Physiology PA

what determines body weight increase or decreases

energy intake vs expenditure

metabolism

all chemical rxns in body’s cells to sustain life

what kind of processes are involved in metabolism

anabolic (energy used), catabolic (broken down to harvest energy)

regulation energy metabolism involves

interplay bw ingested nutrients, hormones, substance exchange

energy acquisition by body is _______ __while energy expenditure is__ ___________

intermittent, continuous

___________ orchestrates exchange and distribution of substrates bw tissues under fed and fasting conditions

insulin

__________ play major role in energy regulation at times of acute energy needs

glucagon, ctch, cortisol and growth hormones

organs involved in fuel homeostasis

liver (production glucose), brain (uses glucose), m + adipose tissue (store glycogen)

an attribute of __________ is large quantity of free energy from its 2 PO4 bonds

ATP

sources ATP

* combustion carbs (anaerobic glycolysis)
* combustion fatty acids (beta oxidation)
* combustion proteins (hydrolysis)

events of oxidative metabolism when a great amount of energy is demanded

phosphocreatine storehouse used first, then anaerobic breakdown glycogen

metabolic rate

rate of heat liberation during chem rxns, heat as end product

small vs (large) calorie

small is unit of energy (amount heat needed to raise temp in 1g water), large is amount heat needed to raise temp in 1kg water)

basal metabolic rate

min energy expenditure for body to exist

necessities to measure whole-body basal metabolic rate

fasted for 12h, no strenuous activity 1h before

BMR increased and decreased by

increased by thyroid, male sex hormone, growth hormone, fever

decreased by sleep, malnutrition

BMR averages cal/hr

65-70 calories/hour

variations in bmr among ppl are related to differences in

muscle mass, age, genetics, weather (cold - raised), diet (small dispersed meals - raised), pregnancy, supplements (caffeine - raised)

effect of anaerobic exercise on BMR

increases it

direct vs indirect calorimetry measures

direct - heat from body, by calorimeter

indirect - energy equivalent of O2, by EGAIC

energy equivalent of O2

4\.825 calories

regulation food intake and energy storage by

neural center (hunger by lat nuclei of hypothalamus/satiety by ventromed and paraventricular nuclei of hypothalamus), extraneural factors (regulate food intake quantity)

hypothalamus receives signals from

neural + hormonal GIT, chem from blood, fat hormones, cerebral cortex

short term regulation food intake extraneurally

* GIT distention → stretch inhibitory signals by vagi
* PYY, CCK, GLP and insulin released after meals
* oral factors inhibit

int + long-term regulation food intake extraneurally

* blood conc of nutrients - inhibits


* temp regulation (heat exposure decreases calories)
* fat releases leptin - inhibits

feedback mechanisms for food intake control

* stretch r → vagus → inhibition
* PYY, CCK, insulin - inhibition
* ghrelin → stimulates appetite
* leptin - inhibition

usual weight

may be constant or variable, allows estimation % weight loss

intentional vs unintentional weight loss

intentional - 25%

unintentional - 6o%

______ doesn’t differentiate bw fat or lean body mass

bmi

subcutaneous fat accumulation causes what kind of obesity

gynoid/pear shaped obesity

severity of obesity quantified usuing

bmi and waist circumference

anthropometry

estimates body fat at sites of fat deposition (skinfold, arm, waist)

bioimpedance analysis

scales measuring body fat %, electrical current thru body

when should bioimpedence analysis be avoided

after exercise or bath, drinking or meal

thyroid produces

thyroid hormones (T4, T3), calcitonin

thyroid hormones require what for production of active hormones

iodine

__________ hormone is stored in extracell site within colloid

thyroid

thyroglobulin contains

t4 and t3

c/parafollicular cells

make calcitonin for ca+2 and po4

TSH fxn

signals follicular cell to ingest colloid by endocytosis → digested into t4,t3 → target cells → T3, rT3

active form of thyroid hormone vs pre-hormone

T3 vs T4

steps of thyroid hormones

iodide trapped, oxidized to iodine, organified → coupled to T3 + T4

t3 and t4 are almost entirely bound to

proteins (TBG from liver)

regulation T3 and T4 occurs in the following manner

* TRH stimulates TSH release
* TSH stimulate iodine uptake + release T3,T4
* high levels T3+T4 shut off TSH release

high risk ppl for thyroid screening

neonates, pregnants, old, ppl w/ history

diagnosis of hyper and hypothyroidisim should include

TSH and fT4

sample collecting and handling for thyroid fxn

serum or plasma, stored @ 2-8 degrees if not analyzed within a day, neonates by heel puncture after birth

why do hormone level measurements need to be highly sensitive and specific

plasma conc hormones low

RIA for thyroid fxn

top - antibody mixed w/ labeled hormone, antigen antibody complex formed

middle - serum added, unlabeled hormone competes w/ labeled hormone

bottom - free hormone and antibody-hormone complex separated, radioactivity of free hormone measured

types of thyroid pathos

thyroid hyperactivity/secondary hyperthyroidism - increased TSH + fT4

primary hypothyroidism - increased TSH, low fT4

secondary hypothyroidism - low TSH + fT4

primary hyperthyroidism - low TSH, high fT4

serum total vs free t4 and t3

serum total - RIA

serum free - immunometric assays, more accurate

thyroglobulin circulation is proof of

thyroid tissue presence, tumour marker

TRAb

TSH r atb, for Graves

TPO antibodies test

for autoimmune thyroiditis (hypothyroidism)

TPO role

synthesis thyroid hormones by iodination

what predicts onset of hypothyroidism

high thyroid atb

There are situations where _____________________ may be low or high, causing alteration of total T3 and T4 levels. However, free T3, T4, and TSH levels should be norma

thyroid hormone-binding proteins

what alters TBP

OCs raise it, hypoproteinemia lower it

PTH effects of kidneys

increase reabsorption, PO4 excretion, enhance hydroxylation vit D

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secretion of ________ is inhibited by high ca conc

pth

what method is used for in vitro determination of intact pth hormone in serum and plasma

immunoassay

conc inactive pth fragments increases in

RF

limit of thyroid US imaging

can’t determine thyroid fxn, rarely confirms cancer

us elastography of thyroid

virtual palpation of nodule by colour scoring, confirms malignancies

thyroid scan and uptake investigation

nuclear medicine imaging procedure using radiotracers on PET scan, for thyroid’s size shape position and fxn

combined thyroid and parathyroid imaging principle

exam based on differential washout of Tc-99m MIBI from thyroid tissue compared to abnormal parathyroid tissue

amount of glucose in extracell fluid is backed up by

emergency stores glycogen (liver + m) then by gluconeogenesis

glucose homeostasis controlled by

insulin + catabolic hormones (glucoagon, ctch, cortisol, gh)

insulin and glucagon secreted by

pancreatic islets of langerhans, insulin by B cells, glucagon by a cells

molar ratio insulin to glucagon is the key determinant of

pattern of fuel metabolism

blood glucose level reflects balance bw

insulin and the hormones that rise glycemia

first test performed if imbalance of glucose homeostasis

fasting blood glucose level

_______ can use v, cap or a blood and after overnight fast

blood glucose level

interpretation of blood glucose level depends on

measurement technique (nonspecific chemical vs specific enzymatic), blood sample source (lower in v), age (increases w/ age)

screening for glucose testing for dm for who

>25 bmi, >45yo, history gestational or prediabetes

results self-monitoring glucose device

80-100mg/dl normal, >126 is diabetes

OGTT

assesses blood glucose response to carb load, used bcus normal fasting blood glucose level doesn’t exclude diabetes

indications of _________ are family history dm, weight loss, infections, overweight newborns, cataracts and delayed wound healing

OGTT

steps of OGTT

fasting plasma glucose measured, glucose drank, measured again 120m, urine examined

interpretation OGTT

if peak conc is above 11.1mmol/L its dm

glucose tolerance curve

normal - gluclose rises 90→140mg and falls to normal in 2h

slow fall in glucose tolerance curve is due to

either a normal increase insulin secretion doesn’t occur or decreased sensitivity to insulin

how is type 1 vs 2 distinguished

1 has low insulin, 2 has increased insulin

normal blood level insulin

>10 mui/ml

phases of insulin secretion in response to glucose

* acute firstr phase
* incretin effect - secretion is greater when glucose by mouth by peptides in gut

___________ are released from pancreas at same time in equal amounts

c peptide and insulin

diff bw insulin and c peptide

c peptide not extracted by liver at all

how to measure c peptides

radioimmunoassay (decreased in type 1)

glycated hb reflects

conc plasma glucose for previous 3m

new method of testing glycated hb

mmol/mol, by spectrometry or cap electrophoresis

glycated hb test is for

diagnosing diabetes (>48mmol/l) and monitoring glycemic control

what happens in kidneys in person w/ diabetes

max tubular reabsorption rate exceeded, glucose in urine

how to test urinary glucose

test trips based on glucose oxidase rxn

__________ are produced by the liver from fatty acids during periods of low food intake orglucose restriction, they serve as energy source for the cells of the body

ketone bodies

__________ rises if metabolic imbalance occurs in dm

ketone bodies

what tests for ketonuria

only qualitiative - urine test strips based on rxn of sodium nitroprusside → magenta

conditions where unusual increase ketones in blood → urine

disruption carbs, increased fat metabolism, vomiting

ketone meter

for acetone breath in type 1 dm