Topic 4: Homeostatic Control
Hormonal control of the blood sugar level
- The pancreas secretes pancreatic juice - transported to the duodenum through the pancreatic duct
- Islets of Langerhans secrete 2 types of hormones:
Insulin
Glucagon
- Secreted directly into the bloodstream
- Endocrine - outside
- Exocrine - inside
- The pancreas responds to the amount of glucose in the blood
- ==High blood glucose== = pancreas ==secretes insulin== to stimulate the liver to convert excess glucose into glycogen to store it
- %%Low level of glucose%% = pancreas ^^secretes glucagon^^ which stimulates the liver to convert stored glycogen to glucose. It is absorbed into the blood, raising the glucose level then returning it to normal.
Diabetes mellitus
- Disease that occurs when the pancreas does not secrete enough insulin (Type 1)
- OR when the body can no longer respond to the insulin that the pancreas produces (Type 2)
- Also know as ^^chronic high blood glucose^^ or ^^hyperglycaemia^^
The relationship between food intake and health
- The energy in food is described in units called calories
- Carbs, protein and lipids are a source of energy
- Vitamins, minerals and water DO NOT provide energy
- Minerals needed in large quantities = macronutrients
- Minerals needed in small quantities = micronutrients
External factors of malnutrition
| Condition | Cause | Symptom |
|---|---|---|
| Kwashiorkor | high carb intakeinsufficient protein | swollen bellystick-like legsswollen face |
| Marasmus | lack of all food groups - energy deficiency | little / no layer of skin fattight skindeep-set eyes |
| Anorexia | refusal to eat; abnormal body mage; fear of becoming overweight | skeletally thin - may die if continues to refuse food |
| Bulimia | food available but habitual vomiting after binging on high-energy foods | has normal weighttooth erosion from acidic food being thrown up |
| Obesity | excess intake of high energy foods - carbs | person’s body is more than 20% higher than the average person of the same gender/height |