Transcript Slide 1 - squ

Claude Bernard in
1829 said: The
proper functioning
of the cells
depends on precise
regulation of
the composition of
their surrounding
fluid.
Surrounding fluid = Internal environment
= Le Milieu interier
• Water is main solvent in living cells
• Hydrophilic molecules dissolve in water
• Hydrophobic molecules do not dissolve in water
• Amphiphilic - molecule part hydrophilic/part
hydrophobic
Body Water
Intracellular fluid
(inside cells)
Extracellular fluid
(outside cells)
Plasma
(inside
blood vessels)
Interstitial Fluid
(outside
blood vessels)
Major Elements % body wt
Oxygen
65%
Carbon
18%
Water
Hydrogen
10%
Nitrogen
3.4%
= 60% adult male
Mineral Elements
= 50% adult female
Sodium
0.17%
0.28%
Principal organic constituents Potassium
Chloride
0.16%
Calcium
1.5%
• carbohydrates  sugars
Magnesium
0.05%
• fats  fatty acids
Phosphorus
1.2%
• proteins  amino acids
0.25%
• nucleic acids  nuclotides Sulphur
Trace Elements
Iron
0.007%
Zinc
0.002%
Nutrients and
oxygen are
distributed by the
blood
Metabolic wastes
are eliminated by
the urinary and
respiratory
systems
Homeostasis is the ability to maintain
a relatively stable internal
environment in an ever-changing
outside world.
The internal environment of the body
is in a dynamic state of equilibrium.
Concepts of homeostasis dynamic.
Chemical, thermal, and neural factors
interact to maintain homeostasis.
Stimulus: change
in BP
Receptors:
Baroreceptors
Control Center:
Brain
Effector: Heart
Stimulus: stretch
of the uterus
Receptors:
stretch receptors
(cervix)
Control Center:
Brain
Effector: Uterus