5.1.4- Hormonal Communication Flashcards
what are endocrine glands?
glands that secrete hormones directly into the blood.
what is an example of an endocrine?
the pancreas (specifically the inslet of langerhans), as it secretes insulin and glucagon into the blood.
what is endocrine communication detected by?
-target cells/tissues
-this is because the cells have a pacific receptor on their plasma membrane, which is complementary to the shape of the hormone molecule.
what is the adrenal gland an example of?
an endocrine gland
what are the two parts of the adrenal gland that releases hormones?
-cortex (secretes life-vital hormones)
-medulla (secretes non-life vital hormones)
what 3 types of hormones and their examples, are released from the adrenal cortex?
-glucocorticoids, eg-cortisol
-mineralocorticoids, eg- aldosterone
-androgens, eg-sex hormones
what is the secretion of hormones by the adrenal cortex controlled by?
the pituitary gland
what are the two hormones, and their examples, that are released from the adrenal medulla?
-adrenaline, eg-adrenaline
-noradrenaline, eg-noradrenaline
what is the secretion of hormones from the adrenal medulla controlled by?
when the sympathetic nervous system is stimulated
what is the function of cortisol?
-regulates fat carbohydrates and protein metabolism
-stimulates liver to convert fat and protein to glucose
what is the function of aldosterone?
-regulate mineral ion balance
-stimulates kidney and gut to uptake sodium ions to control blood pressure
what is the function of sex hormones?
-smaller effect than oestrogen and testosterone
what is the function of adrenaline?
-fight or flight response
-increased BR, MR, HR
-stimulates liver to hydrolyse glycogen and glucose
-inhibits peristalsis
what is the function of noradrenaline?
-decreases HR, BR
-widens pupils and air passages in lungs
-narrows blood vessels in non-essential organs
what does the histology of the pancreas consist of?
-islet of langerhans (made up of beta and alpha cells, endocrine), in the centre
-blood capillaries
-exocrine cells surrounding centre
-tubule/duct for enzymes in centre of enzyme-secreting cells
what do the exocrine cells in the pancreas do?
secrete enzymes
what is the role of the beta cells in the pancreas?
when there is a rise in blood glucose conc, beta cells detect this and secrete insulin
what is the role of the alpha cells?
when there is a fall in blood glucose conc, alpha cells detect this and secrete glucagon
how does insulin decrease blood glucose back to normal level?
-causes more glucose carriers placed in the plasma membrane so more glucose enters the cell
-stimulates glycogenesis (glucose to glycogen)
how does glucagon increase blood glucose back to normal?
-stimulates gluconeogenesis (amino acids/fats to glucose
-glycogenolysis (glycogen to glucose)
what are the 7 steps to insulin secretion by the pancreas, when blood glucose conc is too high?
-potassium ions diffuse out of open potassium channels
-glucose diffuses into beta cells when blood glucose conc is high
-glucose is used to make ATP in respiration
-ATP closes the potassium channels
-potassium ions accumulate inside the cell, creating a potential difference (cell is more negative inside)
-this change in pd causes calcium channels to open, so calcium ions diffuse into the beta cell
-calcium ions cause vesicles that contain insulin to fuse with plasma membrane, and so insulin is released via exocytosis.
what is type 1 diabetes?
an autoimmune disease, when people are insulin dependent, as their beta cells are unable to produce insulin, due to being attacked by body cells.
what is type 2 diabetes?
when people are unable to effectively use insulin and control their blood sugars.
what causes type 1 diabetes?
-genetics
-family history
what causes type 2 diabetes?
-obesity
-diet high in refined sugars
-family history
-ethnicity
what is the treatment for type 1 diabetes?
daily insulin injection
what is the treatment for type 2 diabetes?
-change in diet
-increased exercise
-tablets that slow down glucose absorption
-insulin rejection
what is one alternative to using insulin injections to treat diabetes?
genetically modified bacteria through genetic engineering
what are the 4 advantages of using insulin produced by genetically modified bacteria?
-produced in pure form, less allergic reaction
-produced in higher quantities
-cheaper to produce
-removes concerns over animal welfare/religious
what are stem cells used for in diabetes treatment?
-promote differentiation into beta cells
-helps user create own insulin
