C L9.1 Programming and Reprogramming Flashcards
1
Q
Pregnancy is the greatest physiological challenge facing women, what are some of the adapations?
A
- 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
Q
Metabolic adaptations during pregnancy
A
- 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
Q
Glucose
A
- Maternal hypoglycaemia in late gestation despite insulin resistance by tissue
- Due to b-cell proliferation and hypertrophy (accommodate ↑ insulin)
4
Q
Blood
A
- 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
Q
Plasma vol and red cell mass
A
- 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
Q
White blood cells
A
- ↑25-30%
- ↓platelets due to hemodilution
- ↓total plasma proteins
- ↓albumin
7
Q
Lipids
A
- ↑40-60%
- ↑cholestorol 40% (essential precrsor for estrogen and progesterone)
8
Q
Coagulation
A
- ↑BF and coagulaton during pregnancy
- Limit blood loss at delivery
9
Q
Output adaptations
A
- LV hypertrophy → Increase CO
- ↑SV at 8 weeks
- ↑HR at 5 weeks
- ↑Fluid retention/oedema
10
Q
BP
A
- ↓BP → promote uterine circulation
- ↑renin & ANG II but regractory (no ↑BP)
- May have postural hypertension
11
Q
ECF & kidneys
A
- 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
Q
Renal adaptations
A
- ↑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
Q
What does increase RBF and GFR lead to?
A
- ↑ filtration of water & solutes
- ↑ urine flow and vol
- But tubules retain Na & water to maintain BV and plasma vol
14
Q
Placental adaptations
A
- Substitutes for fetal organs
- Lungs
- Kidneys
- GIT
- Provides fetus with O2 and nutrients
15
Q
Umbilical cord
A
- Umbilical V → brings O2 to fetus
- Umbilical A → brings waste to mother
16
Q
Fetal cardiovascular adaptations
A
- Adults have 2 separate circulatory system (pulmonary & systemic)
- Fetal heart → 1 system (L & R ventricles function in parallel to perfuse body and placenta)
17
Q
Fetal hemoglobin affinity
A
- Much lower PO2
- Lower O2 saturation
- Higher hemoglobin conc
- Carry more O2 from mother
- Higher affinity for oxygen
- O2 consumption is high
18
Q
4 unique fetal shunts
A
- 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
Q
Adaptations at birth - umbilical circulation
A
- Clamped umbilical cord (lose umbilical A & V)
- Vessels bringing deO2 blood disintegrate
20
Q
Adaptations at birth - Ductus venosus
A
- Closed 1-3 weeks after birth (later in premature babies)
- Trigger unknown
21
Q
Adaptations at birth - Foramen ovale
A
- Mechanical atrial pressure
- Baby takes first breath → pressure gradient change → mechanical pressure close forman ovale
22
Q
Adaptations at birth - ductus arteriosus
A
- 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
