Hormonal Communication (key points)

Question 1

Adrenal cortex has an outer capsule surrounding 3 layers of cells which are?

Answer 1

zona glomerulosa
zona fasciculata
zona reticularis

Question 2

zona glomerulosa is the….
and secretes…
what do they do?

Answer 2

outermost layer
mineralcorticoids
control conc. of sodium and potassium in the blood, maintain blood pressure

Question 3

zona fasciculata is the…
and secretes…
what do they do?

Answer 3

middle layer
glucocorticoids
control metabolism of carbohydrates/lipids/proteins in liver

Question 4

zona reticularis is the…

and secretes…

Answer 4

innermost layer
precursor molecules (if enzymes not present for cortisol release) used to make sex hormones
cortisol can also be secreted if enzymes are present

Question 5

Adrenal medulla secretes…

Answer 5

adrenaline

noradrenaline

Question 6

The adrenal cortex uses what to produce a range of hormones?

Answer 6

cholesterol

and they are steroid based so can enter cells

Question 7

process of steroid hormone entering cell

Answer 7

passes plasma membrane of target cell
bind to specific receptor in cytoplasm
receptor-steroid hormone complex enters nucleus
binds to other receptor on chromosomal material
binding stimulates mRNA production which codes for production of proteins

Question 8

exocrine cells in the pancreas are called…
where are they located?
tubules join to form?

Answer 8

acinus (acini plural)
in small groups surrounding tubules
intralobular ducts which combine to form the pancreatic duct

Question 9

releasing insulin

Answer 9

K channels open Ca channels closed so K flows out cell so inside more negative than outside
glucose conc. high outside cell so moves into cell
metabolised to produce ATP (glucokinase enzyme)
extra ATP causes K channels to close
less negative inside
change in p.d opens Ca channels
Ca causes vesicles with insulin to fuse with the membrane to release by exocytosis

Question 10

process if glucose is too high

Answer 10

detected by beta cells, target cells are liver and muscle
insulin bind to specific membrane-bound receptor on target cell
activates tyrosine kinase
causes phosphorylation of inactive enzymes
cascade of enzyme-controlled reactions in cell
more transporter proteins specific to glucose placed into membrane so more glucose enters cell and converted to glycogen

Question 11

what is it called when glucose is converted to glycogen?

Answer 11

glycogenesis

Question 12

process if glucose is too low

Answer 12

detected by alpha cells, target cells are liver
glucagon binds to receptors on target cell
stimulates G protein
activates adenyl cyclase
convert ATP to cAMP
activates enzyme-controlled reaction in cell
glycogen to glucose
fatty acids in respiration
amino acids/fats to glucose

Question 13

what is it called when glycogen is converted to glucose?

Answer 13

glycogenolysis

by phosphorylase A

Question 14

what is it called when amino acids/fats are converted to glucose?

Answer 14

gluconeogenesis

Question 15

type 1 diabetes

Answer 15

usually starts in childhood
from autoimmune response where body attacks beta cells
or from viral attack
can’t store glucose as glycogen so glucose stays in blood longer at high concentrations and when conc. falls there is no store to release glucose

Question 16

type 2 diabetes

Answer 16

can produce insulin but not enough or responsiveness to insulin declines (receptors lose ability to respond t insulin)
glucose conc. permanently raised so damages organs and circulation
from obesity, lack exercise, high sugar diet, Asia/Afro-Caribbean origin, family history

Question 17

type 1 diabetes treatment

Answer 17

insulin injections
insulin pump therapy (permanently under skin)
islet cell transplant
pancreas transplant
stem cells to grow new islets of Langerhans (bone marrow/placenta)

Question 18

type 2 diabetes treatment

Answer 18

changes in lifestyle - lose weight, exercise, monitor diet

medication - reduce glucose liver releases into blood/ boost insulin released

Question 19

advantages of using insulin from bacteria

Answer 19

exact copy of human insulin so faster acting and effective
less chance of tolerance to insulin
less chance of rejection
lower risk of infection
cheaper than animal extraction
manufacturing more adaptable to demand
less moral objections