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Endocrine System (BIOLOGY)
- A communication system that uses
hormones as its signalling
molecules- in the bloodstream
- Hormones are chemical
messengers- carry signal from
endocrine glands to target cells
- Amino-acid derived
- E.g. adrenaline, insulin & glycagon
- Polar- not soluble in the
phospholipid bilayer of their
target cells
- Binds to complementary receptors on target cell
- Uses 1st + 2nd messengers
- 1st messenger= non-steroid hormone
- 2nd messenger= cAMP
- 1st messenger= non-steroid hormone
- Activates G protein
- Activates adenyl cyclase
- converts ATP to cAMP
- cAMP brings about response in the cell
- e.g. activation of enzyme, opening a
channel protein or protein synthesis
- e.g. activation of enzyme, opening a
channel protein or protein synthesis
- cAMP brings about response in the cell
- converts ATP to cAMP
- Activates adenyl cyclase
- Uses 1st + 2nd messengers
- Binds to complementary receptors on target cell
- E.g. adrenaline, insulin & glycagon
- Steroid
- e.g. oestrogen + testosterone
- Non-polar- soluble in the phospholipid
bilayer
- Diffuses into target cell + has a direct effect on DNA in
nucleus
- e.g. activation of an enzyme, opening channel protein or protein synthesis
- e.g. activation of an enzyme, opening channel protein or protein synthesis
- Diffuses into target cell + has a direct effect on DNA in
nucleus
- e.g. oestrogen + testosterone
- Amino-acid derived
- Endocrine glands
- Ductless glands, that manufacture
and release hormones directly into
the bloodstream
- Exocrine glands- produces +
secrete other substances into
ducts (e.g. pancreatic duct,
salivary duct)
- Ductless glands, that manufacture
and release hormones directly into
the bloodstream
- Hormones are chemical
messengers- carry signal from
endocrine glands to target cells
- Adrenal Gland
- A pair of glands,
above the kidneys
- Manufacture + secrete adrenaline (+ other hormones)
- Manufacture + secrete adrenaline (+ other hormones)
- Adrenal Cortex
- 3 distinct layers of
cells
- ZONA GLOMERULOSA
- ZONA FASCICULATA
- ZONA RETICULARIS
- ZONA GLOMERULOSA
- uses cholesterol to produce a range of
hormones
- So steroid based + can have a direct effect on DNA of target cell
- So steroid based + can have a direct effect on DNA of target cell
- 3 distinct layers of
cells
- Cortex + Medulla: well supplied w/blood to
secrete hormones into
- Adrenal Medulla
- Manufactures and secretes adrenaline (+ nonadrenaline)
into the bloodstream
- Adrenaline is an amino
acid derived hormone- so polar
- It uses a 1st + 2nd
messenger; that brings
about a response in
the cell
- It uses a 1st + 2nd
messenger; that brings
about a response in
the cell
- The effects of adrenaline are widespread
+ prepare the body for activity
- Pupil dilation, increased heart + breathing rate, decreased
digestion, vasoconstriction- raises blood pressure
- Pupil dilation, increased heart + breathing rate, decreased
digestion, vasoconstriction- raises blood pressure
- Adrenaline is an amino
acid derived hormone- so polar
- Manufactures and secretes adrenaline (+ nonadrenaline)
into the bloodstream
- A pair of glands,
above the kidneys
- The Pancreas
- Small organ below the stomach
- Endocrine Function
- Islet of Langerhans
contain alpha and beta
cells
- If beta & alpha cells detect blood
glucose levels as too high...
- Beta cells release insulin
- target cells are liver, muscle and brain cells
- look at 'ACTIONS OF INSULIN'
- look at 'ACTIONS OF INSULIN'
- look at 'RELEASE OF INSULIN FROM
BETA CELLS'
- target cells are liver, muscle and brain cells
- Beta cells release insulin
- Is beta and alpha cells
detect blood glucose
levels as too low...
- Alpha cells release
glucagon
- target cells are hepatocytes
- look at 'ACTIONS OF GLUCAGON'
- look at 'ACTIONS OF GLUCAGON'
- target cells are hepatocytes
- Alpha cells release
glucagon
- If beta & alpha cells detect blood
glucose levels as too high...
- Islet of Langerhans
contain alpha and beta
cells
- Exocrine Function
- Manufactures + secretes digestive juices into
the small intestine via, the pancreatic duct
- Exocrine cells are
grouped into...
- acini
- Acini are grouped into small lobules,
separated by connective tissue
- Acini cells secrete digestive juices into the tiny tubules in the centre
- Tubules join to form intralobular ducts, which make up the pancreatic duct
- Pancreatic duct- carries digestive enzymes into the small intestine
- Pancreatic duct- carries digestive enzymes into the small intestine
- Tubules join to form intralobular ducts, which make up the pancreatic duct
- Acini cells secrete digestive juices into the tiny tubules in the centre
- Acini are grouped into small lobules,
separated by connective tissue
- acini
- Digestive juices contain the enzymes...
- Trypsinogen
- inactive protease converts into trypsin
- inactive protease converts into trypsin
- Lipases
- Amylases
- Contains sodium
hydrogencarbonate (alkali)
- Trypsinogen
- Exocrine cells are
grouped into...
- Manufactures + secretes digestive juices into
the small intestine via, the pancreatic duct
- Endocrine Function
- Small organ below the stomach
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