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Homeostasis
Homeostasis
• The regulation of an organism’s internal
environment to maintain conditions suitable
for life.
• The internal equilibrium of the body, the
ultimate gauge of its proper functioning,
involves the maintenance of a constant rate
of certain molecules in the blood.
• Disruption of homeostasis of the body
systems can cause disease and possibly
death.
• Body temperature, pH Levels and hormone
levels are examples of mechanisms that are
regulated by the body to maintain
homeostasis.
Maintaining homeostasis of
body temperature
• The hypothalamus maintains body
temperature.
– Too warm- perspire and lose heat by
evaporation
– Too cold- shiver and increase metabolism to
generate heat
• Too much heat can result in heatstroke.
• During this condition body temperatures
can reach 110 °F, as the body loses it’s
ability to rid itself of heat.
– Skin becomes hot and dry
– Blood rushes to head and face
– Convulsions, brain damage, and death may
follow
Hypothalmus gland in the frog
Maintaining homeostasis of
body temperature
• Too little heat can result in
hypothermia.
• During this condition, body
temperature falls below 95°F.
• If the body’s core temperature falls
below 90°F the heart can’t pump
blood and it will contract erratically.
Maintaining homeostasis of
hormone levels
• The endocrine system plays an
important role in the maintenance of
homeostasis.
• Example: glucagon and insulin maintain
a balanced blood glucose level.
• These hormones are considered
antagonistic because their actions have
opposite effects.
– Increase in glucose concentration following
glucagon secretion is counteracted by an
insulin secretion.
Maintaining homeostasis of
hormone levels
• Most hormones use negative
feedback which is the release of
an initial hormone stimulates the
release or production of other
hormones or substances that
inhibit further release of the initial
hormone.