Physiology Flashcards
What is the upper limit of ALP in 3rd trimester?
Why are they higher?
approx 230
Secreted by the placenta
What are the changes to biliary physiology in pregnancy?
What is it that causes this effect?
Think Female Fat Forty Fertile
- Increased stone making aka lithogenic index
- INHIBIT gallbladder emptying (like progesterone does to the stomach)
- INCREASE cholesterol production
- INCREASE concentration of bile acids
- INHIBIT canalicular excretion of bile from the liver into the bile ducts
2x inhibit, 3x increase
Cause = circulating oestrogen and progesterone
What are the 4 phases of wound healing?
What are the predominant cell types within the first 48h and after?
- Haemostasis
- Inflammatory
- Proliferation (collagen deposit and angiogenesis)
- Remodelling (collagen alignment)
First 48h - haemostasis and inflammatory - polymorphonuclear neutrophils. They kill debris and bacteria. They phagocytose at 48h and therefore on day 3-4 MACROPHAGES are main type
What is the initial substance holding platelets together
Fibrin
What increases the minute ventilation in pregnancy
Progesterone. It increases the sensitivity of the CNA respiratory centres to CO2
Describe the physiological changes in pregnancy with the lungs?
What changes?
What stays the same?
Pressure from gravid uterus causes:
20%:
- 20% Increase in O2 consumption
- 20% decrease in expiratory reserve capacity
- 20% decrease in functional residual capacity
5% reduction in TOTAL LUNG CAPACITY
50%:
- 50% increase in tidal volume
- 50% increase in minute ventilation in first trimester
FEV1 and FVC stay the same
Acidosis is corrected for by increased bicarb secretion from kidneys
Increased minute ventilation –> Po2 increases, Pco2 decreases - PROGESTERONE
What is the normal oxygen consumption in non-pregnant woman of 75kg?
How does this increase in pregnancy?
250ml/minute
Increases by 20% to make 300ml/minute
Describe the changes to the renal in pregnancy.
How does blood flow change?
50-60% increase in renal blood flow due to the increased cardiac output.
Increased secretion of bicarbonate to balance the pH
When do most of the cardiac changes occur in pregnancy?
What are the changes to the cardiovascular system?
In first trimester. Therefore most cardiac problems present at this point.
CHANGES:
Cardiac output = amount of blood pumped out by heart in 1 minute. Therefore SV x HR
Stroke volume = increases by 30%
Peripheral vascular resistance = decreases by 30%
Cardiac output = increases by 30-50%
Total blood volume = increases by 40-50%
HR = increases by 15 beats/min
BP = diastolic decreases in 1/2 trimester by approx 15 then increases towards the end to pre-pregnancy level
What is included in the eGFR calculation?
What is NOT included?
Which calculator is recommended by NICE?
Creatinine
Age
Sex
Ethnicity
UREA NOT INCLUDED
Calculator = MDRD
What are the effects of vasopressin?
What activates it?
Increase aquaporins in collecting duct - RETAIN WATER
Increase urea channels for urea uptake from collecting duct
Increase sodium reabsorption in ascending loop of henle - also for water retention
Causes vasoconstriction
ACTS ON COLLECTING DUCT AND ALH AND peripheral vessels
STIMULATED BY:
Hypothalamus detects increase in serum osmolarity - causes release - THIS IS THE PRIMARY ONE
BARORECEPTORS - detect low BP and stimulate release
What is it during wound healing that activates the INTRINSIC pathway and EXTRINSIC pathway?
Intrinsic = tissue factor
Extrinsic = damaged endothelium
EDE-FIT
What is absorbed at the PCT?
GAC-BUPPS
Remember the GAC is 100% and the BUPPS is not 100%
Glucose
Aminoacids
Carboxylate
Bicarbonate
Urea
Potassium
Phosphate
Sodium
What is the average weight of a non-pregnant pre-menopausal uterus vs a pregnant one
40g
volume = 10ml
1.2kg
volume = 5000ml
How much HBF is present at 6 months
What about at birth?
What about in the first trimester?
<2%. Mostly replaced by adult haemoglobin
50-90% at birth
First trimester - HBE - embryonic. And the primary bit of this is Gower 1
There is also Gower 2, portland 1 and portland 2
At 10-12 weeks HBF becomes the main type
What is triggered in the body when Ca is low?
Release of PTH - causes:
resorption from bone
Vitamin D increase - increase absorption from gut
Reasborption from kidneys
What is pre-autologous blood depositing?
Do we do it in pregnancy?
Tkaing someones own blood to give back to them later.
Can be stored for 5 weeks
NOT recommended in pregnancy.
What is the most common cause of hypercalcaemia?
What age group?
Primary hyperparathyroidism
Post-menopausal
What is the direct vs indirect coombs test?
DIRECT
- In vivo
- Used to detect antibodies or complement attached to red cells (DIRECTLY ATTACHED)
- Used to detect RhD and ABO incompatibility
INDIRECT
- In vitro
- Used to detect antibodies in the SERUM (indirect)
- Used in cross matching
Complement cannot be detected in the serum with the indirect coombs because complement is only activated when attached to the surface of cells
Where is calcitonin produced?
What is the function?
How does it do this?
Thyroid C-cells aka parafollicular cells
Function - lower calcium levels
INHIBIT:
- Absorption of Ca from gut
- Reabsorption from kidneys
- Osteoclast activity
STIMULATE:
- osteoblast activity
What happens to phosphate, PTH and ALP in:
- Myeloma
- Sarcoidosis
- Calcium alkali syndrome
- Hyperthyroidism
- Hyperparathyroidism
- Malignancy
- Vitamin D excess
Myeloma - usually isolated hypercalcaemia. Everything else normal
Hyperthyroidism/sarcoidosis/calcium alkaki syndrome - low PTH, because the calcium is high. Everything else normal
Hyperparathydoisism - high PTH, low phosphate, normal ALP
Malignancy - High ALP - think bone mets. Everything else normal
Vitamin D excess - low ALP, low PTH, high phosphate
How long does it take for a wound closed by primary closure to reach full tensile strength?
How long until remodelling is done?
12 weeks
3 weeks
When listening to the heart in pregnancy - what is normal? What is abnormal?
Normal:
- 3rd heart sound
- LAD
- Systolic murmur
- T wave flattening in lead 3
Abnormal:
- Diastolic murmur
Looking at a set of LFTs, what is decreased or increased in pregnancy?
Decreased:
- ALT
- Bilirubin
- Albumin
Increased:
- ALP
- GGT
What is the typical lifespan of the following cells:
Basophil (WBC)
Platelet
RBC
WBC - 2-5 days
Platelet - 5-9 days
RBC - 120 days
How does the recommended intake of iron, folic acid and the vitamins change in pregnancy
FOLIC ACID - 3x increase
Iron and Vit C- just less than 2x increase
Vit A and D is the SAME
What effects so calcitonin and PTH have on phosphate
BOTH decrease.
Calcitonin and PTH decrease phosphate reabsorption from the kidneys
