Blood Glucose Lab

Review of Biochemistry

• Glucose is a monosaccharide (simple sugar).

• Respiration – a process in cells where glucose is broken down for energy

• Polysaccharide - many sugars joined together

• Glycogen – a polysaccharide– Many glucose molecules joined

together– When you have extra glucose,

your liver joins glucose molecules together and makes glycogen

– Acts like a temporary glucose storage

Review of Digestion and Circulation

• When you eat carbohydrates your digestive system breaks the complex carbohydrates (polysaccharides and disaccharides) into monosaccharides (like glucose).

• The monosaccharides (like glucose) are absorbed into the blood from the small intestine.

• The blood carries glucose to all cells of the body so they can make energy.

ENDOCRINE SYSTEM

• Endocrine system – chemical signaling by hormones

• Endocrine glands – hormone secreting organs

• Hormones – chemical signals that are secreted into body fluids (usually blood) and communicate regulatory messages throughout body– Regulate growth, development,

reproduction, metabolism, and behavior

HUMAN ENDOCRINE GLANDS

• Hypothalamus• Pineal gland• Pituitary gland• Thyroid gland• Parathyroid glands• Thymus• Adrenal glands• Pancreas• Ovary or testis (gonads)

Human endocrine glands surveyed in this chapter

PANCREAS• Islets of Langerhans -

endocrine cells scattered throughout the pancreas

• In the Islets of Langerhans:–Alpha cells make glucagon–Beta cells make insulin – Insulin and glucagon are antagonistic hormones.

– Both hormones are secreted into the blood from the Pancreas

• Metabolic balance requires a minimum of 90 mg glucose/100 ml blood.

• When blood glucose rises over 90mg/100ml: – Insulin lowers blood glucose by

stimulating body cells to take in glucose (take it out of blood).

– Insulin also slows glycogen breakdown in liver so less glucose.

• Before blood glucose reaches 90mg/100ml:–Glucagon signals liver cells to break down glycogen into glucose and release glucose into blood

–Signals liver cells to convert amino acids and glycerol into glucose and release glucose into blood

Glucose homeostasis maintained by insulin and glucagon

Diabetes Mellitus• Caused by a deficiency of insulin or loss

of response in target tissues (body cells)

• Result is high blood glucose levels – so high that a diabetic’s urine contains glucose

• More glucose in urine means more water needed in urine = thirst

• When cells don’t get the glucose they need they break down fat instead, which forms harmful, acidic metabolites.

• Type I diabetes mellitus– Insulin dependent– Autoimmune disease where

immune system attacks pancreas ( cells) and cannot make insulin

– “Juvenile” (adults too)– Inheritance may play a minor

role– Potentially caused by infections

• Type II diabetes mellitus– Non-insulin dependent– Often inherited (although related to

poor diets and lack of exercise)– Either insulin deficient or lack of

response in target cells– Accounts for 90% of all diabetics– 7th most common cause of death in the

USA– Gastric by-pass surgery (duodenum and

jejunum removal) ends diabetes in most obese patients

• Gestational diabetes – happens to pregnant women (may be from hormones from placenta causing insulin resistance in mom)