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Slide 1

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B1f- Staying in balance…read more

Slide 2

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Is the maintenance of a constant internal
I involves balancing inputs and outputs and
managing negative feedback to ensure cells
can operate affectively
Homeostasis controls;
Blood glucose levels
Body temperate (37.5)
Water content
Carbon dioxide levels…read more

Slide 3

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Controlling body temperature
Body temperature should be maintained at 37.5 degrees
Celsius so that enzymes are at there optimum
Body temperature is lowered by vasodilatation where the
blood vassals near the skin widen to allow more blood to
flow making it easier for heat to escape. The body also
sweats, this keeps us cool because when water
evaporates of our skin it takes heat with it.
Our Body temperature is raised by Vasoconstriction
where the blood flows further into the skin to stop heat
escaping by the capillaries near the surface constricting.
The body also shivers which generates heat by muscle
contraction.…read more

Slide 4

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Sex hormones
Sex hormones are responsible for the
secondary sexual characteristics developing
during puberty
Change Male Female
Voice breaks Yes No
Hair grows on face and Yes No
Hair grows under arms Yes yes
Pubic hair grows Yes Yes
More muscular Yes No
Genitals develop Yes Yes
Sperm production starts Yes no
Breasts develop No Yes
Hips widen No Yes
Periods start No yes…read more

Slide 5

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Sex hormones-Female
The female sex hormones are oestrogen and progesterone. These
hormones control the menstrual cycle
Oestrogen causes the lining of the uterus to thicken and re-
grow blood vessels
Progesterone maintains the lining of the uterus. A fall in
progesterone levels trigger menstruation
Ovulation is controlled by these hormones as well as hormones
produced in the brain called FSH ( follicle stimulating hormone)
and luteinizing hormone(LH) that are highest at ovulation.
Fertility can be controlled by the use of artificial hormones like
those contained in the contraceptive pill which prevent ovulation
or other drugs that work the other way around.…read more

Slide 6

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Diabetes is caused the body not having
enough insulin to sugar into glycogen to be
stored in the liver.
Type one Type two
·Juvenile onset ·Adult onset
·Insulin dependant ·Insulin independent
·No insulin made ·Insulin produced but the
·Regular insulin injections body has a tolerance.
and also artificial pancreases ·Diet reduces fats and
are being developed. sugars and also exercise will
use up the glucose in the
blood.…read more


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