Hormonal communication

• Hormone


  Molecule released by endocrine glands directly into the blood to act as chemical messengers to carry a signal to target cells
• Endocrine Gland


  Glands that secrete hormones directly into the blood due to the capillaries running through them
• Exocrine Gland


  Gland that secretes enzymes into a duct that leads to the duodenum in the pancreas
• Target Cell


  Cells that have specific receptors in their membrane that the hormones are complementary in shape to.
• Types of hormone


  Steroid based, non-steroid based
• How are steroid based hormones detected?


  Hormone passes through phospholipid bilayer of cell, bind to receptors in the cytoplasm or nucleus to form a hormone-receptor complex, complex acts as a transcription factor that can facilitate or inhibit the transcription of a gene
• How are non-steroid based hormones detected?


  Original hormone acts as a first messenger, binds to receptor in the plasma membrane, activates secondary messenger, secondary messenger can trigger events in the cell
• Example of secondary messenger

  cAMP
• Why are steroid based hormones detected in the way they are?


  They are lipid soluble
• Why are non-steroid based hormones detected in the way they are?


  They are hydrophilic so can't get through the phospholipid bilayer
• Examples of endocrine glands

  Thyroid, pituitary, adrenal, testis, pineal, thymus, pancreas, ovary
• Name and function of hormone secreted by thyroid gland


  Thyroxine, controls rate of metabolism and rate that glucose is used up in respiration
• Name and function of a hormone secreted by pituitary gland


  ADH, increases reabsorption of water in the kidneys
• Name and function of hormone secreted by adrenal gland


  Adrenaline, increases heart and breathing rate for the fight and flight response
• Name and function of hormone secreted by testis


  Testosterone, controls sperm production
• Name and function of hormone secreted by pineal gland


  Melatonin, control of daily cycle
• Name and function of hormone secreted by thymus gland


  Thymosin, promotes production and maturation of white blood cells
• Name and function of hormone secreted by pancreas


  Insulin, converts excess glucose into glycogen in the liver
• Name and function of hormone secreted by ovary


  Oestrogen, controls ovulation
• Structure of adrenal gland


  Made of adrenal cortex and medulla, cortex is the outer region, medulla is the inner region
• Hormones produced by the adrenal cortex


  Glucocorticoids, mineralocorticoids, androgens
• Examples of glucocorticoids with their functions


  Cortisol to regulate metabolism and regulate blood pressure, corticosterone to regulate immune response and suppress inflammatory reactions
• Examples of mineralocorticoids with their functions


  Aldosterone to control blood pressure by maintaining the pressure between salt and water
• What controls the release of hormones from the adrenal cortex?


  Hypothalamus, hormones released from the pituitary gland
• What controls the release of hormones from the adrenal medulla?


  Stimulation of the sympathetic nervous system
• Hormones secreted by the adrenal medulla


  Adrenaline, noradrenaline
• Role of noradrenaline


  Works with adrenaline to increase heart rate, widen pupils and air passages in the lungs and narrow blood vessels in non-essential organs
• Type of glandular tissue in the pancreas

  Endocrine, exocrine
• What does the exocrine tissue in the pancreas make?


  Amylases, proteases, lipases, pancreatic juice
• How does the exocrine tissue in the pancreas function?


  Products secreted into a duct that leads to the pancreatic duct which goes to the duodenum
• What does the endocrine tissue in the pancreas make?


  Insulin, glucagon
• Where is the endocrine tissue in the pancreas?


  Islets of Langerhans
• What do Islets of Langerhans look like under a microscope?


  Large spherical clusters, stained light pink
• Different types of cells in the Islets of Langerhans


  Alpha, beta
• What do acinar cells look like?


  Berry-like clusters
• What do alpha cells make?


  Glucagon
• What do beta cells make?


  Insulin
• How to differentiate between alpha and beta cells?


  Differential stain, beta cells are stained blue, alpha cells are stained pink
• Glycogenolysis


  When glycogen is broken down in liver and muscle cells to release glucose into the bloodstream
• Gluconeogenesis


  Production of glucose from non-carbohydrate sources