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