blood sugar homeostasis and disease

2. 11.2 Regulation of
blood sugar

3. Objectives
• To comprehend the balance of blood sugar and its significance.
• To understand the regulation of blood sugar.

4. Blood sugar
• Blood sugar is the glucose in blood.
• The normal level of blood sugar in human body is 90-100 mg/100ml
blood.

5. Importance of maintaining a stable blood
sugar
• High
• Hypertonic solution
• Water leaves the cell
• Disrupt cellular metabolism
• Too high ( > 180 mg / 100 mL)
• Exceeding reabsorption limit of
nephron
• Glucose is lost through urine
• Body lost nutrient
• Too low ( < 40 mg / 100 mL)
• Functional brain failure
• Unconscious

6. Blood level is regulated with hormones
• Organs:
• Liver – store glycogen
• Pancreas – release hormones
• Hypothalamus – regulate
hormone secretion in the
pancreas

7. Endocrine tissue of pancreas
• The Islet of Langerhans
胰岛/ 兰氏岛 are tissues of
pancreas that secrets
hormone into the blood.
• Alpha cells secret
glucagon胰高血糖素.
• Beta cells secret insulin
胰岛素.

8. Insulin胰岛素
• Latin insula ‘island’ + -in (noun)
• Increases the absorption of blood
sugar by cells.
• Encourage the break down of
glucose as a source of energy.
• Promote the conversion of
glucose into glycogen by muscle
and liver cells.
• Blood glucose

9. Glucagon胰高血糖素
• from Greek glukus ‘sweet’ + agōn ‘leading,
bringing’
• Causes the liver to convert stored
glycogen into glucose.
• Decreases fatty acid synthesis in
adipose tissue and the liver
• Promoting lipolysis in adipose tissue
and the liver to produce glucose
• Blood glucose

10. Blood sugar is controlled with negative
feedback mechanism
Beta cells
Alpha cells

11. Homeostasis of blood sugar

13. Malfunction of the control mechanism
• When blood sugar control
mechanisms aren’t function
properly, the amount of
blood sugar will be too
high to causes the kidney
unable to reabsorb all the
glucose in the proximal
convoluted tubule.
• Glucose will be excreted in
the urine.
• This medical condition is
called diabetes mellitus.

14. Diabetes mellitus糖尿病
• via Latin from Greek,
literally ‘siphon’,
from diabainein ‘go
through’; mellitus is from
Latin mellitus ‘sweet’.

15. Types of diabetes
• Type 1 DM results from the pancreas's
failure to produce enough insulin.
• Type 2 DM begins with insulin resistance,
a condition in which cells fail to respond to
insulin properly. As the disease progresses
a lack of insulin may also develop.
• Gestational diabetes
妊娠糖尿病 occurs when
pregnant women
without a previous
history of diabetes
develop high blood
sugar levels.

16. Type I diabetes is a type of autoimmune
disease
• Can occur at any age. It is most often diagnosed in children,
adolescents, or young adults.
• Cannot be prevented.

18. Differences in recovery of blood sugar level
• The blood sugar level of a diabetic person recovers slower than a
healthy person and has a persistent high blood sugar.

19. Fluctuation of the insulin level

20. Treatment of diabetes
• Diabetes mellitus is a chronic disease,
for which there is no known cure
except in very specific situations.
• Management concentrates on
keeping blood sugar levels as close to
normal, without causing low blood
sugar.
• This can usually be accomplished with
a healthy diet, exercise, weight loss,
and use of appropriate medications
(insulin in the case of type 1 diabetes;
oral medications, as well as possibly
insulin, in type 2 diabetes).
• Pancreases or islet cells transplant
and genome therapy may be
performed for patients of type 1
diabetes.

22. Summary
• Blood sugar level is controlled by
pancreas.
• The alpha cells of the Islet of
Langerhans secrets glucagon,
while the beta cells secrets
insulin.
• Glucagon increases the blood
sugar level.
• Insulin decreases the blood sugar
level.