hormonal communication Flashcards
endocrine gland
secretes its product directly into blood ( lymph)
target cells
possess a specific receptor on cell surface membrane, complementary hormone
exocrine gland
secretes its products in a duct
endocrine system
group of glands that release hormones into blood
eg of glands
pituitary gland - LH & FSH
pancreas - insulin
protein hormones
INSOLUBLE over bilayer
-bind to cell surface and release as secondary messenger inside cell
(Enzyme catalyses second messenger)
steriod hormones
can pass through the membrane & enter cell and nucleus
-has an effect on DNA in the nucleus
adrenaline
hormone released from adrenal glands
-stimulates breakdown of proteins & fats into glucose
-increases blood volume and pressure
-uses cholesterol to produce steroid hormones when stressed
adrenal glands
Found on top of kidneys
-each gland has outer layer (cortex)
-good blood supply - to transport adrenaline straight into blood
adrenal cortex
zona glomerolusa (outer layer)
secretes mineral orcoticoids eg aldosterone (that regulates blood pressure)
adrenal medulla
secretes adrenaline and nor-adrenaline in response to stress
short term response - increased HR and BR
increased rate of glycogen breakdown into glucose
nor-adrenaline is just always in circulation and work together to increase HR
3 regions of adrenal gland
zona glomerulosa
zona fasciculata - middle layer secretes glucorticoids (cortisol increases sugar levels)
zona reticularis (inner layer) secretes precursor molecules (androgens -sex hormones)
pancreas
gland found below stomach
made of 2 cell types ( alpha & beta)
hypoglycemia
low blood sugar
hyperglycemia
high blood sugar
when low blood sugar
alpha cells in islets of langerhans detect low sugar level
alpha cells then secrete glucagon
target cells in liver have a receptor for glucagon where glycogenolysis occurs to produce more glucose into the blood
when high blood sugar
beta cells in the islets of langerhans detect high sugar level
beta cells then secrete insulin
insulin binds to receptors on liver
(tyrosine kinase activated)
glycogenesis occurs to reduce glucose level
type 1 diabetes symptoms
hyperglycemia
-excretion of glucose in urine
-excessive thirst and hunger
-weight loss
type 1 diabetes
auto-immune disease
body doesnt produce insulin
treatments = pancreas transplant, healthy balanced diet, excercise
type 2 diabetes
body doesnt react to insulin
insulin is still produced
linked with obesity
normally acquired later in life
type 2 diabetes treatments
medication to either increase insulin release or make the beta cells more sensitive to insulin
