C L9.1 Programming and Reprogramming Flashcards Preview

Cardio Phys > C L9.1 Programming and Reprogramming > Flashcards

Flashcards in C L9.1 Programming and Reprogramming Deck (22):
1

Pregnancy is the greatest physiological challenge facing women, what are some of the adapations?

  • Adaptations required to:
    • ↑CO and BV (have another organ - the placenta)
    • Maintain uteroplacental perfusion
    • Maintain fetal demands
  • Duration = 40 weeks (from  last menstrual period); 38 weeks from fertilisation

2

Metabolic adaptations during pregnancy

  • Weight gain
  • Altered body shape
  • Uterus, breast, BV, maternal stores
    • To support and accommodate growing fetus
    • Exponential fetal growth in late gestation
  • ↑Metabolic rate, O2 consumption, fat stores
    • Breast tissue and uterine muscle are major O2 consumers

3

Glucose

  • Maternal hypoglycaemia in late gestation despite insulin resistance by tissue
    • Due to b-cell proliferation and hypertrophy (accommodate ↑ insulin)

4

Blood 

  • Blood loss:
    • Vaginal delivery = 500-600
    • Caesarean = 800-1200
  • Changes needed to support maternal and fetal circulation and tissues
  • ↑BV (30-50%)
    • Begins at 6 weeks, peaks at 32 weeks

5

Plasma vol and red cell mass

  • Plasma vol
    • ↑40-50%
  • ↑Red cell mass (25-30%)
    • Not as great as plasma or BV
    • Physiological anemia and hemodilution
      • RBC increase is slower than plasma vol 

6

White blood cells

  • ↑25-30%
  • ↓platelets due to hemodilution
  • ↓total plasma proteins
    • ↓albumin

7

Lipids

  • ↑40-60%
    • ↑cholestorol 40% (essential precrsor for estrogen and progesterone)

8

Coagulation

  • ↑BF and coagulaton during pregnancy
  • Limit blood loss at delivery

9

Output adaptations

  • LV hypertrophy → Increase CO
    • ↑SV at 8 weeks
    • ↑HR at 5 weeks
    • ↑Fluid retention/oedema

10

BP

  • ↓BP → promote uterine circulation
  • ↑renin & ANG II but regractory (no ↑BP)
  • May have postural hypertension

11

ECF & kidneys

  • ECF = plasama + interstitium
  • ECF vol needs to stay constant for homeostatic mech
  • Kidneys are the main factors for ECF
    • Pregnancy resets vol sensors → altered renal BF, GFR

12

Renal adaptations

  • ↑Renal blood flow (↑40-80%)
  • GFR (↑30-50%)
    • Creatinine clearance used for indication of GFR
  • ↑Kidney size ↑by 1cm - ↑RBF & glomerular hypertrophy
  • Renal hyperfiltration

13

What does increase RBF and GFR lead to?

  • ↑ filtration of water & solutes
  • ↑ urine flow and vol
  • But tubules retain Na &  water to maintain BV and plasma vol

14

Placental adaptations

  • Substitutes for fetal organs
    • Lungs
    • Kidneys
    • GIT
  • Provides fetus with O2 and nutrients

15

Umbilical cord

  • Umbilical V → brings O2 to fetus
  • Umbilical A → brings waste to mother

16

Fetal cardiovascular adaptations

  • Adults have 2 separate circulatory system (pulmonary & systemic)
  • Fetal heart → 1 system (L & R ventricles function in parallel to perfuse body and placenta)

17

Fetal hemoglobin affinity

  • Much lower PO2
  • Lower O2 saturation
  • Higher hemoglobin conc
    • Carry more O2 from mother
    • Higher affinity for oxygen
    • O2 consumption is high

18

4 unique fetal shunts

  • Ductus venosus
    • Abdominal umbilical V to IVC → via R atrium → formane ovale
  • Foramen ovale
    • Bypass R atrium → L atrium
  • Ductus arteriosus
    • R vent → pulmonary A → straight to descending aorta
  • Umbilical circulation
    • 1 vein brings O2 blood placenta to fetus
    • 2 arteries remove deO2 blood

19

Adaptations at birth - umbilical circulation

  • Clamped umbilical cord (lose umbilical A & V)
  • Vessels bringing deO2 blood disintegrate

20

Adaptations at birth - Ductus venosus

  • Closed 1-3 weeks after birth (later in premature babies)
    • Trigger unknown

21

Adaptations at birth - Foramen ovale

  • Mechanical atrial pressure
  • Baby takes first breath → pressure gradient change → mechanical pressure close forman ovale

22

Adaptations at birth - ductus arteriosus

  • Pressure gradient closes it → pulmonary A becomes dominant
  • Closes 2 days after birth
  • O2 mediated prostagladin inhibition
  • Patent ductus (when it stays open) → deO2 blood mixed with O2 blood from the lungs