1. Module 2

1.37. Page 5

Lesson 5

Module 2—The Endocrine System

Self-Check

 

Apply what you have learned about diabetes mellitus by completing the following questions. Check your answers and file your work. Consult your teacher for clarification of any concepts you may not understand.

 

SC 3. Complete the flow chart that illustrates normal blood glucose regulation through negative feedback.

 

SC 4. Complete a table like the one shown by comparing Type 1 diabetes with Type 2 diabetes.

 

A Comparison of Type 1 Diabetes with Type 2 Diabetes

Feature Type 1 Diabetes Type 2 Diabetes
Cause    
Onset    
Age of Onset    
Predisposition    
Insulin Production    
Immediate Symptoms    
Long Term Effects    
Treatment    

 

SC 5. FMEN 1 wreaks havoc with the levels of Emily’s pancreatic hormones. At different times in her life, tumours have grown in different areas of her pancreas. When tumours affect the beta cells, there is an oversecretion of insulin. Emily then becomes hypoglycemic.

  1. Differentiate between hyperglycemia and hypoglycemia.

  2. Describe what happens to the blood glucose level when there is an oversecretion of insulin.

  3. Outline how a person, such as Emily, reacts to hypoglycemia.

  4. Explain what other hormone may also be oversecreted as the pancreas tries to deal with the low blood glucose levels.

  5. What can Emily do to alleviate the symptoms quickly?

Use the following graph to answer question SC 6.

 

This graph shows an individual’s blood glucose levels over time.

 

SC 6.

  1. What occurred at Point X?
  2. Identify the endocrine secretion represented by A.
  3. What happened at Point Y?
  4. Identify the endocrine secretion represented by B.
Check your work.
Self-Check Answers

 

SC 3. The completed flow chart representing normal regulation of blood glucose through negative feedback should resemble the following.

 

A flow chart diagram is shown. The diagram has a general structure of two circles arranged side-by-side. The circle on the left is labelled “Rise in Blood Glucose.” The circle on the right is labelled “Fall in Blood Glucose.” A box in the centre of the diagram labelled “Normal Blood Glucose 75–110 mg/100 mL blood” is common to both circles. The circle on the left has arrows indicating a counterclockwise direction. From the common box, an arrow is to a box labelled “Beta Cells in Pancreas.” An arrow labelled “Secrete” extends from this box to an empty box. From the empty box, two arrows labelled “Causes” extend to two empty boxes. From the two empty boxes are two converging arrows labelled “Results” into an empty box. The final empty box has an arrow back to the common box. The circle on the right has arrows indicating a clockwise direction. From the common box, an arrow is drawn to a box labelled “Alpha Cells in Pancreas.” An arrow labelled “Secrete” extends from this box to an empty box. From the empty box, an arrow labelled “Causes” extends to another empty box. From the empty box is an arrow labelled “Results” into an empty box. The final empty box has an arrow back to the common box.

 

SC 4. The table comparing Type 1 and Type 2 diabetes should resemble the following.

 

A Comparison of Type 1 Diabetes with Type 2 Diabetes

Feature Type 1 Diabetes Type 2 Diabetes
Cause

autoimmune disease where antibodies destroy beta cells in pancreas and little or no insulin is produced

receptors on target cells do not respond to the insulin produced; insulin resistance develops
Onset

rapid

gradual
Age of Onset

childhood

adulthood, although more cases in young people recently
Predisposition

none known

obesity increases risk of development significantly
Insulin Production

very little or none

insulin produced but ineffective
Immediate Symptoms

fatigue, low energy, glucose in urine, increased volume of urine, increased thirst, weight loss, smell of nail polish on breath

fatigue, low energy, glucose in urine, increased volume of urine, increased thirst, no smell of nail polish on breathe
Long Term Effects

blindness, kidney failure, nerve damage, gangrene, increased risk of heart attack and stroke

blindness, kidney failure, nerve damage, gangrene, increased risk of heart attack and stroke
Treatment

insulin injections, islet transplantation in experimental stages

control diet, lose weight, increase exercise, drugs to decrease insulin resistance

 

SC 5.

  1. Hyperglycemia occurs when blood glucose levels rise significantly over normal values and stay at an elevated level. This condition is usually caused by a lack of insulin. Hypoglycemia occurs when blood glucose levels fall significantly below normal values and are not raised. This condition is caused by the oversecretion of insulin.

  2. When there is an oversecretion of insulin, cells are stimulated to take up large amounts of glucose and the liver and muscle cells are stimulated to convert large amounts of glucose to glycogen for storage. Adipose (fat) cells are stimulated to convert glucose to fat. All actions significantly lower blood glucose levels below normal values.

  3. When a person, such as Emily, is hypoglycemic, he or she becomes anxious, nervous, develops trembling in his or her hands, and has a feeling of weakness. Insufficient glucose to the brain cells causes disorientation, which may progress to convulsions, coma, and possibly death.

  4. Through negative feedback, low blood glucose levels stimulate the alpha cells in the pancreas to secrete glucagon, which instructs cells to convert glycogen back to glucose as well as to convert non-carbohydrates such as fats and proteins to glucose.

  5. Emily can raise her blood glucose levels by eating something with a lot of glucose in it or she can inject glucagon.

SC 6.

  1. At Point X, the person ate something with sugar in it.
  2. A represents the secretion of insulin by the pancreas.
  3. At Point Y, the person probably did some exercise.
  4. B represents the secretion of glucagon by the pancreas.