hormonal communication

Question 1

what is an exocrine

Answer 1

• have ducts
• secrete enzymes into the ducts which opens into the body cavity e.g. small intestine, stomach etc.

Question 2

what is an endocrine

Answer 2

• ductless gland
• secrete hormones into blood stream

Question 3

what is the definition of a hormone

Answer 3

• chemical messenger (cell - signalling molecule)
• produced by endocrine gland
• travels in blood plasma
• from gland to their target organ -> specific target
• released in small concentrations + have widespread and long lasting effects.

Question 4

what are the two types of hormones

Answer 4

• non - steroid (protein and amine)
• steroids

Question 5

what is a non - steroid hormone

Answer 5

• water soluble (hydrophilic) + polar
• do not enter cells
• bind to specific receptors on the plasma membrane

Question 6

what is a steroid hormone

Answer 6

• lipid soluble (hydrophobic) + non polar
• diffuse, directly through the phospholipid bilayer + bind to complementary receptors, inside the cell

Question 7

how can one hormone, have different effects on different targets

Answer 7

• different receptors may be present
• second messenger may activate different channels/enzymes
• different secondary messengers, may be activated
• second messenger level may increase or decrease within the cell

Question 8

describe how adrenaline controls heart rate

Answer 8

• binds to a G protein coupled receptor, on a plasma membrane of SAN cells in the heart.
• adenyl cyclase activated which converts ATP -> cAMP

Question 9

describe how steroid hormones move through the bilayer

Answer 9

• dissolves through phospholipid bilayer
• binds to a complementary receptor in the cytoplasm
• forms a hormone receptor complex (HRC)
• HRC acts as a transcription factor
• transcription factors, either assist or inhibit the expression of a certain gene
• if the transcriptions factor promotes gene expression a new protein could be produced.

Question 10

which responses, are faster, hormonal or neuronal

Answer 10

neuronal

Question 11

what is an endocrine gland

Answer 11

a ductless gland, that secretes hormones directly into the blood stream.

Question 12

give 4 examples of steroid hormones

Answer 12

• testosterone
• oestrogen
• cortisol
• insulin

Question 13

give 4 examples of non - steroid hormones

Answer 13

• adrenaline
• ADH
• glucagon
• insulin

Question 14

explain why steroid hormones can pass easily through the plasma membrane but other protein hormones cannot

Answer 14

steroid hormones, are lipid soluble (hydrophobic + non polar) thus meaning they can dissolve through the phospholipid bilayer

Question 15

what are the 3 outer layers of the adrenal gland

Answer 15

• zone glomerulus
• zone fasciculata
• zone reticulosis

Question 16

what is the function of the Zona glomerulosa

Answer 16

• acts on cells in the collecting duct + diastral conculcated tubule in the nephron
• increases sodium uptake back into blood stream
• increase water potential of blood

Question 17

what is the function of the Zona fasciculata

Answer 17

• controls metabolism of carbohydrates, fats and proteins in the liver.
• causes glycogenesis
• causes an increase in blood glucose levels

Question 18

what is the function of the Zona reticularis

Answer 18

• androgens are converted into sex hormones
• e.g. testosterone + oestrogen
• ( secondary sexual characteristics)

Question 19

describe the action of adrenaline on the liver cells

Answer 19

• the hormone adrenaline is hydrophilic -> cannot pass directly through plasma membrane
• it binds to the receptor on the surface of the cell -> complementary shape
• the G protein binds to and activates adenylyl cyclase enzyme
• this converts ATP into the second messenger cyclic AMP (cAMP)
• this activates other enzymes - protein kinases which activate other enzymes (cascade effect)
• this leads to a response -> glycogen broken down to glucose

Question 20

why can adrenaline have such a long effect if adrenaline only stays in the blood stream for 1-3 minutes

Answer 20

adrenaline, can be secreted continuously by the adrenal gland, over a long period of time.

Question 21

what stimulus leads to an increased secretion of insulin

Answer 21

• high blood glucose levels

Question 22

state the two specific ion channels that span the cell membrane of the beta cells

Answer 22

• K+ channels
• calcium channels

Question 23

why must blood sugar levels not get too high

Answer 23

to high blood sugar levels, will result in dehydration

Question 24

why must blood glucose not get low

Answer 24

• starving the body of glucose leads to reduced production in ATP, which in turn can lead to a loss of bodily functions, e.g. drowsiness’s.

Question 25

how many types of diabetes are there

Answer 25

2

Question 26

what is type 1 diabetes - insulin dependent diabetes

Answer 26

- autoimmune disease - immune system destroys pancreatic B - cells, no insulin, therefore muscle/ liver cells have no glycogen stores.

Question 27

what is type 2 diabetes - non - insulin dependent diabetes

Answer 27

- insulin, produced, but it does not bind to receptor. - receptors has changed shape.

Question 28

islets of Langerhans (endocrine)

Answer 28

- lightly stained - large spherical clusters - produce and secrete hormones

Question 29

pancreatic acini (exocrine)

Answer 29

- darker stained - small, berry like clusters - produce and secrete digestive enzymes.

Question 30

what are the risk factors associated with type 2 diabetes

Answer 30

- obesity - lack of exercise - high sugar diet - genetic component

Question 31

what are the symptoms of diabetes

Answer 31

- BGL remains high from a long time after a meal. - glucose loss in urine - dehydration - no glycogen stores, therefore to high blood glucose levels between meals

Question 32

what is an example of a past diabetes treatment

Answer 32

- insulin extracted from animal pancreas e.g. pigs

Question 33

what is one advantage and one disadvantage of past diabetes treatment

Answer 33

- tried and tested method (A) - needs to purified (D)

Question 34

what is an example of current insulin treatment

Answer 34

genetically modifying bacteria to produce human insulin

Question 35

what is one advantage and one disadvantage of current diabetes treatment

Answer 35

- less risk of allergic reaction (A) - side effects of pump ( such as hared lumps under the skin) (D)

Question 36

what is a example of future diabetes treatment

Answer 36

transplant of pancreas

Question 37

what is one advantage and one disadvantage of future diabetes treatment

Answer 37

- patient can now produce insulin, so more physiological control of BGL (blood glucose levels) (A) - not enough pancreases available due to donor shortage (D)

Question 38

what is transplant of pancreatic stem cell - derived pancreatic islet cells

Answer 38

pluripotent stem cells, can differentiate into B - cells and increase the mass of the islets and increase the secretion of insulin

Question 39

what is immunotherapy

Answer 39

pluripotent stem cells can also protect B - cells from autoimmune attack by inhibiting T - cell proliferation and reduce the inflammatory response.

Question 40

what is gene therapy

Answer 40

there are opportunities to use genetic modification to provide enhanced endocrine function and survival and modulate the immune response.

Question 41

what is developmental biology

Answer 41

opportunities, to study the function and longevity of human islet cells with varied genotypes, and develop new drugs for treatment.

Question 42

what is the main treatment for type 2 diabetes

Answer 42

- lifestyle change - losing weight - regular exercise - healthy, balanced diet