chapter 20 pt. 2

the 3 BV coming into the RA

• SVC, IVC, pulmonary veins??

3 major openings in the RA to receive blood

• IVC, SVC, coronary sinus

aorta

• biggest artery; thick walls

• blood vessels go to these walls

  • holes in the wall (big enough to see with naked eye)

• blood vessel that has blood vessels

vaso vasorum

• small vessels that supply larger vessels (arteries and veins) in their walls

coronary arteries

• arteries that go to the heart

• run along the coronary sulcus of the myocardium

  • main fcn: supply heart with blood

coronary shunt

???

• when blood clors

• life-threatening because blood can’t go to heart?

cardiac veins

• returns deoxygenated blood from the myocardium to the right atrium

amniotic sac

• fluid filled sac that contains and protects a fetus in the womb

what oxygenates embryo

• the mother, NOT the lungs

• vessels in the umbilical cord

• blood coming to fetal heart is already oxygenated because of mother

lungs role in fetal circulation

• do not oxgetnate blood

• still need the blood circulating the lungs for those to develop

the two structures that allow the fetal circulation to bypass the lungs

• foramen ovale

• ductus arteriosus

foramen ovale

• hole between RA/LA - exists before developing

• the atriums don’t need to be separated because all blood is oxygenated

• naturally forming hole - should close after birth

  • teens-20s

  • should happen when young, but not as early as we think

• athletes get physicals b/c big risk to still have this

• BECOMES fossa ovalis - depression in RA

ductus arteriosus

• duct/tube between two ARTERIES (aorta and pulmonary artery)

• most blood needs to go to the body; does that through here

• becomes a ligament - blood can no longer go from pulmonary artery to aorta

• PDA

when babies scream at birth

• forces lungs to open up, closes ductus arteriosus

patent ductus arteriosus (PDA)

• when the DA doesn’t close - not life-threatening because babies don’t do much

• can hear blood flowing through on stethoscope

• needs to be fixed immediately (contrary to foramen ovale)

umbilical

• connects baby to fetal placenta

umbilical vessels

• how mom oxygenates blood

  • on the fetal side of the placenta

  • mothers vessels found in the uterus

• carry blood back and forth to placenta

umbilical veins

• mom’s half

• brings blood to heart via. belly button

• have high O2 concentration - good it from mom

• umbilical vein carrying oxygenated blood with nutrients from the placenta to the fetus

• BYPASS LIVER

main function of liver before birth

• makes blood cells (before bone marrow is needed)

ductus venosus

• becomes ligment

umilical arteries

• fetal side relative to the heart

• leaving fetal heart → placenta (where waste products delivered to mom; she pees them out)

2 circulations

• pulmonary (to lungs)

• systemic (to heart)

• 2 sides; separate, however, 2 atria beat together, 2 ventricles beat together

  • because electrical)

cardiac muscle

• striated; auto-rhythmic

• stimulates itself to start action potentials

• electrically, cardiac muscle of the atria and ventricles behave as a single unit

CPR

• chest compressions are first step because we are “touching the heart”

  • physically stimulates it to start breathing on your own

intercalated discs

• cellular connection that allow the heart to send APs from one cell to another without a NT in between

conduction path of heart

• SA node → AV node → AV budle → R/L bundle branches → purkunje fibers

• measured by EKG/ECG

sinoatrial node

• pacemaker of heart; starts conduction pathway

• located on medial side of RA

• internal stimulus, acts faster than rest, why it is start

electrocardiogram

• written recording of electrical path of AP going through heart

• 12 leads, we only use one (lead 2)

• you can have something wrong with your heart but normal ekg, or vise versa

how is NS involved in heart beat

• doesn’t stimulate heart to beat (autorhythmic)

• just tells heart to beat faster/slower

refractory period

• occurs between APs

• 2 types

  • absolute and relative

relative refractory period

if stimulus is strong enough, AP can happen earlier in the relative refractory period

absolute refractory period

• np matter how strong the stimulus, it will happen at the same time

• to give the heart a break → needs to be a time delay so blood can move through order (atria contract, then ventricles contract)

  • allows blood to fill chambers

P-wave

• atrial depolarization

QRS complex

• ventricle depolarization

• happens at the same time as atrial repolarization, so can’t screen for AR in this lead

T wave

• ventricular repolarization

cardiac cycle; 2 parts

• systole

• diastole

systole

• the contraction - emptying chambers of blood

  • atrial systole and ventricle systole

diastole

• the relaxation and filling chambers with blood

heart is muscle

• needs to be exercised like skeletal muscle!

• more trained, better cardiac cycle

lub

• atrioventricular valves closing

dub

• semilunar valves closing