Biochemistry for nurses

1. Biochemistry for nurses
Regulation of Blood Glucose

2. Biochemistry for nurses
Alternation between Anabolism and Catabolism
The human body alternates between Anabolic and Catabolic states:
Anabolism:
• Synthesis of complexe molecules from smaller units (ex: from glucose
to glycogen)
• Growth (body size increases)
• Needs energy (powered by catabolism)
Catabolism:
• Breaking down of large molecules into smaller units (ex: from starch to
glucose)
• Synthesis of ATP molecules (cellular respiration)
Glucose Metabolism:
The hormone Insulin supports Anabolic Activities.
The hormone Glucagon supports catabolic Activities

3. ATP molecule is
the source of
ENERGY!
Biochemistry for nurses
Alternation between Anabolism and Catabolism

4. Biochemistry for nurses
Glucose Metabolism (Anabolism + Catabolism)

5. Biochemistry for nurses
The Brain requires Blood Glucose
 The Brain requires a constant
supply of blood glucose
 Glucose is the only energy source
for the brain (cannot use fats!)
Hypoglycemia (low blood glucose): Sometimes caused when
diabetic takes too much of insulin (Insulin shock).
Symptoms: Mental confusion, slurring of speech, coma and then death
Treatment: Give glucose.

6. Biochemistry for nurses
Blood Glucose is controlled mainly by the Liver
Immediately after meals, blood glucose comes
from meal.
Between meals (starvation), blood glucose
comes from the Liver and Kidneys.
During starvation, Liver provides 80% of blood
glucose and the Kidneys provide 20% of blood
glucose.

7. Biochemistry for nurses
Blood Glucose is controlled mainly by the Liver
Liver makes glucose in 2 ways:
1) Breaks down liver glycogen (glycogenolysis)
2) Converts other types of small molecules into glucose (gluconeogenesis), many
small molecules can be converted to glucose:
 Lactate and Pyruvate: Mainly come from muscular activity.
 Glycerol: supplied by adipose tissue when triglycerides are broken down (Fats).
 Amino Acids: 20 of the 22 amino acids can be converted to glucose.

8. Biochemistry for nurses
Blood Glucose is controlled mainly by the Liver
 Delivery of glucose to the
blood is controlled by
Insulin and Glucagon.
 Brain receives a constant
80 mg/min (does not
change much in exercice)
 Amount delivered of
glucose to other tissues
depends upon body state
(rest or exercice)
 At rest total glucose output to the blood is about 130 mg/min (80 to brain,
50 to other tissues)
 During exercice total can increase to about 2500 mg/min

9. Biochemistry for nurses
Insulin is the only hormone that can lower blood glucose
 Muscle, adipose and liver tissues require Insulin to transport glucose
into the cells: In these tissues, Insulin increases the number of glucose
transporters in the cell membrane.
 Brain does not require Insulin to transport Glucose into cells
 After a meal, blood sugar rises and this stimulates the release of
Insulin from the pancreas
 Insulin stimulates the synthesis of Glycogen (glycogenesis) for the
storage of glucose.
Average Blood
Glucose level =
0.8 to 1.4 g/l

10. Biochemistry for nurses
Glucagon can raise blood glucose
 Between Meals, when blood glucose is
low a large amount of Glucagon is
secreted by the pancreas which rises
blood sugar (glycogenolysis).
 Other hormones can also raise blood glucose especialy during stress and
vigorous exercice. They are 3 major hormones:
1) Cortisol secreted by adrenal glands (situated above the kidneys) in response to
stress and low blood glucose
2) Adrenaline secreted by adrenal glands (brain and above kidneys) in response of
extrem stress
3) Growth hormone is also a stress hormone secreted by the Adenohypophysis
(Brain) which raises blood glucose and stimulates growth cell reproduction and
cell regeneration.
Glucagon raises Blood Glucose
Insulin lowers Blood Glucose

11. Biochemistry for nurses
Diabetes Mellitus
 Diabetes = excess production of urine
 Mellitus = Sweet (refers to sugar in urine)
Diabetes Mellitus results when
Insulin is deficient or Ineffective
Type 1: (Insulin is deficient)
 Occurs early in life due to autoimmune destruction of pancreatic cells.
 Low Insulin output
 High blood glucose
 Glucose in urine
 Excess urine flow
Treated with Insulin injections, careful balance of diet and exercise is advised.
Diabetes Mellitus is of 2 types:

12. Biochemistry for nurses
Type 2: (Insulin is Ineffective)
 Occurs later in life associated with Obesity.
 Insulin is normal but is ineffective (Insulin
resistance)
 Many of the symptoms are same but less severe
(high blood glucose, glucose in urine and
excess urine flow)
 Cause is unknown, but may be insulin receptor
disease
May be reversed if weight is lost.
Diabetes Mellitus is of 2 types: