Module 5.4

Question 1

what is the endocrine system

Answer 1

communication using hormones as signalling molecules

Question 2

what does the endocrine system use to transport signals

Answer 2

the blood

Question 3

what do endocrine glands do

Answer 3

manufacture and release hormones directly into the blood in capillaries running through the gland

Question 4

how are hormones detected

Answer 4

target cells and target tissues
for peptide hormones the target cell must posses a specific receptor on their plasma membrane that is complimentary in shaped to that of the hormone

Question 5

what are non-steroid hormones known as and why

Answer 5

first messengers
bind to cell surface membrane and initiate an effect inside the cell (usually cause the release of another signalling molecule (the second messenger))

Question 6

how do peptide hormones work

Answer 6

G protein is activated when hormone binds to the receptor
G protein activates effector molecule (usually adenyl cyclase)
adenyl cyclase converts ATP to cAMP
cAMP is the second messenger which may initiate an enzyme cascade or act directly on a protein to alter the activity of the cell

Question 7

what are the two parts of the adrenal glands

Answer 7

adrenal medulla (inner)
adrenal cortex (outer)

Question 8

what are the three layers of the adrenal cortex

Answer 8

zona glomerulosa (outer)
zona fasciculata (middle)
zona reticularis (inner)

Question 9

what hormones does the adrenal cortex produce

Answer 9

steroid hormones
cortisol
aldosterone
precursor androgens

Question 10

what hormones does the adrenal medulla produce

Answer 10

adrenaline
noradrenaline

Question 11

action of steroid hormones

Answer 11

passes through plasma membrane of target cell
binds with specific receptor in cytoplasm
receptor-steroid complex enters the nucleus and binds to specific receptor on chromosomal material
binding stimulates production of mRNA which code for the production of proteins

Question 12

what does aldosterone do

Answer 12

help control concentrations of sodium and potassium in the blood
as a result they contribute to maintaining blood pressure

Question 13

what does cortisol do

Answer 13

helps to control the metabolism of carbohydrates, fats and proteins in the liver

Question 14

what do precursor androgens do

Answer 14

taken up by the ovaries or tests and converted to sex hormones

Question 15

role of adrenaline

Answer 15

prepare the body for activity
relax smooth muscles in bronchioles
increase HR and stroke volume
vasoconstriction to raise bp
conversion of glycogen to glucose
inhibits the gut
dilates pupils

Question 16

what are the two functions of the pancreas

Answer 16

exocrine - secretion of pancreatic juices containing enzymes into the gut
endocrine - islets of Langerhans secrete hormones into the blood

Question 17

where are the endocrine cells in the pancreas

Answer 17

islets of Langerhans

Question 18

what do islets of Langerhans contain

Answer 18

alpha cells
beta cells

Question 19

what do alpha cells secrete

Answer 19

glucagon

Question 20

what do beta cells secrete

Answer 20

insulin

Question 21

what channels do beta cells have and which are normally open

Answer 21

potassium and calcium ion channels
potassium is normally open
calcium is normally closed

Question 22

why are potassium ion channels normally open

Answer 22

potassium ions diffuse out of the cell to make the inside of the cell more negative

Question 23

what happens to beta cells when glucose concentrations outside the cell are too high

Answer 23

glucose molecules move into the cell
glucose is used to produce atp

Question 24

what happens when there is extra atp in beta cells

Answer 24

potassium channels close

Question 25

what happens when potassium channels close

Answer 25

potassium can no longer diffuse out of the cell making the cell less negative inside change in potential difference opens calcium ion channels

Question 26

what happens when calcium ion channels are open

Answer 26

calcium ions enter the cell and cause insulin secretion by making vesicles containing insulin move to the cell surface membrane and fuse with it to release insulin by exocytosis

Question 27

what happens when blood glucose is too high

Answer 27

high blood glucose concentration detected by beta cells insulin is secreted target cells are liver cells, muscle cells and other body cells e.g. in the brain target cells have membrane bound receptors binding of insulin to receptors activates enzyme cascade

Question 28

what does insulin do

Answer 28

more transporter proteins specific to glucose are placed into the cell surface membrane more glucose enters the cell glucose is converted to glycogen for storage more glucose is converted to fats more glucose is used in respiration

Question 29

what is the conversion of glucose to glycogen called

Answer 29

glycogenesis

Question 30

what happens when blood glucose drops too low

Answer 30

detected by alpha cells glucagon is secreted into the blood targets hepatocytes in the liver glucagon bind to membrane bound receptor activates G protein ATP to cAMP enzyme cascade

Question 31

what does glucagon do

Answer 31

glycogen is converted to glucose more fatty acids are used in respiration amino acids and fats are converted unto additional glucose

Question 32

what is the conversion of glycogen to glucose called

Answer 32

glycogenolysis

Question 33

what is the conversion of amino acids and fats to glucose called

Answer 33

gluconeogenesis

Question 33

what is diabetes mellitus

Answer 33

when the body is no longer able to produce insulin

Question 34

type 1 diabetes

Answer 34

usually starts in childhood autoimmune response where the immune system attacks the beta cells insulin dependent

Question 35

type 2 diabetes

Answer 35

non-insulin dependent produce insulin but not enough cells are less responsive to insulin can be brought on by obesity, high sugar diet, lack of exercise, ethnicity

Question 36

treatment for type 1 diabetes

Answer 36

insulin injections islet cell transplant pancreas transplant stem cell treatment

Question 37

type 2 diabetes treatments

Answer 37

change in lifestyle loose weight exercise diet monitoring medication

Question 38

source of insulin for treating diabetes

Answer 38

genetically modified bacteria