Unit 3 & 4

• What does the endocrine system secrete into extracellular fluid?

  Hormones
• How do endocrine glands transport hormones?

  Through the blood
• What is an example of an endocrine gland?

  Hypothalamus
• What is an example of an exocrine gland?

  Salivary gland
• What are hormones classified as?

  Chemical messengers
• What can hormones influence?

  Target cells/organs
• What types of molecules can hormones be?

  Proteins or steroids
• How do hormones affect cells?

  By binding to specific receptors
• What does saturation refer to in hormone action?

  All receptor molecules occupied
• Are protein hormones lipid soluble?

  No
• Where do protein hormones attach?

  To receptor proteins in the membrane
• What is the effect of protein hormones compared to steroid hormones?

  Quicker and short-lived
• Are steroid hormones lipid soluble?

  Yes
• What happens when steroid hormones bind to receptors?

  They enter the nucleus and bind to genes
• How do hormones change cell functioning?

  By activating genes or altering enzyme shape
• What is enzyme amplification?

  One hormone activates thousands of enzymes
• What happens to hormones after they achieve their effect?

  They are broken down and excreted
• How is hormone secretion controlled?

  By negative feedback systems
• What does the hypothalamus release?

  Releasing and inhibiting factors
• Where is the hypothalamus located?

  At the base of the brain
• What basic functions does the hypothalamus regulate?

  Body temperature, water balance, heart rate
• What is the pituitary gland often referred to as?

  The master gland
• How is the pituitary gland connected to the hypothalamus?

  Via the infundibulum
• What are the two lobes of the pituitary gland?

  Anterior and posterior lobe
• What does the anterior pituitary gland produce hormones under control of?

  Hypothalamus releasing and inhibiting factors
• What are the main hormones produced by the anterior pituitary gland and their effects?

  • Follicle Stimulating Hormone (FSH): Ovarian follicle growth, sperm production
  • Luteinising Hormone (LH): Ovulation, testosterone secretion
  • Growth Hormone (GH): Growth, protein synthesis
  • Thyroid Stimulating Hormone (TSH): Hormone secretion from thyroid
  • Adrenocorticotropic Hormone (ACTH): Hormone secretion from adrenal cortex
  • Prolactin (PRL): Milk secretion in females
• What does the posterior pituitary gland do?

  Stores hormones produced by the hypothalamus
• What hormones are stored in the posterior pituitary gland?

  Antidiuretic Hormone (ADH) and Oxytocin (OT)
• What is the main effect of Antidiuretic Hormone (ADH)?

  Increases water reabsorption in kidneys
• What is the main effect of Oxytocin (OT)?

  Contractions during childbirth
• Where is the pineal gland located?

  Deep inside the brain
• What hormone does the pineal gland secrete?

  Melatonin
• What does melatonin regulate?

  Sleep patterns
• Where is the thyroid gland located?

  In the neck, below the larynx
• What does the thyroid gland secrete?

  Thyroxine
• What does thyroxine control?

  Body metabolism
• What stimulates the release of thyroxine?

  Thyroid Stimulating Hormone (TSH)
• What do parathyroid glands control?

  Calcium and phosphate levels
• What hormone do parathyroid glands secrete?

  Parathyroid hormone (PTH)
• What does PTH do to calcium levels?

  Increases calcium levels