT sodium)
where are the cardiac centers located?
medulla oblongata (cardioacceleratory, cardioinhibitory)
what affect does sympathetic nervous system have on heart rate?
increase both heart rate AND contractility
what affect does parasympathetic nervous system have on the heart?
decreases heart rate HAS NOT IMPACT ON contractility
which thoracic vertebrae innervate the heart?
T1-T5
what does the P represent?
depolarization wave from the SA node through the atria (contraction of atria)
what does the QRS complex represent?
depolarization from AV node to purkinje fibers followed by ventricular contraction
what does the PR (PQ) interval represent?
delay between SA node and AV node
what does the T wave represent?
ventricular repolarization
what is 1st degree heart block?
prolonged PR interval
what can cause a large R wave?
ventricular hypertrophy
what does the QT interval represent?
beginning of ventricular depol through ventricular repol
what does the ST segment represent?
myocardial ischemia, MI would show a big ST elevation
how might T wave change with MI?
T wave inversion
what is QT syndrome?
causes a dysrhythmia when provoked by certain medications
what is inotropic?
having to do with contractility
what is chronotropic?
having to do with rate of heart beat
