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20 terms

Biophysics lecture 5

STUDY
PLAY
1st law of thermodynamics
the change in the internal energy of a substance is equal to the amount of heat absorbed the substance minus the amount of work done by the substeance
heat
is a form of energy called thermal energy
always flows from a hot body to a colder one
1 cal is the needed neargy to heat the 1cm3 of the water to 1 degree in celcius. in fact from 14.5 to 15.5 degree in celcius
heat production
is a principal by product of metabolism
basal rate of metabolism of all the cells of the body, extra rate of metabolism caused by muscle activity including muscle contraction caused by shivering extra metabolism caused by effect of thyroxine hormone + testosterone on two cells
radiation
loss of energy by radiation means loss in the form of infrared heat rays, a type of electromagnetic wave
infrared heat rays are 5-20mm
convection
the removal of heat from the body by convection air currents is commonly called heat loss by convection
evaporation
mainly reserved for sweat glands
in human body temp is on normal level (98 degrees ferehneit) the evaporation of 1 liter sweat losses about 2.4 mj (580kcal) from organisim
basal metabolic rate (BMR)
Is a velocity of organism metabolism, which remains in the physical and psychologicl comfort and also in the temp, after at least 12 hrs for the lost physical effort and after 8hrs of sleeping
basal metabolic rate is intended for the systems work
1/4 of all for the nervous system
1/5 of all for the liver
1/15 of all for the kidneys
1/15 of all for the heart
the rest of the energy for the muscle work
what is the medium day demand for energy
about 2000-3000 kcal
basically depends on a persons lifestyle
the local activity of the cold factor
the 1st phase based on the blood vessels spasm situated in the skin (paleness effect)
the local activity of the warm factor
at the 1st moment the skin blood vessels are opened
after the arterial hypervaemia the skin tissues begins to become a cyanotic reation
the impact of the cold factors on the circulatory system
a hypovolaemia
bradycardia
a decrease of the peripheral vascular resistance
a blood pressure rise
the impact of the warm factors on the circulatory system
a hypervolaemia
a tachycardia
a decrease of the peripheral vascular resistance
a blood pressure fall
the impact of the cold factors on the respiratory system
an increase of the pulmonary minute ventilatin
a respiratory acidosis
the impact of the warm factors on the respiratory system
an increase (300-400%) of the pulmonary minute ventilation
a hyperventilation
a respiratory alkalosis
the impact of the thermal factors (both warm and cold) on the metabolism
a gastric hypersecretion
a hyperperistalsis in the alimentary tract
the impact of the cold factors on the urinary system
a hyperuresis (if it is a short-time impulse)
anoliguresis (if it is a long-time impulse)
the impact of the warm factors on the urinary system
a hyperusresis
the impact of the cold factors on the endocrine system
an increase of the adrenaline, noradrenaline, histamine, rhenine, and tyroxinosis level
the impact of the warm factors on the endocrine system
an increase of the acetylocholine and adenile acid level