Download C.I.R.L Regulation of Body Temperature And Energy Production In

Ch.14 Supplement
» The most common diagnosis of illness is the question: “Do you have a
fever?”
» The healthy temperature range of the human body is 35.8oC-37.2oC
(96.5oF-99oF)
˃ In real practice, it is very difficult to maintain near constant
temperature of a system
˃ Body performs this task flawlessly
˃ The narrow temperature range is essential to proper muscle
function and to control the kinetics of biochemical reactions
» The portion of the brain stem called the hypothalamus regulates body
temperature
» Heat is transferred from the body to its surroundings by convection and
evaporation.
˃ Convection is direct heat transfer to the surrounding air
˃ Evaporative heat loss occurs when sweat is generated. The water in
sweat absorbs our discharged heat, as shown below
H2 O L → H2 O g
∆H o = 44
kJ
mol
˃ During high exhaustion, the body can secrete as much as 4L of water
per hour.
+ The body’s water must be replenished! Without water, the body
can not cool itself and the blood volume decreases, causing heat
stroke.
» Our bodies (system) increase their internal energy by ingesting foods
from the surroundings. The energy is available in the forms of
carbohydrates, fats, and proteins.
» Carbohydrates (i.e. starches/polysaccharides) are decomposed into
glucose soluble in the blood. They are transported to cells and react
with O2
C6 H12 O6 s + 6O2 → 6CO2 g + 6H2 O L
∆H o = −2803
kJ
mol
» 40% of the energy released from this reaction is used to do work in
the form of muscle contractions and nerve activities. The remainder
is used to maintain temperature
» Because carbohydrates break down rapidly, their energy is quickly
supplied to the body, and only a small amount of carbohydrate is
stored. Unused energy is stored as fat.
» Like carbs, fats also produce energy (ex. tristearin)
C57 H110 O6 s +
163
O 𝑔 → 57 CO2 g + 55 H2 O L
2 2
∆H o = −75520
» Fats serve as the body’s energy reserve. They are insoluble in water
(nonpolar) which prevent them from being flushed out in urine, and
they are very energy rich.
kJ
mol
» When you eat protein, your body breaks it down into amino acids that
are used for several purposes. Protein can provide your body with
energy when necessary, but you should not rely on protein as a primary
energy source because it has more important physiological roles to play
» Structure
˃ Structural proteins can be found in every cell in the human body. These
proteins make up connective tissues, hail, nails, skin and muscles.
These proteins enable body movement. As much as 16% of body
weight is accounted for by structural proteins.
» Immunity
˃ When your body is exposed to bacteria and viruses, your immune
system sends out proteins called antibodies. These antibodies seek out
and attack the invading species to multiplying and causing illness.
» Transport
˃ Proteins carry Na+ and K+ in and out of cells in order to maintain
electrolyte balance. Hemoglobin carries O2 from your lungs to your cells
and also takes carbon dioxide from your cells to your lungs, so that it
can be expelled from the body.
1 Food Calorie = 4184 J
Energy Source
Energy Content (J/g)
Carbohydrate
17000
Fat
38000
Protein
17000
The average person needs 100 kJ of
energy per kg of body mass to function
at a minimum level (i.e. stay alive)
• Estimate the energy
content based on the
numbers provided and
compare to the
approximate calorie
content shown?
• How many grams of
cheerios would you need
to eat to run 2.5 miles
assuming the body uses
105 FCal/mi?