Flashcards in Physiology Deck (19):
Sweat glands. Innervated by? Thermal/emotional sweating controlled by? Receptors?
Innervated by SNS.
Thermal sweating controlled by hypothalamus.
Emotional sweating is controlled by cerebral cortex.
Utilises acetylcholine recepetors
What will shift the oxygen Hb curve to the left?
decreased 2-3 DPG
Decreased H+ i.e. increased pH
In a 70 kg man there is a total of 45L of H2O. What does the total body water consist of?
Intracellular = 2/3
Extracellular (plasma (3.5L), interstitial fluids (8.5L), lymph and transcellular fluid) = 1/3
Transcellular is pleural, pericardial, synovial, luminal fluids, bowel)
What is the intracellular component of cations?
K = 145 mmol/L (cells have a high take of K)
Na = 10 mmol/L
Ca = .001 mmol/L
Mg = 40 mmol/L
How do you calculate plasma osmolalarity?
(Na + K) x 2 + glucose + urea
What is the difference between osmolality and osmolarity?
Osmolality = solutes in 1 kg of solution (osmos/kg). Calculate in lab.
Osmolarity = solutes in 1L (osmo/L)
What do is the normal plasma osmolality?
What is the urin osmol?
(Na +K) - (HCO3 + Cl)
Normal AG 10-16
We have a positive anion gap as not all the anions are measured.
Causes of a high anion gap?
Increases in unmeasured anions e.g. lactate, ketones, methanol, alcohol, urea (renal failure), salicylates
( as the cations will increase to compensate for increased anions)
Causes of low AG?
Decreased in unmeasured anions e.g. albumin, phosphate
Increased in unmeasured cations e.g. MM, IgG paraprotein
In a normal AG aciodis, the urine anion gap is used to differentiate the causes. How do you calculate this and what are the causes?
(Na + K) - Cl.
Normal is 0 - 10 mmol/L
Increased = Renal (bicarb loss from kidney), Type I (distal, can't secrete H+ therefore urine pH > 5.5 and low K) and
Type II RTA (Cannot absorb HCO3- therefore pH
Causes of a normal AG? (CAGE) or ABCD
Due to loss of HCO3- from ECF:
GI causes – diarrhea/vomiting, fistulae (pancreatic, ureters, billary, small bowel, ileostomy)
Extra – RTA
Addisons (adrenal insufficiency)
Bicarbonate loss (GI or Renal)
What does the Adrenal cortex consist of?
What does the Adrenal medulla consist of?
ZG = mineralcorticoids (aldosterone)
ZF = glucorticoids (cortisol, corticosterone)
ZR = androgens (testosterone and oestrogens)
- catelcholamines (80% adrenaline, 20% noradrenaline)
Thyroid binding globulin (TGB). What causes a high serum TBG?
Thyroid binding globulin (TGB). What causes a low serum TGB?
Danzol - synthetic steroid ethisterone that suppresses the production of gonadotropins and has some weak androgenic effects. Used in endometriosis.
What is the function of Thyroid binding globulin (TGB)?
Synthesised in the liver.
Binds most of T4 and T3 in blood.
Higher affinity for T4 compared to T3.
Only free hormone is active.
Bound hormones represent a circulating storage pool.
Decreased TGB in hepatic failure
What are the T3 functions? 4Bs
Beta adrenergic effects
Where is T4 converted to T3?
T3 binds receptors with greater affinity than T4.