Homeostasis

Page
1

Slide 1

Homeostasis

Maintaining

an

Internal Balance

Slide 2

Homeostasis

The property of a system, either open or closed, that regulates its internal environment so as to maintain a stable, constant condition.

Multiple dynamic equilibrium adjustment and regulation mechanisms make homeostasis possible.

Source: Wikipedia

Slide 3

Blood Glucose – An Example

Glucose is the simple sugar known as “blood sugar”

Glucose is required for brain function – the brain cannot use any other energy source

A healthy body maintains a blood sugar level of between 80 mg/dL and 110 mg/dL (slightly higher right after meals)

Slide 4

The Role of Hormones

When blood glucose levels are low, the hormone glucagon stimulates the conversion of glycogen in the liver to glucose

Glucagon is a peptide hormone made of 29 amino acids. It is produced in the alpha cells of the (α-cells) of the islets of Langerhans, which are located in the pancreas.

Slide 5

The Role of Hormones

When blood glucose levels are high, the hormone insulin stimulates the conversion of glucose to stored glycogen in the liver.

Insulin is a peptide hormone made of 51 amino acids. It is produced in the beta cells of the

(β-cells) of the islets of Langerhans, which are located in the pancreas.

Slide 6

Slide 7

Slide 8

Type I Diabetes

Autoimmune disease destroys the beta cells of the pancreas

Diabetic is dependent on exogenous insulin

There is currently no cure, though there many approaches under research

In North America, 5 – 10% of diabetics are Type I

Slide 9

Type II Diabetes

A metabolic disorder due to insulin resistance (the cells are insensitive to the insulin that is present)

Onset of disease can be postponed by proper nutrition and exercise

90 – 95% of North American diabetics are Type II.

20% of the population over age 60 are Type II

Slide 10

Blood Calcium: Example #2

Ca2+ ion is essential to organisms. It is functions include:

A component of bone