The Heart Flashcards
The heart is no more than
a transport system pump.
Blood vessels are
the delivery routes for the heart
right side of the heart receives
oxygen-poor blood and pumps it to the lungs to get oxygen.
The left side of the heart receives
the oxygenated blood returning from the lungs and pumps this blood out to the rest of the body.
The heart has two receiving chambers
right atrium and left atrium
The heart has two main pumping chamgers
right ventricle and left ventricle
The medial cavity of the thorax that encloses the heart
the mediastinum
Apex of the heart is located where and does what
apex is the most inferior portion of the heart and can be felt beating in the chest.
Pericardium
A double walled sac that encloses around the heart.
endocardium
third layer of the heart wall. It is white sheet of endothelium which is a layer of simple squamous epithelial cells.
Atria
3 vessels that bring deoxygenated blood back to the heart and into the right atrium
Superior Vena Cava
one of the three vessels that bring deoxygenated blood back to the heart. it drains the head and neck
inferior vena cava
one of the three veins that bring deoxygenated blood back to the heart. It drains the lower body.
Coronary sinus
one of the three vessels that bring deoxygenated blood back to the heart. drains the heart muscle itself
Most superior portion of the heart
the base
The role of All valves
To prevent backflow.
the way that valves open and close are due to
pressure
chrodae tendinae
Heart strings. they anchor the valve
cardiac muscle cells are always in ABSOLUTE refractory, why?
it cannot respond to a second stimulus until the first actions potential is completely done.
if the heart is contracting and it was hit with a second stimulus and didn’t let the cells relax, it wouldn’t be able to fill for the next cycle. Need to be able to receive as well as pump. To prevent Teutonic contraction
The P wave represents
depolarization of the atria and is followed by atrial contraction (systole)
The QRS complex on the surface ECG represents
ventricular depolarization. Contraction (systole) begins after an approximately 50 ms delay and results in closure of the mitral valve.
Diastole
Period of the cardiac cycle when either the ventricles or the atria are relaxing.
systole
Period when either the ventricles or the atria are contracting.
Cardiac Cycle
all events associated with the blood flow through the heart during one complete heart beat. atrial systale and diastole followed by ventricular systole and diastole.
stroke volume
How much blood comes out of the left ventricle in one beat and goes to the AORTA.
cardiac output
the amount of blood pumped out by each ventricle in 1 minute.
end diastolic volume
the amount of blood that collects in a ventricle during diastole
end systolic volume
the volume of blood remaining in a ventricle after it has contracted
How is the stroke volume determined?
The difference between EDV and ESV
SV=EDV−ESV=120mlbeat−50mlbeat=70mlbeat
route of blood flow thru the heart
Right side - Deoxygenated blood enters heart through the SVC, IVC and coronary sinus and fills right atrium, through tricuspid valve into right ventricle, through pulmonary semilunar valve enters the pulmonary trunk goes from pulmonary artery to the lungs to get oxygen From the lungs pulmonary veins carry blood back from lungs and into left atrium, through mitral valve and into left ventricle, through aortic semi-lunar valve and into the aorta. blood then goes out to the rest of the body.
epicardium
The outer layer or The visceral layer of the serous pericardium
myocardium
The middle layer of the heart wall. composed mainly of cardiac muscle and forms the bulk of the heart.
pectinate muscles
muscle bundles in the right atria that look like little ridges of the myocardium.
What is the correct order of conduction system
SA node, AV node, AV bundle, bundle branches, purkinje fibers
EKG records what to bits of information
heart rate and electrical currents through the heart
what are the 3 typical ekg waves
PQRST
P wave
results from atrial depolarization
QRS complex
Atrial repolarization and ventricle depolarization.
T Wave
cased by ventricular re-polarization.
P-R interval
the time from the beginning of atrial excitation and the beginning of ventricular excitation.
how do epinephrine and norepinephrine effect the heart?
epi and norepi enhances heart rate and contractility.
vasoconstriction
narrowing of blood vessels
What’s the difference between arteries and veins
Arteries are blood vessels that conduct blood away from the heart and veins are blood vessels that return blood towards the heart
As the Sympathetic Nervous system is stimulated what happens to the heart?
Heart rate goes up
As the Para Sympathetic Nervous system is stimulated what happens to the heart?
Heart rate decreases
Frank-Starling Law of the Heart
what goes in, comes out. if you put more blood in, it will pump more blood out.
explain cardiac cycle
- ventricular filling, mid to late diastole 2. ventricular systole (atria in diastole) 3. isovolumetric relaxation; early diastole
iso-volumetric contraction
Ventricles - all valves closed. no blood enters or exits the ventricles. There is an increase in ventricular pressure.
iso-volumetric relaxation
No blood goes in or out. early diastole. T wave. ventricular pressure drops rapidly and blood in the aorta and pulmonary trunk flows back into the heart. decrease of pressure.
dicrotic notch
Due to the backflow of blood from the aorta, a small, brief increase in blood pressure as the valves close
heart sounds lub
sound of the av valve closing
heart sounds dub
sound of the semilunar valve closing
why is SA node the pacemaker
Highest number of action potential per minute than any place in the body. continuously generates electrical impulses, thereby setting the normal rhythm and rate in a healthy heart
thickness of left ventricular wall
Needs to be extra strong to send the blood out to the rest of the body. the right ventricular wall is smaller because it only needs to pump to the heart.
Increased pressure in the ventricles would close what valve(s)?
AV valves
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
isovolumetric contraction, ventricular ejection, isovolumetric relaxation
What causes the aortic semilunar valve to close?
greater pressure in the aorta than in the left ventricle
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.
Pressure in the atria would be greater than the pressure in the ventricles.
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
Ventricular Diastole
cardiac output equals
Heart rate times stroke volume
Which of the following would increase cardiac output to the greatest extent?
increase heart rate and increase stroke volume
Which of the following would increase heart rate?
epinephrine and norepinephrine
How would an increase in the sympathetic nervous system increase stroke volume?
increased contractability
How would a decrease in blood volume affect both stroke volume and cardiac output?
decreased stroke volume and no change in cardiac output
trabeculae carnae
branching muscled of the myocardium in the ventricles.
rapid ejection
valves are open
When blood leaves the heart it goes to two places
right side through the pulmonary trunk and into lungs aAND into the aorta and out to the body.
action potential of cardiac muscle compared to skeletal muscle
cardiac muscle has a longer action potential because it has a plateau face that we don’t see in skeletal muscle and it is a prolonged depolarization due to calcium.
which side of ventrical wall is thicker
left
you get your arm in a chippper, you have
low blood volume, low blood pressure, body senses this with the barroreceptors, stress receptors int he aortic arch and carotid arteries towards the head. they are stretch receptors. Baroreceptros have less stretch because there is less blood due to hemorage. They will have less action potentials, cv center and vasomotor to medula. increase in sympathetic stimulation. It will effect the cardiac nerve to the heart and sympathetic nerves to the blood vessels. Heart will increase heart rate. typical negative feedback. norepinephrine will open up calcium channels. Incrase in contractiliyt, stroke voume goes up, cardiac output goes up and output. smooth muscle cells - increase in vosconstrictions, smooth muscle cells will contract which will push the blood forward. increase in peripheral resistance and increase in venous return. Also stimulates the adrenal medula. 80% epinephrine and 20% noepinephrine. they do the same thing. increase heartrate and contractility and increase in vasoconstriction. leads to blood pressure.
when hemorage happens, blood pressure goes up and vasoconstriction happens except in
skeletal muscle which vasodialation
when you have an increase in sympathetic activity
you have a decrease in parasympathetic activity.
with arm in chipper we will have an increase of hormones ADH, Aldosterone, angiotensin II, that will
increase water reabsorbtion back into the blood so that you will make less urine.
Angiotensine II
is a potent vasoconstrictor.
