Year 13 - Hormonal Communication

Question 1

The following terms relate to the metabolism of carbohydrates in the human body:
1 gluconeogenesis
2 glycogenesis
3 glycolysis

Which of these processes will be stimulated when glucagon is released into the bloodstream?

Answer 1

Gluconeogenesis

Question 2

Another hormone produced during pregnancy is oestrogen. Oestrogen is lipid soluble.

Which molecule does oestrogen interact with when it changes cell activity?

Answer 2

DNA

Question 3

What region of the adrenal gland produces the hormone aldosterone and what is the role of the hormone

Answer 3

Cortex
helps control blood pressure by maintaining the balance between salt and water concentrations in the blood

Question 4

What hormone is found in the medulla of the adrenal gland

Answer 4

Adrenaline - increases heart rate
Stimulates glycogenolysis

NorAdrenaline - works with adrenaline in response to stress

Question 5

After the meal, the concentrations of glucose and insulin in the blood increase.

Explain why there is a delay in the increase of insulin concentration following the increase in blood glucose concentration.

Answer 5

Increase in blood sugar is detected by alpha cells
Time is needed for beta cells to release insulin

Question 6

Hormonal control of heart rate is achieved by hormones acting on the sino-atrial node (SAN).

Using your knowledge of the way in which heart action is coordinated, suggest why it can be deduced that hormones act on the SAN rather than on individual cardiac muscle cells.

Answer 6

Hormonal stimulation of SAN leads to a coordinated action of the cardiac muscle and changes heart rate. If done on individual muscle cell, uncoordinated response would occur.

Question 7

A patient was sent for a blood test, known as the haemoglobin A1C (HbA1C) test.
Glucose combines with haemoglobin in the bloodstream to form a ‘glycosylated haemoglobin’ molecule, HbA1C.

The concentration of HbA1C is directly proportional to the mean concentration of glucose in the blood over an eight to twelve week period.

Suggest why a single HbA1C test cannot indicate accurately the mean blood glucose concentration for a period longer than twelve weeks.

Answer 7

HbA1C is contained within red blood cells
Red blood cells have a limited life span of 8 to 12 weeks

Question 8

Insulin is secreted from the beta cells of the pancreas in response to increased blood glucose concentration.
Describe the events that occur

Answer 8

Glucose is metabolised to produce ATP
ATP blocks potassium ion channels and potassium ions build up inside the cell
This causes calcium ion channels to open and calcium enters by diffusion
This causes more calcium ions inside so triggering secretion of insulin by exocytosis

Question 9

After the initial release of insulin from the beta cell, insulin secretion continues even when there is no further glucose intake.

Suggest and explain why the cell continues to secrete insulin.

Answer 9

Continues to secrete if glucose concentration is higher than normal
exocytosis is still being triggered by calcium ions

Question 10

Name the type of differentiated cell that scientists would produce from stem cells in order to treat diabetes mellitus.

Answer 10

Beta cells

Question 11

Skeletal muscle is one of the main tissues where glucose is removed from the blood in response to insulin.

Name the other tissue.

Answer 11

Liver Tissue

Question 12

What hormone regulates metabolism

Answer 12

Glucocorticoids or Cortisol

Question 13

What does glucagon do?

Answer 13

Glucagon stimulates the conversion of glycogen to glucose by liver cells.

Question 14

What is an unpaired t-test

Answer 14

When you are comparing two means

Question 15

Nifedipine blocks Ca2+-channels.

Explain how blocking calcium channels could inhibit insulin secretion.

Answer 15

Ca2+ do not enter the cells so no exocytosis

Question 16

Describe how glucagon is involved in the regulation of blood glucose concentration in a person who is able to regulate their blood glucose concentration correctly (6)

Answer 16

when blood glucose concentration decreases
Glucagon is released by alpha cells in the islets of Langerhans
They promote glycogenolysis where glycogen is turned into glucose
Conversion of amino acids to glucose
Blood glucose levels rise again
This is done in a negative feedback loop to main normal glucose levels

Question 17

Evaluate the treatments of Type 1 diabetes that have been used in the past as well as current and potential future treatments (6)

Answer 17

Type 1 diabetes is treated by insulin. In the past insulin was produced from animal pancreas. E.g. Pig.
Now it is produced from genetic engineering and recombinant bacteria.

The insulin produced from animals is good as it was an early treatment that kept people alive. It was disadvantageous because it had high production cost and many ethical issues.

The insulin produced by humans is good as it has lower production cost and higher purity. It is disadvantageous because side effects can occur and some may not understand the technology.

Future treatments - e.g. transplants. The advantages is that it improves quality of life, and more physiological control. The disadvantages is that it has high start up costs and there is risk of cancer with stem cells.

Question 18

What is the function of nor adrenaline

Answer 18

Increases heart rate
widens pupils
increases blood pressure

Question 18

What is the function of adrenaline

Answer 18

Increases heart rate
Increases blood glucose

Question 19

Which region of the adrenal gland secretes adrenaline

Answer 19

Medulla

Question 20

Skeletal muscle is one of the main tissues where glucose is removed from the blood in response to insulin. Name the other tissue

Answer 20

Liver tissue

Question 21

Gestational diabetes results in high levels of glucose in the blood with normal levels of insulin .
Which type of diabetes is it most similar to?

Answer 21

Type 2 diabetes as insulin is still being produced and beta cells are still working

Question 22

Suggest 2 ways type II diabetes can be managed

Answer 22

Exercise
Manage weight and diet

Question 23

Studies on the effects of hCG in humans have revealed that:
1. Many different tissues are affected by hCG
2. Susceptible cells have glycoprotein receptors on their cell surface
3. These receptors are complementary to the shape of hCG molecules

What can be concluded

Answer 23

hCG is a peptide hormone
It binds to cell surface receptor
uses cAMP as a secondary messenger to bring about response in cell.

Question 24

Heart rate can be increase by the hormone adrenaline, which binds to cardiac cells. Describe how adrenaline binds.

Answer 24

Binds to the cell surface protein. The glycoprotein

Question 25

GI rates the food on a scale from 0 to 100 according to how it raises blood glucose concentration after it is eaten. Why is it necessary for the people to fast overnight before the start of the test?

Answer 25

To ensure that the blood glucose level is normal

Question 26

A doctor for a 59 year old patient to have a series of blood tests. Results of this test indicates whether or not glucose levels are within normal range. What condition was being tested for?

Answer 26

Diabetes

Question 27

Under what circumstances might a patient need to be given a glucagon injection

Answer 27

When blood glucose falls too low

Question 28

Stem cell therapy is a potential future treatments for diabetes. Suggest 3 pieces of information that would be needed to assess the effectiveness of the stem cell therapy.

Answer 28

1. Age of patients 2. Gender 3. Type of diabetes being treated

Question 29

Name type of differentiated cell that scientists would produce from stem cells in order to treat diabetes.

Answer 29

beta cells

Question 30

Which type of diabetes is most likely to be improved by stem cell therapy

Answer 30

type 1. Type 1 causes shortage of beta cells, and stem cell therapy can increase insulin production

Question 31

A person falls into a fast flowing river. State and explain the changes that may occur in the body and increase the persons chances of survival in this situation

Answer 31

Detected by sympathetic nervous system Triggers the adrenal glands to secrete hormones . From adrenal medulla - adrenaline is produced which increases heart rate, increases glucose levels, raises blood pressure. This increases chance of survival rate due to increased rate of respiration - so muscles are able to work longer.

Question 32

Hormonal control of heart rate is achieved by hormones acting on the Sino atrial node. Why do hormones act on the SAN rather than individual cardiac muscle cell.

Answer 32

Hormones acting on individual cardiac muscle cell would produce uncoordinated response, whilst acting on SAN means coordinated response. SAN can initiate heart beat whilst muscle cells cannot.

Question 33

Suggest how adrenaline brings about a response inside the cells of the SAN.

Answer 33

Adrenaline is hydrophilic so cannot pass through membrane Adrenaline binds to its receptor, enzyme adenylyl cyclase is activated. Adenlyl cyclase triggers conversion of ATP into cAMP results in depolarisation Increase in cAMP activates protein kinases, which phosphorylate and hence activate other enzymes