5.4 hormonal communication

Question 1

define endocrine system

Answer 1

communication system that uses hormones as signalling molecules
made of endocrine glands

Question 2

define hormones

Answer 2

cell signalling molecules produced by endocrine glands and are released into the blood
travel to target cells and bind to receptors

Question 3

how does a hormone work

Answer 3

travels to a target cell and binds to specific receptors
initiates a response

Question 4

name the types of hormone

Answer 4

protein
steroid

Question 5

how do protein hormones work

Answer 5

aren’t fat soluble so do not enter the cell
need to bind to receptors on the cell surface membrane
release second messenger into cell

Question 6

how do steroid hormones work

Answer 6

are fat soluble
can enter cell and nucleus
have direct effect on DNA

Question 7

what do endocrine glands do

Answer 7

release hormones into the blood
no ducts

Question 8

what do exocrine glands do

Answer 8

release into ducts

Question 9

what are first messengers

Answer 9

non steroid hormones (protein)
signalling molecules that bind to csm and initiate an effect inside cell (cause release of second messenger)

Question 10

what are second messengers

Answer 10

stimulates change in activity of cell / reaction

Question 11

what is the adrenal gland

Answer 11

(endocrine glands)
a pair of glands lying above the kidney which releases adrenaline (and other hormones)

Question 12

what are the adrenal glands made up of

Answer 12

adrenal cortex (outer layer)
adrenal medulla (inner layer)

Question 13

what is adrenaline

Answer 13

protein hormone that is released from adrenal glands
stimulates body to prepare for fight or flight response

Question 14

functions of adrenaline

Answer 14

relax smooth muscles in bronchiole
increase SV, HR
vasoconstricts to increase bp
stimulates conversion of glycogen to glucose
dilates pupils
increases mental awareness etc

Question 15

hormones released from adrenal cortex (3)

Answer 15

mineralocorticoids
glucocorticoids
cortisol

Question 16

functions of hormones from the adrenal cortex

Answer 16

mineralocorticoids - control leels of Na and K in the blood, maintain blood pressure
glucocorticoids - metabolism of carb, fats, and proteins in the liver
cortisol - stress hormone, can be taken up by ovaries or testes to make sex hormones

Question 17

hormone released from the adrenal medulla (1)

Answer 17

adrenaline

Question 18

describe the function of the pancreas

Answer 18

endocrine - secretes hormones into the blood capillary
exocrine - synthesise and release digestive enzymes

Question 19

describe how the pancreas works as an exocrine gland

Answer 19

secretes substances into a duct
synthesise and release digestive enzymes
exocrine cells are in a small group of cells surrounding tubules - acinus
these cells secrete enzymes they synthesise into the tubule

Question 20

describe what enzymes are produced by the pancreas for the exocrine function

Answer 20

protease = trypsinogen - inactive protease conerted into trypin in the duodenum
amylase
lipase

Question 21

describe how the pancreas works as an endocrine gland

Answer 21

secrete hormones into the capillary
made of Islets of langarhan
islets contain alpha and beta cells = endocrine tissue

Question 22

what do alpha and beta cells produce

Answer 22

alpha - produces glucagon
beta - produces insulin

Question 23

how is insulin released from beta cells

Answer 23

normal blood glucose levels = K+ ion channels are open, Ca+ ion channels are normally closed
potassium diffuses out = cell more negative
high glucose levels = glucose moves into the cell (facilitated diffusion) = metabolised to produce ATP
ATP causes causes potassium channels to close
K+ no longer diffuses out and causes cell inside to become less negative
change in potential difference causes Ca+ ion channels to open
Ca+ ions open and Ca+ enter
causes vesicles of insulin to fuse with the membrane and release insulin out of the cell by exocytosis

Question 24

effect of insulin

Answer 24

more transporter proteins specific to glucose are placed in c.s.m
more glucose enters cell
glucose in cell is converted to fats/glycolysis/used in respiration

Question 25

hypoglycaemia

Answer 25

blood glucose concentration drops too low for long periods of time - below 4mmol dm3

Question 26

hyperglycaemia

Answer 26

blood glucose rises too high for long periods of time - over 7 mmol dm3

Question 27

glycogenesis

Answer 27

glucose to glycogen

Question 28

gluconeogenesis

Answer 28

amino acids/fats converted into glucose

Question 29

glycogenolysis

Answer 29

glycogen to glucose

Question 30

glycolysis

Answer 30

glucose to pyruvate

Question 31

describe what happens when blood glucose drops too low

Answer 31

detected by alpha cells
glucagon secreted into blood
detected by receptors on liver cells
converts glycogen to glucose
glucose released in blood

Question 32

describe what happens when blood glucose rises

Answer 32

detected by beta cells
insulin secreted into blood
detected by receptors in the liver and muscles
removes glucose from the blood and converts to glycogen

Question 33

what is diabetes mellitus

Answer 33

a condition in which the body cannot produce sufficient insulin to control blood glucose levels

Question 34

type 1 diabetes

Question 35

type 2 diabetes

Question 36

treating diabetes