body fluids and other Flashcards
What is the normal total body water in a young adult in %
around 60%
What substance is used to measure TBW?
radiolabelled deuterium oxide.
what factors increase and decrease TBW?
increased..
- men
- neonates
- pregnancy
decreased
- obesity
fat has less water than muscle
with regards to active transport, is it sensitive to temperature or anoxia
yes both
anoxia = hypoxia, less ATP
Does cholesterol have hormonal activity?
no
which endocrine condition is cholesterol increased?
myxoedema in hypothyroidism
Thyroid hormones increase levels of LDL receptor which bind and take up LDL including cholesterol.
how does cholesterol circulate the blood?
in lipoprotein complexes
cholesterol esters are present in these in small quantities
what is the role of Lactate dehydrogenase ?
catalyses reaction of pyruvate to lactate. uses 1 NADH
which tissues synthesise lactate dehydrogenase?
skeletal muscle
isoenzymes also found in liver and heart
which has a larger blood supply per gram of tissue - the brain or carotid bodies?
carotid bodies - 2L/100g/min
brain - 50ml/100g/min
which peripheral chemoreceptors are more sensitive to oxygen tension rather than content
tension - carotid
content - aortic
Do the carotid bodies contain baroreceptors?
No, there are baroreceptors nearby but they are not contained within. they are 2 separate receptors
what happens to blood glucose in hypothermia?
increases due to drop in insulin production
what happens to the myocardium with hypothermia?
increased irritability
initially bradycardia
<30degrees - VF
how does hypothermia affect coagulation
reduced
what is the solubility factor for CO2 for mmHg and pKA?
the solubility factor for carbon dioxide in plasma = 0.225 mmol L-1 kPa-1 (0.03 mmol L-1 mm Hg-1)
how does pH affect muscles?
Alkalosis may precipitate tetany by increasing protein binding of calcium, thus decreasing free ionised plasma calcium levels.
how does aldosterone affect pH?
reabsorption of Na in exchange for H
therefore alkalosis of plasma
how do TOTAL calcium levels vary with plasma protein conc
the more plasma protein - the more Ca binds to this and then reduces free Ca, causes negative feedback and increase in Ca to keep constant levels of free ca
hence total calcium has increased
how does calcium conc change with pH
at higher pH, less H bound to plasma proteins, hence more room for Ca, so free Ca reduced
how is PTH related to Ca?
PTH increases when drop in unbound/free Ca
what is the daily loss of iron from the body?
Daily loss is 0.5-1 mg, mainly in the faeces.
how is iron carried in plasma?
in ferrous form Fe3+ bound to transferrin
where are pseudocholinesterases found?
plasma
placenta
brain
kidney
pancreas
(synthesised by liver)
