Homeostasis

• What is homeostasis?

  Maintenance of stable internal conditions
• Why is homeostasis important for living things?

  It keeps internal conditions stable despite external changes
• What is a positive feedback loop?

  Increases distance from the original level
• How does a positive feedback loop function?

  More of one thing leads to more of another
• What is a negative feedback loop?

  Promotes stability by returning values to normal
• What happens when a variable goes beyond the acceptable range?

  Mechanisms activate to restore normal levels
• What is the consequence of homeostasis?

  It requires energy to maintain stability
• What organ is involved in glucose homeostasis?

  The pancreas
• What are the two types of glands in the pancreas?

  Exocrine and endocrine glands
• What do exocrine glands do?

  Secrete substances through a duct
• What do endocrine glands secrete?

  Hormones directly into the bloodstream
• What hormone is secreted by alpha cells in the pancreas?

  Glucagon
• What hormone is secreted by beta cells in the pancreas?

  Insulin
• What happens when blood glucose levels are high?

  Beta cells secrete insulin
• What is the function of insulin?

  Opens glucose channels in body cells
• What does insulin stimulate besides glucose uptake?

  Conversion of glucose to glycogen
• What is glycogen?

  A polysaccharide made of glucose
• What happens when blood glucose levels are too low?

  Alpha cells secrete glucagon
• What does glucagon stimulate?

  Conversion of glycogen into glucose
• How does glucagon affect blood glucose levels?

  Raises blood glucose levels
• What is diabetes?

  A condition of chronically elevated blood glucose
• What are the two types of diabetes discussed?

  Type 1 and Type 2 diabetes
• What causes Type 1 diabetes?

  Immune system attacks beta cells
• What is the treatment for Type 1 diabetes?

  Inject insulin and monitor blood sugar
• What causes Type 2 diabetes?

  Decreased sensitivity to insulin
• What is the treatment for Type 2 diabetes?

  Diet changes and exercise
• What is thermoregulation?

  Regulation of body temperature
• What are the two types of thermoreceptors?

  Peripheral and central thermoreceptors
• What role does the hypothalamus play in thermoregulation?

  Monitors and interprets temperature information
• What hormones are involved in thermoregulation?

  TRH, TSH, and thyroxine
• What does thyroxine do?

  Increases cellular metabolism and respiration
• How do muscle contractions help regulate body temperature?

  Generate heat through ATP production
• What is the function of adipose tissue in thermoregulation?

  Insulates and generates heat
• What is uncoupled respiration?

  Respiration that produces heat, not ATP
• What happens during vasodilation?

  Blood vessels expand to increase blood flow
• What is the role of sweating in thermoregulation?

  Absorbs heat before evaporating
• How does the body respond to high temperatures?

  Vasodilation and sweating occur
• What is the importance of negative feedback loops in homeostasis?

  They help maintain stable internal conditions