Hormonal communication Flashcards
(36 cards)
what is the endocrine system
The endocrine system is a communication system within the body, like the nervous system
It works by releasing hormones directly into the blood
whatt are the two types of hormones
-Protein and peptide hormones
-Steroid hormones
What are protein/peptide hormones
hormones that are ni soluble;e in the phospholipid bilayer and therefore do not enter the cell its self, instead they bind to receptors on the phospholipid bilayer of the target cell
What are steroid hormones
These are hormones that are derived from cholesterol, they are soluble in the phospholipid bilayer and can therefore enter the cell and bring about a change directly form inside the cell, for example editing a gene
What is the difference between endocrine and exocrine glands
Endocrine glands are ductless, they release their substances directly into the bloodstream via capillaries that ru inside the glands
Exocrine glands release their substances via a duct onto the body surface, for example sweating
First and second massagers
Non steroid hormones are usually known as first messengers, they bind to s receptor on the cell surface membrane. this usually causes the release of a secondary messenger within the cell its self
What is the G protein and how does it act
The G protein is activated when a first messenger binds to the receptor, this causes the G protein to make an inactive protein active and therefore make it the secondary messenger
What’s a good example of an effector molecule and what does it do
adenyl cyclase, converts ATP into cAMP
Describe the function of an adrenal gland
the adrenal cortex and the adrenal medulla
What is the adrenal cortex and what happens within it
The adrenal cortex is situated on the outside of the adrenal glad which is on top of the kidneys
IT has three distinct levels of cells
-Zona glomerulosa, the outermost leyer, secretes mineralocorticoids
Zona fasciculata, middle layer , releases glucocorticoids
zona reticularis releases precursor molecules though to make up sediment hormones
what type of hormones are released by the adrenal gland
steroid hormones
What are some examples of what hormones released from the adrenal gland do
Glucocorticoids eg cortisol help to control the metabolism of carbohydrates, cortisol is released in Times of stress it stimulates the production of glucose from stored compounds such as glycogen fats and proteins
Adrenaline
adrenaline os not a sertoid hormone, it stimulates:
- relaxing of smooth muscles in bronchi
-increasing stroke volume in the heart
-general vasoconstriction to increase4 blood pressure
-increased hr
-increased mental awareness
-dilating pupils
inhibits the action of the gut
Where is the pancreas
Below the stomach
What are the 2 main secretions from the pancreas
Pancreatic juices containing enzymes that are secreted into the stomach
Hormines which are secreted fro9m the langerhans into the blood
What is the pancreas’ exocrine function
the release of digestive enzymes
The exocrine cells are in groups surrounded by tiny tubules. Each group of cells is called an acinus. Acini secretee the enzymes into the tubule at the centre of the group. These combine to form a duct
What is the pancreas’ exocrine function
Dispersed in small patches among the acini are the islet of langerhans
The islet of langerhans contain both alpha and beta cells
What is the roll of beta cells in the pancreas
These cells make up the exocrine tissue in the pancreas
What is the roll of alpha cells in the pancreas
These secrete glucagon and insulin
Describe the release of insulin
When insulin is released from the islets of langerhans, it brings about An effect which lowers blood glucose
how is insulin released from beta cells in the pancreas
The cell membrane of beta cells contains both calcium and potassium channels
potassium ion channels are usually open and calcium channels are usually closed
when glucose levels outside the cell are high, glucose moves into the cell
this can be used to synthesis atp
The extra ATP causes the potassium channel to close
Potassium can no longer diffuse out of the cell and makes. the water potential inside the cell more negative
The change in water potential opens up the calcium chanell
This means that calcium can diffuse into the cell
This therefore triggers the release of insulin
what is the normals blood gluecose concentration
4-6mmol
when is someone hypoglycaemia
When someone’s blood glucose is allowed to drop below 4mmol for extended periods of time
What are the effects of hypoglycaemia
inadequate delivers of glucose to the body muscles and tissues
This may simply cause fatigue and irritability, but it could also cause impairment of brain function In survey cases
What is hyperglycaemia
When a persons blood glucose is allowed to rise above 7mmol for extended periods of time
