Physiology Flashcards
Half life of LH
60 mins
Half life of FSH
170 minutes (3h)
Half life of hCG
24 hours
Structure of GnRH
Decapeptide (10x peptides)
Source of cholesterol in term foetus
De novo synthesis in their own liver
Post menopausal ratio of uterus:cervix
1:1 or cervix is bigger than uterus 1:2
Largest cell in human body
Oocyte
How is magnesium excreted by the body?
Kidneys and faeces
Haldane effect
The ability of deoxygenated hemoglobin to carry more carbon dioxide (CO2) than in the oxygenated state, reflecting a tendency for an increase in pO2 to diminish the affinity of Hb for CO2
Umbilicus: how many arteries/ veins?
2 arteries (deoxygenated blood)
1 vein (oxygenated blood
When can the quadruple test be done and what does it include?
What indicates Down’s syndrome?
Second trimester (14-20 weeks)
Beta hCG, inhibin A, AFP and estradiol
Raised bHcG, raised inhibin A
Low AFP and low estradiol
What does the combined test involve and when can it be done?
Results suggestive of downs/ patau/ Edwards?
Nuchal translucency & PAPP-A/ beta hCG
11+2 until 14+1 gestation
Downs: Raised NT, low PappA, raised bhCG
Edwards & Patau: Raised NT, low PappA and bhCG
What happens to 2,3 DPG in pregnancy?
Increased concentration (by 30%) –> decrease in maternal red cell O2 affinity, facilitating transport of oxygen across placenta
How much does total lung volume decrease by in pregnancy?
200ml
What happens to expiratory reserve volume in pregnancy? (therefore functional residual capacity)
It reduces
How does minute ventilation/ volume change in pregnancy?
It increases by 40%
Difference between fetal Hb and adult Hb
Fetal Hb has higher affinity for O2 and can resist denaturation by strong acid/ alkali more than adult Hb
Path of sperm penetration
Corona radiata
Zona pellucida
Perivitelline space
Plasma membrane
Face presentation diameter
9.5cm (when hyperextended)- submento-bregmatic
Coagulation factors that increase during pregnancy
all except XI and XIII
3 fold increase in cortisol in pregnancy. Mechanism?
Increased unopposed oestrogen
Prolactin levels in pregnancy compared to pre-pregnancy
10 fold increase
Changes in blood composition during pregnancy
- Platelet count reduces
- Increased coagulation factors (VII, VIII, IX, X, XII)
- Increased fibrinogen
- Increased ESR
- Protein S levels reduce (physiological anticoagulant)
- Reduced XI and XIII
- Antithrombin III and protein C are unchanged
How much does renal blood flow increase by in pregnancy?
How much does eGFR increase by?
How much do kidneys increase in size?
50-60%
eGFR: 40% (by end of 1st trimester)
Around 1cm