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Hormones


Hormones are signalling molecules that travel
long distances in the blood. They are secreted
by endocrine (ductless) glands. The adrenal
gland is an example.



Hormones have a unique function (doesn't
affect other cells). They have a specific
complimentary shape to the receptors in the
plasma membrane of cells in…

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Region of the adrenal Hormones secreted Target organs Functions of
gland hormones

Adrenal cortex Mineralcorticoid; Kindey, gut Stimulates increase in
aldosterone absorption of sodium
ions leading to an
increase in blood
pressure
Glucocorticoids; Liver Stimulate increase in
cortisol and blood glucose
corticosterone concentration by
gluconerogenesis
Adrenal Medulla Catecholamines; Liver Examples:…

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Adrenaline, noradrenaline 160-190 seconds
Antidiuretic hormone (ADH) 10-30 minutes
Insulin 5 minutes
Glucagon 5-10 minutes
Anabolic steroids Between 30 minutes and 16 hours.


First and second messengers.
Adrenaline as it is derived from amino acids, like insulin and glucagon, cannot cross cell membranes,
whereas lipid soluble steroid hormones such as…

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Pancreas
The exocrine function is the manufacture and secretion of pancreatic fluids which contain digestive
enzymes such as lipase, amylase and trypsin and alkaline sodium hydrogen carbonate. Small groups
of cells called acini (1x acinus) surround tiny tubules, in which they synthesise and secrete the
pancreatic fluids into. The tubules…

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Pancreas is an organ has both endocrine and
exocrine functions which include:

Secretion of enzyme by the exocrine gland
by:
Pancreatic cell are distributed in to small
groups surrounded by tiny tubules
The cells secrete digestive enzymes into the
tubules
The tubules join the pancreatic duct
Which carries fluid into…

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As a meal is absorbed into the blood stream the concentration of glucose may increase by 50%. The
following events occur when the blood glucose concentration rises above the set point:

(1) The increasing concentration of glucose acts as a stimulus that is detected by cells in the islets
of…

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After a meal has been absorbed completely and also during exercise the blood glucose
concentration may decrease below the set point. The following events then occur

(1) cells stop releasing insulin. This means that cells take up less glucose.
(2) cells in the islets of Langerhans respond to decreasing concentrations…

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Blood concentration too low:

cells detects change
secretes glucagon hormone
glucagon travels to target cells (hepatocytes)
cause conversion of glycogen to glucose, respiration of fatty acids and conversion of
amino acids to glucose

























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The regulation of insulin






(1) In the normal range of blood glucose concentration:
a. Membrane potential is at 70mV ATPpotassium ion channel proteins are open and
some potassium ions diffuse out of the cell
b. Voltage gated calcium channels are shut, the membrane is impermeable to calcium
ions.
(2) Blood…

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Less glucose diffuses into the cell when the glucose concentration falls below the set point. Less
respiration occurs and the decrease in ATP concentration causes the ATPgated potassium ion
channel proteins to open.

Glucose is transported in solution in the plasma. There is not much glucose in the bloor or…

Comments

Izzy Mason

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Thanks really useful :)

Swallowtail

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This excellent set of notes include detailed information, flow diagrams and clear annotated diagrams outlining hormone action, first and second messengers, the regulation of glucose levels, the function of adrenaline and control of heart rate. The clear images will aid memory of the key factual information. Although designed with the OCR A2  specification in mind, they could be useful to any student needing to study these topics.  

Nimra

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can you make some more notes on all topics for a2 level ocr?

goldner1

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this really helped me find my center THANKS :)

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