Lecture 03, 4

• What hormones are secreted by the pancreas?

  Insulin, glucagon, and somatostatin
• What is the function of glucagon?

  It increases blood sugar levels
• What is the primary function of insulin?

  It increases glucose uptake by cells
• What percentage of islet cells in the pancreas are alpha cells?

  25%
• What is the role of somatostatin in the pancreas?

  It helps regulate gastrointestinal function
• What happens when there is not enough insulin?

  It can lead to diabetes
• What are the processes involved in glucose turnover?

  • Glycolysis: Glucose breakdown to lactate
  • Glycogenolysis: Glycogen breakdown to glucose
  • Gluconeogenesis: Conversion to glucose from pyruvate
• What is the mechanism of insulin action?

  It involves a negative feedback loop
• How does insulin facilitate glucose transport?

  By recruiting GLUT 4 to the plasma membrane
• What do oral hypoglycaemic drugs do?

  They mimic insulin action by blocking K channels
• What are the two parts of the adrenal glands?

  Adrenal cortex and adrenal medulla

  
• What hormones are produced by the adrenal cortex?

  Corticosteroids, mineralocorticoids, and androgens
• What is the primary function of catecholamines?

  They mediate the 'fight or flight' response
• What is the role of chromaffin cells in the adrenal medulla?

  They secrete catecholamines into the blood
• How does catecholamine secretion occur?

  Through exocytosis after cell depolarisation
• What are the effects of catecholamines on metabolism?

  • Increases metabolic rate
  • Enhances glycogenolysis and gluconeogenesis
  • Promotes lipolysis
  • Decreases insulin secretion
  • Increases glucagon secretion
• What cardiovascular effects do catecholamines have?

  They increase heart rate and contractility
• What stimulates catecholamine secretion?

  Sympathetic nervous system activation
• What is the primary function of aldosterone?

  It regulates sodium and potassium balance
• What is Addison's disease characterised by?

  Fatigue, muscle weakness, and hyperpigmentation
• What are the stages of the menstrual cycle?

  1. Menstrual phase (Days 1-5)
  2. Follicular phase (Days 7-12)
  3. Ovulation (Day 14)
  4. Luteal phase (Days 15-28)
• What hormones regulate the menstrual cycle?

  Estrogen and progesterone
• What is the average length of the menstrual cycle?

  28 days
• What happens during the luteal phase of the menstrual cycle?

  The corpus luteum secretes hormones
• What hormone is responsible for milk production?

  Prolactin
• What initiates parturition?

  A drop in progesterone and estrogen ratio
• What is the role of relaxin during pregnancy?

  It softens tissues for childbirth
• What is the function of GnRH?

  It stimulates FSH and LH release
• What happens to hormone levels after the placenta is removed?

  Prolactin inhibition is lifted
• How does suckling affect lactation hormones?

  It stimulates prolactin and oxytocin release