Honmones Flashcards
Describe the steps in endocrine communication
A stimulus is detected by receptors on endocrine glands which causes hormone to be released into the blood and effect target cells which coordinate a response
How are hormones detected?
The hormone is the first messenger and carries info from the endocrine gland to the receptor where it binds and activates an enzyme in the cell membrane
Enzyme increases production of secondary messenger which activates a cascade inside the cell
Describe the structure of the adrenal gland
Endocrine glands found just above the kidneys, each has an outer cortex and inner medulla
What is the function of the cortex of the adrenal gland?
Secretes steroid hormones
Cortisol and aldosterone
Stimulates breakdown of fats and proteins into glucose
Increases blood volume and pressure -increase intake of Na and water by kidneys
Surpresses immune system
What is the function of the medulla in the adrenal gland?
Adrenaline and noradrenaline
Increase heart and breathing rate
Causes glycogenolysis
Construct blood vessels to non essential organs
What are the two types of gland in the pancreas and what do they do?
Exocrine
- digestive enzymes and alkali fluid(pancreatic juice)
- secreted in pancreatic duct then into duodenum
Endocrine
- insulin (b cells) and glucagon (a cells) in islets of langerhan
- into blood stream
Roles of insulin
Bind to liver and muscle cell receptors
Increase rate of absorption of glucose by cells as is binds to cell membrane and increases its permeability to glucose
Increase respiratory rate
Increase glycogenesis (activates enzymes that convert glucose to glycogen)
Increase glucose to fat
Inhibit release of glucagon
How is insulin secreted?
When glucose concentration is high, more glucose enters beta cells by facilitated diffusion
Increases rate of respiration making more ATP
this causes potassium channels to close so Potassium ions can’t get through membrane so becomes more positive
B cell is depolarised so calcium ion channels open and diffuse in
Causes vesicles to move to and fuse with beta cell membrane and release insulin by exocytosis
What causes type 1 diabetes?
Autoimmune disease which attacks and destroys beta cells
Don’t produce insulin
Causes of type 2 diabetes
When beta cells don’t produce enough insulin or when cells don’t respond to insulin (insulin receptors)
related to obesity
Treatment of type 1
Insulin injections- pump or needle
Islet cell transplant
Healthy balanced diet
Regular excersuze
Treatment of type 2 diabetes
Change in lifestyle
- diet(balanced and low carb)
- excersize
- losing weight
Anti diabetics such as metaformin
What are the 2 potential treatments for diabetes mellirus?
Genetically modified bacteria
-used to b extracted from animal pancreas but now made by gm bacteria
Stem cells
-grow stem cells into beta cells
These implanted into pancreas of the person with type 1
Would now be able to make insulin as normal - could cure
what are the advantages of GM bacteria producing insulin?
they produce human insulin which is more effective than pig insulin and less likely to cause rejection/trigger an allergic response
it is cheaper than extracting from animals
people prefer for ethical and religious reasons
how does glucagon regulate blood glucose concentration?
when blood glucose concentration decreases
1 (glucagon) released by the , alpha / , cells in ,
islets of Langerhans / pancreas
2 promotes / AW ,
conversion of glycogen to glucose /
glycogenolysis ,
in , liver / muscle / effector , cells ;
3 ref gluconeogenesis / described ;
4 ref conversion of triglycerides to (free) fatty acids /
lipolysis /
increased use of fatty acids in respiration ;
5 negative feedback ,
reduces / inhibits , the secretion of glucagon ;
6 glucagon , reduces / inhibits , insulin secretion ;
