Lecture 5 Flashcards
all of the chemical reactions in the cell of the body
metabolism
the rate of heat liberation during chemical reactions measured by the rate of oxygen utilization
metabolic rate
humans use oxygen to extract approximately ____ calories from food to meet daily energy requirements
2550 cal
what is the minimum level of energy to exist
___% of daily energy expenditure
basal metabolic rate (BMR)
50%
what has more energy glucose or glycogen?
glycogen
energy currency, ATP and GTP are made from _______. what are they responsible for and how much energy do they supply?
carb, fats, protein
transferring energy from food for cellular function
7300 calories per mole (can reach 12000) from phosphate BONDS
combustion of carbohydrates produces ______ through what two processes?
glucose
glycolysis (anaerobic)
citric acid cycle (aerobic)
combustion of fatty acids process is _______
beta oxidation
combustion of proteins happens in _____?
degradation of amino acid intermediate compounds of CAC
-acetyl CoA
-carbon dioxide
formation of peptide linkages between amino acids use ATP and can require _____ calories per linkage and _____ high energy peptide bonds
5000
4
what is the compound found in muscle that stores more high energy phosphate bonds than ATP?
phosphocreatine
phosphocreatine has _____ calories per mole, but is not usable unless ______.
ADP is transfered to make ATP, resulting in creatine
________, or energy derived from nutrients WITHOUT use of oxygen.
________ are the only nutrients that can be used to provide energy this way
anaerobic
carbs
the best source of energy by anaerobic metabolism is ______ breakdown into _____, not free glucose. explain?
glycogen
pyruvic acid
2 moles of glucose=2 moles of ATP (plasma)
1 mole of glycogen=3 moles ATP (in the cell)
lower bc glucose had to be phosphorylated to get into cell
energy derived from foods only with the use of oxygen
aerobic
what is the order of utilization of energy
ATP
Phosphocreatine stores
Glycogen breakdown
energy yield kJ/g for carb protein fat and alcohol
carb 16
protein 17
fat 37
alcohol 29
what equation shows the control of enzyme-driven metabolic reactions?
michaelis-menten equation
ex: turning ADP back to ATP
can only do it so fast until u reach a max rate at concentration
what is the rate limiting factor determined by?
rate of rxn of the slowest step in the process
the amount of heat energy required to raise the temperature of one kilogram (about 1 quart) of water one-degree celsius?
Kilocalorie (Calorie)
basal metabolic requirements for heat eliminated from the body at rest when temp is normal is ____ to _____ Calories per day?
energy required for activity?
2000-2400
6000 Cal/day
when using energy for many thins, they all create ____.
heat
quantifying the bmr can be done by measuring the amount of oxygen consumed by the tissues of the body measured as the oxygen uptake in the lung, or ______.
rate of oxygen utilization
quantifying the BMR
what is normal oxygen uptake?
250 ml/min or
3.5 to 4.0 ml/kg/min
what is the procedure for measuring BMR?
- no eating for 12 hrs
- following a restful night of sleep
- no strenuous activity 1 hr before measure
- eliminate all factors causing excitement
- room temp of 68-80 degrees
- no physical activity during test
comparasson of height and weight of someone to tell if they have excess body weight
BMI
method for determining reasonable estimate of ideal body weight?
Hamwi method
Hamwi formula
MEN
- 106 plus 6 lbs for inch over 5 ft
WOMEN
- 100 plus 5 lb for inch over 5 ft
+ or - 10% for frame size
influence on metabolic rate of thyroid hormone increase
increase metabolic rate
influence on metabolic rate of testosterone
increase metabolic rate
influence on metabolic rate of thyroid hormone decrease
decrease metabolic rate
influence on metabolic rate of growth hormone
increase metabolic rate
influence on metabolic rate of sleep
decrease metabolic rate
influence on metabolic rate of malnutrition
decrease metabolic rate
influence on metabolic rate of fever
increase metabolic rate
influence on metabolic rate of sympathetic activation (epinephrin/norepinephrine)
increase metabolic rate
influence on metabolic rate of brown fat
increases metabolic rate
the older you get, the ____ brown fat you have.
where is it found?
what do they do?
less
lower neck and supraclavicular regions of an adult
release heat to warm you up
core body temperature is constant within ___ to ___ degrees Celsius except for when you have a fever. Average body temp is ___ to __ F
when you have a fever, it is _____
1-1.5
97-99.5
101 or above
what is feedback gain
human changes 1 degrees celsius for every 25 degrees celsius environmental temperature change
the temperature of skin rises and falls depending on surroundings, critical set point around ___ degrees F
98.8
core temperature is more accurate in _____
rectal
heat loss originates from _____
internal organs
two factors of heat loss include ___ and ____?
- how rapidly heat is conducted from where it is produced to the skin
- thru vascular system and bloodflow - how fast heat is transferred from skin to surroundings
what does our body do to prevent heat loss if we are too cold?
vasoconstriction of blood from going near the surface so the blood stays warmer
what are the main ways heat is lost from the skin?
radiation 60% - heat waves
conduction 18% - straight to objects or air
evaporation 22% - through sweat
how does sweating occur?
increase in temperature
stimulation by the anterior hypothalamus
autonomic pathways of the spinal cord
sympathetic outflow to the skin
sweat gland production
what is dissolved in sweat? what does this?
urea (double that in plasma-liquid part of blood)
lactic acid (4 times that of plasma)
potassium (1.2 times that of plasma)
sodium and chloride (body can adjust how much it gets rid of)
eccrine glands
what happens to unacclimatized individual?
low rates of sweating
-most sodium, chloride, and liquid reabsorbed
-urea, lactic acid, potassium high bc they stay the same even though less liquid
then more rapid sweating
- sodium and chloride ions go from 5 to 50-60 mEq/L
unacclimatized individual loses less than ____ /hour max of sweating. Acclimation occurs after ____ weeks, which would then lose ____/liter
1 L
1-6 weeks
2-3 L
as someone is acclimatized they _____ the amount of sodium and chloride lost in sweating. What is responsible for this change?
decrease
increased secretion of aldosterone by the cortices of the adrenal glands
as for salt…
an unacclimatized person loses ___ grams of salt per day and lose ____ fluid.
an acclimatized person loses ____ grams of salt per day and lose _____ fluid
15-30 grams
less fluid
3-5 grams
more fluid
thermoreceptors in _____ detect blood temperature and thermoreceptors in the ___ detect external temperature
hypothalamus
skin
where do we have temperature regulating centers?
- heat and cold sensitive neurons in the anterior preoptic area of the hypothalamus
- skin receptors
- deep body receptors in spinal cord, abdominal organs, great veins
what does the posterior hypothalamus do in temperature regulation
integrates all the signals from anterior hypothalamic-preoptic area as well as peripheral deep body and peripheral receptors to control heat producing and heat conserving reactions in the body.
what mechanisms does our body do if we are too warm
vasodilation skin vessels
sweating
reduced heat production
what mechanisms does our body do when we are too cold?
vasoconstriction of skin vessels
heat production through shivering (posterior hypothalamus)
sympathetic stimulation of heat production thru brown fat (chemical thermogenesis)
thyroxine secretion
-hypothalamus releases thyrotropin releasing hormone
-anterior pituitary releases thyroid stimulating hormone
fever, also called ______, due to infectious and non infectious causes.
hyperthermia
fever fro infectious cause can be brought on by _____
pyrogens
- cytokines (interleukin-1 or IL-1)
- endotoxins (from gram negative organisms)
hyperthermia not from infectious causes can include?
brain lesion
heatstroke (105 F)
hypothermia, when body temp reaches ____ degrees F ________ is impaired. At ____ degrees, it is now unable to fix or regulate the temperature at all.
94 degrees F
hypothalamic regulation
85 degrees F
what can cause a drop in temperature?
sedatives reduce the reactivity of the hypothalamus, such as in critical care, or from surgeries.
what are the hypothalamus effects when the body is too hot?
vasodilation of blood vessels inhibits sympathetic centers in posterior hypothalamus
-vasodilates at the skin level
-increases heat transfer (8 fold from baseline)
sweating
decrease in production of heat
-shivering and chemical thermogenesis inhibited
1 degree celcius in body temperature causes enough sweating to remove ____ times basal heat production
10 times
what does hypothalamus do when the body is too cold?
vasocontriction
-stimulation of sympathetic centers
piloerection
increase in thermogenesis (production of heat)
what is piloerection?
hairs all over the body stand up when erector pili muscles contract
- impacts in other mammals more with more hair to ainsulate air layer
how does shivering work/ what happens to make you start shivering?
body temp falls below set temperature
brain stem causes signals that increase skeletal muscle tone
tone increases until shivering occurs (not voluntary)
shivering can increase body heat production in muscles by _____ times
4-5 times
how does non shivering chemical thermogenesis work?
epinephrin and norepinefrin release
uncouples oxidative phosphorylation
increases energy release from food intake, but doesn’t cause formation of ATP
energy released as heat, not as a result of metabolic processes
primarily in brown fat
____ are released by infectious products, such as _____ and _____.
pyrogens
-toxic bacteria
-degenerating body tissues
pyrogens cause the hypothalamus to ______.
initiate warming through heat conservation and heat production
pyrogens are phagocytized by ________, ______, and _______.
This releases ______
lymphocytes
tissue macrophages
blood leukocytes
cytokines
these cytokines then induce formation of _______
- what is thought to be the most important cytokine?
prostaglandins
-Interleukin-1 (IL3)
what do these prostaglandins then do?
cause hypothalamus to induce the fever response
what do aspirin and ibuprofin do?
inhibit production of prostaglandins, which is responsible for fever
why do chills happen?
because the pyrogens increase the body’s set point
- to accommodate, the body initial lower temp is too low and the heat production and conservation strategies are initiated
what are the sweats?
“flush” or the sweats occur when the hypothalamus resets back to the normal target temperature, and the body tries to dump the heat.
- clinical improvement
-breaking the fever
