5.1.4 Hormonal communication

Question 1

endocrine gland purpose

Answer 1

produce and secrete hormones directly into the blood, don’t have ducts

Question 2

exocrine gland purpose

Answer 2

don’t produce hormones

secrete molecules into a duct which carriers them to where they are needed

Question 3

adrenal medulla location and purpose

Answer 3

centre of adrenal glands

makes and secreted adrenaline and noradrenaline

Question 4

adrenaline causes

Answer 4

relax smooth muscle in bronchioles
increase stroke volume and heart rate 
vasoconstriction 
glycogen->glucose
dilates pupils
increases mental awareness
inhibits action of gut
body hair erects

Question 5

non-steroid hormone features

Answer 5

protein/amino acid based hormone
can’t dissolve in cell surface membrane of target cells and get inside
must bind to a receptor

Question 6

why non-steroid hormones are first messengers

first messenger definition

Answer 6

transmit signal around the body and

initiate change inside the cell when they bind to a receptor

Question 7

second messenger function

Answer 7

transmits signal inside the cell

causes effect on the cell

Question 8

adrenal cortex function

Answer 8

uses cholesterol to produce steroid hormones

Question 9

3 layers of adrenal cortex (outside to inside)

Answer 9

Zona Glomerulosa
Zona Fasciculata
Zona Reticularis

Question 10

Zona Glomerulosa function

Answer 10

secreted mineralcorticoids (e.g. aldosterone)
help to control sodium and potassium levels in blood and blood pressure

Question 11

Zona Fasciculata function

Answer 11

secretes glucocorticoids (leg. cortisol) hells control metabolism of carbs, protein and fats in liver

Question 12

Zona Reticularis function

Answer 12

secretes precursors to sex hormones

Question 13

how steroid hormone causes change in cell

Answer 13

enters cell by dissolving in cell surface membrane
bind with receptor in cytoplasm
receptor-hormone complex enters nucleus, binds to another receptor on chromosome
causes mRNA to be made, produces proteins

Question 14

how different types of hormones are released and take effect on target cells using adrenal glands as example model answer

Answer 14

endocrine glands release hormones
that travel in the blood
to target cells

adrenal medulla releases non-steroid hormones (e.g. adrenaline)
adrenaline acts as first messenger, binds to complementary shaped receptor on cell surface membrane
G-protein activates adenyl cyclase
converts ATP into cyclic AMP (cAMP)
cAMP is the second messenger (causes effect in cell)

adrenal cortex releases steroid hormones
dissolved into cell surface membrane
binds to receptor in cytoplasm
receptor-hormone complex binds to receptor on chromosome
causes mRNA then proteins to be made

Question 15

how hormones travel all around body in blood yer still have specific effects

Answer 15

endocrine gland make and secrete hormones directly into blood
hormone bind to specific complementary receptors on cell surface membrane of target cells
hormones will not affect cells without these receptors
target cells grouped into target tissue

Question 16

“pancreatic juice” juice composition

Answer 16

amylase
trypsinogen (precursor to trypsin - protease enzyme)
lipase
sodium hydrogen carbonate (alkali to neutralise stomach acid)

Question 17

exocrine function of pancreas

Answer 17

majority of cells produce digestive enzymes (“pancreatic juice”)
these cells form groups (acini) that secrete enzymes into tubules that lead to pancreatic duct which takes them to the small intestine

Question 18

endocrine function of pancreas

Answer 18

islets of Langerhans contain alpha and beta cells
they detect changes in blood glucose levels
they produce and secrete hormones directly into closely associated capillaries

Question 19

alpha cells function

Answer 19

produce and secrete glucagon

Question 20

beta cells function

Answer 20

produce and secrete insulin

Question 21

pancreas under micrograph

Answer 21

most cells = exocrine
group of cells surrounding smallest hollow tubes = acini
slightly larger circular(ish) hollow tubes = branch of pancreatic duct
patches (circularish) with different staining = islets of Langerhans

Question 22

releasing of insulin beta cell mechanism

Answer 22

cell membrane has potassium and calcium ion channels
calcium ion channels normally closed, potassium ion channels normally open - potassium ions flow out
when blood glucose concentration is high, glucose moves into cell
glucose metabolised, produces ATP
ATP closes potassium ion channels
potassium ions accumulates, alters potential difference across cell membranes, inside becomes less negative
change in potential difference open calcium ion channels and Ca2+ ions enter cell
calcium ions causes vesicles of insulin to fuse with cell membrane, releasing insulin by exocytosis

Question 23

diabetes mellitus definition

Answer 23

disease when you can’t control blood glucose levels effectively

Question 24

hyperglycaemia definition

Answer 24

blood glucose concentration too night

leads t organ damage in the long term

Question 25

hypoglycaemia definition

Answer 25

blood glucose concentration too low
not enough glucose to cells esp. to brain
causes tiredness and irritability
to brain damage, seizures, death

Question 26

Type I diabetes features

Answer 26

insulin dependent diabetes
autoimmune response - attack and destroy own B cells
can’t produce sufficient insulin
can’t store glucose as glycogen, excess glucose remains in blood, hyperglycaemia
when blood glucose falls, no/little glycogen to release glucose, causes hypoglycaemia

Question 27

Type II diabetes features

Answer 27

non insulin-dependent diabetes
number of receptors on target cells for insulin decline and cells unresponsive to insulin
can still produce insulin (less though)

Question 28

risk factors of Type II diabetes

Answer 28

age
obesity
refined sugar rich diet
certain ethnicities
family history

Question 29

treating Type 1 diabetes

Answer 29

monitor blood glucose levels
insulin injections
insulin pump, permanently pumps insulin at steady rate into bloodstream
islet/beta cell transplant (healthy beta cells from dead donor implanted into pancreas of patient)
pancreas transplant

Question 30

advantages of obtaining insulin from genetically engineered bacteria perfect answer

Answer 30

old method of obtaining insulin was from pigs
engineered insulin is cheaper (food stock cheaper than that for pigs)
less risk of infection than with pig insulin
human insulin produced is more effective on humans than pig insulin
avoids side effects/allergies/immune response some people may experience with pig insulin
ethically advantageous as no animal rights associated with bacteria as there are with pigs
also caters to more people (e.g. Jews)

Question 31

future treatment of type I diabetes

Answer 31

stem cells could be used to grow new Islets of Langerhans with B cells can produce insulin, cures Type I diabetes

Question 32

Type II diabetes treatment

Answer 32

control of carbohydrate intake
regular exercise
sometimes insulin injectors or drugs to slow down absorption of glucose

Question 33

what happens when hyperglycaemia detected

Answer 33

beta cells secrete insulin
insulin reached target cells (e.g. muscle cells, liver cells)
binds to receptors on target cells causing:
more transporter proteins for glucose placed into cell surface membrane
more glucose entering cells
glucose in cells converted to glycogen (glycogenesis) or fats for storage
more glucose used in respiration

Question 34

what happens when hypoglycaemia detected

Answer 34

glycogen converted to glucose (glycogenolysis)
more fatty acids used in respiration
amino acids and fats converted into additional glucose, gluconeogenesis

Question 35

gluconeogenesis definition

Answer 35

metabolic pathways that results in generation of glucose from pyruvate and lactate