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hormone revision (controlling heat rate (Medulla oblongata responsible for…
hormone revision
structure and function of the pancreas
Function
exocrine glad
To produce enzymes and release them via a
duct
into the
duodenum
roles
responsible for producing
digestive enzymes
and alkaline fluid known as
pancreatic juice
they are secreted into ducts
endocrine gland
To
produce hormones
and
release
them
into
the
blood
roles
pancreas responsible for producing insulin and glucagon in the islets of Langerhans
Islets of Langerhans
Alpha cells of islets of Langerhans
These
produce
and secrete
glucagon
larger
and
more numerous
beta cells
alpha cells stain
pink
Beta
cells of islets of Langerhans
produce
and secret
insulin
Beter cells stain
blue
controlling heat rate
controlled by the
autonomic nervous system
Medulla oblongata
responsible for controlling heart rate.
one centre increases heat rate - by sending
impulses
through the
sympathetic
nervous system
transmiterd by the
accelerator
nerve
one centre decreases heart rate by sending
impulses
through the
parasympathetic
nervous system.
transmiterd by the
Vagus nerve
information received by receptors in the blood vessels
TWO TYPES
Baroreceptors (pressure)
detect
pressure change
in the blood
They are present in the
Aorta
Venna cava
carotid arteries
if the blood pressure is to high, impulses are sent to the
medulla oblongata
medulla oblongata
sends impulses along
parasympathetic
neurones to the SAN
This will decreases the heart rate
Chemoreceptors
(chemical)
Detect changes in the level of
particular chemicals
in the
blood
such as
carbon dioxide
They are located in the
carotid artery
medulla
Aorta
sensitive to
changes
in the
pH level
of the blood
high
Carbon dioxide- pH of the blood
decreases
carbonic
acid forms when reacted with
water
in the blood
if the low pH is detected a responses is triggered to increase heart rate.
blood there fore
flows
more quickly
to the
lungs
so the
carbon dioxide
can be
exhaled
also influenced by the presence of hormones
adrenaline and noradrenaling affect the pacemaker
They
increase
the heart rate by
increasing
the
frequency
of
impulses
produced by the SAN
SAN
-
Sino-atrial node
Fight or flight response
Action of adrenaline
Trigger the liver cell to undergo
glycogenolysis
so
glucose
is released into the
bloodstream
increase
in respiration more
ATP
available for
muscle contractions
Adrenaline-
Hydrophilic
so can not pass through the
cell membrane
When adrenaline binds to
specific receptor
the
enzyme adenylyl cyclase
is activated
1)
The
ADRENALINE
approaches receptor site.
2)
ADRENALINE
fuses to receptor site in doing so
ACTIVATES
an enzyme
INSIDE
the MEMBRANE
3)
ACTIVATED
enzymes to convert
ATP
to
CYCLIC AMP
it actas as a SECONDRY MESSSENGER
The
SCONDRY MESSENGER
activates other enzymes that convert
glycogen
to
glucoses
Adenyly cyclase triggers the conversion of
ATP
into
cyclic Adenosine Mono-Phosphate (cAMP)
Happens in the inner surface of the cell membrane in the cytoplasm
increase in cAMP levels activates specific enzyme
protein kinases
which
phosphorylate
which activate other enzymes.
Activates enzymes
glycogen
glucose
ATP
CYCLIC AMP
( Second messenger)