First Aid Flashcards
Where does fetal erythropoiesis occur?
Yolk sac | 3-8 wks
Liver | 6 wks - birth
Spleen | 10-28 wks
Bone Marrow | 18 wks to adult
What is fetal hemoglobin composed of?
α2 γ2
What is adult hemoglobin composed of?
α2 β2
Why does HbF have a higher affinity for oxygen?
Less avid binding of 2,3-BPG (left shift)
Where in the fetal circulation is there the highest concentration of O2
Umbilical vein
Starting in the umbilical vein, trace the flow of O2
Umbilical vein → Ductus venosus → IVC → RA → foramen ovale → LA → Aorta → Body
In the fetal circulation, deoxygenated blood flowing into the SVC goes where?
RA→ RV → main PA → patent ductus arteriosus → descending aorta
What causes the foramen ovale to close?
1st breath → ↓resistance in pulmonary vasculature → LAP>RAP
What causes the ductus arteriosus to close?
↑O2 (respiration) + ↓ prostaglandins (placental separation)
What drug can be used to close a PDA? To keep it open?
Indomethacin PGE (E1 and E2)
What is the fetal structure that turns into the ligamentum teres hepatis, contained in the falciform ligament
Umbilical vein
What do the umbilical arteries become?
Medial umbilical ligaments
What does the notochord become?
Nucleus pulposus of intervertebral disc
What do the ductus arteriosus and ductus venosus become?
Ligamentum arteriosum and venosum
What does the foramen ovale become?
Fossa ovalis
What does the allantois become
Urachus-median umbilical ligament
What supplies the SA and AV nodes?
RCA
What determines whether a person has Right or Left dominant circulation? Which is more common?
Right-dominant = PDA arises from RCA Left-dominant = PDA arises from LCX 85% = right dominant
When does coronary blood flow peak?
Early Diastole
What symptoms can enlargement of the L atrium cause?
Dysphagia - presses on esophagus
Hoarseness - compression of L recurrent laryngeal n. (CNX)
How do you compensate CO during early exercise? Late exercise?
↑ HR and SV
↑ HR only - SV plateaus
Which phase is decreased w/ ↑ HR?
Diastole - decreased filling time, ↓ preload
What things affect Mean Arterial Pressure (MAP)?
CO * TPR
What things affect Stroke Volume?
SV CAP - SV increases w/
Contractility ↑
Afterload ↓
Preload ↑