chapter 14 - hormonal communication Flashcards
What is the function of the adernal gland?
- Its an endocrine gland that secretes hormones
Where is the adernal gland found and what is it made up of?
- its found above the kidney
- its made of the cortex and medulla
What is the role of the cortex in the Adernal gland?
- its secretes steroid hormones which are stress hormones (cortisol and aldosterone)
- The release of these hormones causes -
- This promotes gluconeogenesis(making glucose from non carbs) for respiration
- it also causes the kidney to reabsorb more Na and H20 increasing blood volume and pressure
- supresses the immune system
What are hormones are released by the cortex in the Adernal gland?
- cortisol
- aldosterone
What is the role of the medulla in the Adernal gland?
- secretes hormones(adrenaline and noradrenaline) which increases heart rate and breathing rate
- promote glycogenolysis for respiration
- Divert blood to muscles and brain
What is the pancreas and its role?
- its an endocrine gland and it releases hormones
Where is the pancreas found and what does it contain?
- its found below the stomach
- it contains the islets of Langerhans, which contain alpha and beta cells
What hormones do alpha and beta cells produce?
- alpha cells produce glucagon
- beta cells produce insulin
What is meant by a fight or flight response?
- its a response to a threatening stimulus coordinated by the nervous and endocrine system
How does the body coordinate a flight or fight response?
- its coordinated by the autonomic NS
- sympathetic NS releases noradrenaline (neurotransmitter) at neuromuscular junctions
- Adrenaline is secreted into blood by adernal glands
- the adrenaline then binds to specfic receptors on target tissue
What is the affect of noradrenaline and adrenaline being released?
What is the purpose of these affects?
- increased heart rate
- increased blood pressure
- increased breathing rate
- increased blood flow to skeletal muscle
- liver converts glycogen to glucose
- it increases respiration, more ATP for skeletal muscle
How does the body respond to an increase in blood glucose levels?
- receptors in the pancreas detect an increase in blood glucose
- Beta cells in the islet of Langerhans secrete insulin
- insulin binds to receptors in liver and muscle cells which increases their permeability to glucose
- As a result, more glucose in reabsorbed by facillitated diffusion
- As a result, glycogenesis
- As a result, increases the rate of respiration
- this is an example of negative feedback
How does the body respond to a fall in blood glucose levels?
- receptors in the pancreas detect low level of glucose in the blood
- alpha cells in the islet of langerhans secrete glucagon
- Glucagon bins the receptors on liver cells
- As a result, Gluconeogenesis
- As a result, glucogenolysis
- As a result, decrease in respiration
At normal blood glucose levels, what is occuring in a beta cell with regards to charge and ion channels?
- k ion channel is open and and k diffused in beta cell
- inside of beta cell is relatively negative (-70)
- calcium ion channel is closed
At high blood glucose levels, what is occuring in a beta cell?
- As blood glucose levels rise, more glucose enters by facillitated diffusion
- Glucose is respired to form ATP
- ATP blocks the K ion channel
- this causes the membrane to depolarise
- which causes the calcium ion channel to open and calcium diffuse into beta cells
- As a result, the vesicles containing insulin are released by exocytosis
What is glycogeneisis?
What is gluconeogenesis?
What is glycogenolysis?
- Producing glycogen from glucose (promoted by insulin)
- producing glucose from non carbs (promoted by glucagon)
- breaking down glycogen into glucose (promoted by glucagon and adrenaline)
what is the mechanism of adrenaline in terms of its role in blood glucose regultion
- it activates glycogenolysis and secreation of glucagon
- it inhibits glycogenesis and the secreation of insulin
what is diabetes?
what is the difference between hyperglycaemia and hypoglycaemia?
- diabetes is an illness where blood glucose levels are not controlled
- hyperglycaemia is high blood glucose concentration
- hypoglycaemia is dangerously high low blood glucose concentration
What are the causes of both type 1 and type 2 diabetes?
- type 1, immune system kills beta cells so cant make insulin
- type 2, obesity, lack of exercise and poor diet lead to beta cells not making enough insulin and liver and muscle cells stop responding to insulin
What age category would you see type 1 and 2 diabetes in?
- type 1, children and young adults
- type 2, adults and elderly
What are the treatments for type 1 and type 2 diabetes ?
- type 1, insulin injections (however too much insulin can lead to hyperglycaemia), avoid simple carbs, eat at regular intervals, regular exercise to use up glucose
- type 2, eat healthy, lose weight, regular exercise, use of drugs
What are the treatment choices for diabetes?
- genetically modified bacteria
- use of stem cells
What are the advantages of using genetically modified bacteria to treat diabetes?
- it makes human insulin so there are fewer immune reactions
- insulin produced has no contamination
- made in large quantities
- faster and cheaper
What are the disadvantages of genetically modified bacteria to treat diabetes?
- it uses genetically modified bacteria so some people have religious and ethical issues surrounding this
How are stem cells used to treat diabetes?
- inject stem cells into the beta cells of the islet of Langerhans
- uses totipotent embryonic stem cells
- which differentiate into functional beta cells which produce and secrete insulin
What are the advantages of using stem cells to treat diabetes?
- patients don’t need to inject insulin
- treatment lasts lifetime
What are the disadvantages of using stem cells to treat diabetes?
- requires the use of embryonic stem cells so there are some religious and ethical objections
- stem cells may develop into other types of cells and cause harm (tumour and cancers)
