topic 5.1.4: hormonal communication

Question 1

define endocrine gland

Answer 1

a group of specialised cells that secrete hormones directly into blood

Question 2

what is the difference between steroid and non-steroid hormones?

Answer 2

steroid:
lipid soluble, diffuse into cell to receptor inside
non-steroid:
water soluble, bind to receptor on membrane which triggers 2nd messenger

Question 3

describe the hormones released from the adrenal medualla

Answer 3

non essential, triggered by sympathetic nervous system, catecholamines
eg adrenaline, noradrenaline (increased heart rate, widened pupils, vasoconstriction of blood vessels)

Question 4

describe the hormones released from the adrenal cortex

Answer 4

essential, triggered by pituitary gland
glucocorticoids eg cortisol (controls how body converts to energy)
mineralocorticoids eg aldosterone (maintains blood and water conc in blood to control blood pressure)

Question 5

describe the action of adrenaline

Answer 5

binds to receptor on liver cell (1st messenger), adenylyl cyclase activated in cell which converts ATP to cyclic AMP (2nd messenger), enzymes convert glycogen to glucose

Question 6

describe endocrine tissue in the pancreas

name, appearance, types

Answer 6

islets of langerhans- less dense than exocrine, small spherical clusters
alpha cells secrete glucagon, beta cells secrete insulin

Question 7

describe exocrine tissue in the pancreas

name and appearance

Answer 7

acini- more densely packed

Question 8

what is glycogenolysis?

Answer 8

glycogen broken down into glucose in response to glucagon

Question 9

what is gluconeogenesis?

Answer 9

production of glucose from non carbs in response to glucagon

Question 10

what is glycogenesis?

Answer 10

production of glycogen in response to insulin

Question 11

what happens when blood glucose falls?

Answer 11

alpha cells release glucagon, conc increases through glycogenolysis, gluconeogenesis and stopping liver cells from absorbing glucose

Question 12

what happens when blood glucose rises?

Answer 12

beta cells release insulin, conc lowers through glycogenesis, increase in respiration and increase in glucose conversion to fat

Question 13

how is insulin secretion controlled?

Answer 13

at normal conc, k+ channels open in beta cells. conc increases, glucose enters cells through transporters, glucose used in resp to make atp which binds to k+ channels so they close, k+ trapped in cell which causes depolarisation, voltage gated ca2+ channels open and ca2+ enters which triggers exocytosis of insulin

Question 14

describe the symptoms, cause and treatment of type 1 diabetes

Answer 14

cells unable to produce insulin, could be result of autoimmune disease, treated with insulin injections

Question 15

describe the symptoms, cause and treatment of type 2 diabetes

Answer 15

receptors unresponsive to insulin, develops due to obesity or poor diet, controlled through regulating carb intake, exercising and sometimes insulin injections