body fluids and other

Question 1

What is the normal total body water in a young adult in %

Answer 1

around 60%

Question 2

What substance is used to measure TBW?

Answer 2

radiolabelled deuterium oxide.

Question 3

what factors increase and decrease TBW?

Answer 3

increased..
- men
- neonates
- pregnancy

decreased
- obesity

fat has less water than muscle

Question 4

with regards to active transport, is it sensitive to temperature or anoxia

Answer 4

yes both
anoxia = hypoxia, less ATP

Question 5

Does cholesterol have hormonal activity?

Answer 5

no

Question 6

which endocrine condition is cholesterol increased?

Answer 6

myxoedema in hypothyroidism

Thyroid hormones increase levels of LDL receptor which bind and take up LDL including cholesterol.

Question 7

how does cholesterol circulate the blood?

Answer 7

in lipoprotein complexes
cholesterol esters are present in these in small quantities

Question 8

what is the role of Lactate dehydrogenase ?

Answer 8

catalyses reaction of pyruvate to lactate. uses 1 NADH

Question 9

which tissues synthesise lactate dehydrogenase?

Answer 9

skeletal muscle
isoenzymes also found in liver and heart

Question 10

which has a larger blood supply per gram of tissue - the brain or carotid bodies?

Answer 10

carotid bodies - 2L/100g/min
brain - 50ml/100g/min

Question 11

which peripheral chemoreceptors are more sensitive to oxygen tension rather than content

Answer 11

tension - carotid
content - aortic

Question 12

Do the carotid bodies contain baroreceptors?

Answer 12

No, there are baroreceptors nearby but they are not contained within. they are 2 separate receptors

Question 13

what happens to blood glucose in hypothermia?

Answer 13

increases due to drop in insulin production

Question 14

what happens to the myocardium with hypothermia?

Answer 14

increased irritability
initially bradycardia
<30degrees - VF

Question 15

how does hypothermia affect coagulation

Answer 15

reduced

Question 16

what is the solubility factor for CO2 for mmHg and pKA?

Answer 16

the solubility factor for carbon dioxide in plasma = 0.225 mmol L-1 kPa-1 (0.03 mmol L-1 mm Hg-1)

Question 17

how does pH affect muscles?

Answer 17

Alkalosis may precipitate tetany by increasing protein binding of calcium, thus decreasing free ionised plasma calcium levels.

Question 18

how does aldosterone affect pH?

Answer 18

reabsorption of Na in exchange for H
therefore alkalosis of plasma

Question 19

how do TOTAL calcium levels vary with plasma protein conc

Answer 19

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

Question 20

how does calcium conc change with pH

Answer 20

at higher pH, less H bound to plasma proteins, hence more room for Ca, so free Ca reduced

Question 21

how is PTH related to Ca?

Answer 21

PTH increases when drop in unbound/free Ca

Question 22

what is the daily loss of iron from the body?

Answer 22

Daily loss is 0.5-1 mg, mainly in the faeces.

Question 23

how is iron carried in plasma?

Answer 23

in ferrous form Fe3+ bound to transferrin

Question 24

where are pseudocholinesterases found?

Answer 24

plasma
placenta
brain
kidney
pancreas

(synthesised by liver)

Question 25

how does GFR change with body temp?

Answer 25

no change, same GFR in hypothermia

Question 26

what happens when 1L isotonic saline is infused? to fluid volumes, GFR and ANP

Answer 26

increased ECF volume
increased GFR, increased ANP production

Question 27

why does isotonic saline not move into intracellular fluid compartment?

Answer 27

cell membrane impermeable to sodium ions
no net movement of water because isotonic

Question 28

what substrates can be used for gluconeogenesis?

Answer 28

lactic acid
glycerol
glucogenic amino acids

can occur in liver and kidneys

Question 29

what is the molecular weight of albumin?

Answer 29

67000 Daltons

Question 30

what is the most abundant intracellular cation?

Answer 30

K+
then Mg

Question 31

what are the normal levels of Mg in blood?

Answer 31

0.7-1.05mM

Question 32

where does isotonic fluid distribute?

Answer 32

ECF

Question 33

where does hypotonic fluid distribute?

Answer 33

ICF and ECF
e.g. glucose 5% - glucose gets metabolised and then is effectively hypotonic.

Question 34

in the glycolayx model where are the colloid osmotic forces acting?

Answer 34

colloid osmotic forces act between the intravascular and sub-glycocalyx spaces

Question 35

in the glycolayx model, what is the main determinant of fluid movement in healthy individuals?

Answer 35

hydrostatic pressure

Question 36

where does normal saline distribute?

Answer 36

ECF only

Question 37

what are safer tetrastarches or hetastarches?

what are the side effects of these starches?

Answer 37

tetrastarch

pruritis, coagulopathy and renal failure

Question 38

which fluid is associated with biggest risk of anaphylaxis?

Answer 38

Gelatins are associated with the greatest risk of severe anaphylactoid reactions