Module 5: Hormonal control

Question 1

What is an endocrine gland

Answer 1

a group of cells specalised to secrete hormones to target cells through blood plasma

Question 2

The pancreas and adrenal gland are both examples of what kind of gland

Answer 2

endocrine

Question 3

Describe the action of a peptide hormone-like adrenaline

Answer 3

• Adrenaline is a first messenger
• the binding of adrenaline activates adenyl cyclase
• this converts ATP to cAMP
• cAMP is a secondary messenger which can cause a cascade of reactions inside the cell
• For example :making glucose more readily available by catalysing breakdown of glycogen into glucose

Question 4

Describe the action of steroid hormones

Answer 4

• because they are lipid-based can diffuse through the plasma membrane
• bind to receptor in cytoplasm
• this can form a hormone-receptor complex
• which in turn can become a transcription factor

Question 5

What are the two parts of the adrenal gland

Answer 5

• cortex
• medulla

Question 6

What kinds of hormones does the cortex secrete and list their roles

Answer 6

-secretes steroid hormones

Glucocorticoids

• stimulate the breakdown of proteins and fats into glucose
• suppress the inflammatory response

Mineralocorticoids
-maintain salt conc to regulate blood pressure

Andorgens

Question 7

What kinds of hormones does the medulla secrete and list their roles

Answer 7

Peptide hormones

proudces adrenaline and noroadrenaline

adrenaline: increases heart rate and blood glucose conc
noradrenaline: dilate pupils, cause vasoconstriction

Question 8

Describe the histology of the pancreas

Answer 8

Pancreatic acini
Islets langerhans
Alpha cells
Beta cells

Question 9

State the role of alpha cells

Answer 9

To secrete glucogon

Question 10

State the role of beta cells

Answer 10

to secrete insulin

Question 11

What is the role of insulin

Answer 11

activates enzymes to turn glucose into glycogen
can also increase rate of respiration of glucose in muscle cells

Question 12

what is the role of glucogon

Answer 12

activates enzymes to break glycogen into glucose
decreases rate of respiration of glucose in cells

Question 13

What does glycogenisis mean

Answer 13

when glycogen is formed from glucose
happens due to insulin being released

Question 14

What is glycogenolysis

Answer 14

when you break down glycogen into glucose

Question 15

What is gluconeogenisis

Answer 15

process of forming glucose from glycerol and amino acids

Question 16

State the stages of negative feedback when

glucose concentration is high

Answer 16

stimulas: rise in blood glucose conc
receptor: pancreas detects change away from normal
communication response: beta cells in the _islets of langerhan s_ecrete insulin and stops glucagon secretion
effector: Liver and muscles respond by taking up more gluocse, glycogenesis, cells respire more glucose

Question 17

Stages of negative feedback when blood glucose concentration is low

Answer 17

stimulas: fall in blood glucose conc
receptor: pancreas detects change away from normal
communication response: alpha cells secrete glucogn and stops insulin secretion
effector: Liver cells
-cells respire less glucose, gluconeogensis happens, glycogenolysis happens

Question 18

Describe the mechanism of insulin secretiton by beta cells

Answer 18

• Blood glucose conc is high, so glucose enters beta cells by facilitated diffusion
• glucose is respired/metablosied/phosphorolated to produce ATP
• ATP blocks pottassium ion channels, causing them to close
• so there is a build up pottassium ions in the cell
• membrane is depolarised
• depolarisation causes volatge gated claiucm ion channels to open and Ca ions enter by diffusion
• increase in Ca ions results in movement of vessciles
• then describe exocytosis

Question 19

What is type 1 diabeties and what does it do to the body and what is the consequence of this

Answer 19

What is it?
Autoimmune disease

What does it do?
-Attacks and destroys beta cells

Consequence
-Unable to proudce insulin

Question 20

What is type 2 diabetes, how does it affect the body and what are the consequences

Answer 20

What is it
-when beta cells don’t proudce enough insulin, or body cells don’t properly respond to insulin

How does it affect the body
-insulin recptors on cells don’t work properly, so cells don’t take up enough glucose

Consequence
-higher blood glucose level

Question 21

How is type 1 diabetes treated

Answer 21

insulin therapy: taking regular insulin injections throughout the day, or an insulin pump

islet cell transplantation: allows pancreas to produce its own insulin

Having a carefully planned diet and regular excersise

Question 22

What are the treatments of type 2 diabetes

Answer 22

Lifestyle changes: eating a healthy balanced diet, getting regular excerise

medication:
metaformin (acts on liver cells telling them to reduce amount of glucose released into body), sulfonylureas (stimualte pancreas to proudce more insulin), Thiazolidinediones (make body cells more sensative to insulin)

Question 23

What are the advantages of using insulin from GM bacteria

Answer 23

• cheaper
• larger quantaties can be proudced
• GM make human insulin which is more effective than pig insulin (pig insulin may vause allergic reactions)
• people may prefer GM insulin due to ethical and religous reasons

Question 24

How can stem cells be used to treat diabetes in the future

Answer 24

Stem cells can be grown into beta cells
can be implanted into a persons pancreas
so body can produce its own insulin